Saturday, March 31, 2007

The Winged Tiger in our Woods

I overheard a conversation some time ago. A woman was lamenting the disappearance of her cat. It was outside at night, and never returned. In the woods near her home, she had seen the tracks of a fisher. With a wavering voice, she concluded that her beloved tom had been taken by the fisher.

The out-of-doors can be a dangerous place for all manner of animals. A house cat out-of-doors is a predator; it captures and kills many birds and rodents, and sometimes brags of its prowess by depositing a carcass at the feet of its owner (or cat servant). Sometimes the cat lover will complain about the carcass, but rarely about the unseen toll that the out-of-doors cat may take on other wildlife.

However, fair is fair. Out-of-doors, the distinction between predator and prey is rarely a firm distinction. Beloved domesticated kitty and untamed wild animal means nothing when they all roam, unleashed through the woods, shrubs and fields. Predator may become prey. Predatory house cat may be preyed upon, and not return home come morning.

I was tempted to interrupt the woman whose quavering voice lamented the loss of her beloved tom that beloved kitties are not killed by fishers if they are kept indoors. I did not say that to her. I say it now to all cat owners. Your outdoor cat is a predator. It is also fair prey. Keep it inside. End of sermon.

Pound for pound and ounce for ounce, the fisher may be the most formidable four legged predator in our woods, quite capable of killing an animal larger than itself, including tame pussy cats and of holding off, or even taking down, most slobbering house dogs. However, I suspect it takes the blame for more house cat disappearances than it deserves. The true tiger in our woods is not fur bearing, but feathered - a stealth hunter.

Bubo virginianus - The Great Horned Owl. One of the folk names for the Great Horned Owl is Cat Owl. When food is short, wrote Edward Forbush, the early twentieth century Massachusetts ornithologist, “the owl will attack even the domestic cat, and usually with success.”

The Great Horned Owl is our most widespread owl, found throughout North and South America, and adapted to a wide variety of habitats. “Powerful” and “dangerous” are the adjectives most frequently used by writers from the early nineteenth to the early twenty-first centuries to describe this bird. John James Audubon knew it as one of the most common species along the shores of the Ohio and Mississippi Rivers. “The Great Horned Owl,” Audubon wrote, “lives retired, and it is seldom that more than one is found in the neighbourhood of a farm, after the breeding season; but as almost every detached farm is visited by one of these dangerous and powerful marauders, it may be said to be abundant. The havoc which it commits is very great. I have known a plantation almost stripped of the whole of the poultry raised upon it during spring, by one of these daring foes of the feathered race, in the course of the ensuing winter.”

The Great Horned Owl may have an equal in the Western Hemisphere as a predator, but it has no superior. And in our neighborhoods, it has no superior. The imperial looking Bald Eagle doesn’t begin to compare as a predator. Our national symbol is quite content to feed on a deer carcass (something a Great Horned would never do), or steal fish from an osprey. The Bald Eagle is an adept fish hawk. When necessary, it is capable of taking the similarly sized Canada Goose. But the Great Horned Owl can also take the Canada Goose is spite of the goose weighing three times as much as the owl; it may take a Wild Turkey which can weigh even more than the goose. And, the Great Horned has been observed driving the Bald Eagle away from its aerie and appropriating the nest for its own use. Again, quoting Forbush: “The Great Horned Owl is no respecter of persons. It kills weaker owls from the Barred Owl down, most of the hawks and such nocturnal animals as weasels and minks.” In Texas during a three night period, a Great Horned took a Cattle Egret, a Great Blue Heron, and a gray fox.

The Great Horned Owl has many enemies that hate him, but none that are dangerous, except for humans. It has earned the particular enmity of the crow. And for good reason - its depredations among the crow population can be prodigious. It will take old and young crows from the nest at night and during the winter will pick crows off of their night roosts. It is crows that will most often give away the Great Horn’s presence during the day. When you see crows noisily flying around the top of a tree, it is quite likely that they are mobbing their most dangerous enemy. Eventually the crows’ harassment may stir the desultory owl into flight; as it leisurely flies off, the crows continue their uproarious pursuit. Pete Dunne writes: “Absolutely hated by crows, who amuse themselves by gathering around roosting owls and haranguing them with a gritty vehemence they inflict on no other enemy.” - except that there is nothing amusing about the crows’ actions. The presence of the Great Horned Owl is a mortal danger to the crows. The crows may be courageous and bold during the day, but when night descends they cede any advantage they might have to the powerful stealth hunter of the night.

