Thursday, February 21, 2013


Juvenile Cooper's Hawk eating what might have been a Red-winged Blackbird(?)... 
(It's hard to tell at this point, especially with some Norway spruce twigs in the way.)
Note that it's wings are spread out to "mantle" (hide) it's prey.
- All photos and editorial content © Dave Spier -

What birds are visiting your feeders? Probably cardinals and jays and chickadees and juncos and doves and the usual winter mix that comes to partake of seeds and suet. What do all these birds have in common? They attract what many people consider uninvited guests -- the bird hawks, members of the genus Accipiter, a word that comes from the Latin verb meaning "to seize." I know one is around our yard when the feeder birds become very still or suddenly disappear. Hawks are a natural part of the web of life and they help keep everything in balance. I'd prefer they catch starlings and house sparrows, but it seldom seems to work that way.

In much of the United States, from Washington to Iowa to Massachusetts and south, there are two Accipiter species likely to visit your yard in winter, the Sharp-shinned (Accipiter striatus) and the Cooper's Hawk (A. cooperii), but they are difficult at best to separate. Male Sharp-shinned Hawks are about 11 inches long, roughly the size of a blue jay. Like most hawks, the females are significantly larger. Female sharpie's are 14 inches long, about the size of a pigeon, but slimmer. Here's the problem. Male Cooper's Hawks are about the same size as female sharpie's and maybe an inch longer. The larger female Cooper's is approximately the size of a crow.

An adult Sharp-shinned Hawk eating what might have been a Mourning Dove 
(judging by the color of the feathers on the snow after the hawk left - but its hard to tell).

Plumages of our two bird hawks are virtually identical, making it that much harder to tell one from the other.  Juveniles of both are brown on top and streaked lengthwise underneath.  Juvenile Cooper's have thinner, darker, tear-drop-shaped streaks, but that is subjective and requires some experience for comparison. The juvenile's yellow eyes turn orange and then red as Accipiters mature.  Adults are gray or blue-gray on top, hence the nickname "blue darter."  The cap or crown is darker like charcoal, especially on Cooper's. (Sometimes a Cooper's Hawk will raise its hackles giving it a small crest.) Sharpie's have more of a hood, meaning the dark crown extends down the nape, wheras Cooper's have a lighter nape.

Underneath, adults of both species are light colored with rufous cross barring on the chest giving way to white under the tail.  At all ages, the tail is coarsely barred with dark bands. Under ideal conditions, subtle differences in the tail can be discerned. Sharp-shins have a square or notched tip on a slightly narrower tail. Cooper's tails are slightly wider or fanned with rounded ends due to the outer tail feathers being shorter than the inner ones (but molting could confuse the issue). A white tail tip is more noticeable on Cooper's, but this can be masked by feather wear. Cooper's have white bellies whereas sharpie's tend to have more smudged or "dirty" bellies (another subjective call).

juvie Cooper's again showing a slight crest and making the eye appear closer to the front
(by comparison, Sharpie's eyes appear larger and more centered on the head)

The third and largest member of the Accipiters, the Northern Goshawk (Accipiter gentilis) is a bird of Canada, the north woods and the Rockies. The name "goshawk" comes from the Old English word goshafoc, meaning "goose hawk." I have no photos of this species, but a distinguishing characteristic is a light line (called a supercilium) above the eye. This line is white in adults and it contrasts with a dark line through the eye. Adults are also gray on the back and light gray on the belly, but never rufous like the smaller bird-hawk adults. Juvenile goshawks are brown and streaky and have pale-tipped greater coverts overlapping the inner (secondary) wing flight feathers.

All of these raptors have relatively short wings for maneuvering between woodland trees. The small sharp-shin can even adeptly chase prey through bushes. I watched as one hunted chickadees. It was an aerial acrobat making contorted maneuvers, weaving and diving through the sumac and other shrubs in hot pursuit of black-caps. Accipiters have long tails to aid in sudden, sharp turns. Although small birds are the staple diet of our Accipiters, they will take other prey. Sharpie's will take mammals up to Red Squirrel size; Cooper's up to Gray Squirrel.

adult Sharp-shin again, showing square corners on the tail and a small, rounded head
with the crown extending down the back of the head and forming a "hood"

Mouse- and insect-eating hawks like the kestrel and redtail perch in the open and watch the ground for signs of motion.  Accipiters prefer to hide in a tree or bush while they eye your feeder.  When they attack, their flight is swift and low.  From the side, sharp-shins appear "neckless;" they keep their heads pulled in and wings pushed forward, compressing their short necks.  Overhead, this gives them a "T" shape.  Cooper's have  longer necks and larger heads, and overhead have the appearance of a cross.  During migration, sharpie's will intersperse bursts of rapid flapping with glides and they may circle briefly if they encounter a thermal (an updraft).  Cooper's flight is more direct and determined.

