The Center for Birds of Prey

South Carolina's Center for Birds of Prey
© 2009 Dave Spier

On our February trip south, we stopped at the South Carolina Center for Birds of Prey located about 15 miles northeast of downtown Charleston. It's on Seewee Road just east of U.S. Route 17 next to the Francis Marion National Forest. If you're coming from the Georgetown or McClellanville direction, it's about three miles southwest of the Sewee Visitor Center. [for a map, go to their website, http://www.thecenterforbirdsofprey.org/visit_us.htm and scroll to the bottom of the page] The raptor center is open to the public on Thursdays, Fridays and Saturdays (except holidays) from 10:00 am to 5:00 pm. Weather permitting, there are guided walking tours at 10:30 and 2:00 followed by free-flight demonstrations at approximately 11:30 and 3:00. You also can walk around on your own to see all of the raptors.
Most of the birds are housed in large outdoor pens. The afternoon we were there, Education Director Stephen Schabel, Jr. (Steve) started our tour at the vultures. The Black Vulture, Coragyps atratus, normally depicted with black legs, had one gray leg and one pale-yellow, the result of urination. The ureic acid is thought to act as an antibiotic and a coolant as it evaporates. The Turkey Vulture, Cathartes aura, (in the same pen) stayed on the ground in the back corner. A notable difference between the two genera is their sense of smell. The black has little or none, while the Turkey Vulture has a good sense of smell, at least based on the size of its olfactory lobe in the brain. Vultures are technically not raptors because they do not use their feet to catch prey.
Next stop was an American Kestrel, Falco sparverius, that had imprinted on humans. The otherwise healthy bird, taken as a hatchling, would be ill-equipped to survive in the wild and find a mate. A much larger Peregrine Falcon, Falco perigrinus, is housed separately. In the wild, peregrines eat pigeons and ducks which they can knock down by diving at speeds over 200 mph.
Owls are well represented at the center. The next pen was a British Barn Owl, Tyto alba alba, about half the size of its American counterpart. Barn Owls have their own family, Tytonidae, separate from all other owls. At another stop, a well-camouflaged Great Horned Owl stayed out of the sunlight. These owls want to be seen only during courtship, so a white patch under the chin opens when they are calling to each other. These birds have long wings and live on the edge of the woods, although I have found them nesting in mature forests. Members of the genus Bubo are sometimes referred to as "eagle owls." The center also has a Barred Owl, Strix varia, one of the "wood owls" genus. These birds have shorter, rounded wings and longer tails for life inside the forest. Barred Owls generally prefer wet, bottomland woods. (If you have time, or come early, walk to the Owl Wood, a separate area with more species.)
The guided tour serves as an introduction to the variety of raptors in the avian world, but there's time for only a limited number of species. For a few of the other birds you can see at the center, go to their website, http://www.thecenterforbirdsofprey.org/the_birds.html but even that is very incomplete because they have over 30 bird-of-prey species.
Following the guided tour, the group proceeded to the free-flight field. First up was a Harris' Hawk, Parabuteo unicinctus, a dark buteo of the Southwest. Because this species is a cooperative hunter, the white on the adults' tails allows them to keep track of each other. After the Barred Owl flight, which turned into the Barred Owl perch because of the wind, an active Eurasian Kestrel was brought out. This bird can see UV light which allows it to hunt voles by detecting their urine marks. The final highlight of the show was a Tawny Eagle, a magnificent bird that put on quite a show.
The raptor center is a bit expensive ($12/adult), but I look at it as a charitable contribution to help support their work. In addition to their medical and rehabilitation efforts and on-site educational tours, they offer off-site education programs and they do research and field studies related to the "protection of wild bird populations and their habitats." (For more detail, see http://www.thecenterforbirdsofprey.org/research.htm )
More photos taken during our visit to the center can be found at http://picasaweb.google.com/northeastnaturalist/BirdsOfPreyCaptive#