The Great Horned Owl shares habitat with the Red-tailed Hawk. If you have the hawk, you almost certainly have the owl. One is diurnal, the other nocturnal. The Great Horned Owl nests early, often as early as February when winter still holds its grip. It will sometimes appropriate an old Red-tailed Hawk nest.

In our regenerated Vermont woodlands, it is very difficult to sight a Great Horned Owl. One time on a wooded Newfane hill, I was sure there was a Great Horned in a tree overhead - the mobbing crows gave away its presence with their loud and wild cawing. But the owl was impervious to the crows and I never saw a shadow of its flight.

At night it is easier to know its presence. I have often heard this owl at night as it queries the dark landscape and answers itself: “Whooo’s awake? ... Meee, too .... Whooo’s awake? .... Meee too.” The owl is probably calling for its mate, but he is also telling me that the night belongs to him.

One January day in Arizona, I saw three Great Horned Owls. I was with people who knew where they roosted. They led the way through the desert to a copse near a watering hole where we searched the bare trees for the owl. Its appearance as it perched on the limb conveyed a somnolent disregard for us, or perhaps a haughty arrogance. But as it turned its head and blinked in my direction I felt a sleepy malice in his stare. I was glad that I was too big to be in danger from this winged tiger. At least, I think I was too big.

Photos of Great Horned Owl taken near Willcox, AZ, January, 2005, during "Wings over Willcox" Birding Festival.
Quotation from J.J.Audubon, Birds of America, reprint of 1871 edition. Forbush, et al, A Natural History of American Birds, 1953. Pete Dunne's Essential Field Guide Companion, 2006.

Saturday, March 24, 2007

Signs of Spring Are Everywhere

Last weekend’s winter storm notwithstanding, March is the month of Spring’s return. As the dark snow clouds thickened, the change of the seasons was everywhere. Even non-birders will have seen the signs - the curling trails of smoke and rising clouds of vapor from sugar shacks - automobiles thickly crusted with mud - snatched conversations about impassable dirt roads. A mid-March snow storm is a brief hiatus in the calendar’s turn, a temporary pause. Spring is coming ... and the signs are everywhere.

Last Friday, before the snows began, I went out to look at Spring. I gave myself an edge by traveling to Vermont’s tropics - Vernon. In every bare pasture and fallow field, robins were hurrying about, busy feeding. With the robins were the Red-winged Blackbirds ... all males, feeding, yes, but often finding time to proclaim from a tree top their “conk-a-ree” while flashing their red epaulets. They come north before the females to claim their territory.

The blackbirds are one of the surest signs of Spring, and the red-wings are not the only blackbird on the move. On my pre-snow storm Spring survey, dove-sized blackbirds with long keel-shaped tails flew across the road and perched in trees - Common Grackles.

Other smaller, nondescript blackbirds were among the flocks of robins and red-wings feeding in the fields. When these blackbirds were closer to the road or when I paused to scan with my binoculars, I could see the brown heads of the cowbirds. Among North America’s native species, most birders loath the Brown-headed Cowbird; it is a brood parasite, dropping its eggs indiscriminately in the nests of smaller songbirds like the colorful warblers, or songster thrushes, seriously threatening the reproductive success of its hosts. But in March, even the cowbird’s return is noted, because it is a sign of spring.

For the last couple of months, I have known the birds coming to my feeders. When I did my backyard feeder count in mid-February, I knew I would have thirty juncos, twenty jays, twelve chickadees, six titmice, eight doves, six pigeons, four downies, and a pair each of cardinals, nuthatches, Hairy Woodpeckers, and Tree Sparrows.

