GRASSHOPPER SPARROW
The first time you find a grasshopper sparrow you wonder how many you have passed by over the years without knowing. You watch it sing and realize that you have probably been ignoring its thin, buzzing sounds as part of the aural backdrop of a sun-warmed pasture.
Unlike most birds, both male and female grasshopper sparrows sing their primary song, which consists of a couple of introductory tics followed by a hissing trill that trails off weakly as though swallowed by the wind. The male also sings a second song that is entirely different - a rapid jumble of squeaky and buzzy notes usually given in flight.
Just as easily overlooked as its songs is the beauty of the grasshopper sparrow. From a distance, even through binoculars, it is a beige bird with a ragged little tail and an oversize head.
In the hand, you see what another grasshopper sparrow sees: soft, warm tones on the face and breast, a bit of gold above the eye, burnt umber and chestnut on the scapulars, and a shimmer of iridescent chartreuse on the shoulder. The way it perches up on a wild rose bush to sing then flutters weakly over the pasture and dives into the grass gives it an indescribable gestalt that is similar to but not quite the same as that of its cousin, the Baird's sparrow, which can often be found singing nearby. Their genus, Ammodramus, seems to have created sparrows designed to exasperate birdwatchers with stingy views, but in truth it's their ecological niche that makes them difficult to see. You will never see a grasshopper sparrow out in the open scratching for seeds like a white-throated sparrow. It nests on the ground and finds its food on or near the ground among the forest of grass stems, coming to the surface now and then to sing or chase off another male. Fittingly, the grasshopper sparrow simply slips away unnoticed at the end of its breeding season. As soon as it stops singing in July, bird observers lose track of it, so no one has been able to figure out exactly when it leaves for its wintering grounds.
The grasshopper sparrow comes and goes in small colonies, nesting in an area for a while and then moving on. Though it is nowhere near as sporadic as the dickcissel, some years it can be hard to find. During the first twenty-five years of recording birds on the Wascana plains, Saskatchewan Museum of Natural History staff never found a single grasshopper sparrow. By 1933, though, the same year the dickcissels showed up, the province's chief game guardian, Fred Bradshaw, was finding grasshopper sparrows in vacant lots on the west edge of Regina; he estimated that at least fifty pairs were in the area. Although the grasshopper sparrow has adapted to disturbed grasslands, bird surveys indicate it is declining by 3.7 per cent per year across its range, and since 1980 in Canada it has declined by more than 6 per cent per year.
LARK BUNTING
The lark bunting is another vagabond prairie bird that will suddenly take a notion to nest in an area for a couple of years and then move on. One of the most gregarious of grassland songbirds, it roves southern Texas and northern Mexico in massive winter flocks looking for grasslands that have received enough moisture to support their numbers. Coming north in spring, the flocks separate into smaller colonies, setting up to breed on sage prairie, shrubby grassland, or even cultivated fields.
Severe drought at the heart of the lark bunting range in the northern states, southwestern Saskatchewan, and southeastern Alberta sometimes pushes the colonies northward in search of moister conditions. During the droughts of the early 1930s, early 1950s, 1964, and 1985-86, numbers of lark buntings came as far north as the Regina plains to breed. Range maps show the large geographical zone that encompasses all the places where they have been known to show up to breed now and then. However, in most years lark buntings are rarely found outside the core of their range.
The lark bunting is an oddity among North American birds. It is the only member of its genus and, unlike any other sparrow on the continent, the male changes its dress from a black-and-white tuxedo in summer (ranchers on the northern plains call it the "white-winged blackbird") to a drabber suit of browns and greys the rest of the year. And unlike many grassland birds, lark buntings are out in the open, demanding attention. People see them along roadsides, flying above crops and pastures at midday, drinking from the cattle trough, perching on fence posts. Like mobs of teenagers, they seem to do everything as a group. The males sing in communal songflight, rising in unison and then falling with their wings held above horizontal as they let out their bizarre choral arrangement of low whistles, toots, and percussive trills and buzzes. It has a chanting cadence that belongs to scrubby sagebrush prairie, and hearing it is, as Frank Roy wrote in Birds of the Elbow, "a memorable auditory experience, perhaps without parallel in the prairie bird world."
The lark bunting's nomadic habits make it one of the toughest birds for population researchers to nail down, but all states and provinces except Montana have shown a steady decline, which has been confirmed by Christmas Bird Count data from the southern states.
GREATER SAGE GROUSE
Sage grouse need large sage flats the way brook trout need streams. They court and nest in sagebrush, live there year-round, and eat sage buds and leaves to survive, especially in winter. Their droppings are the colour of sage, and people who have tasted their flesh say that it tastes strongly of sage.
The northern species of sage grouse is called "greater" because there is a smaller species that lives south of the Colorado River, the Gunnison sage grouse. The greater sage grouse is the largest grouse on the continent, with males weighing in at as much as seven pounds. Early sightings of this bird in Canada indicate that its range originally extended to the sage flats flanking the South Saskatchewan River where it crosses the Alberta-Saskatchewan border and turns eastward. Today, despite the survival of large sage flats in both provinces, the Canadian population is restricted to two small pockets: one in southeastern Alberta and southwestern Saskatchewan, and the other in the Grasslands National Park area. Some estimates suggest that by 1970, the continental population had already undergone an 85 per cent reduction from a pre-settlement estimate of 10 million. Since the mid-1970s, Canada's breeding population of sage grouse has decreased from between six and eight thousand birds to fewer than (some would say much fewer than) one thousand birds. The total number of leks in Canada has fallen by half since 1998, according to the Committee on the Status of Endangered Wildlife in Canada. The U.S Fish and Wildlife Service is monitoring greater sage grouse decline all across its range, and regularly reviews it for inclusion under the federal Endangered Species Act.
As always, the initial loss of habitat from agricultural settlement is the primary cause, but with the amount of sagebrush land remaining fairly stable in the last twenty-five years, biologists believe that something else is hastening the sage grouse's withdrawal from the northern plains. Oil and gas development in sage flats may be a more significant factor than it will be possible to prove outright. West Nile virus mosquitoes breeding in ponds made at shallow gas wells is only part of the problem. Compressor stations, where natural gas from several wells is collected and pressurized into pipelines, make enough noise to drown out the courting sounds of males on leks up to a mile away. Females use the acoustic sounds of males on leks first to locate them and then to choose who they will mate with. Some power lines erected to serve oil and gas facilities cross near nests and leks, giving avian predators an unnatural advantage in an otherwise horizontal habitat with dense ground cover. Roads and well sites destroy sagebrush and introduce weeds, degrading the quality of the habitat and allowing terrestrial predators easier access.
While overgrazing sage flats is not good for sage grouse, the opposite-no grazing at all - may be detrimental too. The kind of patchy landscape maintained by wild bison provided sage grouse with lightly grazed places where they could nest in dense cover, as well as more heavily grazed areas where they could forage outside of the nesting season. Greater sage grouse have declined in both grazed and ungrazed sage flats, but it may be worth asking whether the lack of any grazing in the east block of Grasslands National Park has contributed to the decline of its sage grouse population.
The most vexing side of sage grouse decline, however, is the low rate of juvenile survival. Biologists are trying to learn whether it is caused by problems with genetic diversity, predation, disease, or food, but for now all that can be said for certain is that young sage grouse on the northern Great Plains are not making it to breeding age in numbers sufficient to keep the population stable.
Excerpted from Grass, Sky, Song, published in Canada by HarperCollins. A Phyllis Bruce Book. Copyright 2009 Trevor Herriot. Pen-and-ink drawings by Trevor Herriot. All rights reserved.