Red-breasted Nuthatches

The Red-Breasted Nuthatch
© 2008 Dave Spier

At less than five inches long, the Red-breasted Nuthatch (Sitta canadensis) is a little smaller and stubbier than its white-breasted cousin (discussed in the previous blog). The belly and breast are orangish, but paler on the female. There is a bold black stripe that runs from the beak through the eye to the back of the head. Above this black stripe is a distinct white stripe (called a supercilium, although it’s easier to think of it as an eyebrow) and then a black crown, or in the case of the female, a grayish crown. The White-breasted Nuthatch has a beady black eye on a white face, making it a quick distinction from the Red-breasted Nuthatch’s black eye stripe.
Both nuthatch species have the habit of spiraling head-first down tree trunks, giving them the unique nickname, “downheads.” The red-breasted is found in conifers or mixed deciduous and coniferous woods and prefers older stands with some decaying trees. They nest in knotholes or excavate a rotten branch or stump, but abandoned woodpecker holes or nest boxes will suffice in a pinch. Red-breasted Nuthatches apply conifer resin around the entrance to their nest cavity. It’s believed the sticky resin discourages predators and competitors. The feisty little nuthatch also chases away other species like wrens, woodpeckers and White-breasted Nuthatches that might want its nest hole. The five or six light-colored eggs are marked with reddish-brown squiggles and hatch in about 12 days. The helpless babies are fed insects and spiders (yummy!) and grow for two to three weeks before leaving the nest
The word “nuthatch” is a corruption of the English term “nuthack” originally applied to European nuthatches. White-breasted nuthatches will hack apart acorns, beechnuts, hickory nuts and cherry pits, but the natural diet of the red-breasted is limited to seeds extracted from evergreen cones plus insects and other invertebrates gleaned from bark crevices. In civilized parts of their range they frequent white-suet feeders where they will linger for what seems like hours. They also visit seed feeders but like the chickadees, they dash in, grab a seed and fly off. They interact well with juncos, chickadees, titmice and White-breasted Nuthatches, even the larger jays and cardinals, but they don’t seem to like the larger woodpeckers like the hairy. They have to be constantly on the lookout for predators, mainly Sharp-shinned and Cooper’s Hawks which find bird feeders to be a great invention for concentrating prey in one spot. That’s why it’s best to place feeders close to dense escape cover like bushes. Cats are another problem and it’s best to keep them indoors if you feed birds.
The call of the red-breasted has been likened to a toy tin horn as it gives a series of “ank, ank, ank” notes. Pairs stay together year round and use the call notes to keep in touch. The Red-breasted Nuthatch is somewhat migratory, so its numbers fluctuate from time to time, depending on the abundance of cone seeds in its home range. Some of our summer birds may go south, but in other years some Canadian birds may come here for the winter. Across Canada, into the Adirondacks and New England they live in boreal spruce-fir forests. When migrating south, some observers claim that, given a choice, they prefer pine and hemlock, although a report from the Village of Wolcott indicates they’re just as much at home in a row of tall arborvitae trees.
Contact me at northeastnaturalist@yahoo.com or visit my photo websites http://picasaweb.google.com/northeastnaturalist and http://www.flickr.com/photos/dave_spier
(This copyrighted article and photo first appeared in the Times of Wayne County, January 7, 2008. All rights reserved.)

White-breasted Nuthatches

 There are two nuthatches likely to be found in New York and the Northeast throughout the year. The common White-breasted Nuthatch prefers deciduous woods and yards while the less common Red-breasted Nuthatch prefers conifers and evergreen woods. 

 Mention White-breasted Nuthatch, and the first thing that comes to mind is the image of a bird walking head-first DOWN the trunk of tree. Most birds clamber up a tree, or at least perch upright on the trunk. Why would one species reverse the pattern? Simple -- they find food that other birds miss. It gives them a unique perspective on their world. It also gives them a unique nickname, the “downhead.”

 

 Many people are familiar with nuthatches. Perhaps you have a pair or family group coming to your feeder. The white-breasted species (Sitta carolinensis) is a small “songbird” (in the order Passeriformes), although its “song” is more a series of soft, nasal notes resembling “what, what, what” all on the same pitch. Its call is a nasal “yank.” 

 This bird is only five or six inches long, not that you’ll get close enough to measure it. It’s not as tame as the chickadees and titmice with which it often travels. The White-breasted Nuthatch has blue-gray wings, back and tail-center plus a white face and underparts. The cap, or more accurately the crown-stripe, is black on the male, grayer on the female. When viewing the bird from below, you’ll see the rusty-tan patches under the tail. The stubby tail, if you’re lucky enough to see it fanned in flight, has a white stripe on either side. By comparison, the larger Tufted Titmouse, duller gray on top and white underneath, has a longer tail and crested head while the smaller Black-capped Chickadee has a black throat. The White-breasted Nuthatch has a beady black eye on a white face, making it a quick distinction from the Red-breasted Nuthatch’s black eye stripe discussed in a future blog. 