Last Saturday, with the deepest snow cover of the winter and a four foot barrier built by avalanching roof snow to surmount in order to reach the feeders, signs and sounds of Spring abounded. Red-wings joined the juncos and jays to feed on the seed which I scattered across the top of the new snow. Grackles joined doves on the bulk feeder. Song sparrows scratched beside the Tree Sparrows and squabbled about who was going to eat that seed. And when I stepped outside, I heard the “conk-a-ree” of the red-wing, the “cooooo” of the dove, the “peeer, peeer” of the titmouse, and the discordant songs of the starling. Spring!

Along with the singing of our wintering birds, the large flocks of robins and mixed blackbirds are the most obvious avian signs of Spring to most people. But the signs are everywhere, although you may have to go looking and be alert for them.

Vermont’s state bird is the Hermit Thrush. Considered by many to be the premier vocalist among our birds, its ethereal, flute-like song carries through our late-Spring and early-Summer woodlands. Unlike the other woodland thrushes, the Hermit Thrush winters in southern North America, sometimes as far north as southern Connecticut. It is the first thrush (not counting the robin and bluebird) to return to our neighborhoods. But during March, this premier songster is silent, moving quietly through woods and thickets. He’s still curious. When I’ve seen movement in a brushy tangle, I’ve sometimes been able to “phish” him into the open where his spotted breast and upright, rufous tail betray his identity.

As the ice goes out of our rivers and ponds and the waters open, waterfowl move north. On my pre-snow storm survey, I found a hundred Common Goldeneyes in the Connecticut River near Stebbins Island. Between dives, the drakes were doing their whip-lash display for the hens. I also saw a couple dozen Hooded Mergansers, although if I had wandered around the old beaver pond with my neighbor I would have seen, as he did, a pair of hoodies in a small pool; they were probably on an early reconnaissance for a hollow tree in a wetlands to use for nesting.

Where there is open water, there will soon be a kingfisher or two, rattling from tree branch perch to tree branch perch.

Shorebirds are returning. Two weeks ago friends in West Brattleboro heard the “peent” of the American Woodcock (yes, the woodcock is a shorebird). Secretive and nocturnal - both when it feeds and when it migrates - the woodcock starts to move north from its southern wintering range as early as January. Its migration peaks in March. We can be concerned for the earliest woodcocks to arrive in our woods, especially those caught in last week’s storm. They feed almost entirely by probing soft ground for earthworms. With a foot of new snow and refrozen ground, survival for the earliest arrivals is challenging.

Killdeer are also being reported, although we will not see (or hear) significant numbers until later in the month. I remember one recent winter’s end, when the spring thaw took a long time because of the depth of the snow pack. Only the road edges by the Retreat pastures were snow free, but there were dozens of killdeer working those snow free edges, and dozens more scurrying across the snow fields, as well as the ice on the West River. It is still early to expect to see killdeer in any numbers, but this noisy plover is likely to betray his presence at any time with his strident “keeldee” as he flies over head or dashes across a barren patch of ground - or snow covered pasture.

Humans are diurnal creatures. We have color vision because we are genetically intended to be active during the day and to sleep at night. But if your genes are screwy and you’re active at night, then listen for owls. The Spring breeding season begins as early as February for the Great-horned Owl, and for the Northern Saw-whet Owl and Barred Owl it is swinging into full activity. They are hooting, tooting and calling, seeking mates, defending territory, and preparing to nest.

It is hard to imagine why some birds would be incubating eggs in such (to us) foul weather, but it is undoubtedly timed to the emergence of food sources. With the melting of winter snows, chipmunks, mice, and voles emerge from their winter quarters, sometimes atop the remaining snow, or just beneath the matted, and now snow free, grasses. Many birds return. And all of life seems distracted with the advent of the breeding season. There will soon be much food available for the soon to hatch owlets.

So too for the eagles, whose nesting seems timed to coincide with the running of the shad and salmon. Last Friday the Vernon/Hinsdale eagles appeared to be incubating. Where early in the week they were observed moving sticks about their aerie - some last minute nest remodeling - with the approaching snow storm one was seated deep in the nest, a sign that an egg had been laid.

It’s Spring! Forget the snow. The signs of Spring are everywhere!

Photos: Top - Ring-necked Ducks near the Vernon Dam in March. Middle - Hermit Thrust returns early to Vermont woods.

Wednesday, March 21, 2007

Fox Sparrows in South Newfane

The Fox Sparrow which first visited my feeders was back today. Mid afternoon it finally overcame its skittishness and stayed just outside the window, making photographs possible. This bird passes through in early Spring and late Fall on its migration. Last Fall, for whatever reasons, it was missed. It's a treat that this large and beautiful sparrow has returned.

Saturday, March 10, 2007

The Uncertain Future of the Red Knot

The Red Knot is a plump, medium sized sandpiper usually seen along our Atlantic coast during Spring and Fall migration. John James Audubon, in The Birds of America, began his description this way:

“The Knot, good reader, is a handsome and interesting species, whether in its spring or in its winter plumage, and provided it be young and fat, is always welcome to the palate of the connoisseur in dainties. As to its habits, however, during the breeding season, I am sorry to inform you that I know nothing at all, for in Labrador, whither I went to examine them, I did not find a single individual.”

We should not criticize Audubon for his failure to learn of the Red Knot’s nesting habits. The nest went undiscovered to science until June, 1909, when Admiral Peary photographed one in the high arctic after his dash to the North Pole.

Nor should we be too critical of Audubon for commenting on the Knot’s tastiness. He was a man of his time, and even scientists studied wildlife for their “usefulness” to society - in the Knot’s case, as a dainty delicacy. Its flavorfulness may even explain its name. One account of the name origin has the Danish King Canute, or Knut, dining on a strange coastal bird. His compliments to his chef led his courtiers to dub the bird, Knuts, or Knots.

An alternative account of the origin of the Red Knot’s name also features King Canute. This one notes that the Knot often feeds in the water, even as the tide is coming in. Where the Sanderling chases the waves, running to and fro with the coming and going of the tide, the Knot seems to hold its ground, as though trying to hold back the tide itself. A legend associated with King Canute has the Danish monarch attempting to hold back the tide, futilely we can be sure. Hence the association of the Knot (Calidris canutus) and Knut.

The Red Knot is a circumpolar nester. The North American subspecies (one of two subspecies) was once the most abundant sandpiper to be seen along the coast. Forbush reports that in spring and autumn “their hosts were marshaled on the flats of Barnstable County, and around Tuckernuck and Muskeget islands they collected in immense numbers and rose in ‘clouds’ before the sportsman’s gun.”

And, that was the first challenge faced by the Red Knot to its survival as a species - a combination of its habit to gather always in large flocks of its own kind, and the advent of modern killing technology. However, it was not the sports hunters which nearly did in the species, but the market hunters of the late nineteenth century. These exploiters employed technology and organization to “harvest” as many birds as possible and “reap” the profits. The numbers of Knots fell precipitously. The species was in danger of joining the Carolina Parakeet and the Passenger Pigeon on the list of extinct birds.

It was saved by the Federal Migratory Bird Law which went into effect in 1913. The hunting season was closed on nearly all shorebirds, and just in time for the Red Knot. In the following decades, the Red Knot recovered to some degree. Hunting still poses a danger on some of its South American wintering grounds and along migration routes in South America. But the most serious danger to the Red Knot lies in the Delaware Bay.

While a few Red Knots winter along the Atlantic coast, most winter in southern Argentina and Chile. Every year, they travel 9 to10 thousand miles to Arctic Canada to nest. On the first stage of their northward journey, they travel 3 to 4 thousand miles (usually non-stop) to the shores of the Delaware Bay. Their flight is timed so that they arrive at the Delaware Bay when the Horseshoe Crabs are crawling ashore to lay their eggs. Having burned their fat reserves, the Knots feed almost exclusively on the crab eggs.

The number of Red Knots stopping at the Delaware Day has been as high as 150,000 birds. However, by the early years of this century, the number had suddenly dropped to around 15,000 birds, a 90% decline. Surveys in South America also show a precipitous decline. What happened?

