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Koje su vrste ove ptičice?

Koje su vrste ove ptičice?


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Pokušavam spasiti živote ovih mladunaca i moram poznavati njihovu vrstu da bih znao kako/čime ih hraniti. Molim vas pomozite mi što prije.


Ako ste u Europi, to su mladunče obične žige (Apus apus).

Postoji web stranica posvećena njima, sa stranicom o tome kako ih odgajati: http://www.commonswift.org/Hand_rearing_Swifts.html

Vrlo su krhke i uz pogrešnu prehranu mogu razviti deformacije perja. Također zahtijevaju kontinuirani napor jer jedu vrlo često. Odgajao sam ih par puta i kad polete je veličanstveno, ali lako je nešto pogriješiti. Ako imate neki centar za oporavak ili stručnjaka u blizini, predlažem da ih predate.


Savjeti za identifikaciju beba ptica

Identifikacija beba ptica može biti izazov kako mlade ptice rastu, često mijenjajući duljinu perja, boje i oznake u samo nekoliko dana. Mnogi su ptičari bili i zbunjeni i uzbuđeni kada su pronašli mladu pticu koju u početku nisu prepoznali, nadajući se da je to nova vrsta koju će dodati na njihov popis života. Međutim, ako razumijete kako ptičice izgledaju i kako se ponašaju, nećete se prevariti. Kada saznate što gledate, uživat ćete gledati ove zabavne mlade ptice kako prolaze kroz svoj rani životni ciklus.


Razumijevanje ponašanja životinja

Ciljevi lekcije

  • Navedite primjere ponašanja životinja.
  • Objasni zašto je ponašanje životinja važno.
  • Opišite urođeno ponašanje i kako se ono razvija.
  • Navedite načine na koje se ponašanje može naučiti.

Provjerite svoje razumijevanje

  • Što je životinja?
  • Koji su primjeri životinja koje se međusobno vrlo različito ponašaju?

Rječnik

  • ponašanje životinja
  • uvjetovanje
  • navikavanje
  • urođeno ponašanje
  • učenje uvidom
  • instinkt
  • naučeno ponašanje
  • promatračko učenje
  • refleksna ponašanja

Primjeri ponašanja životinja

Lajanje, predenje i igranje samo su neki od načina na koji se psi i mačke ponašaju. Ovo su primjeri ponašanja životinja.

Ponašanje životinja je bilo koji način na koji životinje djeluju, bilo same ili s drugim životinjama. Možete li se sjetiti drugih primjera ponašanja životinja? Što je s kukcima i pticama? Kako se ponašaju? Slike u Lik ispod, Lik ispod, Lik ispod, Lik ispod, Lik ispod, Lik ispod, i Lik u nastavku su prikazani samo neki od načina na koje te i druge životinje djeluju. Pogledajte slike i pročitajte o ponašanju. Razmislite zašto se životinja tako ponaša.

Ova mačka vreba miša. Po prirodi je lovac.

Ovaj pauk je zauzet vrtenjem mreže. Ako ste ikada ušli u paukovu mrežu, znate koliko paukova mreža može biti ljepljiva. Zašto pauci pletu mreže?

Ova majka pas doji svoje štence. Na koje druge načine se psi majke brinu za svoje štence?

Ova ptica koristi svoj kljun kako bi dodala više trave u svoje gnijezdo. Za što će ptica koristiti svoje gnijezdo?

Ova osa počinje graditi gnijezdo. Jeste li vidjeli ovakva gnijezda na zgradama u kojima živite? Zašto ose grade gnijezda?

Ovaj zec bježi od lisice. Jeste li ikada vidjeli zeca kako trči? Mislite li da biste mogli trčati tako brzo?

Ovaj gušter sjedi na stijeni na suncu. Gušteri vole ležati na kamenju i

Važnost ponašanja životinja

Zašto se životinje ponašaju na način na koji se ponašaju? Odgovor na ovo pitanje ovisi o tome kakvo je ponašanje. Mačka juri miša da ga uhvati. Pauk vrti svoju ljepljivu mrežu kako bi uhvatio kukce. Pas majka doji svoje štence da ih hrani. Sva ova ponašanja imaju istu svrhu: dobivanje ili pružanje hrane. Sve životinje trebaju hranu za energiju. Potrebna im je energija za kretanje. Zapravo, potrebna im je energija samo da bi ostali živi. Bebe životinje također trebaju energiju za rast i razvoj.

Ptice i ose grade gnijezda kako bi imale sigurno mjesto za pohranjivanje jaja i uzgoj mladih. Mnoge druge životinje grade gnijezda iz istog razloga. Životinje štite svoje mlade i na druge načine. Na primjer, majka pas ne samo da doji svoje štence. Također ih pere jezikom i štiti ih od čudnih ljudi ili drugih životinja. Sva ova ponašanja pomažu mladima da prežive i odrastu u odrasle.

Zečevi bježe od lisica i drugih grabežljivaca kako bi ostali živi. Njihova brzina je njihova najbolja obrana. Gušteri se sunčaju na kamenju kako bi se ugrijali jer ne mogu proizvesti vlastitu tjelesnu toplinu. Kad im je toplije, mogu se kretati brže i biti budniji. To im pomaže da pobjegnu od grabežljivaca, kao i da pronađu hranu.

Sva ova ponašanja životinja su važna. Pomažu životinjama da dobiju hranu za energiju, osiguravaju da njihovi mladi prežive ili osiguravaju da sami prežive. Ponašanje koje pomaže životinjama ili njihovim mladima da prežive povećavaju njihovu kondiciju. Čitali ste o fitnesu u Evolucija poglavlje. Životinje s većom kondicijom imaju veće šanse da svoje gene prenesu na sljedeću generaciju. Ako geni kontroliraju ponašanja koja povećavaju kondiciju, ponašanja postaju češća u vrsti. To se zove evolucija prirodnom selekcijom.

Urođeno ponašanje

Sva ponašanja prikazana na gornjim slikama načini su na koje se životinje ponašaju prirodno. Ne moraju naučiti kako se ponašati na ove načine. Mačke su prirodno rođeni lovci. Ne moraju učiti loviti. Pauci vrte svoje složene mreže bez da su naučili kako to učiniti od drugih pauka. Ptice i ose znaju graditi gnijezda bez učenja. Ova ponašanja se nazivaju urođenim.

An urođeno ponašanje je svako ponašanje koje se prirodno javlja kod svih životinja određene vrste. Urođeno ponašanje se također naziva instinkt. Prvi put kada životinja izvede urođeno ponašanje, životinja to čini dobro. Životinja ne mora prakticirati ponašanje kako bi ga ispravila ili postala bolja u tome. Urođena ponašanja su također predvidljiva. Svi pripadnici vrste imaju urođeno ponašanje na isti način. Iz gore opisanih primjera vjerojatno možete zaključiti da urođena ponašanja obično uključuju važne radnje, poput prehrane i brige za mlade.

Postoje mnogi drugi primjeri urođenih ponašanja. Na primjer, jeste li znali da pčele plešu? Pčela je unutra Lik ispod je pronašao izvor hrane. Kada se pčela vrati u svoju košnicu, odradit će ples, koji se zove ples vitlanja. Način na koji se pčela kreće tijekom svog plesa govori drugim pčelama u košnici gdje da pronađu hranu. Medonosne pčele mogu plesati mahanje, a da ga ne nauče od drugih pčela, tako da je to urođeno ponašanje.

Kada se ova pčela vrati u svoju košnicu, odradit će ples kako bi rekla ostalim pčelama u košnici gdje je našla hranu.

Osim što grade gnijezda, ptice imaju i druga urođena ponašanja. Jedan primjer javlja se u galebovima. Prikazani su galeb majka i dva njena pileta Lik ispod. Jedan od pilića kljuca crvenu mrlju na majčinom kljunu. Ovo urođeno ponašanje uzrokuje da majka hrani pile. Kod mnogih drugih vrsta ptica pilići širom otvaraju usta kad god se majka vrati u gnijezdo. Ovo je ono u čemu su ptičice Lik u nastavku rade. Ovo urođeno ponašanje, zvano gaping, uzrokuje da ih majka hrani.

