Story in the Snow

[scanned Kodachrome II slide]

A Story in the Snow

© Dave Spier

Birder's journal March 21, 1971: I was following the redtail along the ridge, not so much to get a photo of it as we were both heading in roughly the same direction. I was a minute or two behind the hawk when I exited the woods and entered a partly-scrubby opening on the north end of the drumlin. More by luck than anything else, I came upon the story written as clearly as if words had been used. The mouse tracks ended in a depression, surrounded by the hawk's wing and tail feathers imprinted on the surface as it lifted into the air, prey in tow, while a drop of blood on the snow was all that remained of the hapless creature.

This could have been written a week ago; we've had no shortage of snow and cold weather this winter. There is a timeless element to many of nature's stories. It's likely a story that has been written over and over again across the intervening years.

immature Red-tailed Hawk (note barred tail)

 

For more information on Red-tailed Hawks, 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 ebirder_14432@yahoo.com 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, Heading Out, and a Naturalist's Viewpoint. 

Accipiters

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 northeastnaturalist@yahoo.com 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. 

Kingfishers

© Dave Spier

 

There are two requirements for finding kingfishers in winter: open water and an overhanging perch, usually a tree branch. The bird's main diet is small fish retrieved by diving into the water. In warmer weather, crayfish are on the menu.

The Belted Kingfisher, Megaceryle alcyon, appears big-headed, but it's due mostly to feathers that fan into a double crest. The color is bluish-gray like its back, wing tops, and a wide "necklace." In contrast there is a white collar, belly and underwings. Females have an additional tan belly-band and flanks (sides), which might add a touch of camouflage. The kingfisher's bill is heron-like, possibly the result of convergent evolution resulting from the same prey items.

Unless you're anticipating a kingfisher, chances are your first clue to its presence is the loud "rattling" call as it flies away. You can listen to a recording of this sound on the All About Birds website, which also has a range map and information on behavior, habitats and summer nesting. (Kingfishers dig a tunnel into sand banks or muddy stream banks to hide their nest. The deepest can be eight feet long.)

The interactive eBird range map indicates that Belted Kingfishers have been recorded in all 50 states plus much of Canada, Mexico, Central America and the Caribbean. Nearly a hundred other kingfisher species are found in mainly tropical regions around the world.

_____________________ 

Corrections, comments and questions are always welcome at northeastnaturalist@yahoo.com 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.

 

Kestrels

American Kestrels (revised with new links and photos)

© Dave Spier

They're easiest to see when they sit on power lines and watch the grass below. In the absence of these utility perches, they may simply turn into the wind and hover on beating wings. Oil droplets coating the bird's eyes filter out haze and glare. Retinas, each packed with a million light-collecting cells, give it vision eight times better than a human's. Theoretically they could see a mouse from the top of the Empire State Building. After prey is spotted, the hawk drops like a stone and reaches out with needle-sharp talons. I've also heard of them gliding downhill and grabbing a mouse running across the snow, a most foolish thing for rodents to do. This maneuver caught the attention of two crows which gave chase, causing the kestrel to drop its prey. Undaunted, the hawk circled back and retrieved its fallen victim.

The American Kestrel, Falco sparverius, was once known as the sparrow hawk, a name derived from its habit of eating small songbirds, but in reality these comprise only one-third of the hawk's winter diet. On an annual basis, mice and other small rodents, plus a few frogs and reptiles represent a much larger proportion of its intake. During warm weather it eats primarily insects, and late in summer the kestrel dines almost exclusively on juicy grasshoppers which are plentiful and easy to catch. This earned the bird the nickname "grasshopper hawk" from early ornithologists. Kestrels also eat crickets, cicadas, moths, beetles and ants. Small snakes are readily dispatched, but large snakes present a problem if they wrap themselves around the bird's legs. Small roadkills, and songbirds that fly into windows, are a source of easy meals.