Beginning in the 1990s, commercial fishermen began harvesting Horseshoe Crabs for use as bait in eel pots. The eels, like the shorebirds, love the eggs. The preferred time to harvest the crabs is in the spring when the females are filled with thousands of eggs. Hand harvesters work just off shore as the crabs are coming ashore and take only the females. Past studies have indicated that crabs normally lay 4,000 eggs per meter. In 2005, the survey found about 1,500 per meter.

In 1982, aerial survey flights saw the beaches lined with crabs four deep (that’s vertical depth!) and miles across, and estimated the shorebird peak during the third week of May at one million birds. The survey task is much less daunting today. “Along the New Jersey coast, the ribbon of life had been abraded to frayed and broken strands. The numbers of crabs and birds reduced to a vestige,” wrote Pete Dunne just a few years ago.

The consequence for the shorebirds is that there is simply not enough food for them to regain their fat reserves for the next stage of their migration. This has been especially dire for the Red Knot, but at least five other species of shorebirds also feed heavily, if not exclusively, on the Horseshoe Crab eggs during their spring migration. All have experienced sharp population declines. For example, prior to 1988, as many as 272,000 Semi-palmated Sandpipers were counted in one day along the Delaware and New Jersey shores of the Delaware Bay. After 1988, no day count has exceeded 100,000.

When I posted the sighting of a Red Knot on Cape Ann two weeks ago, one respondent wrote: “Birders better rush to go see it since according to the National Audubon Society, the NJ Audubon Society, The American Bird Conservancy, Defenders of Wildlife, et al., ... Red Knots have less than 35 months to live and will be extinct by 2010.”

Conservation organizations, such as Audubon, have succeeded in convincing New Jersey and Delaware to impose limits on the harvesting of crabs along their coastlines. With abundant evidence of an ecosystem disaster in the Delaware Bay - or at least a species disaster for the Red Knot (impeding extinction is rather serious for a species) - one would think that the Endangered Species Act would come into play, and that the federal government would employ its considerable power to provide protection. Unfortunately, the alacrity and competence with which the current Washington administration has handled such things as natural disaster and war management, extends into the Department of Interior. The Secretary of the Interior claims the Department is “fast-tracking” the possibility of listing the endangered Red Knot as a “threatened” species (not endangered) and may have a decision in a couple of years.

Canute’s sandpiper, the red-breasted sandpiper, the beach robin - C. canutus rufa, - officially the Red Knot - may not have a couple of years. Its epic migrations are in danger of becoming mere memories, tales to be read about, but never to be witnessed.

Notes on Photos: Top - Small group of Red Knots at Matt's Landing, NJ, on Delaware Bay, May, 2006. Middle - Red Knots feeding along a jetty at Reed's Beach, NJ, on Delaware Bay, May, 2005. Bottom - Single Red Knot feeding with Ruddy Turnstones and Laughing Gulls on Reed's Beach, May, 2005

Saturday, March 03, 2007

A Rare Wintering Red Knot on the Massachusetts Coast

It was early afternoon when we started clambering over the rocks at Halibut Point. The sun had broken through the hazy clouds and lent a hint of spring to the day. Even so, our final quest for the day had some urgency to it. Snow was moving eastward and we wanted to begin our return to Vermont ahead of the storm.

For several hours we had been working our way slowly around the rugged coastline of Cape Ann. All of the expected wintering sea ducks, grebes, gulls, and alcids were scattered in the cold waters. The diving ducks gave us brief looks before disappearing beneath the surface, then popping back; the drakes occasionally paused in their feeding activities to display for the hens. We had a few unusual sightings - Ruddy Ducks and Ring-necked Ducks on Niles Pond - arctic white Glaucous Gulls here and there.

Beneath the lighthouse at Eastern Point a drake Barrow’s Goldeneye was among the Common Goldeneyes. It was the same location where we had seen a Barrow’s a few years ago on another winter coastal birding excursion. Near Bass Rocks, there was a single drake King Eider. Close to shore, we both had our most satisfying sighting of this rare New England wintering sea duck.

