Thursday, 10 February 2011
Australian National University
Babies crying with hunger may attract annoyed looks from bystanders,
but in the bird world noisily crying nestlings are likely to pay the
ultimate price, according to the authors of a new study from The Australian
National University.
The study, conducted by PhD researcher Tonya Haff and Professor Robert
Magrath of the Research School of Biology at ANU, shows that in the bird
world nestlings who noisily beg for food will attract predators.
Additionally, it could explain why young birds are honest about their
food needs: if calling wasn't risky, then nestlings would simply exaggerate
their hunger to get more food. The researchers' paper is published in
Biology Letters.
The research was conducted on white-browed scrubwrens in the
Australian National Botanic Gardens. By playing recordings of the sound of
hungry youngsters at more than 90 nests, the researchers have revealed for
the first time that noisy hunger can be fatal.
"By playing back hungry nestling calls at active nests of scrubwens we
found that predators - in the Botanic Gardens that means Pied Currawongs -
only approached nests playing calls of hungry nestlings, and not those where
the young called more modestly," said Ms Haff.
"So loud begging does attract predators, making begging worthwhile
only when the young are really hungry. It's further proof that there really
is no such thing as a free lunch. "
Ms Haff said that the research also potentially sheds light on why
nestlings are honest in their requirements for food.
"Nestlings want as much food as they can eat to help them grow and be
strong once they leave the nest, but parents tend to provide a bit less. The
question, then, is why don't nestlings just keep begging more and more
loudly so that their parents give them more food? In fact, we know that
nestlings tend to beg below their maximum potential call rate or call
amplitude, and escalate calling only when they are really hungry. Thus,
begging seems to be an 'honest' signal."
She added that the research offered new opportunities for researchers
to understand the forces behind signal honesty such as the tradeoffs between
being fed and the risk of predation.
http://www.sciencealert.com.au/news/20111002-21831.html?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+sciencealert-latestnews+%28ScienceAlert-Latest+Stories%29
&
http://news.anu.edu.au/?p=6771
*******************************************************************************************************
This is the email announcement and discussion list of the Canberra
Ornithologists Group.
Please ensure that emails posted to the list are less than 100 kb in size.
When subscribing or unsubscribing, please insert the word 'Subscribe' or
'Unsubscribe', as applicable, in the email's subject line.
List-Post: <>
List-Help: <>
List-Unsubscribe: <>
List-Subscribe: <>
List archive: <http://bioacoustics.cse.unsw.edu.au/archives/html/canberrabirds>
List manager: David McDonald, email
<>
|
