Bird decline, insect decline and neonicotinoids

Anthropogenic habitat loss is usually cited as the most important cause of recent species’ extinctions. We statistically compared areas in Canada where imperiled species currently occur, versus areas where they have been lost. Using multiple regressions, we relate the numbers of species that had suffered range reductions in an ecoregion to variables that represent present habitat loss, pesticide use and human population density. We find high losses of imperiled species in regions with high proportions of agricultural land cover. However, losses of imperiled species are significantly more strongly related to the proportion of the region treated with agricultural pesticides. The relationship between species losses and area treated with pesticides remains significant after controlling for area in agriculture. Our results are consistent with the hypothesis that agricultural pesticide use has contributed significantly to the decline of imperiled species in Canada. Habitat conversion per se may be a less important cause of species declines than how that converted habitat is used.

We reviewed the historic and present distribution of Greater Sage-Grouse (Centrocercus urophasianus) in Canada and found that the species has been eliminated from approximately 90% of its estimated historic distribution. Sage-grouse have been extirpated from British Columbia and reduced to remnant populations in Alberta and Saskatchewan. Estimates of the size of the population decline in Canada range from 66 to 92% over the last 30 years based on currently occupied habitat. The number of active lek sites has continued to decline, suggesting that some habitats have become unsuitable to support viable sage-grouse populations. Number of yearling males recruiting to leks each spring has been low, suggesting that production and overwinter survival of young are the major problems related to the decline. Low chick survival rate, with only 18% surviving to 50 days of age, is the most likely parameter contributing to the population decline.

A dozen environmental groups are threatening the federal government with legal action unless it overrules two provinces and takes emergency steps to save sage grouse (Centrocercus urophasianus). They say the distinctive bird could be gone from Alberta within a year if nothing is done quickly. The threat comes in a letter sent Wednesday to federal Environment Minister Peter Kent, in which the groups say Canadian law requires Ottawa to preserve threatened species if provincial governments aren't doing the job. Scientists say a species that numbered 20,000 a few years ago across the southern prairies is down to 13 male birds in Alberta and 43 in Saskatchewan. "The probability of them being around in the next couple years is slim," said biologist Mark Boyce of the University of Alberta. "They've just gone down, down, down."

The Sidamo Lark (Heteromirafra sidamoensis) is endemic to Ethiopia. Always a rare sight, the elusive bird may soon vanish from the prairie grasses of Ethiopia forever. Listed as Vulnerable since 2000 on the IUCN Red List, it was uplisted to Endangered in 2007, and then further to Critically Endangered in 2009. Its habitat already restricted to less than 100 square kilometers, the lark is rapidly losing territory as local residents, the Borana ethnic group, convert grassland into heavily grazed pasture. Unless the Borana are allowed to resume their nomadic ways, within the next few years the Sidamo lark will likely become the first known bird species to vanish from mainland Africa, researchers say.

Tallgrass prairie butterfly surveys in recent decades in four states in the USA indicate numerous declines of prairie-specialist butterflies including Speyeria idalia, Oarisma poweshiek, Atrytone arogos, Hesperia dacotae, and H. ottoe in fire-managed preserves, including large high-quality ones.

The Sage Grouse (Centrocercus urophasianus) is the largest grouse in North America, where it is known as the Greater Sage-Grouse. Its range is sagebrush country in the western United States and southern Alberta and Saskatchewan, Canada. The greater sage-grouse is known for its elaborate courtship dance on the Prairies, but its enthusiastic display of virility might not be enough to save the endangered species from being wiped out in Alberta as soon as next year. A group of scientists hope to come up with ways to prevent the eventual extinction of the sage-grouse. Cliff Wallis from the Alberta Wilderness Association says the numbers have dropped to 30 in Alberta from the thousands 25 years ago. Wallis says the Alberta and federal governments are aware of the plight of the sage-grouse, but so far have failed to act. Cam Aldridge from Colorado State University says a similar decline of the species is occurring in the United States as well.

In Canada, the Prairie population of Loggerhead Shrikes Lanius ludovicianus excubitorides occurs in central and southern Alberta and Saskatchewan, and in southern Manitoba. They feed on grasshoppers, beetles, mice, small birds, snakes, lizards and frogs. Scientists observing a nest with eight nestlings watched as the parent birds appeared with a grasshopper every four minutes over the space of an hour! The last 100 years have witnessed the gradual decline of this subspecies. Pesticides are a critical factor in this decline.