hello tweets.

yet more interesting observations of the birds that we so love ....

regards,

Deborah Wisti-Peterson email:nyneve at u.washington.edu
Department of Zoology, University of Washington, Seattle, Wash, USA
Visit me on the web: http://students.washington.edu/~nyneve/
<><><>Graduate School: it's not just a job, it's an indenture!<><><>


---------- Forwarded message ----------
Date: Fri, 17 Mar 2000 22:20:14 -0800

> By Discovery.com News
>
> March 16, 2000 -- Human children who fight for food at the dinner
> table might learn some table manners from an unlikely source: the barn
> owl.
>
> According to the current issue of New Scientist, researchers in
> Switzerland have found that barn owl nestlings work together to make
> sure that the hungriest chick eats first instead of fighting over
> food.
>
> For their study, the researchers focused on the intensity of the cries
> of young barn owls. Prior to the Swiss experiment, most scientists
> believed that nestlings cry out solely to attract their parents'
> attention, but they had no explanation for why many species' young cry
> out at night when their parents are clearly out of earshot.
>
> For his study, Swiss zoologist Alexandre Roulin from the University of
> Bern chose two siblings from a group of barn owls and gave one of the
> birds dead mice to eat during the day. That night, the hungry nestling
> cried louder and more than its fully fed sibling. Once the hungry bird
> had been fed, however, the other nestling began to beg more -- even
> though it had already eaten earlier in the day.
>
> In a second experiment, Roulin found that as more chicks were in a
> nest, each nestling cried out less. The experiment's findings dispute
> the belief that as more chicks are in a nest, the louder each one will
> cry in order to drown the others out. Roulin and his team speculate
> that the barn owl chicks don't beg as loud when they only have a small
> chance of getting any food.
>
> "If one nestling is more hungry than the other, the value of the food
> for it is higher," Roulin explained in New Scientist. "A hungry
> nestling will fight physically for the prey."
>
> The less hungry nestling would probably not fight for the food against
> a hungrier sibling, since it has less motivation and is unlikely to
> win the fight. Instead of fighting, the nestlings monitor each other's
> hunger levels by the loudness of their cries, Roulin said. The
> hungrier the birds become, the louder their cries. Therefore, the less
> hungry birds will hear the loud cries of their siblings, give up the
> food and conserve their energy until they are truly hungry.
>
> "Nobody has really looked before at the situation of nestlings
> communicating in the absence of the parents," Becky Kilner, a
> zoologist at Cambridge University, told New Scientist.
>
> Kilner said the research is an interesting new approach and wondered
> whether other birds species behave the same way.