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I feature images of Crested Caracaras from time to time — they’re my favorite desert bird species. At times, I’ve shown images of immature birds and at others adults. With this species there are pretty striking differences between young and older birds. Today, I’m posting an image that shows those differences.
The adult and immature bird are the same size — young Caracaras attain full size at about the time that they fledge and leave the nest. The bird on the left of the image is in its first year with predominately chestnut plumage on its back and a beige neck. The adult, on the right, has black plumage with a white neck.
Skin color also is different between young and mature Caracaras. The youngster has pale legs and the bare flesh between its beak and eye is pink. By contrast, the adult has yellow legs and its facial skin is deep orange.
The young Caracara’s plumage will gradually change with each successive molt. It will not acquire fully adult colors until it is more than three years old.
It’s unclear why some species of birds, including Crested Caracaras, manifest juvenile and adult plumage. Other species seem to get along fine without distinctive juvenile plumage, or they transition very quickly from juvenile to adult plumage. Perhaps the plumage differences and the slow change from juvenile to adult plumage is a way of denoting a Caracara’s sexual status and readiness to mate.
I can think of one other species that features a years-long transition from juvenile to adult plumage and that is the Bald Eagle. However, eagles and Caracaras are not closely related. That suggests that these slow transitions may be an ancient trait that ancestral birds manifested millions of years ago.
Image made with a Canon R5, Canon EF 400mm f4 DO II lens+Canon EF1.4x telextender, M setting (auto ISO), ISO 800, f5.6 @ 1/3200.
Sonoran Images 