Making Sense of Hawks

We started our hawkwatch Saturday, and we've had a few things to look at so far. (The first couple of weeks are always rather slow -- if you want to be sure that you're catching the entire migration, you've got to put up with some slow days.)

This beauty came by last Sunday:

He's an immature Red-tailed Hawk (Buteo jamaicensis). He didn't appear to be migrating, though, which isn't surprising. We know they nest in the park where we count.
On Monday, this lovely lady took a look at our site:

This is a female American Kestrel (Falco sparverius). She had caught something, possibly a grasshopper, and we watched her eat on the wing as she went by.

The Kestrel is, as the Latin name suggests, a falcon, in the family Falconidae and the order Falconiformes. She's got a strongly hooked, sharply pointed bill, strong feet with large pointed claws, and long, sharply pointed wings to enable her to fly very fast and maneuver very efficiently. The hawk is in the family Accipitridae (Accipiter simply means hawk in Latin). While the wings aren't sharply pointed, the bill and feet are very similar, and the wings are still long enough to allow for impressive flying abilities. Both families also specialize in eating not only other animals, but frequently other chordates. It's probably not a surprise that traditionally, then, the Accipitridae has been included in the Falconiformes.

What may be a surprise, though, is that they are no longer placed there. In fact, Accipitridae is now in the order Accipitriformes (formed when they were removed from Falconiformes). What's probably more of a surprise is that the Accipitriformes are now considered to be the sister group to a clade of owls, trogons, hornbills, kingfishers, and woodpeckers, while the Falconiformes are seen as the sister group of a clade composed of songbirds and parrots.

And what should we make of this guy:

This is a Turkey Vulture (Cathartes aura), in the family Cathartidae. The family is strictly New World, with 7 species, 3 of which are found in North America. (There are a few finds that suggest they were more widespread in the Pleistocene.) He has a nicely hooked bill, but the feet aren't nearly as strong, and while he's also a chordate eater, he very rarely kills for a meal. Vultures are patient critters that wait for animals to die on their own before they dine.

Historically, they have been placed in the Falconiformes. Before that order was split, though, the Cathartidae were moved into the Ciconiiformes, with a number of authors arguing that they were actually similar to storks. (This discussion only applies to the Cathartidae -- Old World vultures have always, to my knowledge, been included in the Accipitridae.) Some authors subsequently have placed them in an order all their own, Cathartiformes, while others have actually argued for a label of incertae sedis (aka "we have no idea what these things really are!"). The same large-scale analysis that led to the Accipitriformes, though, supported placing the Cathartidae back with the hawks, and at the moment, the AOU checklist has them in Accipitriformes with the hawks, eagles, kites, and Secretary Bird.

Through it all, we've been faithfully counting all of them, and we'll of course continue to do so. Knowing about the evolutionary history is wonderful, but keeping them around is a pretty important goal as well, and we hope that keeping track of them is a small part of that. With luck, I'll never have to try to communicate the thrill that we used to get watching them sail past.

Oh, and just because, here's a King Vulture (Sarcoramphus papa) from the St. Louis Zoo: