Bird Tales With a Bite
Their "gross beaks" may be the reason for their renown, but these five species also have some interesting stories to tell
UNLESS you've had an evening grosbeak lock its massive mandibles on your index finger and not let go, you have no idea of the strength in the jaws of this boldly dressed songbird whose genus name translates as "kernel-cracker." The first time it happened to me, I wasn't wearing gloves. That's a mistake you never repeat when facing a cage crowded with burly finches that are as pugnacious as they are gluttonous for sunflower seeds. I've got a scar to remind me.
It was the winter of 1962 and I had recently earned a bird-banding license from the U.S. Fish and Wildlife Service (FWS) after an apprenticeship with my mentor in all things ornithological, Gene Kenaga, who at the time was president of the Michigan Audubon Society. My first project was to complete a census of the usual suspects that visited my feeding station on the outskirts of Midland: blue jays, cardinals, chickadees, nuthatches, goldfinches.
That was before evening grosbeaks started tumbling from the snow-laden sky like bronzed autumn leaves falling from the big sugar maple in my front yard. By mid-May, when the last hangers-on vacated the premises for unknown (to me) nesting places, nearly 400 of them wore shiny new FWS-issued anklets that, I hoped, would shed light on the travels of "my" grosbeaks.
History doesn't credit the French explorer who coined the sobriquet grosbec for this tenant of northern coniferous forests. The name would come to be shared with four other large songbirds, each with its own niche in the immense North American landscape, whose gross beaks are used for such chores as crushing cones, seeds and hard-bodied insects, or nipping buds and bundles of tender pine tree needles.
I now live in the Hudson Valley of New York, and while the calendar tells us the vernal equinox occurs on March 20, it's not truly spring to me until rose-breasted grosbeaks show up in my woodlot around May 1. Indeed, of all the stored memories from a lifetime of watching birds, none is more indelible than seeing five awesome males on a Droll Yankee feeder at the same time.
The black-headed grosbeak with its melodious song assumes the role of harbinger of spring in foothill woodlands, streamside groves and lush gardens across most of the West. The South's delegate to this loosely related group is the blue grosbeak, which looks like the familiar indigo bunting on steroids. The most embarrassing moment of my neophyte birding days, when I knew next to nothing about bird distribution, was summoning Kenaga to see the "blue grosbeak" I had just added to my life list. In central Michigan? Unlikely! Think indigo bunting.
Making it the fifth of its kind is the pine grosbeak, whose excursions well south of its home in subarctic and boreal forests are so infrequent that it's been years since I saw a flock of these remarkably tame finches harvesting winter buds in a neighbor's butternut tree.
Photo, left: © WAYNE LANKINEN; Photo, right: © MICHAEL QUINTON
NORTHERN BEAUTIES: Though widespread in spruce and fir woodlands in the Far North, pine grosbeaks, such as this adult female (left) and male (right) in Alaska, rarely venture far into the lower 48 states. Often found foraging together in small flocks, the birds are methodical feeders that frequently exhaust a forest food source before moving on to another.
Big and beautiful, predictable or capricious, the grosbeaks captivate their human audiences in an inimitable way. And all of them have stories to relate, especially the way those enormous bills serve their life styles. None, though, are as fascinating as the evening grosbeak's tale, beginning with the origin of the species' vernacular name, a lovely misnomer that has endured for more than 175 years.
The first words penned about the evening grosbeak are found in the journals of Henry Schoolcraft, who made early topographical surveys of the upper Great Lakes and was the government Indian agent at Sault Ste. Marie, Michigan, on April 7, 1823, when he wrote: "During severe winters in the north, some species of birds extend their migrations farther south than usual. This appears to have been the case during the past season. A small bird, yellowish and cinereous, of the grosbec species, appeared this day in the neighborhood of one of the sugar-camps on the river below, and was shot with an arrow by an Indian boy, who brought it to me. The Chippewas call it Pashcundamo, in allusion to the stoutness of its bill, and consequent capacity for breaking surfaces."
The mention of sugar camps refers to the evening grosbeak's delight in sipping maple sap flowing from snipped-off twigs. As for breaking surfaces, it can crush food items that require a force of up to 125 pounds in testing devices--even rock-hard cones hanging on bald cypress trees, a feat otherwise credited only to the now-extinct Carolina parakeet.
Later that same year, one Major Delafield, a government boundary agent, encountered a grosbec flock near a dense cedar swamp northwest of Lake Superior. He remembered the bird in Schoolcraft's possession, noted how "its mournful cry about the hour of my encamping [which was at sunset] attracted my attention" and surmised that "this bird dwells in such dark retreats, and leaves them at the approach of night." Schoolcraft, meanwhile, sent his specimen to William Cooper, an ornithologist at the Lyceum of Natural History in New York City. With Delafield's journal pages in hand, Cooper in 1825 named the new species Fringilla vespertina, meaning "finch of the evening." And for the next 100 years and more, naturalist writers such as Elliott Coues would wax lyrical about "the tuneful romance which the wild bird throws around the fading light of day."
Truth is, there's nothing romantic about the screeching of a flock of evening grosbeaks, and males apparently do not even have a typical song in their vocal repertoire. Moreover, as Arthur Cleveland Bent, the legendary compiler of avian life histories, observed: "Ordinarily, the species is not crespular, and in fact it might better be called ‘morning grosbeak' for it is most active early in the day." Yet while taxonomists move the bird from genus to genus to genus--currently it's Coccothraustes, which reflects a close kinship to the Old World hawfinch--that poetic popular name has survived.