To the birds at your feeder, it makes no difference what species is chasing them. It's strictly a matter of life or death. The faster birds survive; the slower stragglers (read "old, sick or injured") don't. Remember the old saying, "Survival of the fittest?" If you want to help your seed eaters survive, locate your feeder(s) close to escape cover. The denser the better... Discarded Christmas trees can be staked next to the feeder and also serve as a wind break. (You also might consider placing a baffle or skirt around the bottom of the tree to prevent cats from hiding underneath.) In my younger days, when I had fewer back problems, we bought a live Christmas tree every year and planted it in the spring. Some of those trees are pretty big now and several of our feeders hang from the inner branches. If your zoning regulations permit, a loose brush pile also provides escape cover and winter storm protection for birds and small mammals. At least the House Sparrows will appreciate it and roost there overnight. Our Carolina Wren also uses the brush pile -- when it's not in the thicket across the road.

Okay, look out the window again at your feeder. Now, what do you see?

For more information, photos and sounds, visit the All About Birds website and type in the species of interest. An interactive range map (zoomable to your location) can be found in the eBird Explore Data section. Again, type in the species.

Corrections, comments and questions are always welcome at or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out

Monday, February 11, 2013


© Dave Spier

The Merlin (Falco columbarius) was once known as the Pigeon Hawk, a strong indication of its diet, even though it's about the same size as a pigeon. Unfortunately it also captures and consumes smaller birds. The Merlin is a very fast flier, nicknamed the "bullet bird," and intermediate in speed between the slightly-smaller kestrel and the larger Peregrine. Like all falcons, the wing tips are usually pointed. Accipiters fly with rounded wings. The Merlin somewhat resembles the Peregrine in appearance but without the bold facial pattern. The adult male Merlin is gray on the back, streaked on the front, and has a weakly-barred, dark tail and a thin, white stripe above the eye. Females and juveniles are dark-brown on the back, streaked underneath and often have more white on the throat, while males are buff or light brown underneath. Some individuals show a dark tail with narrow, whitish bands.

Perched juvenile Merlins can sometimes be misidentified as a juvie Accipiter. Get a photo if at all possible. When I was at the Audubon Center, we had such a case, but in the photo, a small detail in the shape of the bill was the key. Falcons have a notch in the upper mandible toward the tip; it's used to break the neck of its prey as I recall. The notch is often hard to see, though.

Merlins nest at higher elevations, primarily in areas like the Adirondacks, and then disperse and wander after the breeding season. They also breed across most of sub-arctic Canada and Alaska in the Boreal Forest zone and the northern prairies. They prefer open woods and edges. Unlike kestrels which lay their eggs inside tree cavities or nest boxes, Merlins take over nests of other raptors or crows in the open tree tops.

During migration they can turn up anywhere in the continental United States, and most Merlins spend the winter from coastal Alaska down through the western states to the Gulf coast and northern South America according to one range map. Other maps include the Great Plains in its winter range. I'm writing this now because I just had a Merlin on top of a conifer (last two photos) in the northern part of the Finger Lakes region of New York. (This is not the first winter I've seen them around this area.) They prefer open woodland, but can be found in grasslands, fields, marshes and seacoasts.

For more information, photos and sounds, visit the All About Birds website. An interactive range map (zoomable to your location) can be found in the eBird Explore Data section.

Corrections, comments and questions are always welcome at or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist.

Saturday, February 2, 2013

Tree Sparrows

They migrate across southern Canada and winter in the colder portions of the lower 48 from Washington to Maine and south as far as Oklahoma. Contrary to their name, you're just as likely to find them in some bushes or feeding on the ground with the juncos. Their natural food is fallen weed seeds picked off the snow. If the snow grows deeper, they will cling to the taller plants while they pluck the seeds. In the winter they obtain water by eating snow.

Tree sparrows do not defend winter territories, but they do form dominance hierarchies and they sometimes spend the night as a group under the snow to escape bitter cold wind. Otherwise they individually roost in conifers or marshes.

tree sparrow at the Montezuma Audubon Center, Savannah, NY

In April they will head north to breed in the Arctic, generally above the tree line. They even nest on the ground, albeit in open, scrubby areas with alder thickets, dwarf willows, birches and stunted spruce. During the short summer, they eat primarily insects and spiders instead of seeds. For a bird that spends so much of its time on the ground, why would it be named "tree sparrow"? I have yet to find a good reason, but I often see them perched in trees or bushes. I suspect that early ornithologists first encountered this species sitting on tree branches.

Not quite as drab as some sparrow species, the American Tree Sparrow (Spizella arborea) sports a rusty cap, chestnut line behind the eye, some rufous on the shoulders and sides, an isolated dark spot on a gray breast, and a white wing bar. (At close range, you might notice part of a second wing bar.) One of this sparrow's distinctive field marks is a bicolored bill, dark on top and yellow on the lower mandible. This species' back is light brown with dark streaks, and the long, notched tail has dark-gray feathers with pale edges. Males and females are nearly identical and juveniles are similar but more streaked.

Tree sparrows are preyed on by Accipiters, kestrels, screech owls, weasels, foxes and even Red Squirrels. The average life expectancy is two to three years, but one tree sparrow was recorded as surviving 10 years and nine months.

For more information, photos, similar species and typical voice sounds, visit All About Birds. eBird provides an interactive range map of this strictly North American species (zoomable to your location).

Corrections, comments and questions are always welcome at or connect through my Facebook page and photo page. There's also a community-type page for The Northeast Naturalist. Other nature and geology topics can be found on the parallel blogs Adirondack Naturalist and Heading Out.