Ova majka galeb će hraniti svoje pile nakon što kljune crvenu mrlju na njezinom kljunu. Ponašanje kljucanja i hranjenja je urođeno.

Kada ove ptičice širom otvore usta, majka ih instinktivno hrani. Ovo urođeno ponašanje naziva se zjapanjem.

Drugi primjer urođenog ponašanja kod ptica je kotrljanje jaja. To se događa kod nekih vrsta ptica vodotoka, kao što je prikazana sivkasta guska Lik ispod. Sive guske prave gnijezda na tlu. Ako se jaje otkotrlja iz gnijezda, majka guska svojim kljunom ga gurne natrag u gnijezdo. Vraćanje jaja u gnijezdo osigurava da će se jaje izleći.

Ova ženka sive guske je vodena ptica koja se gnijezdi na zemlji. Prije nego što se njeni pilići izlegu, majka štiti jaja. Svojim će kljunom gurnuti jaja natrag u gnijezdo ako se otkotrljaju. Ovo je primjer urođenog ponašanja. Kako bi ovo ponašanje moglo povećati majku gusku

Urođeno ponašanje u ljudskim bićima

Sve životinje imaju urođena ponašanja, čak i ljudska bića. Možete li zamisliti ljudska ponašanja koja se ne moraju učiti? Velika je vjerojatnost da ćete teško razmišljati o bilo čemu. Jedina istinski urođena ponašanja kod ljudi nazivaju se refleksna ponašanja. Javljaju se uglavnom kod beba. Poput urođenog ponašanja drugih životinja, refleksno ponašanje kod ljudskih beba može im pomoći da prežive.

Primjer refleksnog ponašanja kod beba je refleks sisanja. Novorođenčad instinktivno sišu bradavicu koja im je stavljena u usta. Lako je vidjeti kako se ovo ponašanje razvilo. Povećava šanse da se beba hrani i preživi. Drugi primjer refleksnog ponašanja kod beba je refleks hvatanja. Ovo ponašanje je prikazano u Lik ispod. Bebe instinktivno hvataju predmet stavljen na dlan. Njihov stisak može biti iznenađujuće jak. Što mislite kako bi ovo ponašanje moglo povećati bebine šanse za preživljavanje?

Jedno od rijetkih urođenih ponašanja kod ljudi je refleks hvatanja. Javlja se samo kod beba.

Naučeno ponašanje

Skoro sva druga ljudska ponašanja se nauče. Naučeno ponašanje je ponašanje koje se javlja tek nakon iskustva ili prakse. Naučeno ponašanje ima prednost u odnosu na urođeno ponašanje. Fleksibilniji je. Naučeno ponašanje može se promijeniti ako se uvjeti promijene. Na primjer, vjerojatno znate put od svoje kuće do škole. Pretpostavimo da ste se preselili u novu kuću na drugom mjestu, pa ste do škole morali ići drugim putem. Što ako je praćenje stare rute bilo urođeno ponašanje? Ne biste se mogli prilagoditi. Srećom, to je naučeno ponašanje. Novu rutu možete naučiti kao što ste naučili staru.

Iako većina životinja može učiti, životinje s većom inteligencijom bolje su u učenju i imaju više naučenog ponašanja. Ljudi su najinteligentnije životinje. Oni ovise o naučenom ponašanju više od bilo koje druge vrste. Druge visoko inteligentne vrste uključuju majmune, naše najbliže rođake u životinjskom carstvu. Uključuju čimpanze i gorile. Obojica su također vrlo dobri u učenju ponašanja.

Možda ste čuli za gorilu po imenu Koko. Psihologinja dr. Francine Patterson odgojila je Koko. Dr. Patterson želio je saznati mogu li gorile naučiti ljudski jezik. Počevši kada je Koko imala samo godinu dana, dr. Patterson ju je naučio koristiti znakovni jezik. Koko je naučio koristiti i razumjeti više od 1000 znakova. Koko je pokazao koliko gorile mogu naučiti. Vidjeti Razgovor s Kokom na http://www.pbs.org/wnet/nature/koko/ za dodatne informacije.

Razmislite o nekim od ponašanja koje ste naučili. Oni mogu uključivati ​​vožnju bicikla, korištenje računala i sviranje glazbenog instrumenta ili sport. Vjerojatno niste naučili sva ova ponašanja na isti način. Možda ste sami naučili neka ponašanja, samo vježbajući. Druga ponašanja koja ste možda naučili od drugih ljudi. Ljudi i druge životinje mogu naučiti ponašanja na nekoliko različitih načina.

Sljedeće metode učenja će biti istražene u nastavku:

  1. Navikavanje (formiranje navike).
  2. Učenje promatranjem.
  3. Kondicioniranje.
  4. Igra.
  5. Učenje uvidom.

Navikavanje

Navikavanje je učenje naviknuti se na nešto nakon što je neko vrijeme bio izložen tome. Navikavanje obično uključuje navikavanje na nešto što je dosadno ili zastrašujuće, ali nije opasno. Navikavanje je jedan od najjednostavnijih načina učenja. Javlja se u gotovo svakoj vrsti životinja.

Vjerojatno ste mnogo puta naučili kroz navikavanje. Na primjer, možda ste čitali knjigu kada je netko uključio televizor u istoj prostoriji. U početku je zvuk televizije mogao biti neugodan. Nakon nekog vremena, možda to više niste primijetili. Ako jeste, navikli ste se na zvuk.

Još jedan primjer navikavanja prikazan je u Lik ispod. Vrane i većina drugih ptica obično se boje ljudi. Izbjegavaju se približiti ljudima ili odlete kad im se ljudi približe. Vrane koje slijeću na ovo strašilo naviknule su se na "čovjeka" na ovom mjestu. Naučili su da strašilo ne predstavlja opasnost. Više se ne boje prići blizu. Navikli su se na strašilo.

Ovo strašilo ovim vranama više nije strašno. Navikli su se da je na ovom mjestu i naučili da nije opasno. Ovo je primjer navikavanja.

Možete li vidjeti zašto je navikavanje korisno? Dopušta životinjama da ignoriraju stvari koje im neće naškoditi. Bez navikavanja, životinje bi mogle gubiti vrijeme i energiju pokušavajući pobjeći od stvari koje zapravo nisu opasne.

Opservacijsko učenje

Učenje promatranjem je učenje gledajući i kopirajući ponašanje nekog drugog. Ljudska djeca na ovaj način uče mnoga ponašanja. Dok ste bili dijete, možda ste naučili kako vezati cipele gledajući kako vam tata veže cipele. Nedavno ste možda naučili plesati gledajući pop zvijezdu kako pleše na TV-u. Najvjerojatnije ste naučili rješavati matematičke zadatke gledajući svoje učitelje kako rade zadatke na ploči u školi. Možete li se sjetiti drugih ponašanja koje ste naučili gledajući i kopirajući druge ljude?

Druge životinje također uče kroz promatranje. Na primjer, mladi vukovi uče biti bolji lovci promatrajući i kopirajući vještine starijih vukova u svom čoporu.

Drugi primjer promatračkog učenja je kako su neki majmuni naučili kako oprati hranu. Učili su gledajući i kopirajući ponašanje drugih majmuna.

Kondicioniranje

Kondicioniranje je način učenja koji uključuje nagradu ili kaznu. Jeste li ikada trenirali psa da donese loptu ili štap nagrađujući ga poslasticama? Ako jesi, koristio si kondicioniranje. Drugi primjer kondicioniranja prikazan je u Lik ispod. Ovaj laboratorijski štakor naučen je "igrati košarku" tako što je nagrađen kuglicama hrane. Kondicioniranje se događa i kod divljih životinja. Na primjer, pčele nauče pronaći nektar u određenim vrstama cvijeća jer su u tim cvjetovima već pronašle nektar.

Ovaj štakor je naučen staviti loptu kroz obruč tako što je za takvo ponašanje nagrađen hranom. Ovo je primjer uvjetovanja. Što mislite da bi se dogodilo da štakor više ne bude nagrađivan za ponašanje?

