March 2018 Bird Photo of the Month

The Lookout © J. R. Williams
Double-crested Cormorant (Phalacrocorax auritus)

Yes, this is your ordinary, common Double-crested Cormorant with its brilliant emerald eye surrounding the dark pupil in a breeding adult. For a brief time, with its new darker feathers and more intense orange facial skin, the adult may grow two short tufts of feathers to attract its mate, for which it is named – ‘double-crested.’ Yet those crests are visible only when erect, resulting in an infrequently seen, poor field mark. The word ‘Cormorant’ comes from Medieval Latin (corvus marīnus , literally “sea-raven”), an apt name as it often rides the water surface looking for fish before diving to grasp a fish with its strong bill. The hooked bill tip allows a better grip.
 
Thousands of North American Double-crested Cormorants migrate south in fall on both the Mississippi and Atlantic flyways to join Florida’s permanent residents along rivers, lakes, and coastal areas to forage for prey.  Some migrants continue south to the Gulf of Mexico, Belize, Cuba, and Puerto Rico.  Often, cormorants roost and nest along coastal areas but fly inland during the day to freshwater habitats to forage.

Double-crested Cormorant © J. R. Williams

Being black may serve to enhance their stealth in capturing fish but absorption adds to heat stress in Florida’s sun. They can always dive into the water to cool, or, especially when incubating eggs on nests, they flutter (~500 flutters/min) their gular (throat) skin to bring air over mucous membranes of their mouth and esophagus to find relief. After fishing, cormorants climb on a nearby spot to spread their wings to dry, not because it is too hot, but because theyhave to dry their wings to fly with less weight. Their fishing cousin, the Anhinga, does likewise.  We can readily distinguish the species by their bills: hooked vs. spear-like, and by their tails and necks: short vs. long.

Juanita Baker, Coordinator
Florida Bird Photo of the Month
Pelican Island Audubon Society

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