Wednesday, May 4, 2011

Leucistic Red-tailed Hawk

While the writing and posting here at the ol' PicusBlog has been slow lately, the birding (thankfully) hasn't been.  Spring is now in full swing here in eastern Massachusetts, with a lot of early migrants lighting up the list-servs like so many colorful christmas tree lights.  Warblers that we don't expect to see for a few more weeks are already being seen in many places, and I hope to have lots of posts over the next few weeks of birds seen and photographed.

BUT, I simply could not let this go more than 24 hours without posting.  Yesterday afternoon I finally caught up with an individual bird that I've been hoping to see for some time now, and was lucky to even get off a few photos. I've seen reports of a leucisitc Red-tailed Hawk posted in our area occasionally over the last few years - usually somebody who has seen the bird soaring just out of sight as they are cruising down Rt 95/128.  Not too long ago, I received a tip that a large white bird had been seen somewhat regularly near a small swampy area in an office park a few miles down the road from where I work.  I figured it HAD to be this same bird. Interestingly, this is a location I visited a lot in the last two years as I can usually see Eastern Kingbirds, Tree Swallows, Kingfishers, Great Blue and Green Heron, as well as a number of dragonflies.  So I've started going back in the last two weeks when I have some time after work or if I was able to get away from the office for an hour.  And I finally saw her yesterday.  I'll definitely be heading back more hoping to get better photos - hopefully a bit closer (pics are pretty heavily cropped) and in better light, but for now, I really wanted to share these.  I hope you like them!

I've been asked already a few questions from Facebook friends and family about this bird (easy to post to FB right away).  Questions like - how do you know it's a Red-tailed Hawk, how do you know it is female, and what does leucistic mean?  Even draining away the typical color on a Red-tailed Hawk, once you've seen a large number of them (and honestly, I see them easily over 300 days a year while traveling the highways of the area), you can pretty quickly ID them by size and shape.  In the raptor world where this is sometimes little to no sexual dimorphism (i.e. males and females look the same), and particularly in hawks and falcons, the females are bigger than the males, and this particular bird struck me as quite big and bulky, so I am presuming a female.  And finally, what is leucism (and why isn't this an albino)?  To answer that I go to Cornell Lab of Ornithology for a more scientific explanation (click the lin kfor a fuller explanation and examples.) My non-scientific summary of this is that both leucism and albinism are genetic mutations that affect the way an individual bird looks.  In albinism, the mutation prevents the production of melanin (which is needed to create the darker colored feathers in the bird) and these individuals show pink in bare skin areas like legs and usually have light or pink eyes.  In leucistic birds, the melanin is produced but the mutation prevents it from being deposited properly in the feathers. Therefore, sometimes you get "partially leucistic" birds that might have white patches, or birds that are almost all white as with the hawk above, or anywhere in between where the bird looks pale or "bleached."