Yesterday I photographed a white-morph Gyrfalcon in Salt Lake City...yes, Salt Lake City, where Gyrfalcon is a rare bird! Not only that, but white-morphs are especially uncommon (as well as true dark-morphs), but the catch is that this bird was an escapee falconry bird. Oh well, however, the bird was still very enjoyable to see up close and watch in flight. It flew around a few times crossing over fairways (did I mention it was on a golf course?) and it was a sight to see regardless. Everything else about it besides being captive was pure GYR! And, being on a golf course gave me an itch to get out and hit a few balls. Here are some pics ('click' to enlarge) I got where the jesses on the legs were hidden. I did take many more photos with the jesses visible, and even though some are full frame and beautiful, I don't really find them desireable. And, if anyone is willing to take a stab at the age of the bird, go for it -- white ones can be tricky, but not with views like this.

It is known that adult Harlan's Red-tails often have unbanded, mottled, or a mix of unbanded/banded remiges (primaries and secondaries), but of course there are exceptions to EVERY rule. Here are a few Red-tails that show varying degrees of banding to the remiges. The first 3 are adult Eastern Red-tails (the 2nd bird shows several Krider's traits). The 4th bird is a juvenile Western that also had a tail pattern simlar to the remiges (broken bands that create a mottled effect). The last 2 are adult Harlan's for comparison. Just thought I'd show these for future reference...I have a bunch of examples from my own collection, but it is valuable to show that others are documenting this stuff too. Collaboration is important!

Just thought I'd post a few "brown" (adult female or juvenile) Prairie Merlins for anyone to reference. The first 4 images are Prairie Merlins, the rest are Taiga Merlins for comparison. No explanation needed, basically, the Prairie Merlins are pale compared to Taiga.

Brian Sullivan and I just submitted an article to be printed in North American Birds on the "Northern" Red-tailed Hawk, referred to as B.j. abieticola, also referred to as "Canadian" Red-tailed Hawk. This is the heavily marked borealis type that often gets confused for Western Red-tailed Hawks reported in the eastern half of the U.S. in winter. Keep an eye out for these types….

What is abieticola? Well, Jon Ruddy from Ontario just did a piece on this taxon for eBird regarding the variants he sees in his neck of the woods, and it should be up on the site soon. Today, abieticola is thought of as a form of the Eastern Red-tailed Hawk (B.j. borealis), but not enough is known about it to say either way if it is a separate subspecies, as some have proposed in the past. It does inhabit a wide-ranging but specific area, and can be told from "southern" borealis (or what we think of as typical lightly marked borealis), but there is much overlap in the plumages of the two types, and they interbreed in southern Canada and the very northeastern half of the US. The purpose of our article is to bring some attention to the subject and get birders to document and take a second look at Red-tails in general. The article shows over 20 different individuals and gives a sense of the plumage variation within this type, so hope people see it.

Here are some "Northern" Red-tails, but the variation is extensive and shown in the print article:

Kevin Hood and I started a site where people can share photos and information about Red-tailed Hawks in the British Columbia area. We are particularly interested in seeing what kind of variation in plumage we might find since the area is very understudied and relatively a mystery. Please pass this note on to anyone you might think is interested, and here is the link for anyone who wants to check it out. We just made the blog active today.

http://bcredtails.wordpress.com/

I love when people share photos with me because there is so much to see out there; the plumage variation is endless for some species. I also get excited when I see birds like the one below in my inbox! My first thought as I saw this image ('click' to enlarge) was "could this be another hybrid buteo?" So I opened the image to full size for a closer look. This bird was photographed by Jill Smith in Prowers County, CO and she was happily willing to let me post it on the blog (thanks Jill). She had sent the photos to Christian Nunes originally, who thought I'd like to see them (thanks Christian).

So is this bird a hybrid? Well, I don't pull the hybrid card quickly, I like to rule out any odd variation of one species first. But, if a bird clearly shows traits of two species and is beyond the plumage of a single species, I feel safer call that bird a hybrid. And confirmed mixed pairs and hybrids are being found in greater numbers than ever now with the amount of photographers out there these days!
 
Let me hear your thoughts on this bird...

Does that title capture any attention? Well, I've been looking at ways to sex adult Red-tailed Hawks by plumage since the late 1980's, and guess what....YOU CAN'T! I checked thousands of adult Red-tails from the East and West and came up with some differences, but they don't hold enough water to make even a half-definitive statement about sexing -- did I waste all that time or what? What I found I will share anyway for fun. One thing to remember, when you have a bird in-hand, size is evident, so if tail patterns match with the smallest or largest individuals, it lacks great significance anway, but if it's a bird in flight or a bird in a photo, it could be fun to notice tail patterns. 

I looked at the width of the sub-terminal tail band on adult Red-tails as well as the darkness to the red color and found that the smallest Red-tails (ones that take 7A bands and weighed under 900 gms healthy) tended to have broader sub-terminal bands and darker reddish tails than "large" Red-tails (weighing over 1200 gms and requiring 7D bands). The real issue (besides overlap in these traits) is that most Red-tails fall between these measurements and show a sub-terminal band intermediate in width! Another issue arises when comparing light-morph to dark-morph birds, birds from different geographic locations, or factors that could effect tail color (fading, etc.).

By the way, there is overlap in the sub-terminal tail band width of adult male and female Swainson's Hawks as well, so do not use that trait on its own to sex Swainson's Hawks, especially when sexing dark-morph birds! I should also mention that there is a paper on sexing Western Red-tailed Hawks using a combination of measurements authored by Kara Donohue that you can download here:

http://onlinelibrary.wiley.com/doi/10.1111/j.1557-9263.2006.00003.x/abstract

 Presumed male Eastern

 Presumed male Western

 Presumed female Eastern

  Presumed female Eastern

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.