Kestrels are the smallest members of the falcon family, a group that is no longer considered close relatives of the true hawks. Male kestrels are nine inches long while the larger females may reach 12 inches. On average they're about the size of a robin or blue jay which makes all these birds vulnerable to larger winged predators, especially Cooper's Hawks. On the other hand, kestrels will not tolerate competitors in their hunting territory and have been known to chase off larger, but less agile, raptors like the redtail. The falcon family also includes the kestrel's larger and more famous cousin, the Peregrine, which is uncommon in the northern Finger Lakes Region of New York.

If you're close enough, kestrels are easy to recognize. In addition to small size, on a white face look for bold black marks creating a "mustache" and "sideburns." Males have gray wings and rusty-red tails ending with a black band and white feather tips. Females are mostly rufous-brown with fine cross-barring on the back, wings and tail. The lighter undersides of both are spotted, giving way to white under the tail. The wings and tail are relatively long, much like the larger harriers which also hunt the open countryside. (Harriers, also displaying sexual plumage dimorphism, are in a different family.) Unlike harriers, falcons are noted for flying with pointed wingtips, an advantage for faster speed. Peregrine falcons, which can reach a diving speed of 200 mph, are the fastest animals on earth.

Kestrels are year-round residents throughout New York and most of the United States, and a summer breeder across much of Canada and the northern Great Plains states. You can find an interactive range map on eBird under Explore Data -> Range...Maps.

Kestrels nest in tree cavities, often taking over old woodpecker holes, but the cutting of dead trees for firewood results in a shortage of natural nesting cavities. Fortunately, kestrels readily take to large nest boxes erected specifically for the purpose. The size should be at least eight inches square inside and 15 inches tall with a three-inch entrance hole centered three inches below the top. Mount it at least 10 feet above the ground. As controllers of insect and mouse populations, kestrels are valuable to gardeners and farmers, and nest boxes are one way to encourage their presence.

For more information, visit All About Birds.

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

Harriers

© Dave Spier

At this rate, it just might spend the winter here. Sometimes it flies close to the building, passing the west windows, and then disappears across the field. I doubt it's hunting the birds at the feeder, but they are within the realm of this raptor's diet. Mostly it flies low over the grasslands and the marsh while it looks for small mammals, especially Meadow Voles (also called field mice) which are caught with a sudden pounce. Sometimes this large bird's flight drifts lazily back and forth, then stops momentarily to hover. In warmer weather it hunts snakes, frogs and insects. When all else fails, carrion is eaten.

The Northern Harrier, once known as the marsh hawk, is a slender and buoyant hawk with a somewhat owl-like face. The hawk's long wings and tail are designed for life in the open. If it tips a bit sideways toward you, watch for the distinctive white rump patch. When soaring, the wings are held in a shallow V with the tail fanned. At low altitudes, the tail is usually closed and the wings held flat to the sides. In a steep glide, the wings are sharply bent and swept back like a fighter jet.

In the winter, harriers hang around with Short-eared Owls and share the same fallow, grassy fields where mice have had time for a population explosion. Both raptors will use fence posts as hunting perches while they listen for prey. Though unrelated, the facial disks of both harriers and owls are thought to help focus sounds on the ears.

The harrier's Latin name, Circus cyaneus, refers to its circling flight and the supposedly blue plumage of the males. The color is actually gray, but that's only half accurate because females and juveniles are brown, an unusual disparity for raptors. Juvenile harriers are orangish underneath, like the two photos. The name "harrier" is Old English for "harassing with hostile attacks." Other colloquial names include blue hawk, mouse hawk and white-rumped hawk. Males are smaller and more agile and catch smaller prey, including birds. The harrier flying past the Montezuma Audubon Center (Rt. 89, Savannah, NY) was a larger, brown female probably more intent on a larger meal than the tiny goldfinches at the feeder.