But the bird has certainly earned the name given it by the French Canadians, le grosbec errant ("the roving grosbeak"). Evening grosbeaks have descended on feeding stations in all of the 48 contiguous states during winter irruptions that are apparently triggered, as Schoolcraft surmised, by a dearth of pine cones in their usual environs.
In Schoolcraft's time, however, the evening grosbeak was rarely seen east of Lake Superior until the winter of 1855. That season, small flocks (scouting parties?) turned up in Toronto. And over the next 35 years, wandering grosbeaks were collected as far south as Indiana and Kentucky, and a few reached western New York. Then came the winter of 1890 and the first of several spectacular invasions by thousands of evening grosbeaks into eastern Canada and New England, all the way to the Atlantic shore.
Photo: © STEVE AND DAVE MASLOWSKI
SEED LOVERS: The proliferation of bird feeders in North America has helped the evening, black-headed (above) and rose-breasted grosbeaks all prosper throughout their ranges. One observer reported seeing a female grosbeak shell and eat 43 sunflower seeds in a single backyard visit.
Inevitably, some of the visitors liked what they found, stayed to nest and their progeny populated the North Woods from Newfoundland and Maine to Manitoba and Minnesota. "No other species that we know of has staged so massive a trek across our continent," wrote the late Robert Arbib, editor of American Birds magazine.
Conventional wisdom attributes the evening grosbeak's spectacular eastward range expansion to the widespread plant-ing of box elders as street trees and farm-country windbreaks. A smallish and short-lived maple, the box elder produces copious clusters of winged seeds that last all winter, providing those pioneering flocks with a dependable food supply. Since then, however, the box elder has fallen out of favor as an ornamental tree because it litters sidewalks and lawns with windrows of seeds. But the proliferation of bird feeders stocked with sunflower seeds has kept the birds fat and sassy on their travels. One observer reported that a female grosbeak shelled and ate 43 sunflower seeds in a single visit, enough for a fourth of its daily energy needs.
Pine grosbeaks, on the other hand, rarely descend on feeding stations south of the Canadian border except in Minnesota, where large numbers show up nearly every year. Virginia Tech University ornithologist Curt Adkisson notes, however, that pine grosbeak irruptions into the Northeast occurred more frequently in the past. He speculates that there has been a dramatic population decline in eastern Canada due to large-scale clear-cutting operations.
Unlike other grosbeaks, the diet of this plump, red-and-gray finch consists almost exclusively of buds, fresh needle growth, fruit and seeds--except during nesting season, when it raises its young mainly on insects and spiders. Wintering flocks are especially attracted to frozen crab apples and mountain ash trees with their clusters of shiny orange-red berries, and they will exhaust a good food source before moving on.
The feeding habits of some black-headed grosbeaks, meanwhile, take a surprising twist in winter. This flashy western bird with its yellowish vest can be found nesting in a potpourri of habitats, from aspen groves and pine forests to orchards and willow-lined desert streams. It is one of the most common songbirds in some areas. In his book, Lives of North American Birds, Kenn Kaufman writes, "In midsummer, the oak woodlands often resound with the insistent whining whistle of young black-headed grosbeaks begging for food." In California groves, the main course might be oak moth larvae, pupae and adults, with figs or strawberries for dessert.
In fall, black-headed grosbeaks migrate to central Mexico where birds that settle in montane spruce forests plunder swarms of wintering monarch butterflies. Monarchs are famous for having few enemies; their caterpillars feed on toxic milkweed and a predator that tastes one isn't likely to try again. The grosbeaks, however, are immune to the poison's emetic effects, though researchers report that the birds reduce the intake of the noxious chemical by discarding the insects' wings and gorging on monarchs once every eight days.
East of the Great Plains, the deciduous woodlands belong to the rose-breasted grosbeak with its colossal white bill, an appendage that is often stained with wild berry juice. In my opinion, this is the most stunningly dressed of all our Neotropical migrants. Yet the "rosebird" of olden days is heard more often than seen as it flits through the forest penthouse, whistling. Kaufman describes the bird's tune perfectly as "an improved version of the American robin's voice." If inspired, it may sing all night.
Rose-breasted grosbeak nests are so loosely built that it is sometimes possible to count the eggs from below. The parent birds share incubation duties and the male will care for the fledglings while the female starts a second nest. She becomes so possessive of a good mate that other females vying for his attention will be driven away.
As for the blue grosbeak, the story is that there's not much to tell. A bird of edge thickets rather than woody habitats, you might find it warbling from roadside wires anywhere in the South. But Jim Ingold, a biologist at Louisiana State University, relates that "while the bird is widespread throughout its breeding range, it is generally scarce and virtually all aspects of its biology are poorly known." We do know that blue grosbeaks use their thick, black-and-silver bills to crunch bugs and and other prey, but there are few details about their foraging habits or nesting ecology.
And yes, Ingold says, making me feel a little better about that long ago goof, indigo buntings are often mistaken for blue grosbeaks. Close relatives, they share the same habitat and sing similar songs. The problem is, indigos are so common that the occasional blue grosbeak gets lost in the aural clutter. I'm still looking for my first one.
New York writer Les Line is a field editor of this magazine.