Tuesday, April 26, 2011

American White Pelican 1

On 23 April I came upon three large, odd, birds at the edge of Circle Lake in Rice Co.  Snow Geese?  Large, unkempt plumes erupting from their crowns and napes suggested not.  How about sleeping American White Pelicans with their bills hidden under their scapulars? Perhaps not sleeping...notice that all three have their eyes wide open.
The "horn" on the top of the White Pelican's bill is a fibrous, epidermal plate.  The exact function of this structure is not known, but probably is used in courtship or in territorial conflicts.  The "horn" appears in the early spring and is lost after breeding.  Both sexes have the "horns," which are quite variable in size.  Males tend to have larger "horns" than females, at least compared to the female with whom he mates.  The plumage of the sexes is similar.  Although males tend to be slightly larger than females, I doubt identifying pelican sex by size is very reliable.

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