Ljudi uče ponašanja i kroz uvjetovanje. Malo dijete bi moglo naučiti odlagati svoje igračke tako što će biti nagrađeno pričom za laku noć. Starije dijete moglo bi naučiti učiti za testove u školi tako što će biti nagrađeno boljim ocjenama. Možete li se sjetiti ponašanja koje ste naučili tako što ste bili nagrađeni za njih?

Uvjetovanje ne uključuje uvijek nagradu. Umjesto toga može uključivati ​​kaznu. Mališan bi mogao biti kažnjen time-outom svaki put kada zgrabi igračku od svog mlađeg brata. Nakon nekoliko tajm-auta, možda će naučiti prestati uzimati bratove igračke.

Pas bi mogao biti izgrđen svaki put kad skoči na sofu. Nakon ponovljenih grdnji, mogla bi se naučiti kloniti se sofe. Ptica se može razboljeti nakon što pojede otrovnog kukca. Ptica bi mogla naučiti iz ove "kazne" kako bi u budućnosti izbjegla jesti istu vrstu insekata.

Učenje kroz igru

Većina mladih sisavaca, uključujući ljude, voli se igrati. Igra je jedan od načina na koji uče vještine koje će im trebati kao odrasli. Razmislite o tome kako se mačići igraju. Nabacuju se na igračke i jure se. To im pomaže da nauče kako biti bolji grabežljivci kad odrastu. Igraju se i velike mačke. Mladunčad lavova unutra Lik u nastavku se istovremeno igraju i vježbaju svoje lovačke vještine. Psi unutra Lik ispod se igraju potezanja konopa s igračkom. Što misliš, što uče igrajući se zajedno na ovaj način?

Ostale mlade životinje igraju se na različite načine. Na primjer, mladi jeleni igraju se trčeći i podižući kopita. To im pomaže da nauče kako pobjeći od grabežljivaca.

Igraju se ova dva lavića. Ne samo da se zabavljaju. Uče i kako biti bolji lovci.

Oni se stvarno igraju. Ova igra borbe može im pomoći da nauče kako biti bolji grabežljivci.

I ljudska djeca uče igrajući se. Na primjer, igranje igara i sporta može im pomoći da nauče slijediti pravila i raditi s drugima. Beba unutra Lik ispod se igra u pijesku. Ona uči o svijetu kroz igru. Što mislite da bi mogla učiti?

Igranje u pješčaniku zabavno je za malu djecu. Također im može pomoći da uče o svijetu. Na primjer, ovo dijete možda uči da je pijesak mekan.

Insight Learning

Učenje uvidom je učenje iz prošlih iskustava i razmišljanja. Obično uključuje smišljanje novih načina rješavanja problema. Učenje uvidom općenito se događa brzo. Životinja ima iznenadni bljesak uvida. Učenje uvidom zahtijeva relativno veliku inteligenciju. Ljudska bića koriste učenje uvidom više od bilo koje druge vrste. Iskoristili su svoju inteligenciju za rješavanje problema u rasponu od izuma kotača do letenja raketa u svemir.

Razmislite o problemima koje ste riješili. Možda ste shvatili kako riješiti novu vrstu matematičkog problema ili kako doći do sljedeće razine videoigre. Ako ste se za to oslanjali na svoja prošla iskustva i rasuđivanje, tada ste koristili učenje uvidom.

Jedna vrsta učenja kroz uvid je izrada alata za rješavanje problema. Znanstvenici su mislili da su ljudi jedine životinje dovoljno inteligentne za izradu alata. U stvari, vjerovalo se da izrada alata razlikuje ljude od svih ostalih životinja.

1960. stručnjakinja za primate Jane Goodall otkrila je da čimpanze također izrađuju alate. Vidjela je kako čimpanza skida lišće s grančice. Zatim je zabio grančicu u rupu u nasipu termita. Nakon što su se termiti popeli na grančicu, izvukao je grančicu iz rupe i pojeo kukce koji su se prilijepili za nju. Čimpanza je napravila alat za "pecanje" termita. Koristio je uvid da riješi problem. Od tada, čimpanze su viđene kako izrađuju nekoliko različitih vrsta alata. Na primjer, oštre štapove i koriste ih kao koplja za lov. Koriste kamenje kao čekiće za razbijanje oraha.

Znanstvenici su također promatrali druge vrste životinja koje prave alate za rješavanje problema. Vidjela se kako vrana savija komad žice u kuku. Tada je vrana upotrijebila udicu da izvuče hranu iz cijevi.

Prikazan je primjer gorile koji koristi štap za hodanje Lik ispod. Ovakva ponašanja pokazuju da druge vrste životinja mogu koristiti svoje iskustvo i razmišljanje za rješavanje problema. Oni mogu učiti kroz uvid.

Ova gorila koristi granu kao alat. Naslanja se na nju kako bi održala ravnotežu dok poseže u močvarnu vodu kako bi uhvatila ribu.

Sažetak lekcije

  • Ponašanje životinja je svaki način na koji se životinje ponašaju. Ovo ponašanje može biti samostalno ili s drugim životinjama.
  • Ponašanja koja povećavaju kondiciju mogu se s vremenom razvijati. Ovaj proces se odvija prirodnom selekcijom.
  • Urođeno ponašanje je ponašanje koje se događa prirodno. Ovo ponašanje se javlja kod svih pripadnika vrste.
  • Naučeno ponašanje je naučeno ponašanje. To se događa samo kroz iskustvo ili praksu.

Pitanja za pregled

Podsjetiti

1. Navedite dva primjera ponašanja životinja.

3. Navedite tri načina na koje se ponašanje može naučiti.

Primijenite koncepte

4. Identificirajte jedan nedostatak urođenog ponašanja.

5. Koja je razlika između naučenog ponašanja i urođenog ponašanja?

6. Zašto je igra važna za bebe?

7. Objasnite kako možete koristiti kondicioniranje da naučite psa da sjedi.

Kritičko razmišljanje

8. Objasnite kako se vjerojatno razvilo valjanje jaja sivih gusaka.

9. Opišite kako refleks hvatanja može pomoći bebi da preživi.

10. Viđena je vrana kako ispušta orahe na kamen da razbije ljuske, a zatim jede meso orašastih plodova. Nijedna druga vrana u jatu nikada nije primijećena kako puca orahe na ovaj način. Koja vrsta učenja bi mogla objasniti ponašanje ove vrane?

Daljnje čitanje / Dopunske veze

Zaklada CK-12. Srednja biološka škola, Poglavlje 34, “Ponašanje životinja”.

  • Melvin Berger. Psi donose novine, ali mačke donose miševe: i druge fascinantne činjenice o ponašanju životinja. Školski, 2004. (monografija).
  • Paolo Casale i Gian Paolo Faescini. Ponašanje životinja: instinkt, učenje, suradnja. Barrons Juveniles, 1999. http://asci.uvm.edu/course/asci001/behavior.htmlhttp://news.bbc.co.uk/1/hi/sci/tech/2178920.stmhttp://news.nationalgeographic .com/news/2005/10/1025_051025_gorillas_tools.htmlhttp://school.discoveryeducation.com/lessonplans/programs/animalinstincts/http://science.jrank.org/pages/3608/Instinct-Classic-anim-examples .htmlhttp://www.biology-online.org/dictionary/Insight_learninghttp://www.britannica.com/eb/article-48658/animal-behaviourhttp://www.discoverchimpanzees.org/behaviors/top.php?dir =Tool_Use&#38topic=Termite_Fishinghttp://www.janegoodall.org/http://www.keepkidshealthy.com/newborn/newborn_reflexes.htmlhttp://www.nature.com/hdy/journal/v82/n4/full/6885270a .htmlhttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1236726#pbio-0030380-b03http://www.unmc.edu/Physiology/Mann/mann19.html

Točke za razmatranje

Zatim ćemo raspravljati o vrstama ponašanja životinja.

  • Jeste li ikada gledali dugu liniju mrava kako marširaju od svog mravinjaka? Što su radili? Kako su mogli surađivati? Što mislite što objašnjava ovakvo grupno ponašanje?

Klasifikacija ptica

Postoji oko 10.000 živih vrsta ptica. Gotovo svi mogu letjeti, ali postoji nekoliko izuzetaka.

