EPOW - Ecology Picture of the Week

The Eagle with the Long Crest

Long-crested Eagle (Lophaetus occipitalis), Family Accipitridae
Kenya, Africa

Explanation:  Sporting a fairly unique feathered crest is this Long-crested Eagle that appeared briefly on perch at Serena Mountain Lodge on the slopes of Mt. Kenya in eastern equatorial Africa.  

Long-crested Eagles occur widely in sub-Saharan Africa.  They often perch alone on prominent locations where they can survey the area.  They call with high screams while in flight, and feed on rodents and other small mammals.

But oh, that crest! 

Yet, this is not at all the only raptor with a crest.  Also displaying crests to varying degree are Crested Goshawks, Crested Serpent Eagles, and Crested Hawk-eagles of Asia, Southern Crested Caracaras of South America, and others.  

And many more non-raptorial bird species have evolved crests, as well ... such as Crested Barbets, Gray-crested Helmet-shrikes, and Crested Guineafowl of Africa, White-crested Elaenias of South America, Sulphur-crested Cockatoos and Crested Pigeons of Australia, Crested Kingfishers of Asia, Great Crested Grebes of Australasia, Stellar's Jays of North America, and many others.

It is interesting to note how crests have appeared in so many bird species.  

What is the purpose of the crest?  It may be to signal species identity, territorial ownership, or breeding prowess.  

That some dinosaurs also sported crests -- at least of the bony kind (did any also sport some feather-like attachment?) -- and that birds might be descendants of dinosaurs ... is an intriguing correlation, which may or may not itself signal an evolutionary relationship.  Probably, though, it is more a case of convergent evolution, here the same adaptation has developed in different evolutionary lines to serve generally similar functions.