By the time we had reached Halibut Point, there was only one wintering species that we expected to see which was still missing - the Purple Sandpiper. A few other shorebirds may winter in small numbers along the New England coast north of Boston, but only the hardy Purple Sandpiper is to be expected. My friend, a Massachusetts native who has birded this coastline since a young age, led the way across the rocks. “I always see purples here.”

But not this day. We went over the rocks until the entire cove between Halibut Point and Andrews Point was in view and we scanned the entire rocky coastline joining the two points. There were no flickering movements to suggest these high arctic wintering shore birds. Disappointing - but both of us know that there are no guarantees when birding, and this winter has been strange in many ways.

As we turned back, still scanning the rocks for movement, we found a single shorebird roosting on a rock, head tucked beneath its wing. It is easy to identify the birds you expect to see, but we were now looking at a bird we did not expect to see. We studied it through our scopes, noted the speckled sides, the white eye stripe, the dark tips of the primary feathers, the gray tail feathers, the scaly feathers of the back. It had yellow legs, a straight dark bill, and barring on the rump that was just visible between the folded wings.

A Red Knot. But what was a Red Knot doing on the Massachusetts coast north of Boston in the winter? Red Knots winter in southern Argentina. They are famous for their epic migration journeys - 20,000 miles in round trip flight each year, from Tierra del Fuego to the high arctic and back. We returned to the car, checked our field guides to confirm our identification, then made the half mile walk back to the rocky shore with a camera. The knot had not moved. I collected digiscoping images for documentation. Moving to within twenty feet of the resting bird, it finally moved, walked a little; plump as the bird is, perhaps waddled better describes its two legged movement. Then it flew briefly, before returning to its roosting place. The flight allowed a look at the wing patterns, further confirming the identification. We backed away. The bird was so “tame,” so reluctant (seemingly) to move, that we concluded it already had enough stress, and we did not need to add more. Far out of its normal range, this Red Knot was trying to survive a New England winter. It was roosting on a rocky shoreline, where its preferred habitat would normally be open tidal flats and sandy beaches.

Back in the comfort of our homes and while the snow swirled outside, we learned that there are a scattering of winter records for the Red Knot in Massachusetts, and that most field guides show a winter range from southern Massachusetts southward along the Atlantic Coast. Our sighting of the Red Knot was rare, but not unusual.

I read the bird e-mails for Massachusetts. I had seen no sighting reports for the Red Knot, so the next morning, I had our sighting posted. A few hours later, a reply to the posting speculated (reasonably) that our Red Knot was the same bird which had been seen at Halibut Point on the Christmas Bird Count for Cape Ann on December 17. The respondent noted that Red Knots “winter to some extent on the south shore, but rarely north of Boston,” and wondered if this may be the first record for Essex County.

Later in the day, the same writer returned with more information. He had learned that Red Knots used to winter in some numbers in Revere, just north of Boston. The highest count of 130+ knots was recorded in February, 1974.

He found just one previous record for the Red Knot in Essex County. North of Halibut Point is Crane Beach in Ipswich, and yet further north is Plum Island near Newburyport. Both are visible from Halibut Point on a clear day. In mid-January, 1967, 30+ Red Knots were reported at Crane Beach.

Our Red Knot was probably a first year bird. Like many shorebirds, the adults leave the breeding grounds before the young are able to fly. A few weeks later, the young follow. The only guide the juvenile birds have as to where they should go is in their genetic encoding. Many stray, or don’t make the complete journey. A few may end up on a New England coast in winter, where they need to figure out how to feed themselves, avoid predators, and reconnect with their kind in the spring so that they can pursue their purpose in life - transmitting their genes to a new generation.

In addition, the Red Knot is facing extreme challenges to its very ability to survive, not just in the struggle for individual survival, but in its existence as a species. Surveys from the Delaware Bay where the birds rest, feed and stage on their northward journey have estimated their numbers at 15,000, a 90% decline in the last ten years. I will return to the endangered status of the Red Knot in a future column.

Forty years ago, almost to the month, a naturalist with a deep rooted love for birds, counted over 30 Red Knots on a northern Massachusetts beach. Last week, a few miles from that same beach, I stood next to his son when his son spotted one Red Knot roosting on the rocky shoreline.


Related Posts with Thumbnails