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Re: How Pelicans learn to fish
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