Ever notice how similar in appearance adult female and juvenile Rough-legged Hawks are to each other? Check out the 2 pics below, can you tell which is the juvenile and which is the adult? There are several tip-offs, so if you notice them please say why in the comments so everyone can learn. By the way, that is the only reason I do this blog -- to teach and hear other's thoughts, it makes it all worth it! And thanks for the pics Vic.
Top bird is an adult female, bottom is a juvenile. Tip offs for me are the dark eye and clearly marked dark terminal markings on the under tail for the adult. Juvi has pale eye and more smudgy under tail. Chest and head on juvis seems to more often have that buff wash to it, and more clean white background on adult females.
The second bird has an unstreaked patch below the throat, a buffy throat and chest, blurred tail bands, and a whiter crown. So it is a juvenile light morph. The first bird has a white, uniformly streaked throat and chest and a dark band. It is a female light morph.
The first bird is a light morph female because it is uniformly white on the throat, chest, and tail. It is also uniformly streaked on the throat and chest and the tail band is dark. The second bird is a light morph juvenile because it is mostly buffy with a blurred tail band, lighter crown, and an unstreaked patch beneath the throat.
As a person who almost never gets to see these hawks because of where I live (NE Ohio), I was going to say that the eye color, and undertail feathers and bands were probably the traits that differentiate the two birds. I know that eye color and tail feather patterns change in other hawks as they mature. I have seen a young Cooper's hawk with blue eyes. And, I know red tails don't start out with red tails.
What a beautiful bird. The raptor of the arctic tundra. The bird that is synonymous with long, cold, freezing winter days and nights. That puffy dark blob perched on a tree at a distance and the one hovering with slightly longer wings than other raptors.
That adult is spectacular. The fluffy super white of the under-tail coverts and the white on the head is almost a strong silver. Those large, dark chocolate eyes gazing at something far away and the contrast of the yellow fleshy cere and lips with the (smaller than usual) marble colored beak is perfect.
Juvy......a bit boring by the adult's standards but still very pretty and you can see on that bird exactly how it gets its name. Jerry, very cool that you were able to get two photos of almost the same exact posture.
Ken, I've seen some photos of a blue-eyed juvy coops too. Really amazing to say the least. Here's the link http://www.flickr.com/photos/jim_mcculloch/5819634849/in/photostream/
Hi Hatem -- getting all poetic! Actually the photos are Vic Berardi's. I feel like only using my photos is a bit odd when others have great photos too...I like sharing everyone's photos!
Jerry - I even kept it at a minimum, my friend! :)
Sorry, I did know they were Vic's photos I just meant finding two of almost the same posture was pretty cool and sorry Mr Vic didn't mean to credit Jerry and not you for the photos!
BTW, has there ever been any published material or researched data on why this particular buteo's beak is smaller than the majority (if not all) of the other buteos, at least NA ones? Typically we've known the shape of beaks to be some sort of dietary adaptation such as the one on the snail kite and turkey vultures and fish eagles etc. But this bird feeds on the main items most buteos feed on and so the smaller beak seems really odd. Is it possibly climate related?
Hatem - That is the thought, that it is climate related, and I believe it to be true. Red-tails from the north tend to have smaller feet and bills as well.
16 Comments:
Top bird is an adult female, bottom is a juvenile. Tip offs for me are the dark eye and clearly marked dark terminal markings on the under tail for the adult. Juvi has pale eye and more smudgy under tail. Chest and head on juvis seems to more often have that buff wash to it, and more clean white background on adult females.
Great photos Vic!
The second bird has an unstreaked patch below the throat, a buffy throat and chest, blurred tail bands, and a whiter crown. So it is a juvenile light morph. The first bird has a white, uniformly streaked throat and chest and a dark band. It is a female light morph.
The first bird is a light morph female because it is uniformly white on the throat, chest, and tail. It is also uniformly streaked on the throat and chest and the tail band is dark. The second bird is a light morph juvenile because it is mostly buffy with a blurred tail band, lighter crown, and an unstreaked patch beneath the throat.
As a person who almost never gets to see these hawks because of where I live (NE Ohio), I was going to say that the eye color, and undertail feathers and bands were probably the traits that differentiate the two birds. I know that eye color and tail feather patterns change in other hawks as they mature. I have seen a young Cooper's hawk with blue eyes. And, I know red tails don't start out with red tails.
Ken Andrews
Maple Heights, Ohio
What a beautiful bird. The raptor of the arctic tundra. The bird that is synonymous with long, cold, freezing winter days and nights. That puffy dark blob perched on a tree at a distance and the one hovering with slightly longer wings than other raptors.
That adult is spectacular. The fluffy super white of the under-tail coverts and the white on the head is almost a strong silver. Those large, dark chocolate eyes gazing at something far away and the contrast of the yellow fleshy cere and lips with the (smaller than usual) marble colored beak is perfect.
Juvy......a bit boring by the adult's standards but still very pretty and you can see on that bird exactly how it gets its name. Jerry, very cool that you were able to get two photos of almost the same exact posture.
Ken, I've seen some photos of a blue-eyed juvy coops too. Really amazing to say the least. Here's the link http://www.flickr.com/photos/jim_mcculloch/5819634849/in/photostream/
Hi Hatem -- getting all poetic! Actually the photos are Vic Berardi's. I feel like only using my photos is a bit odd when others have great photos too...I like sharing everyone's photos!
Jerry - I even kept it at a minimum, my friend! :)
Sorry, I did know they were Vic's photos I just meant finding two of almost the same posture was pretty cool and sorry Mr Vic didn't mean to credit Jerry and not you for the photos!
BTW, has there ever been any published material or researched data on why this particular buteo's beak is smaller than the majority (if not all) of the other buteos, at least NA ones? Typically we've known the shape of beaks to be some sort of dietary adaptation such as the one on the snail kite and turkey vultures and fish eagles etc. But this bird feeds on the main items most buteos feed on and so the smaller beak seems really odd. Is it possibly climate related?
Hatem - That is the thought, that it is climate related, and I believe it to be true. Red-tails from the north tend to have smaller feet and bills as well.
Really?! That was just a shot in the dark! Very interesting tidbit about the northern red tails also. Thanks, Jerry.
Sure thing!
Interesting post and neat tidbit about the bill size in the comments.
Ron - I love when you find things interesting!
As always Jerry, a great post, and always something to learn from each and every one!
Also, thanks for using a couple of my pics!
Thank you Vic...and everyone knew which was which!!!
I learn so much from you Jerry.
Mia - that is very nice to hear!
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