Ptice koje ne lete

Neke su ptice izgubile sposobnost letenja tijekom svoje evolucije. Prikazano je nekoliko ptica koje ne lete Lik ispod. Oni uključuju noja, kivija, nandu, kazuara i mou. Sve ove ptice imaju duge noge i prilagođene su za trčanje. Pingvini prikazani na slici također su ptice koje ne lete, ali imaju vrlo različit oblik tijela. To&rsquos jer su prilagođene za plivanje, a ne za trčanje.

Ptice koje ne lete. Ptice koje ne lete i koje su prilagođene za trčanje uključuju noj, kivi, nandu, kazuar i mou. Pingvini su ptice koje ne lete prilagođene za plivanje.

Ptice leteće

Ptice koje mogu letjeti podijeljene su u 29 redova koji se razlikuju po svojim fizičkim osobinama i ponašanju. Stol u nastavku opisuje sedam najčešćih narudžbi. Kao što je prikazano u tablici, većina letećih ptica su ptice koje sjede, poput medojeda opisanog u posljednjem redu tablice. Red ptica sjedećih ima više vrsta od svih ostalih ptičjih redova zajedno. Zapravo, ovaj red ptica je najveći pojedinačni red kopnenih kralježnjaka.


Otisak čovjeka u pticama i važnost surogat majčinstva

Utiskivanje je oblik učenja u kojem životinja stječe osjećaj za identifikaciju vrste. Ptice ne znaju automatski što su kada se izlegu – one se vizualno utiskuju u svoje roditelje tijekom kritičnog razdoblja razvoja. Nakon utiskivanja, identificirat će se s tom vrstom za cijeli život.

Otiskivanje za divlje ptice ključno je za njihov trenutni i dugoročni opstanak. Na primjer, predrasle ptičice (kao što su patke, guske i purice) započinju proces otiskivanja ubrzo nakon izlijeganja tako da slijede odgovarajuću odraslu osobu, pružajući im sigurnost.

Utiskivanje omogućuje mladunčadima da razumiju primjereno ponašanje i vokalizaciju za svoju vrstu, a također pomaže pticama da se vizualno identificiraju s drugim pripadnicima svoje vrste kako bi kasnije u životu mogle odabrati odgovarajuće partnere.

Vrijeme faze utiskivanja varira od vrste do vrste, a neke vrste ptica su podložnije neodgovarajućem utiskivanju na osobe koje se brinu o ljudima iz razloga koji nisu u potpunosti razumljivi.

Što se događa ako se ptica utisne na ljude?

Ako se mlade ptice utiskuju u ljude, poistovjetit će se s ljudima za cijeli život. Obrnuti proces utiskivanja je nemoguće - ove su ptice vezane za ljude doživotno i identificirat će se s ljudima, a ne s vlastitom vrstom.

Utiskivanje na ljude ne znači da će ptice biti "prijateljske" prema ljudima, niti znači da nužno uživaju u blizini ljudi. Ptice s ljudskim otiscima nemaju straha od ljudi, a taj nedostatak straha ponekad može dovesti do agresije prema ljudima. Nije neobično da utisnuta ptica pokazuje teritorijalno ponašanje prema ljudima baš kao što bi to činila s pripadnicima svoje vrste.

Ptice s ljudskim otiscima također često imaju poteškoća u komunikaciji s drugim pticama svoje vrste – vokalizacija, položaji i strah od ljudi sve su stvari koje ptice uče od svojih roditelja, braće i sestara i drugih ptica. Obično ih ne prihvaćaju druge ptice njihove vrste, vjerojatno zato što ptice s ljudskim otiscima pokazuju čudna ponašanja i nemaju sposobnost pravilne komunikacije.

U konačnici, utisnute ptice nađu se u "sivom području" - ne mogu na odgovarajući način komunicirati ni s ljudima ni s vlastitom vrstom.

Ptice koje su utisnute ljudima smatraju se neprikladnima za puštanje natrag u divljinu zbog ovih neprikladnih interakcija. Neki od ovih pacijenata mogli bi biti prikladne obrazovne životinje. Centar za divlje životinje ima nekoliko ptica otisnutih ljudima, uključujući Gusa sova s ​​prutom, Jaza, američku vranu, Edie, američku vjetrušku i Buttercup, crnog supa.


Što Centar čini kako bi spriječio otisak mladih ptica na ljudima?

Kada se ljudi moraju brinuti za siročad ili ozlijeđene ptičice, osoblje Centra za divlje životinje poduzima posebne mjere opreza kako bi spriječilo njihovo neprikladno otiskivanje na ljudima. Kontakt s ljudima sveden je na minimum, rehabilitacijsko osoblje rukuje samo pticama tijekom procesa hranjenja i čišćenja. Osoblje za rehabilitaciju, studenti i volonteri ne razgovaraju s pacijentima.

Ponekad skrbnici nose maske i šešire kako bi prikrili ljudske osobine.

Što se tiče ptica pjevica, pokušavamo držati bebe zajedno u skupinama iste vrste, a to je obično dovoljno da spriječimo njihovo utiskivanje na ljude. Kod naših mladih grabljivica, smještaj kod zamjenskog roditelja daje im najbolju šansu za otisak na odgovarajućoj vrsti.

Zašto su surogati tako ključni za Centar?

Surogati mladim pripadnicima svoje vrste pružaju uzor odrasloj osobi kako bi se suprotstavili njihovoj interakciji s ljudskim skrbnicima. Surogat roditelj pokazuje primjereno ponašanje za svoju vrstu i pojačava njihovu opreznost prema ljudima. To omogućuje mladim pticama da budu puštene natrag u divljinu s odgovarajućim ponašanjem, vokalizacijom i reakcijama na ljude.

Razina interakcije između surogata i bebe razlikuje se u svakoj situaciji. Neki surogati preuzimaju aktivnu ulogu u brizi za svoje "posvojene" mlade tako što ih hrane ili čiste. Drugi surogati ne pokazuju majčinski ili očinski instinkt, ali njihova prisutnost osigurava da bebe mogu vizualno utisnuti odgovarajuću vrstu.

Ima li Centar surogat?

Centar je dom jednog surogata grabljivice koji se ne može pustiti - Papa G’Ho, Velika rogata sova.

Papa G’Ho je primljen u Centar 2001. godine nakon što je zadobio ozljede krila i stopala, vjerojatno od udarca vozila. Unatoč rehabilitaciji, Papa G’Ho nikada nije povratio svoju sposobnost tihog letenja, što je ključno za lovni uspjeh sova u divljini. Budući da bi bučni let spriječio njegovu sposobnost samostalnog preživljavanja, ne može se pustiti natrag u divljinu.

Iako nije pušten na slobodu, osoblje Centra jako pazi da Papa G'Ho ostane "divlji" kako bi osigurali da sove koje uzgaja mogu preživjeti i napredovati same. Papa živi u zoni za pacijente u Centru za divlje životinje i nije izložen za grupe izleta ili otvorene kuće.

Papa je pomogao u uzgoju više od dva tuceta sova otkako se pridružio Centru kao surogat. On igra ključnu ulogu u odgoju zdrave, divlje siročadi velike sove u Centru. Gledajte Papa G'Hoa u akciji u četvrtoj epizodi Neukroćena!

Povremeno, obrazovne životinje Centra za divlje životinje mogu imati privremenu zamjensku ulogu, ako je njihovo ponašanje primjereno i ako ih se može ukloniti iz upotrebe za programe informiranja. Centar također koristi odrasle pacijente grabljivice koji su izlječivi i medicinski stabilni, osobito u slučajevima kada Centar nema na raspolaganju odraslu osobu te vrste za udomljavanje mladih, kao što su sove s kočom, sove ušare i orlovi ćelavi.

Što je sa sisavcima? Morate li se brinuti da će bebe sisavaca utisnuti ljude?

Kritično razdoblje razvoja sisavaca razlikuje se od ptica. Sisavci se vizualno ne utiskuju u svoje skrbnike, ali mogu postati pitomi ili naviknuti na ljude ako se njima ne postupa na odgovarajući način. To se posebno odnosi na sisavce koji imaju produljeno razdoblje juvenilnosti – mladunčad bijelorepanog jelena i mladunčad crnog medvjeda su najbolji primjeri.

