November Quiz: Answer

To refresh your memory, here is the photo from November’s Bird Quiz. It was taken in Colorado during the month of January. Don’t read any further if you want one last chance to identify this bird.

11 November_Hawk Trip-ElPasoCo-CO_LAH_3239-001

Most people will recognize this bird as a raptor—a carnivore that captures and eats prey. It’s clearly not an owl, so the logical place to start is with the diurnal (daytime) birds of prey.

Happily, all the various sorts of hawks, eagles, falcons, and the like are grouped into one part of the field guide, making our search much easier. But before we get around to searching through the pages for a look-alike bird, let’s be sure we’ve taken a good look at our subject.

When identifying raptors, our instinct is to start with size. After all, eagles are huge, most hawks are large, and falcons and accipiters (bird-eating birds such as a Sharp-shinned Hawk) are much smaller. However, if the bird in question is soaring overhead, it’s very difficult to determine relative size. A close-flying kestrel can appear to be the same size as a high-flying DC10 jet!

In this case, however, our bird is conveniently sitting on an electrical support pole. We have a general idea of how big those are, so we have something for comparison. Conclusion? This is a pretty large bird.

Next is to determine which kind of raptor we have. It’s not an accipiter—it’s much too big. For the same reason, it’s not a falcon either—but let’s not rule either of these out quite yet. Imagine that our bird was in mid-air. How can we know it’s not a falcon or accipiter if we can’t determine its size?

Falcons are pretty easy to ID in silhouette because of their general outline. Their wings are long and pointed (as befits an athletic flyer, but not a bird that soars), and they have a fast wing beat. Kestrels, the smallest North American falcon, often sit on wires, so we can get a good look at the dark “helmet” markings on their head.

Accipiters have proportionately short wings and long tails. They prefer wooded habitats where their short wings make it easier to pursue prey through dense forest.

That leaves us with the other raptors commonly found in Colorado: two eagles, the Northern Harrier, and four members of the genus Buteo (what we commonly think of as hawks). Of course, it could be a stray bird from elsewhere, but we don’t need to consider those until we’ve eliminated the likely suspects.

Let’s start with the eagles. This bird is not a Bald Eagle—everyone recognizes those.  Golden Eagles are uniformly dark brown with golden brown heads. Besides, they’re huge, and this bird is large and solid but not that big.

Is it a Harrier? The Northern Harrier (formerly known as a Marsh Hawk) hunts by soaring up and down a marsh or flat field. They listen for their prey much in the same way that owls do. Not surprisingly, their head feathers form an owl-like facial disk, which magnifies sound and directs it to the ear holes. Imagine an owl’s head on a hawk’s body. Our bird doesn’t look like an owl.

Colorado has four Buteo species: Red-tailed, Rough-legged, Swainson’s, and Ferruginous Hawks. Odds are our bird is one of these. There is a relatively easy way to distinguish sitting Buteos, based on their patterns of light and dark feathers. While the plumage of all these hawks can be overall light or dark, the same pattern holds within each species:

  • Red-tailed Hawks: Dark, light, dark. The head is dark. The upper chest is lighter. They have a “cumberbund” that’s darker. This pattern is easier to see on some birds than others, but they all follow the general rule. The red tail helps, but juveniles lack that salient feature. Most hawks you see will be Red-tails.
  • Rough-legged Hawks: Light, light, dark. They’re similar to a Red-tail but have a light head. So… light head, light chest, dark stomach. Also, they’re only in Colorado in the wintertime.
  • Swainson’s Hawks: Dark, dark, light. Their head is dark on top. They have a dark neck band similar in placement to the colors on a PhD’s graduation robes. And their stomach is light. These hawks are here only in the summer, migrating to Argentina for the winter. These are petite hawks.
  • Ferruginous Hawks: Light, light, light. Light feathers everywhere on the front of the body. They may have a dark or rusty back, and their legs are a rusty red-brown (hence their name); they look like they’re wearing rusty legging. Their legs appear as a reddish V on flying birds. Ferruginous Hawks sometimes have a rusty tail that makes you think they’re a Red-tail. These are massive birds. They sometimes tuck their heads, giving them a flat-topped appearance.

Go back and look at our bird. The head is silhouetted, so it’s hard to tell if it’s light or dark. However, it does appear flattened. The chest and belly are definitely light. We can’t see the tail. The legs appear whitish as well, but again, it’s hard to see. What do you think? Yes, it’s a Ferruginous Hawk. Here it is the same bird in flight, showing those rusty legs:

11 Ferruginous Hawk_SE-CO_20100414_LAH_2332.nefFerruginous Hawk_E ElPasoCo-CO_LAH_2009

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