Re: How Pelicans learn to fish

[Mike Habib <habib@jhmi.edu>]

No specific ones that I know of, but I haven't looked carefully.  In both cases 
the skull is large and largely thinned-walled, but that probably isn't a diving 
correlate, per se.  Maybe someone else here has looked at that in more detail.

--Mike H.


On Nov 2, 2010, at 7:47 PM, Dan Chure wrote:

> Any structural convergences in the skull?
> 
> Dan
> 
> On 11/2/2010 5:21 PM, Mike Habib wrote:
>> The only diving birds that fold back the wings in a "knife" position are 
>> gannets and boobies (i.e. sulidae).  Pelicans actually don't tuck their 
>> wings all that far back on dives; I doubt it's beyond the normal joint 
>> excursion for a modern bird.
>> 
>> One bit of interest, though, is that the ratio of bone wall thickness to 
>> total bone diameter in pelicans is very similar to that in derived 
>> pterodactyloids. It's about the same as Pteranodon, for example.
>> 
>> Cheers,
>> 
>> --Mike Habib
>> 
>> 
>> On Nov 2, 2010, at 7:13 PM, Dan Chure wrote:
>> 
>>> Are there any osteological correlates to pelican diving behavior?  One 
>>> would be joints that allow the wings to be rotated backwards, but do all 
>>> diving birds do that or does diving occur in other ways in other birds?
>>> 
>>> Dan
>>> 
>>> 
>>> On 11/2/2010 2:05 PM, Richard W. Travsky wrote:
>>>> Of course the first thing I thought of was pterosaurs...
>>>> 
>>>> http://www.nytimes.com/2010/10/26/science/26qna.html
>>>> 
>>>> Q. How do pelicans learn to dive for fish?
>>>> 
>>>> A. Young pelicans learn to feed themselves through a combination of trial 
>>>> and error, imitation of adult birds and instinct, bird experts suggest.
>>>> 
>>>> In the United States, the Eastern brown pelican (Pelecanus occidentalis 
>>>> carolinensis) and the California brown pelican (Pelecanus occidentalis 
>>>> californicus) make dives onto schooling fish from impressive heights or 
>>>> float on the surface to scavenge fish. A dive from 30 to 60 feet up, or 
>>>> even higher, hits the water with considerable force. Fish a few feet below 
>>>> the surface are scooped up, and water drains from the sides of the pouch. 
>>>> They tilt their heads back and swallow on the spot.
>>>> 
>>>> For young pelicans, some early experience in diving for fish comes during 
>>>> their time in the nest, when they graduate from feeding on half-digested 
>>>> fish bits regurgitated by their generous parents to retrieving fish from 
>>>> the famously capacious pouched parental bills and even their gullets. The 
>>>> nestlings may dive in shoulder deep to make the parents disgorge fish. 
>>>> Pelicans are well fed in the nest for 9 to 11 weeks, by which time they 
>>>> are fully feathered and ready to go out on their own.
>>>> 
>>>> Their diving success rate is highly variable and depends on experience. 
>>>> Adult California brown pelicans bring up fish from around two-thirds of 
>>>> their dives, while novices appear to have a lot of trouble; fewer than 
>>>> half survive their first year out of the nest.
>>>> 
>>>> 
>>>> 
>>>> Didn't know the mortality rate was that high.
>>>> 
>>>> Much has been written and speculated regarding pterosaur flying, but
>>>> what about smacking the water?
>>>> 
>>>> 
>>> 
>> Michael Habib, M.S.
>> PhD. Candidate
>> Center for Functional Anatomy and Evolution
>> Johns Hopkins School of Medicine
>> 1830 E. Monument Street
>> Baltimore, MD 21205
>> (443) 280-0181
>> habib@jhmi.edu
>> 
>> 
>> 
>> 
>> 
> 
> 

Michael Habib, M.S.
PhD. Candidate
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
(443) 280-0181
habib@jhmi.edu