Jeleni su krdo životinje, a držanje mladunaca zajedno ili jedan blizu drugog u vanjskim ograđenim prostorima Centra pomaže u sprječavanju njihovog navikavanja na ljude. Samci uzgojeni sami imaju veći rizik od neprikladnog povezivanja sa svojim ljudskim skrbnikom.

Kako bi se spriječilo moguće pripitomljavanje i navikavanje na ljude, Centar ponekad udomljava mladunčad crnog medvjeda sa starijom ženkom medvjedića koja je zdrava i stabilna. Uz starijeg medvjeda kao uzora i zaštitnika, mladunci mogu bolje replicirati prirodna ponašanja i interakcije. Surogati crnog medvjeda obično su proveli najmanje godinu dana u divljini i u stanju su mladuncima usaditi oprez kod ljudi.

Dok su neki mladi sisavci osjetljiviji na navikavanje na ljude, mnoge vrste malih sisavaca imaju relativno kratak stadij juvenilnosti i manja je vjerojatnost da će se povezati sa svojim ljudskim skrbnicima kada im se pruži odgovarajuća rehabilitacijska skrb. Sa svim vrstama beba sisavaca, osoblje nastoji biti što manje ruku, kako bi se smanjio stres na životinju i rizik od pripitomljavanja i navikavanja.

Kako mogu saznati više o surogat majčinstvu u Centru za divlje životinje?

Posjetivši Critter Corner na našoj web stranici, možete biti u tijeku s trenutnim pacijentima u Centru. Ovdje ćete pronaći priče pacijenata i novosti o nekim pacijentima bez roditelja u Centru. Također možete pronaći poveznice na našu Critter Cam. Papa G’Ho se često prikazuje na Critter Camu kada u proljeće odgaja mlade velike rogate sovice. Ptice siročad najčešće se primaju u Centar u proljetnim i ljetnim mjesecima, stoga redovito provjeravajte nove informacije o pacijentima.


Megapodi

Većina ptica prima roditeljsku skrb (Marš Pingvina, bilo tko?), ali megapodi - skupina ptica nalik kokošima porijeklom iz istočne Australije, Nove Gvineje, Indonezije i Filipina - velika su iznimka.

Ove ptice "čak niti ne inkubiraju izravno svoja jaja", kaže Roby. Umjesto toga “oni grade veliki humak od raspadajuće vegetacije i polažu svoja jaja u humku.”

Prema The Handbook of Bird Biology, humci mogu biti “veličine automobila”.

Roditelji kontroliraju temperaturu humka “uklanjanjem ili dodavanjem više vegetacije”, kaže Roby, ali nakon što se potomci rode, prokopaju se iz humka i “bježe u grmlje, a da nisu vidjeli svoje roditelje”.

Pilići mogu letjeti u roku od 24 sata.

“Majke krokodili daju svojim mladima više brige nakon izlijeganja nego megapodi”, napominje Roby. Doista, bebe crocs su među rijetkim gmazovima koji primaju roditeljsku skrb, uključujući i nošenje u maminim divovskim ustima. (Pogledajte video: Najsmrtonosniji na svijetu: ubojica Croc nosi bebe u raljama)


Deformacije kljuna kod kopnenih ptica

Tijekom posljednjih 20 godina, stanovnici Aljaske bili su svjedoci zapanjujućeg porasta deformiteta kljuna među crnoglavim pilićima i drugim vrstama ptica koje žive. Ovu bolest, nazvanu poremećaj ptičjeg keratina (AKD), karakterizira iscrpljujući prekomjerni rast kljuna i druge abnormalnosti keratiniziranog tkiva. Pogođene ptice imaju poteškoće s hranjenjem i čišćenjem i mogu patiti od visoke stope smrtnosti.

Pilić s crnom kapom s deformiranim kljunom koji pokušava jesti na balu

(Zasluge: Sherry Shiesl. Uz dopuštenje: Sherry Shiesl)

Počeli smo s istraživanjem 1999. i od tada smo identificirali više od 3000 oboljelih crnoglavih pilićica na Aljasci – najveća koncentracija grubih deformiteta ikada zabilježena u populaciji divljih ptica! Increasing numbers of other species, including Northwestern Crows, Downy Woodpeckers, Steller’s Jays, and Black-billed Magpies have also been observed with beak deformities throughout the state. Growing numbers of reports from North America and Europe suggest that AKD may be spreading to a larger geographic area.

In 2016, we identified a novel picornavirus (Poecivirus) in Alaskan Black-capped Chickadees with AKD. We’ve subsequently confirmed a strong association between Poecivirus and beak deformities in chickadees and detected a closely related virus in other species with similar beak deformities. Together, this evidence suggests that Poecivirus is a likely candidate cause of AKD. Our current investigations are focusing on understanding more about this virus, including how it may be contributing to beak deformities, whether it occurs in multiple species, and how it is transmitted. Previously, we examined potential factors, such as environmental contaminants, nutritional deficiencies, and parasites, found no clear evidence linking these to AKD in Alaskan birds.

Reports from the public help us to determine where and how many birds are affected. If you see a bird with a beak deformity, please contact us.


These Are The World's Weirdest Birds

There are almost 10,000 bird species flying the skies, roaming the lands, and diving the waters of our planet. Some of them are pretty similar to one another, perhaps because the two species diverged only relatively recently. But some of them are so unique you won't believe they're not made up.

The species listed below come from a recent paper in Trenutna biologija , which aimed to identify the species most in need of our conservation efforts. As I wrote in Conservation Magazine last week, the researchers measured each bird's evolutionary distinctness. "It's a way to assess how evolutionarily unique a species is by comparing its genome with the genomes of its closest relatives. Those who are least related to - or more different from - their closest phylogenetic relatives would be more evolutionarily distinct." As a result of being so evolutionarily distinct, some of the birds with the highest levels are also quite unique.

Here are some of the weirder birds we found while browsing the data, which is freely available .

1. Kagu

The only place on Earth you'll find a wild Kagu is in New Caledonia , a small island east of Australia. It may look like your average bird, but it's the only surviving member of both its genus and its family. Mating pairs, which last quite a long time and possibly for life, occupy large territories, 22-62 acres in size. For most of the year, the male and female live in their own, but each breeding season they come together to co-incubate a single egg. The species is so emblamatic of New Calendonia, that the nation's TV station used to play its song each night as it went off the air.

Why is it weird? It's the only bird species that has "nasal corns," small structures over the nasal openings. It's thought that they evolved to prevent dust and other particles from entering the nose, since the Kagu spends so much time rooting around the dirt with its beak its prey.

2. Christmas Island Frigatebird

The slightly awkward looking Christmas Island Frigatebird comes from, you guessed it, Christmas Island, a small Australian territory in the Indian Ocean. They're particularly threatened by the introduced yellow crazy ant, which you may remember from National Geographic's Great Migrations as the species that eats the Christmas Island crabs. Alive.

Why is it weird? The Christmas Island Frigatebird captures its prey in one of two ways. One is it eats flying fish while they're above the sea's surface, relying on marine predators to drive the fish out of the water. That's not that weird. The second, more interesting way, this: while in flight, the bird steals food that other seabirds and gulls have managed to nab themselves, all while airborne. Scientists call them "aerial kleptoparasites." We like to call them "sky pirates."

3. Philippine Eagle

This impressive raptor is the world's longest, measuring some three feet from beaktip to tail, though it isn't quite the world's heaviest (Steller's Sea Eagle) or bulkiest (Harpy Eagle). As an apex predator, it was once called the "Philippine Monkey-Eating Eagle," because it was believed that it preyed only on monkeys. We now know that it hunts much more opportunistically, taking whatever meat it can find, including, yes, monkeys. The fact that it doesn't exclusively dine on primate flesh doesn't make it any less terrifying.

Why is it weird? If being the longest eagle in the world and dining on monkey meat isn't enough, it's also got a fascinating relationship with human culture. It was made the national bird of the Philippines on July 4, 1995. As a result, if you kill one, you can look forward to spending twelve years in prison.

