Sunday, August 17, 2014

Some Chocolate Goodness For an ID Challenge

Last Sunday I posted the following image to Birdtalk and UBIRD, Utah's two main listservs for birders. It was an invitation for subscribing birders to identify the species of the hawk since it is a type of hawk not often seen in Utah. I used the word "type" loosely. The species is actually very common from spring to early fall since these hawks breed in Utah. The color, however, is not so common. Dark morphs of this species make up less than 10% of their total population, but dark morphs of this species are a little more common in the US western states. I chose the image below because some tell-tale traits of the species are hidden behind the pole and beneath the tucked wings. The IDs that were presented to me in response to the invitation suggested dark morph Ferruginous Hawk, primarily because of how dark the bird was and what looked like a large yellow gape. Many birders know that the gape of a Ferruginous Hawk is larger than other hawks and usually a bright yellow. Was that the right answer?

Here's another view of the same bird. She successfully raised a single chick in a nest I located in Lehi, Utah. I studied and photographed her and her mate and then their chick several times after discovering their nest site. Two new clues are shared in the image below. While the gape is yellow and seems long as you'd expect for a Ferruginous Hawk, the legs (tarsi) are missing the feathers that grow all the way down to the feet on a Ferruginous Hawk. Also, the primary feathers of the wings can be seen extending beyond the tip of the tail. Juvenile Ferruginous Hawks have tails that are noticeably longer than the tips of their wings when they are perched. Adult Ferruginous Hawks have tails shorter than their juveniles, but they are still slightly longer than the tips of their wings when perched. That is not the case with our current hawk.

The next two images show the tail and under wings of the bird. It is easier to tell now that this is an adult Swainson's Hawk. She was the most beautiful Swainson's Hawk I'd seen until this past Saturday

Dark Female Swainson's Hawk in Lehi, UT
Dark Female Swainson's Hawk in Lehi, UT
A friend and I were on our way home from an early check for fall migrants on the south end of Utah lake Saturday when I spotted two Swainson's Hawks perched in a tree near the Spanish Fork River in Lakeshore. The larger of the two was facing away from us as we approached. The smaller one, a male, was facing toward us. He had a rather familiar looking plumage. As we passed the tree with the larger bird to our driver's side I could see that it had a very dark chest and belly. I told my friend I was going to stop because that was a beautiful dark hawk. I'm a sucker for raptors, especially the chocolate ones. We passed the hawk to a safe turning point and then stopped the truck so my friend could take over the driving. I took a position in the bed of the truck behind the cab so the truck would become a moving blind. The hawk allowed us to photograph it for a few minutes before it moved to another branch and then eventually flew off to perch on a power pole.

Dark Female Swainson's Hawk in Lakeshore, UT
Dark Female Swainson's Hawk in Lakeshore, UT
That was what I refer to as some real chocolate goodness. I really enjoy observing and photographing dark-morph Red-tailed, Swainson's, and Ferruginous Hawks, especially when they have a smooth chocolate color.

Below is an image of the smaller mate of yesterday's beautiful dark female. Adult males often show gray, rather than a brown/chestnut color in their cheeks. That trait is visible in the image below. Size is usually difficult to assess unless you see two birds perched in close proximity, but yesterday's dark female was noticeably larger than her mate.

Male Swainson's Hawk in Lakeshore, UT
I've enjoyed seeing two truly dark Swainson's Hawks in recent weeks. These hawks are on the move now toward South America. Most Swainson's Hawks will have left Utah by the middle of September so the next few weeks will be the last weeks for locating them in Utah until they return for the next breeding season around the middle of April.


  1. great series of photos and quiz Jeff!

    1. Thanks, Dickson. I'm glad you enjoyed the quiz and the post.