The minutes of peaceful feeding usually end with the noisy arrival of a family of Blue Jays. They are molting in late August and every year one or two sorry-looking individuals show up bald - with few feathers, or may be just a stubble on their heads. Fortunately that's only a temporary state lasting about two weeks until the feathers have regrown.
Although adult, they often look immature because their large eyes are more characteristic of chicks:
Others have more reptilian features:
The naked heads remind us that their ancestors are dinosaurs, not mammals, and that their closest living relatives are the crocodiles. They usually reach maturity within 12 weeks, but retain the large eyes characteristics of juvenile dinosaurs.
In a study published in the journal Nature on 5/27/12 examining this curious fact the authors conclude that
"We have provided a powerful new example of how heterochronic changes, paedomorphic" (retaining juvenile characteristics) "and peramorphic" (early development of adult characteristics) "were crucial in the origin and evolution of birds. We further demonstrate that these changes were driven by an extreme degree of elaboration in vision-associated areas of the brain that parallels the olfactory elaboration of mammals, and possibly by the evolution of the face into a precision grasping mechanism as the hands were co-opted for flight."
There is a very readable illustrated summary of the study in ScienceDaily: Evolution of Birds Is Result of a Drastic Change in How Dinosaurs Developed
Look at the eye of a Pileated Woodpecker. I realize this is not scientific, but tell me you don't see the v-raptors in Jurassic Park.
ReplyDeleteThis comment has been removed by the author.
ReplyDeletehow lovely to have the birds right near to your back door (shame about the bears though). You shared some lovely photographs of another phase in their lives; they're still beautiful
ReplyDeleteInteresting stuff, Hilke! I agree, they do look like dinosaurs, but pretty pitiful in this state I think!
ReplyDeleteI really enjoyed this post, Hilke!
ReplyDeleteVery interesting post filled with great photographs of Blue Jays in their molting stage. Quite a sight those bald jays are! They really do look rather dinosaur-like!
ReplyDeleteInteresting info Hilke! The poor jays don't look so good in this state
ReplyDeletePoor little thing. Looking very sorry for himself.
ReplyDeleteI posted one last year. They are so incredible looking. Great shots. Boom & Gary of the Vermilon River, Canada.
ReplyDeleteThey sure do look different without their feathers!
ReplyDeleteI feel sorry for the birds with their naked heads. The jay looks almost sickly!
ReplyDeleteOur Blue Jays are finally back in full feathers. They can really look motley for a while!
ReplyDeleteGreat photos and very interesting to see birds moulting like that.
ReplyDeleteThey do look reptilian without those lovely feathers.
ReplyDeletePoor guys were not ready for picture day;')~
ReplyDeleteHi there - great pictures of a less than great looking birds. The evolution of birds is such an interesting topic.
ReplyDeleteThanks for linking to WBW
Stewart M - Australia
Beautiful colour on the birds.
ReplyDelete