4. Kakapo

This magnificent bird is also one of the world's rarest. By the end of 2013, there were only an estimated 124 of them in existence. Like many island predators, it evolved on New Zealand with no natural predators of its own. That's why it was so vulnerable to predation by the predators that modern humans brought with them to the island: cats and rats (obviously), but also ferrets and stoats.

Why is it weird? This parrot has so many unique features its hard to know where to begin. It is the world's heaviest and only flightless parrot. It is nocturnal, which is unusual for parrots, and is the only parrot in the world known to mate by lekking . In a lek, males gather in an arena where they form themselves into a sort of mating buffet. The females come by, watch their displays, and pick out their favorite males. It's common in ungulates like deer, and is known to occur among some birds, like prairie chickens, but the kakapo is the world's only parrot to do it. But perhaps their weirdest trait is also ultimately the source of their eventual downfall: they only breed three times, on average, each decade. Breeding occurs only when the fruit of the rimu tree (Dacrydium cupressinum) is in relative abundance.

5. California Condor

I've you've been reading Animals.io9 for a while, then you know we're already a little bit obsessed with California Condors. Using one of the most fascinating sorts of science-based conservation, zookeepers are raising baby chicks in captivity by putting condor puppets on their hands. It's one of the world's longest-living birds, with lifespans stretching up to six decades in the wild. That is, if they can avoid poaching or lead poisoning. They're also eaters of death, feasting primarily on carrion. All living California condors are descended from just 22 individuals, captured in 1987 for a captive breeding program. As of May 2013, there are now 237 living in the wild and 198 in captivity.

Why is it weird? The bird has the largest wingspan of any in North America, and as a result it can be mistaken for a small airplane. In fact, according to John Nielson, author of Condor: To the Brink and Back the birds are confused for aircraft more often than they're confused for other birds.

6. Oilbird

The oilbird, known locally in northern South America as guácharo, is a curious little nocturnal cave-dwelling frugivore. It finds its food by echolocation, much as bats and dolphins do, though some of the frequencies they use are actually audible to humans. It's the world's only flying nocturnal fruit-eating bird (the kakapo, above, is flightless together, the pair are the world's only nocturnal fruit eaters).

Why is it weird? As its name implies, the oilbird is so oily that people used to hunt them and boil them down to extract their oil for use as fuel. It's got 80 million years of evolutionary distinctness, making it one of the most evolutionarily distinct birds in existence.

7. Hoatzin

We've saved the best for last. This beautiful, pheasant-sized bird is native to South America's Amazon and Orinoco deltas. Like many of the birds on our list, it's the only species of it's genus, which is part of why it's so evolutionarily distinct. They're herbivores, feeding mainly on leaves, fruits, and flowers, but because of the way they digest those plant parts, the birds wind up quite stinky. In fact, the Hoatzin is also known locally as the "Stinkbird" for their vaguely manure-like odor. For that reason, it isn't threatened by human poaching it's sort of a last-resort meal. Youɽ have to be really, really hungry to try to capture one of these critters.

Why is it weird? There's a very good reason it's such a foul smelling bird. The Hoatzin has a digestive system unlike any other bird, and actually more like a cow . They have a foregut that they use to break down the plants they eat using bacterial fermentation. It's not a rumen, as ruminants like cattle have instead, evolution operated on part of their digestive anatomy called the crop , a feature common to birds, to make it function much like a cow's rumen. As a result, the crop is so large that it displaces muscles that otherwise would have been used for flight. Hoatzins can still fly, just not all that well.

The Hoatzin has another feature unique among all the world's birds, and it's one that makes it a strong contender to inspire the next SyFy horror flick : it's got two claws on each of its wings!

The wing-claws let the chicks move about tree branches without falling into the water below as soon as they hatch. It's an important feature to avoid becoming the next meal of a Great Black Hawk. When a hawk attacks, the mature Hoatzins fly about to distract the predator, while the chicks hide under thicker cover. If spotted, the chicks do an avian version of stop-drop-and-roll. They plunge into the water, swim away, and use their claws to haul themselves back onto land, up the tree, and into the nest. Because of its claws, some researchers have wondered if the Hoatzin was a direct descendent of Archaeopteryx, which had three claws on each wing. Others think the claws are a more recent adaptation, having emerged as a result of the selective pressure caused by predation. Either way, the Hoatzin may be the most badass bird around. They're a good reminder that dinosaurs still live among us.


Study of Darwin's finches reveals that new species can develop in as little as two generations

A new study illustrates how new species can arise in as little as two generations. The study tracked Darwin's finches on the Galápagos island of Daphne Major, where a member of the G. conirostris species (pictured) arrived from a distant island and mated with a resident finch of the species G. fortis. The offspring developed into a new species that the researchers call the Big Bird lineage.

The arrival 36 years ago of a strange bird to a remote island in the Galápagos archipelago has provided direct genetic evidence of a novel way in which new species arise.

On Nov. 23 in the journal Science, researchers from Princeton University and Uppsala University in Sweden report that the newcomer belonging to one species mated with a member of another species resident on the island, giving rise to a new species that today consists of roughly 30 individuals.

The study comes from work conducted on Darwin’s finches, which live on the Galápagos Islands in the Pacific Ocean. The remote location has enabled researchers to study the evolution of biodiversity due to natural selection under pristine conditions.

The direct observation of the origin of this new species occurred during field work carried out over the last four decades by B. Rosemary Grant and Peter Grant, a wife-and-husband team of scientists from Princeton, on the small island of Daphne Major.

"The novelty of this study is that we can follow the emergence of new species in the wild," said B. Rosemary Grant, a senior research biologist, emeritus, and a senior biologist in the Department of Ecology and Evolutionary Biology. "Through our work on Daphne Major, we were able to observe the pairing up of two birds from different species and then follow what happened to see how speciation occurred."

In 1981, a graduate student working with the Grants on Daphne Major noticed the newcomer, a male that sang an unusual song and was much larger in body and beak size than the three resident species of birds on the island.

"We didn't see him fly in from over the sea, but we noticed him shortly after he arrived. He was so different from the other birds that we knew he did not hatch from an egg on Daphne Major," said Peter Grant, the Class of 1877 Professor of Zoology, Emeritus, and a professor of ecology and evolutionary biology, emeritus.

The bird is a member of the G. fortis species, one of two species that interbred to give rise to the Big Bird lineage.

The researchers took a blood sample and released the bird, which later bred with a resident medium ground finch of the species Geospiz fortis, initiating a new lineage. The Grants and their research team followed the new "Big Bird lineage" for six generations, taking blood samples for use in genetic analysis.

In the current study, researchers from Uppsala University analyzed DNA collected from the parent birds and their offspring over the years. The investigators discovered that the original male parent was a large cactus finch of the species Geospiza conirostris from Española island, which is more than 100 kilometers (about 62 miles) to the southeast in the archipelago.

The remarkable distance meant that the male finch was not able to return home to mate with a member of his own species and so chose a mate from among the three species already on Daphne Major. This reproductive isolation is considered a critical step in the development of a new species when two separate species interbreed.

The offspring were also reproductively isolated because their song, which is used to attract mates, was unusual and failed to attract females from the resident species. The offspring also differed from the resident species in beak size and shape, which is a major cue for mate choice. As a result, the offspring mated with members of their own lineage, strengthening the development of the new species.

Researchers previously assumed that the formation of a new species takes a very long time, but in the Big Bird lineage it happened in just two generations, according to observations made by the Grants in the field in combination with the genetic studies.

The direct observation of the origin of a new species occurred during field work carried out over the last four decades by B. Rosemary Grant and Peter Grant, a wife-and-husband team of scientists from Princeton, on the small island of Daphne Major in the Galápagos Islands in the Pacific Ocean.

All 18 species of Darwin’s finches derived from a single ancestral species that colonized the Galápagos about one to two million years ago. The finches have since diversified into different species, and changes in beak shape and size have allowed different species to utilize different food sources on the Galápagos. A critical requirement for speciation to occur through hybridization of two distinct species is that the new lineage must be ecologically competitive — that is, good at competing for food and other resources with the other species — and this has been the case for the Big Bird lineage.

