Navigation Links
How birds spot the cuckoo in the nest
Date:7/15/2008

It's not always easy spotting the cuckoo in the nest. But if you don't, you pay a high price raising someone else's chick. How hosts distinguish impostor eggs from their own has long puzzled scientists. The problem remained largely unsolved while looking at it through our own eyes. It was only when people started thinking from the birds' perspective that they began to understand how hosts recognise a cuckoo egg in the nest. Marcel Honza from the Academy of Sciences of the Czech Republic explains that birds see UV wavelengths that are well outside our own visual range. Knowing that many bird eggs reflect UV wavelengths, Honza wondered whether altering the reflected UV spectrum of an egg would affect a bird's ability to recognise it as foreign and reject it. Would a blackcap recognise and evict an impostor egg if the reflected UV spectrum were different from the wavelengths reflected by the bird's own clutch? Teaming up with Lenka Polačikov, Honza headed into a near-by forest to test blackcap responses to impostor eggs and publish their findings on July 18th in The Journal of Experimental Biology at http://jeb.biologists.org.

But instead of testing the birds' reactions to real cuckoo eggs, the team found abandoned blackcap eggs, introducing them as impostors to successful blackcap clutches. Having identified nests with well-established clutches, the team coated some impostor eggs in UV blocker, to alter their UV appearance, and others in Vaseline, which didn't alter the egg's UV reflectivity, before planting the impostors in their new nest. Then the team kept their fingers crossed, hoping that the nests weren't washed out by a heavy downpour or raided by a hungry predator, as they waited 5 days to see if the parents rejected the interlopers.

Of the 16 eggs coated in Vaseline, 11 of the impostors were accepted by the nesting parents, while five were rejected; most of the interloper blackcap eggs were visually indistinguishable from the nesting parents' own eggs and were accepted as belonging to the brood. However, it was a different matter for the birds sitting on UV-block-coated impostors. Seventeen brooding parents evicted the strange looking egg, pecking at the shell until they had made a large enough hole to stick their beak in and carry it away. Only 11 blackcaps accepted the interloper with its altered appearance.

The UV appearance of the eggs was very important in enabling the blackcaps to recognise the new eggs as impostors. The blackcaps rejected far more eggs when Polačikov and Honza covered them in UV block. By altering the eggs' UV reflectivity the team had made them stand out from the crowd.

Honza admits that he was surprised that the UV reflectivity had such a significant effect on the blackcap's ability to reject an impostor. Having found that an interloper's UV appearance is key to its acceptance in a clutch, Honza is keen to see whether cuckoos try to outsmart their victims by choosing clutches that closely match their own eggs' UV reflectivity.


'/>"/>

Contact: Kathryn Phillips
kathryn@biologists.com
44-122-342-5525
The Company of Biologists
Source:Eurekalert

Related biology news :

1. Birds migrate together at night in dispersed flocks, new study indicates
2. Want to fly? Dont copy the birds and the bees
3. Killer whales, blind bats, discriminating dolphins, mating birds
4. Migrating songbirds learn survival tips on the fly
5. Birds migrate earlier, but some may be left behind as the climate warms rapidly
6. Bee species outnumber mammals and birds combined
7. Genetic sequencing of protein from T. rex bone confirms dinosaurs link to birds
8. Asian waterbirds stage remarkable comeback
9. Some migratory birds cant find success in urban areas, study finds
10. Birds, bats and insects hold secrets for aerospace engineers
11. High degree of resistance to antibiotics in Arctic birds
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/23/2017)... the first robotic gym for the rehabilitation and functional motor sense evaluation ... Genoa, Italy . The first 30 robots will be available from ... . The technology was developed and patented at the IIT laboratories ... Technology thanks to a 10 million euro investment from entrepreneur Sergio Dompè. ... ...
(Date:4/19/2017)... , April 19, 2017 The ... vendor landscape is marked by the presence of several ... however held by five major players - 3M Cogent, ... companies accounted for nearly 61% of the global military ... companies in the global military biometrics market boast global ...
(Date:4/11/2017)... April 11, 2017 Crossmatch®, a globally-recognized ... solutions, today announced that it has been awarded ... Projects Activity (IARPA) to develop next-generation Presentation Attack ... "Innovation has been a driving force within ... will allow us to innovate and develop new ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... 12, 2017 , ... AMRI, a global contract research, development ... patient outcomes and quality of life, will now be offering its impurity solutions ... new regulatory requirements for all new drug products, including the finalization of ICH ...
(Date:10/11/2017)... ... ... Personal eye wash is a basic first aid supply for any work environment, but most ... you rinse first if a dangerous substance enters both eyes? It’s one less decision, and ... unique dual eye piece. , “Whether its dirt and debris, or an acid or alkali, ...
(Date:10/11/2017)... LAGUNA HILLS, Calif. , Oct. 11, 2017 ... London (ICR) and University of ... prognostic tool to risk-stratify patients with multiple myeloma (MM), in ... nine . The University of Leeds ... by Myeloma UK, and ICR will perform the testing services ...
(Date:10/10/2017)... CALIF. (PRWEB) , ... October 10, 2017 , ... San ... part of its corporate rebranding initiative announced today. The bold new look is ... reach, as the company moves into a significant growth period. , It will also ...
Breaking Biology Technology: