Wednesday, February 8, 2012

Reddish Egret

Reddish Egrets are found along our Gulf Coast states. Nearly brought to extinction by plume hunters in the 1800s, this egret is still relatively uncommon. Only about 2000 pairs inhabit the United States (Lowther and Paul 2002). Others are found in Mexico and the Caribbean.

As you can see in these photos, this egret is dimorphic--it comes in dark and white morphs. Most birds in our country are dark, like in the first photo, taken in Lovers Key State Park on the Florida Gulf coast. Only rarely are white morphs found in the United States, like the one below from Ding Darling National Wildlife Refuge on Sanibel Island, Florida. Curiously, in the Bahamas and Greater Antilles, white birds are more common than dark ones. A couple of other of our egrets and herons display dark and white morphs. The reasons for these difference are not understood. Presumably the colors confer advantages to each type of bird under different environmental conditions.

In any event, as they feed, Reddish Egrets flamboyantly dance with their wings held out. Probably this behavior startles the small fish upon which they feed. Other herons hold out their wings, casting shadows that are attractive to small fish--something similar may be happening here. Finally, casting shadows may help the egret find minnows by reducing the sun's glare off the water.

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