"It is very striking that when we compare the size and shape of the Big Bird beaks with the beak morphologies of the other three species inhabiting Daphne Major, the Big Birds occupy their own niche in the beak morphology space," said Sangeet Lamichhaney, a postdoctoral fellow at Harvard University and the first author on the study. "Thus, the combination of gene variants contributed from the two interbreeding species in combination with natural selection led to the evolution of a beak morphology that was competitive and unique."

Schematic illustration of the evolution of the Big Bird lineage on the Daphne Major island in the Galápagos archipelago. Initially an immigrant large cactus finch male (Geospiza conirostris) bred with a medium ground finch female (Geospiza fortis). Their offspring bred with each other and established the Big Bird lineage. Photos © K. Thalia Grant for G. conirostris and Peter R. Grant for the remainder. Reproduced with permission from K.T. Grant, and Princeton University Press, which first published the remaining images in "40 Years of Evolution"

The definition of a species has traditionally included the inability to produce fully fertile progeny from interbreeding species, as is the case for the horse and the donkey, for example. However, in recent years it has become clear that some closely related species, which normally avoid breeding with each other, do indeed produce offspring that can pass genes to subsequent generations. The authors of the study have previously reported that there has been a considerable amount of gene flow among species of Darwin’s finches over the last several thousands of years.

The breeding of two distinct parent species gave rise to a new lineage (termed "Big Bird" by the researchers). This lineage has been determined to be a new species. This image is of a member of the Big Bird lineage.

One of the most striking aspects of this study is that hybridization between two distinct species led to the development of a new lineage that after only two generations behaved as any other species of Darwin’s finches, explained Leif Andersson, a professor at Uppsala University who is also affiliated with the Swedish University of Agricultural Sciences and Texas A&M University. "A naturalist who came to Daphne Major without knowing that this lineage arose very recently would have recognized this lineage as one of the four species on the island. This clearly demonstrates the value of long-running field studies," he said.

It is likely that new lineages like the Big Birds have originated many times during the evolution of Darwin’s finches, according to the authors. The majority of these lineages have gone extinct but some may have led to the evolution of contemporary species. "We have no indication about the long-term survival of the Big Bird lineage, but it has the potential to become a success, and it provides a beautiful example of one way in which speciation occurs," said Andersson. "Charles Darwin would have been excited to read this paper."

The study was supported by the Galápagos National Parks Service, the Charles Darwin Foundation, the National Science Foundation, the Knut and Alice Wallenberg Foundation, and the Swedish Research Council.

The study, "Rapid hybrid speciation in Darwin's finches," by Sangeet Lamichhaney, Fan Han, Matthew T. Webster, Leif Andersson, B. Rosemary Grant and Peter R. Grant, was published in the journal Science on Nov. 23.

Uppsala University contributed to the content of this press release.


When parenting goes cuckoo

Brood parasites leave their young with another animal who acts as a “foster parent.” Here, the foster parent is a cape robin-chat (right). It is feeding an enormous chick of another species, a red-chested cuckoo (left).

Alandmanson/Wikimedia Commons (CC BY-SA 4.0)

Podijeli ovo:

In Europe, a bird called the common cuckoo uses a sneaky strategy to raise its babies. First, a female cuckoo finds a nest built by a bird of a different species. For example, it might be a great reed warbler. Then, she sneaks into the warblers’ nest, lays an egg and flies away. The warblers often accept the new egg. Indeed, they take care of it along with their own eggs.

The cuckoo chick hatches before the warbler chicks. And it wants all the food from the warbler parents for itself. So the young cuckoo pushes the warbler eggs onto its back, one by one. It braces its feet on the sides of the nest and rolls each egg over the edge. Smash!

“It’s amazing,” notes Daniela Canestrari. She’s a biologist who studies animal behavior at the University of Oviedo in Spain. These chicks “kind of stand up until the egg just falls out.”

It’s not so amazing for the warblers. For some reason, the warbler parents keep feeding the cuckoo chick, even as their own offspring are gone. “This is very bad for the parents because they lose all of their chicks,” Canestrari says.

The common cuckoo is one example of a brood parasite. Such animals trick other animals into raising their young. They sneak their eggs into other parents’ nests.

Brood parasites are “basically looking for foster parents,” says Mark Hauber, a biologist. He studies animal behavior at the University of Illinois at Urbana-Champaign. The “foster parents” are also called “hosts.” Those hosts then feed and protect the parasite’s offspring.

Scientists find this behavior intriguing. And they have witnessed it in birds, fish and insects.

Some researchers are studying whether hosts recognize the alien eggs. Others are exploring how hosts evolve defenses against such parasites. And surprisingly, one team has learned that brood parasites aren’t all bad. Sometimes, they help actually aid their foster family.

A cuckoo chick pushes reed warbler eggs out of their nest. For some reason, the reed warbler parents still keep feeding the cuckoo chick as if it were one of their own.
Artur Homan

Here, raise my kids

Some animals don’t care for their young. They just leave their offspring to fend for themselves. Other animals take a more active role. They forage for food to feed their growing young. They also protect their young from predators and other dangers. Such duties up the chance their offspring will make it to adulthood.

But caring for young animals requires a lot of energy. Adults who gather food for babies might instead have spent that time feeding themselves. Defending their nest against predators could also get a parent injured or killed.

Brood parasites that trick someone else into doing the work can reap the benefits of raising offspring — without the costs. All animals want to pass on copies of their own genes to the next generation. The more young that survive, the better.

Not all brood parasites are as nasty as the common cuckoo. Some parasitic bird chicks grow up alongside their host nestmates. But these nest-crashers can still cause problems. For example, a parasitic chick might hog food. Then some chicks in the foster family could starve.

Some hosts fight back. They learn to recognize foreign eggs and toss them. And if hosts see a parasitic bird, they attack it. Among insects, hosts beat up and sting intruders.

But hosts sometimes just accept the brood parasite. Its egg may look so similar to their own that the hosts can’t tell them apart. After an egg hatches, hosts may suspect a chick isn’t theirs, but they don’t want to risk neglecting it. If they’re wrong, they would have killed one of their young. So they raise the young parasite alongside their own offspring.

Beige egg, blue egg

How closely must an egg resemble its hosts’ for those foster parents to accept it? Some researchers have studied this by using models of eggs made from materials such as clay, plaster or wood. Hauber tried a more advanced technique.

He made fake eggs with 3-D printing. This technology can create 3-D objects out of plastic. A machine melts the plastic, then deposits it in thin layers to build up the desired shape.

With this technique, the researchers created fake eggs with subtle shape differences. Then they watched to see how hosts responded to the different shapes.

Hauber’s team focused on brown-headed cowbirds. These brood parasites live in North America. They lay eggs in the nests of American robins.

Robin eggs are bluish-green and don’t have spots. In contrast, cowbird eggs are beige and spotted. They also are quite a bit smaller than robin’s eggs. Often, the robin throws out the cowbird egg.

Hauber wondered how much the cowbird eggs would need to resemble a robin’s to be accepted. To find out, his team 3-D-printed 28 fake eggs. The researchers painted half of the eggs beige and the other half bluish-green.

All the faux eggs were roughly within the size range of real cowbird eggs. But some were slightly wider or longer than average. Others were a bit thinner or shorter than usual.

The team then visited robin nests in the wild. The researchers snuck fake eggs into the nests. Over the next week, they checked to see if the robins kept — or rejected — the fake eggs.

The results suggest that cowbirds would have more success in robin nests if they evolved to lay bluish-green eggs.

Robins threw out 79 percent of the beige eggs. But they kept all the bluish-green eggs, even though they were smaller than normal robin eggs. Minor shape differences among the fake bluish-green eggs didn’t seem to make a difference. “No matter the shape, they accept those eggs,” Hauber reports. So, he concludes, “The robin seems to pay less attention to size and more to color.”

Alien babies

Brood parasitism also happens in fish. But so far, scientists have found it in only one species: the cuckoo catfish. This fish lives in Lake Tanganyika (Tan-guh-NYEE-kuh) in eastern Africa.

Its hosts are fish species called mouthbrooding cichlids (SIK-lidz). During mating, a female cichlid lays her eggs on the lake floor. Then she quickly gathers the eggs in her mouth and carries them for a few weeks. After the eggs hatch, the little fish swim out of her mouth.