 When not visiting your feeder, the White-breasted Nuthatch, a year-round resident, lives in open woods and suburbs populated by large trees, especially oak and pine. In the spring, it builds a nest in a tree cavity by lining the hole with fur, thin grasses and shredded bark. They seem to prefer knotholes, but abandoned woodpecker holes and nest boxes will suffice. The clutch of speckled creamy-white eggs hatch in two weeks and the chicks fledge in roughly 26 days. 

 The birds live on berries, such as elderberry and Virginia creeper, plus insects found in nooks and crannies of trees – especially dead trees. They also eat nuts which they wedge in bark crevices and hack or “hatch” apart (hence the name “nuthatch,” a corruption of the English term “nuthack”). Acorns, beechnuts, hickory nuts and cherry pits are all on their menu. In the winter, White-breasted nuthatches depend on seeds, some of which may be hidden for later use, but I’ve seen other species find and remove such a cache. They also eat insect eggs or dormant insects found hibernating in bark crevices.

 

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(© 2007 Dave Spier -- This copyrighted article and photo first appeared in the Times of Wayne County [NY], on December 10, 2007. All rights reserved.)

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.)


 

November Trails

November Trails

This blog has been reposted in two parts with additional photos.
part 1 and part 2

Contact me at northeastnaturalist@yahoo.com More nature photos are posted at http://www.flickr.com/photos/dave_spier and http://picasaweb.google.com/northeastnaturalist

Common Loons

Common Loons

© 2008 Dave Spier.
Native Americans referred to this bird as the "Spirit of the Northern Waters." Common Loons breed across Alaska, the entire width of Canada, and the northern-forest zone from Minnesota to the Adirondacks and New England. During their migrations they often stop in the Finger Lakes Region. I've found small flocks resting on Lake Ontario off Chimney Bluffs during calm weather in October and at least several loons will use the Widewaters portion of the Erie Canal in November. This stretch is unaffected by draining the canal for winter because Ganargua Creek passes through here. A large number of loons follow Cayuga Lake as they head south. They're most likely heading for the Atlantic coast where the juvenile birds will remain for three or four years before returning north, but some will go as far as the Gulf Coast. Loons in the western part of their range spend the winter on the Pacific coast. In early spring I've found returning adult loons near the Canandaigua City Pier before boating season gets under way and disturbs them. One of the birds caught a very small sunfish while I was watching.
Loons are large birds. They measure 32 inches in length and have a wing span of nearly four feet. Males are larger than females. From March through October, the adults sport high-contrast black and white plumage. The heads and beaks are black, their necks have white or gray bands, the breast and belly are white, the sides black and the back is extensively checkered. The only color is in the red eyes. Juvenile loons, and adults in winter plumage, are overall gray or dark gray with white on the throat and upper breast. They may have a faint, light gray, partial band around the neck.
On the water, loons ride low like a submarine, an appropriate metaphor becuase they dive to catch their food. A number of adaptions helps them do this. Their feet are far to the rear and to the sides to facilitate paddling underwater and their marrow-filled bones are thicker than other birds. For this reason, loons are heavy birds that require a long stretch of open water to get a running start to become airborne. Once in flight, their thick necks are balanced by large feet trailing to the rear. The relatively small wings make diving easier, but flying is more laborious. The location of the feet at the rear makes it nearly impossible for loons to walk on land, so they nest on the edge of islands where they can just slip into the water if danger approaches.
Loons face a number of manmade threats. Air pollution from mid-western power plants and auto emissions contains sulfuric and nitric acids and mercury. These are carried eastward by prevailing winds and fall as acid rain, in turn killing many of the small fish and organisms that loons depend on for food. Chicks can starve to death before four weeks of age. Acidic water also converts mercury to an organic form that enters the food chain and becomes concentrated in loons at the top of the ladder. Methyl mercury attacks the bird's nervous system, interfering with its ability to catch fish. In high enough concentrations, the birds die from mercury poisoning.
Loons also become entangled in discarded fishing line and die of lead poisoning after they ingest old fishing sinkers which are mistakenly picked up from the bottom along with the small stones used to grind up food in their gizzards. These hazards also afflict a host of other waterbird species. Shoreline development and increased recreational use of northern lakes pose additional threats to loons as they lose traditional nesting sites and face increased boat and jetski traffic,
If you see a loon this fall, you can contact Dave at northeastnaturalist@yahoo.com More nature photos can be seen at http://www.flickr.com/photos/dave_spier and http://picasaweb.google.com/northeastnaturalist

(This copyrighted article and photos first appeared in The Times of Wayne County, October 20, 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.)