Harriers nest in the marshes at Montezuma National Wildlife Refuge (between Rochester and Syracuse, NY). Last April I watched a female repeatedly carry nesting material in her beak and then drop down into the same patch of heavy vegetation. There are indications harriers also may nest in the Northern Montezuma Wetlands Complex around Savannah (Wayne County, NY). They almost certainly nest in the Lakeshore Marshes Wildlife Management Area near Lake Ontario in northeastern Wayne County as well as Howland's Island in Cayuga County. The female does all the incubating while the male brings food. After the eggs hatch, the male continues supplying prey, but only the female tears it up and feeds the young. If something happens to her, the nestlings will starve, even though the male continues to drop whole prey into the nest.

Harriers breed from Alaska across Canada to the Maritimes and south into the United States as far as a line from California to Pennsylvania. Most harriers head south for the winter and return in the spring.

Contact me at northeastnaturalist@yahoo.com More nature photos can be seen at http://picasaweb.google.com/northeastnaturalist and http://www.flickr.com/photos/dave_spier and now my Facebook photo page.

(This copyrighted article - slightly revised here - and photos first appeared in the Times of Wayne County, November 24, 2008. All rights reserved.)


 

Golden Garden Spiders

A female Argiope aurantia, the golden garden spider, hangs upside down as it finishes wrapping its prey in a gauze straight jacket. The heavy zig-zag stitching on the web (called stabilimento) is believed to warn birds that might otherwise wreck the web. The yellow flowers supporting the web are brown-eyed Susans 'Goldsturm.'
© Dave Spier photo # D050779 [resolution reduced for web use]

Golden Garden Spiders

© Dave Spier

The small patch of Brown-eyed Susans 'Goldsturm' has grown over the years and it now spreads along the entire east side of our patio. Sheltered from north and west winds, it catches the morning sun that burns off the dew. Yesterday I was leaving the house and just walking past when a new visitor caught my attention. A great, circular web stretched through a gap between several of the taller plants. A white, zig-zag stitching reinforced the center and there, hanging head down, was a huge multi-colored spider wrapping her prey. The eight black and pink legs easily spanned two inches. The egg-shaped abdomen was black with bright yellow markings. This was a Golden Garden Spider, Argiope aurantia, also known as the Black-and-yellow Orb Weaver.

I've also found these spiders in shrubs, tall grass and fields of wildflowers. They build their elastic webs by first throwing a "bridge" thread (a loose strand of silk) carried on air currents to a second support. From the center of the bridge, they drop down with an anchor thread to form a tripod. A box frame is built around the intended area and more radial spokes are added. Then a few quick spirals of non-stickly thread allow the spider to walk anywhere on the web. Finally, a tight pattern of sticky spirals completes the trap and the spider waits for its victim. They ignore the high-frequency vibrations of dangerous prey such as wasps, but quickly dash out and wrap more delectable goodies such as grasshoppers and other juicy insects. With its potential meal in a gauze straight jacket, the spider bites with fangs and injects a paralyzing venom. Then digestive enzymes are pumped in to liquify the soft body tissues, turning them into a soup that the spider sucks out. All that's left is the insect's exoskeleton.

By the end of the day, the sticky threads are too dry to be effective, so the spider eats the web and spins a new one. The silk, produced by spinnerets under the tip of the abdomen, is a liquid protein that hardens when it contacts the air. Besides the two types used to make webs, their is a third silk used to wrap prey and then another silk to wrap and protect the spider's eggs. Silk can also be used for "ballooning," sort of a magic carpet ride on the air. The heavy, zig-zag stitching, called stabilimento, across the central hub of the web is believed to warn birds that might otherwise blunder through the web. This saves the spider time, energy and material in prematurely rebuilding the web.

Late summer is spider season. Look out across any field just after sunrise and notice all of the dew-soaked webs catching the morning light. Each of these is both home and kitchen to a spider.

Contact Dave at northeastnaturalist@yahoo.com or Facebook. There is also a Facebook page for The Northeast Naturalist.

(This copyrighted article and photo first appeared in the Times of Wayne County, September 1, 2008. All rights reserved.)