The cuckoo catfish messes up that process. When a female cichlid lays eggs, the female catfish rushes in and lays her eggs at the same spot or nearby. The cichlid and catfish eggs now get mixed up. The cichlid later scoops up her own eggs — and those of the catfish.

The baby catfish hatch inside the cichlid’s mouth and then go on to eat her own eggs. The hatchlings that eventually emerge from her mouth look very different from a cichlid.

“It would be like a human female giving birth to an alien,” says Martin Reichard. He is a biologist who studies how animals interact with their environment. Reichard works at the Czech Academy of Sciences in Brno, Czech Republic.

Reichard wondered if cichlids had evolved defenses against the cuckoo catfish. Some cichlid species have lived in Lake Tanganyika with the catfish for a long time. But mouthbrooding cichlids in other African lakes have never encountered cuckoo catfish.

To investigate, his team observed cuckoo catfish and cichlids in the lab. One cichlid species was from Lake Tanganyika, and others came from different lakes. The researchers placed cuckoo catfish with various cichlid species in tanks.

Later, Reichard’s team caught the female cichlids. They squirted water into each fish’s mouth. This flushed out the eggs. Lake Tanganyika cichlids, they found, were much less likely than the other cichlids to carry catfish eggs.

The researchers wondered if Lake Tanganyika cichlids spit out the catfish eggs. To find out, they put female Lake Tanganyika cichlids in one tank. Female cichlids from another African lake, called Lake George, went in a separate tank.

Next, the scientists collected catfish eggs and fertilized them in a dish. They squirted six catfish eggs into each female cichlid’s mouth. Over the next day, the team counted how many catfish eggs ended up on each tank’s floor.

Only seven percent of the Lake George cichlids spit out catfish eggs. But 90 percent of the Lake Tanganyika cichlids had spit out catfish eggs.

It’s not clear how the Lake Tanganyika cichlids know to reject the intruders. Maybe the catfish eggs feel different in the cichlid’s mouth because of their shape and size. Or maybe they taste different.

That defense comes with a downside, however. Sometimes Lake Tanganyika cichlids spit out their own eggs along with catfish eggs. So the price of evicting the parasitic eggs was to sacrifice some of their own. Argues Reichard, that cost is “quite high.”

Smelly roommates

Brood parasites aren’t always bad news. Canestrari has found that some parasitic chicks that aid their foster family.

Canestrari studies a host species called the carrion crow. At first, she wasn’t focusing on brood parasitism. She just wanted to learn about crow behavior.

But some crow nests had been parasitized by great spotted cuckoos. When the cuckoo eggs hatched, the chicks didn’t push crow eggs out of the nest. They grew up alongside crow chicks.

“At a certain point, we noticed something that really puzzled us,” Canestrari says. Nests containing a cuckoo chick seemed more likely to succeed. By that she means that at least one crow chick survived long enough to fledge, or fly out on its own.

The researchers wondered if the reason had something to do with predators. Falcons and wild cats sometimes attack crow nests, killing all the chicks. Could the cuckoos be helping to defend nests from these attackers?

The researchers knew that when they picked up cuckoos, the birds squirted out a stinky liquid. They “always, always produce this terrible substance, which is absolutely disgusting,” Canestrari says. She wondered if cuckoos were sliming predators with the liquid.

So the scientists found crow nests containing a cuckoo chick. They moved some cuckoos to crow nests that weren’t parasitized. Then the researchers monitored whether the nests succeeded. They also watched nests that had never contained a cuckoo chick.

About 70 percent of crow nests with added cuckoo chicks succeeded. This rate was similar to that of chicks in parasitized nests that kept their cuckoos.

But among nests whose cuckoo chicks were removed, only about 30 percent succeeded. And this rate was similar to what is seen in nests that never held a cuckoo.

“The presence of the cuckoo was causing this difference,” Canestrari concludes.

Then the researchers tested whether predators disliked the cuckoo’s stinky spray. They collected the liquid in a tube. Later, they smeared this stuff on raw chicken meat. Then they offered the doctored meat to cats and falcons.

The predators turned up their noses. Most of the cats “didn’t even touch the meat,” Canestrari says. The birds tended to pick it up, then reject it.

Classroom questions

So cuckoo chicks do seem to protect crow nests. “The host is gaining some kind of benefit,” she says. “In some circumstances, a cuckoo chick is not a bad thing.”

Scientists find brood parasites fascinating because they’re rare. Most birds care for their own young instead of shoving the work onto someone else. Notes Hauber, brood parasites “are the exception to the rule.”

Note: This article was updated on October 15, 2019, to fix the definition of a brood parasite and clarify the experiment described in the final section.

Riječi moći

3-D printing A means of producing physical items — including toys, foods and even body parts — using a machine that takes instructions from a computer program. That program tells the machine how and where to lay down successive layers of some raw material (the “ink”) to create a three-dimensional object.

alien A non-native organism.

prosjek (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

ponašanje The way something, often a person or other organism, acts towards others, or conducts itself.

biologija The study of living things. The scientists who study them are known as biologists.

brood A group of related animals that emerges in a specific region in the same year. Depending on the animal type, the collective group is sometimes also known as a year class. (verb) The act of guarding and/or incubating eggs.

carrion The dead and rotting remains of an animal.

cichlids A freshwater fish that has become popular in the aquarium trade. This animal’s family is large and diverse. It includes at least 1,650 species, many of which are eaten. Although found all over the world, they are most diverse in Africa and South America.

clay Fine-grained particles of soil that stick together and can be molded when wet. When fired under intense heat, clay can become hard and brittle. That’s why it’s used to fashion pottery and bricks.

crow The characteristic loud cry of a rooster. (in biology) A type of large black bird with a complex social structure that perches in trees and is known for its boisterous call.

obrana (in biology) A natural protective action taken or chemical response that occurs when a species confront predators or agents that might harm it. (adj. defensive)

okoliš The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of things in the vicinity of an item of interest).

evolve (adj. evolving) To change gradually over generations, or a long period of time. In living organisms, such an evolution usually involves random changes to genes that will then be passed along to an individual’s offspring. These can lead to new traits, such as altered coloration, new susceptibility to disease or protection from it, or different shaped features (such as legs, antennae, toes or internal organs).

promašaj Meaning false or fake. Faux fur, for instance, would not be made from animal products but from some manufactured fibers.

fledge The first time a young bird develops wing feathers and is able to fly.

stočna hrana To search for something, especially food. It’s also a term for the food eaten by grazing animals, such as cattle and horses.

gen (adj. genetic) A segment of DNA that codes, or holds instructions, for a cell’s production of a protein. Potomstvo nasljeđuje gene od svojih roditelja. Geni utječu na to kako organizam izgleda i ponaša se.

generacija A group of individuals (in any species) born at about the same time or that are regarded as a single group. Your parents belong to one generation of your family, for example, and your grandparents to another. Similarly, you and everyone within a few years of your age across the planet are referred to as belonging to a particular generation of humans.

hatchling A young animal that recently emerged from its egg.

model A simulation of a real-world event (usually using a computer) that has been developed to predict one or more likely outcomes. Or an individual that is meant to display how something would work in or look on others.

parasite An organism that gets benefits from another species, called a host, but doesn’t provide that host any benefits. Classic examples of parasites include ticks, fleas and tapeworms.

predator (adjective: predatory) A creature that preys on other animals for most or all of its food.

rasponu The full extent or distribution of something. For instance, a plant or animal’s range is the area over which it naturally exists. (in math or for measurements) The extent to which variation in values is possible. Also, the distance within which something can be reached or perceived.

rizik The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. (For instance: Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.)

vrsta A group of similar organisms capable of producing offspring that can survive and reproduce.

strategija A thoughtful and clever plan for achieving some difficult or challenging goal.

subtle Some feature that may be important, but can be hard to see or describe. For instance, the first cellular changes that signal the start of a cancer may be visible but subtle — small and hard to distinguish from nearby healthy tissues.

Citati

Journal: D. Canestrari et al. From parasitism to mutualism: Unexpected interactions between a cuckoo and its host. Znanost. Vol. 343, Mar. 21, 2014, p. 1350. doi: 10.1126/science.1249008.



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