Prairievogels

Fearing that the Florida grasshopper sparrow (Ammodramus savannarum floridanus) might go extinct in as little as two years, wildlife advocates have begun pressing federal officials to approve an emergency effort to capture some of the birds and breed them in captivity.The Central Florida bird is a subspecies of the grasshopper sparrow found only in vast, treeless prairies south of the Orlando area, including the Three Lakes Wildlife Management Area in Osceola County, where the largest group of the sparrows clings to survival. "We consider this the most endangered bird in the continental United States," warns a letter sent last week to the U.S. Fish and Wildlife Service by Audubon of Florida; Archbold Biological Station; and a University of Central Florida ecologist, Reed Noss. "In light of population levels possibly below 200 individuals and very rapid recent declines of [the sparrow], … we conclude that the risk of delay exceeds the risk of mistakes," the letter states. The bird is small, elusive and hard to study. One of the things it is well known for is being closely related to the dusky seaside sparrow (Ammodramus maritimus nigrescens) of east Central Florida. That bird suffered a sharp decline in numbers because of mosquito-control projects decades ago that wrecked the ecological health of the marshes where it lived.

Breeding Bird Surveys (BBS) conducted by the Biological Resources Division of the U.S. Geological Survey and volunteers throughout the country reveal that grassland birds, as a group, have declined more than other groups, such as forest and wetland birds. There are many examples of population decline in grassland birds, most notably the extinction of the heath hen (Tympanuchus cupido cupido) from the northeastern United States. Over the 25-year period 1966-1991, New England upland sandpiper (Bartramia longicauda) and eastern meadowlark (Sturnella magna) populations declined by 84 and 97 percent, respectively. The greater prairie-chicken (Tympanuchus cupido) has experienced an average annual rate of decline of over 10 percent during this same 25-year period. These examples and others illustrate the decline in grassland birds on a continental scale. While loss of grassland breeding habitat is likely the largest factor contributing to the decline in many grassland bird species, other factors have played a role. Brood parasitism by brown-headed cowbirds, increased use of pesticides and other agricultural chemicals toxic to birds, mortality during migration, and loss of wintering habitats may have contributed to population declines in many species.

Das Präriehuhn (Tympanuchus cupido) gehört zur Ordnung der Raufußhühner. Es kommt in mehreren Unterarten, Großes Prairiehuhn (T. c. pinnatus), Attwari Präriehuhn (T. c. attwari) und Kleines Präriehuhn (T. pallidicinctus) in den USA endemisch vor. Eine weitere Unterart, das Heidehuhn (T. c. cupido), ist ausgestorben. Wie alle Raufußhühner ist das Prairiehuhn plump gebaut und hat befiederte Beine und Zehen. Hahn und Henne zeigen einen deutlichen Sexualdimorphismus. Beide Geschlechter besitzen zwar weitgehend übereinstimmende Merkmale wie Gefiederfarbe, Luftsäcke, Gewicht etc., sie sind beim Männchen jedoch deutlich ausgeprägter und farbiger. Das Präriehuhn kam einst millionenfach in den früheren Prairiegebieten ganz Nordamerikas vor. Von diesen Prairiegebieten sind heute nur noch wenige, stark fragmentierte Areale erhalten. Größere Populationen von T. c. pinnatus leben noch in den Agrargebieten der Bundesstaaten Kansas, Nebraska, South Dakota und Oklahoma. In diesen Staaten ist die Jagd auf diese Tierart erlaubt. Die Populationen in Illinois, Iowa und North Dakota sind kleiner als 300 Tiere. Die Population von T. c. attwateri ist auf kleine Gruppen mit weniger als 1000 Tieren in Südost-Texas geschrumpft. T. c. pinnatus ist in 15 Bundesstaaten vom Aussterben bedroht. Einige Staaten haben in den letzten Jahren begonnen, kleine, isolierte, umzäunte Rückzugsgebiete einzurichten, in denen die Tiere die ursprüngliche Prairievegetation mit zahlreichen Grasarten und lichten Eichenwäldern vorfinden.

A type of sparrow that lives only in Florida has mysteriously plunged in number so dramatically that scientists fear it will vanish forever well before the end of this decade. Florida grasshopper sparrows (Ammodramus savannarum floridanus), which inhabit grasslands in the state's interior south of Orlando, have been listed as endangered for the past 26 years. But the furtive birds have all but disappeared in recent years from one of their last three prairie refuges and, in what has become a wildlife emergency, may now total fewer than 200 in just two counties, Osceola and Okeechobee. The bird, a subspecies of grasshopper sparrows, eats grasshoppers and sings like one, with a "tick, tick, buzz." It also runs — hidden by dry-prairie grasses — as much or more than it flies, bedeviling researchers' attempts to learn more about it.

Lesser prairie-chickens (Tympanuchus pallidicinctus) once covered the prairie land of the Great Plains where they were an abundant game bird. In Oklahoma, the lesser prairie-chicken has declined to the point of becoming a state species of special concern, vulnerable to extinction from limited range, low population and other factors. The trend in Oklahoma since the 1980s, according to Oklahoma Department of Wildlife Conservation data, shows a precipitous decline. At a presentation in 2008 on the Selman Ranch, near Woodward, Okla., Dwayne Elmore, an Oklahoma Cooperative Extension Service wildlife biologist and assistant professor in the department of natural resource ecology and management at Oklahoma State University, expressed his concern to wildlife biologists: "I like to call them the grassland canary. Because, like a canary in a coalmine, it is the first thing that goes when there is something wrong with the prairie; so, that is why I am really interested--not just to have another species around. The reason we want to keep our eye on them is because they are our early warning indicator that something is seriously wrong with the grasslands."

According to the recently released State of Canada's Birds report, grassland bird populations are declining rapidly in the country's prairie region. Bird enthusiasts all over Canada have noticed this decline said Hatter Phil Horch, a longtime birder and Grasslands Naturalists member. "We're seeing tremendous decline in some species," he said – and this includes local populations. "There are some species that get a lot of publicity like burrowing owls (Athene cunicularia) and sage-grouse (Centrocercus urophasianus) and so on, and definitely they are in decline," he said. "But species that a lot of people aren't familiar with are declining as well." There has been loss or degradation of native grasslands and pasture lands through agriculture, such as conversion to "grains, oilseed or fibre crops which provide poor habitat for most birds."

"It's an indicator of the health of the prairies as a whole," said Marty Drut, also with the Grasslands Naturalists - as plants, insects, mammals and other prairie species are also considered at risk. "It's an indication of how we've been treating the environment and how these species are responding to our long-term care of the environment."

For millennia, the flute-like song of the Western Meadowlark (Sturnella neglecta) signaled the beginning of spring in the Willamette Valley. But, to quote Rachel Carson, spring in the Willamette Valley now comes unheralded, and the “early mornings are strangely silent where once they were filled with the beauty of bird song.” This may seem an exaggeration for anyone lucky or unlucky enough to be woken by bird song at daybreak, a not uncommon occurrence for spring in the Valley. Nonetheless the Western Meadowlark’s unique warbling call has declined substantially. Studies vary, but there are indications that, since 1968, the Willamette Valley’s meadowlarks have been declining at 10% a year—the highest rate of decline among all grassland bird species in the Valley. One study reported a 59% decline in detections of meadowlarks between 1996 and 2008. Because of this, Western Meadowlarks have been identified as the “Species of Greatest Conservation Need” by the Oregon Department of Fish and Wildlife. Their breeding habitats are grasslands, prairies, pastures, and abandoned fields, all of which may be found from across western and central North America to northern Mexico. They mainly eat insects, although they will devour seeds and berries.