Monday, April 30, 2007
On Saturday morning, April 28, we were at Pea Island NWR in NC during the morning. I saw a warbler whose ID has me completely stumped. Photos follow. The bird is slightly larger than Yellow-rumped Warbler. Feeding in thick hedge, near ground. At first appeared olive colored on back and head, but when back turned toward me, it was distinctly green. Undertail coverts yellow, becoming less so toward belly. Dark eye. Dark edge to wing wing. No wing bars.
There are three species of cowbirds which appear in North America: Shiny, Bronzed, and Brown-headed. The first two are rare, found only occasionally in southern Florida (Shiny) or along the Texas border (Bronzed). The third, the Brown-headed Cowbird, is common throughout the United States and southern Canada. When birders refer to a cowbird, this is the one they usually mean.
Among most birders, to say that they dislike the cowbird is to understate the case. Distaste edging into hatred is the more likely emotion. I know bird watchers who are gentle pacifists toward all manner of people and circumstances until they encounter the cowbird. Then their pupils contract to pinpoints, their lips become thin, taut lines, and they whisper out curses laden with venom and the craving to administer the fatal dose.
I am not engaging in literary hyperbole when I describe this animus toward the cowbird. A few years ago I attended a conference of the Northeast Hawkwatch Association. One of the presenters described a pair of Cooper’s Hawks which had nested in a public park in the Bronx in New York City. To one of the projected color slides, she matter-of-factly provided this description: “Here’s an early morning photo of the female Cooper’s Hawk breakfasting on a Brown-headed Cowbird.” The audience burst into applause.
Most people consider the cowbird an ugly bird. The female is a dull gray; the male is black with a brown head, with little of the iridescence of the grackles and certainly not the bright red epaulets of the Red-winged Blackbird. A songster it isn’t - squeaky “glug, glug, gleee” seems enough to draw a female’s attention. Cowbirds are free lovers gone amok - completely promiscuous, forming no pair bonds, defending no territory and building no nests.
The opprobrium generated by the Brown-headed Cowbird comes from its breeding practice; it is a brood parasite. The female lays her eggs, one at a time, in the nests of other birds, and then leaves all parenting obligations to the host birds. Hence one of its folk names is Lazy Bird. But the cowbird is also a very successful and adaptable species, so much so that it is threatening the well-being of some of its favorite hosts.
A couple of weeks ago, I was sharing Spring bird notes with a backyard birder in a Brattleboro parking lot. When I said that I tried to chase off the cowbirds which visited my feeders, she countered by reminding me that they were just doing what they had evolved to do. The next day while birding with an ecologist friend, I again got on the subject of cowbirds. Rather than agreeing with the widespread dislike of the cowbird, he argued that their success as a species was due to the cavalier way in which humans have altered natural habitats.
The Brown-headed Cowbird was once limited to the Great Plains, where it followed herds of grazing animals, ground feeding on whatever was stirred up by the hooves. This nomadic feeding life meant that it could not stay in one place long enough to raise young, and so it evolved the practice of parasitizing other species’ nests with its eggs.
When the European settlers cleared the eastern forests and established farms, the cowbird found new open land with forest edge into which it could expand, and new creatures with which to associate. Cows provided the name Cow Blackbird, shortened to cowbird. Its range ballooned. Except for the tundra of the far north and isolated pockets, like mountain tops, the cowbird is everywhere in North America.
Brown-headed Cowbird eggs have been found in the nests of 220 species. Young have been successfully raised by 144 of those species. The female cowbird has been described as a “passerine chicken,” laying as many as 40 eggs in one breeding season. She prefers nests on the ground or in lower branches, but will deposit her egg anywhere, going to the canopy, or entering tree hollows. Even that most formidable territory and nest defender is occasionally victimized - the Eastern Kingbird.
Only about three percent of the cowbird eggs laid result in an adult bird, but this is enough of a success rate to provide a steady increase in the cowbird population. Some birds simply fail as foster parents. Among birds occurring locally which fail as surrogate cowbird parents are Killdeer, Virginia Rail, Spotted Sandpiper, and Ruby-throated Hummingbird. Other parasitized species learn to recognize and reject cowbird eggs; they may destroy the egg, abandon the nest, or rebuild the nest to cover the egg. The Yellow Warbler has been known to cover a cowbird egg and rebuild its nest repeatedly in its effort to avoid raising a cowbird chick. Host species that have been in contact with cowbirds seem most likely to recognize the intrusive egg.
A cowbird egg may coexist with the eggs of the host species. Usually it hatches a day earlier than the host’s eggs. The nestlings are usually larger and grow faster, so they get more than their share of food and often crowd out the other nestlings. Once fledged, their loud and persistent calling causes them to get more food as well.
Cowbirds are edge species; they seldom venture more than a couple of hundred feet into woodlands. But as roads and powerlines continue to cut pathways through the forests, more edge is created resulting in more breeding habitat for cowbirds. One species which has been severely impacted is the Red-eyed Vireo. Once the most common songster in our woodlands, it has been in serious decline in recent decades. Cowbird parasitism is a significant factor in this decline. Various studies have shown that 40 to 70 percent of Red-eyed Vireo nests are parasitized by cowbirds.
Beneath my dislike of the cowbird is my dislike of the cavalier way in which our environment is used and abused. Given the powerful political and financial clout of the environmental abusers, I sometimes feel that the opposition to the abusers is about as effective in preventing environmental abuse as my chasing cowbirds away from my feeder is in preventing cowbird parasitism. But let’s keep at anyway. Harassing the environmental parasites - hopefully more effectively than we have in the past - is more important than harassing the cowbird parasites. And it is essential if our children and grandchildren are going to have the opportunity for Good Birding.
Saturday, April 21, 2007
Two weeks ago another rare waterfowl was found along the lower Connecticut River. Maybe. When the male Eurasian Green-winged Teal flew from New Hampshire’s Connecticut River into Vermont’s Herrick’s Cove it may have created a first record for Vermont for this duck. Or it may have just been another Green-winged Teal.
First some background on the Green-winged Teal. This teal is our smallest dabbling duck. Dabbling ducks feed by turning themselves upside-down in order to feed on plant life beneath the water’s surface. Mallards, American Black Ducks, and Northern Pintails are among the most familiar “dabblers.” Canada Geese, though not ducks, are dabblers. The Green-winged Teal has a length of 14 inches and weight of 12 ounces. Only the Bufflehead, a diving duck, is smaller (L. 13.5 inches). The teal is slightly larger than the Rock Pigeon (L. 12.5 inches, W. 9 ounces), and significantly smaller than the American Crow (L. 17.5 inches, W. 1 pound), although comparing a duck with a song bird is like comparing apples and pears.
The Green-winged Teal, like most waterfowl, is most often observed on swimming on water, and usually with other ducks, usually at a distance, and usually through binoculars or a scope. All of these conditions make it difficult to wrap the mind around its small size. Several years ago in southern Texas during the winter, I walked along a boardwalk in a marshy refuge. Green-winged Teal were feeding in the water below us, not fifteen feet away. I still remember clearly our reaction: “They’re so tiny!”
Green-winged Teal are common and widespread. A few weeks ago when the night roost for migrating waterfowl was just above the Vernon dam, Canada Geese were the most common with an estimated 4000 geese present. The next most common waterfowl was the Green-winged Teal whose numbers were around 500.
This small duck breeds near shallow freshwater lakes and marshes from Alaska, across all of Canada, in the northern Great Plains, and along the St. Lawrence valley. It winters widely throughout the south and west.
The name comes from the bright green speculum on the secondary wing feathers. This green patch is notable when the bird is in flight, and is usually visible when afloat. Apart from the noticeable “green-wing,” the hen is a plain, brown duck with few distinguishing characteristics.
The drake Green-winged Teal, on the other hand, is a stunningly handsome bird. Uppertail coverts are a rich yellow, visible at a distance and giving away its identity when dabbling in its upended manner. Overall, its wings and body are gray, but dappled with pattern; tail feathers are black. The head is a rich, ruddy brown with a broad green strip running from the eye to the neck. A vertical white slash between the breast and sides is a distinguishing mark even at a distance and in poor light when other characteristics are to see.
Hold on to that vision of the vertical white slash as I return to the Eurasian Green-winged Teal which was in Herrick’s Cove last week. This bird did not have the vertical white slash. Instead, it had a bold horizontal white stripe running along the side of its body - or more specifically, a white stripe on the scapulars of the wing. In other respects, it was identical to the teals it was feeding with, and with which it was competing in display before the hens. Even at a distance of a couple hundred yards and through a scope, the white horizontal stripe was prominent. There were two recognizably different teals present.
But now we must move from the relatively straightforward recognition of differing field characteristics to the murkier world of taxonomy - of identifying and acknowledging species.
In Europe, this bird has been known as the Common Teal, and more recently has been renamed the Eurasian Teal. If I were a visiting birder from Great Britain or the Netherlands and had seen the teals in Herrick’s cove last week, I would have listed two birds for my North American list. I would have listed the Eurasian Teal (Anas crecca) and Green-winged Teal (Anas carolinensis). Under the prodding of the Association of European Rarities Committee, all of Europe recognizes these two species.
Not so on our side of the pond. The American Ornithological Union (AOU), which determines taxonomy, has refused to take up the split of this (or these) teal(s). The American Birding Association (ABA), which determines the official bird list for the North American birders who compete for who has the biggest list, has kept lock-step with the AOU.
Consequently, as a North American birder, when I peered across the mud bar at the teals feeding upended, and specifically at the drakes showing off for the hens, I was looking at one species represented by two races. I was looking at Green-winged Teals (Anas crecca carolinensis), our common North American sub-species. And I was looking at a single Eurasian (or Common) Teal (Anas crecca crecca), a sub-species common to Europe and Asia, which somehow wandered out of its normal range.
I am sure you see the disconnect as readily as I do. It is so tempting to have fun with this American isolationism from the rest of the world. Such as - here’s another example of the bad science of the current administration - another “we know more than anyone else in the whole wide world.”
But when you come right down to it, it only matters to a few high testosterone birders and cloistered taxonomists - those who want to have a big and controlled list and those who are the most superior scientists.
It doesn’t matter if I count one species or two species, because I don’t need to show my list to you and I don’t have any need to see yours. What matters is having fun out-of-doors. Watching the birds. Sometimes pursuing a rarity. Enjoying their displays. Appreciating their beauty. Tracking the comings and goings. Having fun.
That’s good birding.
Friday, April 20, 2007
The good news is that "Spring" will be crammed together - I expect the flowers to be glorious, and coming fast on top of one another, rather than in discreet steps during this season when there is the irresistible urge to life.
Saturday, April 14, 2007
Juncos are everywhere! Throughout the winter, the flock visiting my feeders was about twenty-five. With the return of the snows last week, their numbers have exploded. A hundred or more? Counting is almost impossible, since they are constantly hopping about. They are always skittish, dashing for cover on a whim. Hormones are beginning to flow, and that just adds to their jumpiness as they pause to trill their song from a branch end, then spar with a rival.
And it is not just my yard where they are running up the bird feed bills. Every feeder I pass has dashing flits of juncos, flashing their outer white tail feathers as they head for cover. Someone leaned over to me and said, “My yard is a junco-yard.” I thought - don’t worry - the town ordinance prohibits junk in the yard, not juncos.
All along the roadways, little dark birds are pausing briefly for grit and salt, then heading for bush cover.
Juncos - more specifically, Dark-eyed Juncos. Their Latin name is Junco hyemalis. The origin of Junco is uncertain; hyemalis pertains to winter (Latin). Audubon knew these birds as the Common Snow-bird; “snowbird” is still used in popular parlance. Audubon began his description of his “snow-bird” with words that could still be written almost 200 years later: “This is one of our winter visitants from the north, which, along with many others, makes its appearance in Louisiana about the beginning of November, to remain a few months, and again, when spring returns, fly off, to seek in higher latitudes a place in which to nestle and rear its young. So gentle and tame does it become on the least approach of hard weather, that it forms, as it were, a companion to every child.”
Juncos are a different kind of sparrow in the sense that they are not “little brown birds.” There are two species of juncos in North America. The Yellow-eyed Junco is found only in the isolated mountains of southeastern Arizona. Dark-eyed Juncos are found everywhere else. There are six sub-species of juncos: Oregon, Pink-sided, White-winged, Gray-headed, Red-backed, and Slate-colored. The first five are regional populations. With the exception of the Oregon Junco which is widespread west of the Great Plains, the range of the other four regional sub-species is quite restricted. The Slate-colored sub-species is widespread and in winter may range throughout the lower forty-eight states.
The Slate-colored sub-species of the Dark-eyed Junco is the one which we know at our feeders during the winter. We may occasionally see some juncos with tinges of color along their sides or on their backs, and this sometimes gives rise to reports of “Oregon” juncos. The populations wander and mix and interbreed freely, and that’s why these six different juncos have been lumped into a single species. But the slight color we may see on the occasional junco is pale compared to the true “Oregon” form. Nevertheless, watch for those color traces.
Most juncos head to Canada in the spring where they join with other sparrows (White-throated, White-crowned, Harris’, and American Tree) to breed in mature coniferous forests. Some just head to the higher elevations in the East where coniferous forest or late deciduous successional forest become their nesting homes.
Head to any of the higher elevations in Vermont and you will find juncos breeding. I live at an elevation of about 700 feet. I have not found juncos breeding around my home. When I go up a few hundred feet, I hear them singing their simple one pitch trill. At the right time, I may even find them chasing their fledglings, meeting the demands of the young for food. I have found them singing along Steep Way and feeding young atop Newfane Hill.
Forbush reports hiking up Tuckerman Ridge from Pinkham Notch to the top of Mt. Washington in late summer, 1926: “As we neared the region of stunted spruces and balsam first about Hermit Lake, we were greeted by several small groups of Slate-colored Juncos .... [we] clambered up over the steep headwall trail to the Alpine gardens and across the broken rock of the windswept cone to the summit of New England’s highest mountain. And there, higher even than we could climb, perched on the very ridgepole of the hotel at the tiptop of Mount Washington, was a gray and white midget of a bird, greeting us with its cheery Junco song, the only bird which is regularly found in summer in this barren place.”
Right now, they are singing in the apple tree outside the kitchen, and in the maple, and the spruce, though not with great persistence. This is still the warm-up season. Most are on their way to their breeding territory.
Except ... that the snows returned, and the juncos paused on their journey and are flocking to the easy sources of food provided by our feeders. Most are Gray Snowbirds - “leaden skies above, snow below” (Forbush) - some are Black Snowbirds, as fresh and colorful as a two-toned black-or-gray and white bird can be as it sports its breeding plumage. It may still look and feel like winter in most of our neighborhoods, but watch the males (the darker birds). Their passions are on the rise, and they are beginning to chase each other, tails expanded, displaying the contrast of white and black.
For the most part, however, they are feeding - not just to survive the unseasonably cold April, but also to build up their fat reserves for their continuing migration to the northern forests. Audubon described them as a “hopping” bird when it feeds, performing “its little leaps without the least appearance of moving either its feet or legs.” The junco hops and scratches like sparrows, picking at seeds, shifting nervously - quick, active, and alert. Right now it is a seed eater. It seems like it is only eating my seed, but in fact it is foraging through grasses and along shrubby edges, never far from cover. Come summer, it will add protein to its diet in the form of caterpillars, beetles, ants, and insects.
I wrote most of this column on Monday. In the morning there were 150 juncos around my feeders. In the evening, there were barely 30. By mid-week, the number was only 15. By the time this column appears on Friday, we may have received another big delivery of snow. I wonder if the junco numbers will soar again.
Quotations from Forbush and May, A Natural History of American Birds, 1953. This book is basically an abridgment of Edward Howe Forbush, Birds of Massachusetts and Other New England States, 3 volumes, published in 1929 by Massachusetts Department of Agriculture.
Wednesday, April 11, 2007
Saturday, April 07, 2007
A Barnacle Goose spent a few days in Vernon and Hinsdale last week. The Barnacle is a fairly common European goose which winters in the British Isles and northwestern Europe and breeds on arctic islands and coasts, including Iceland and Greenland. It is a rare vagrant to North America, and like most rare vagrants, precipitates “the chase” among birders. For our local birders, the Barnacle was a refreshing change of pace; they did not have to drive hours chasing a rare bird sighting. Instead, birders from hours away came here.
The Barnacle Goose was first sighted on Sunday on the Connecticut River above the Vernon Dam among several thousand waterfowl who were night roosting on the partially open waters. Mid-day Tuesday, I walked in to the bluff overlooking the roosting area on the New Hampshire side. It was a delightfully mild, sunny day. There were a couple thousand Canada Geese, and a variety of ducks, aggregating another thousand or two. I spent two hours enjoying the sun, sitting in the grass, and scanning the flocks. I did not find the Barnacle Goose. Near sunset, when even more birds had arrived at the night roost, other birders found the Barnacle Goose strutting across the ice.
I tried again the next day. Thousands of geese were feeding during the day in old cornfields along Riverside Road in Vernon. After about 45 minutes of unsuccessfully searching the flocks, a sharp young birder came walking down the lane and joined in the search. We moved about carefully, trying for angles which would allow us to see over the dips in the fields. Something spooked the geese, and a thousand or two birds roared into flight. But they did not depart. After whirling over the corn stubble, they gradually settled down. As they were doing so, the sharp young eyes next to me picked out the Barnacle Goose in flight, but lost it when the bird settled among the mass of Canada Geese.
The flock took flight a second time, and he picked it up in flight again. This time when the Barnacle returned to the ground, it was atop a rise and in view. Most of the time, the Barnacle was resting, with its head tucked. But it also stood erect so that we could see its white face, black neck and breast, the sharp contrast with the white belly contrasting with the gray back and wings. We could compare its size with the larger Canada Geese.
A few years ago I went chasing after a Barnacle Goose in Ipswich, Massachusetts. I chose the day after it was last reported, although I did not know that at the time. A couple of weeks later, I saw a Barnacle Goose. It was with a small group of native and exotic waterfowl meandering around a small pond at the Philadelphia Zoo. Obviously, that Barnacle was not a bird which I could count, but it illustrates the problem with some sightings of rare birds and with the Barnacle Goose (a popular bird in avian collections) in particular: Is the rare bird of wild origin, or is it an escapee?
The question arose immediately with the Barnacle Goose in Vernon/Hinsdale with an interesting and informative discussion on the VTBIRD listserve. In general, the decision of most Bird Record Committees has been to reject reports of the Barnacle Goose, or as in the case of the Vermont committee to label it “accepted origin unknown.”
This past history led one of the active participants in the discussion to suggest that bird record committees have gotten themselves into an unscientific bind; it is almost impossible to prove that an individual bird is a wild bird or an escapee. To reject the Barnacle Goose out of hand means that much behavioral evidence, migratory patterns, and documented vagrancy must be ignored.
Our Barnacle Goose turned up during the peak of waterfowl migration. The flocks were moving slowly northward as the ice went out of the river. Two days after I saw the barnie, most of the geese had gone. The Barnacle was with wild, far north nesting geese including many of the “lesser” subspecies of Canada Goose, and several each of Cackling Goose, Greater White-fronted Goose, and Snow Goose. With all other geese in the flock, it was nervous, taking wing with the masses on a whim. Wariness toward humans was especially evident. Even from several hundred yards away, the geese were alert to human movements. All of these factors suggest a “wild” origin.
In addition, those who were able to observe the Barnacle Goose more closely could see no signs of captivity, such as feather wear, leg bands, or unusual behavior from a bird unaccustomed roaming free.
The Barnacle Goose nests in northeastern Greenland, Iceland, and northern Norway. So does the Pink-footed Goose, a species that is rarely kept in captivity, and that in recent years has been reported in the Northeast with some regularity. The Northeast is also well outside of the normal migratory route for Ross’, Cackling, and Greater White-fronted Geese, but these species appear regularly in small numbers. In other words, vagrancy is not unexpected among arctic nesting species. The populations of many of these geese has increased in recent decades, which also means that increased vagrancy might be expected.
For the Barnacle Goose, which seems to cause particular consternation to bird record committees, there is hard evidence (that is, proof) that they occasionally stray to North America. In the fall of 2005 along the Ottawa River in Ontario, a hunter shot a Barnacle Goose with a leg band. The goose had been banded in November, 2004, as a juvenile male (first winter bird) in Scotland. One year later the bird strayed to North America where he inadvertently contributed to the current discussion.
This was not the first occurrence of definitive Barnacle vagrancy. In the fall of 1981 a Barnacle Goose was shot in Newfoundland which had been banded in July, 1977, on Spitsbergen, Norway.
On the other hand, an old-timer who entered the discussion remembered a pair of Barnacle Geese which were released, or escaped, at Grand Manan Island in 1990, produced four offspring and wintered in 90-91 in Nova Scotia and Massachusetts. He opined that such an incidence raises doubt about observations for a long time afterward.
Two state bird record committees will be evaluating the Barnacle Goose seen last week in Vernon (Vermont) and in the Connecticut River (New Hampshire). Vermont has several records of the Barnacle Goose, all with some qualification. If accepted, the Barnacle Goose would be a first record for New Hampshire. The weight of the discussion seems to come down on the side of this Barnacle Goose being a genuine wild bird which went astray - a true vagrant.
However, just suppose that one of the record committees accepts the Barnacle Goose, and the other rejects it, or qualifies its acceptance. There’s a conundrum.
For a couple of hours on a couple of delightful spring days, I went looking for the Barnacle Goose. I saw Killdeer running through the fields, hundreds of Horned Larks swirling about, thousands of blackbirds darkening tree tops, robins rattling across lawns, ducks diving in newly open ponds and foraging across old river ice. The sun was warm. The wind was brisk. The birding was good. The Barnacle Goose made it just a little bit better.
Photos of Barnacle Goose in open water and on the ice in the Connecticut River just above the Vernon/Hindale Dam. Photos were taken by Terry Wright who was the first to find the goose and post the sighting on the VTBIRD listserve. Thank you Terry for permission to use your photos.