Post by Andrei Tchentchik on Mar 1, 2020 14:11:55 GMT 2
(.#A.039).- North America has lost 3 billion birds since 1970.
North America has lost 3 billion birds since 1970.
September 20, 2019.
Goldfinch and blackbirds among the most affected.
WASHINGTON (AFP) The bird population in North America has collapsed by a quarter since 1970, nearly 3 billion fewer birds in the wild, according to a study published yesterday by the journal Science.
Yellow Goldfinch
Rural birds are the most affected, probably due to the reduction of meadows and meadows and the extension of farmland, as well as the use of pesticides that, by killing insects, affect the entire food chain. But forest birds and generalists are also in decline.
However, 90% of the losses occur in 12 bird families, including sparrows, warblers, blackbirds, and goldfinch (species that live in the United States and Canada are not the same). than in other parts of the globe).
American Robin
These figures correspond to the decline observed elsewhere, particularly in France, where the National Observatory of Biodiversity has estimated that the decline of field birds between 1989 and 2017 was 30%.
SOURCES
The US study combines two data sources.
The first comes from the annual surveys carried out each spring at the time of the breeding season by thousands of volunteers, using an identical method, since 1970. On a 40-kilometer country road route, these observers stop every kilometer 3 minutes and count all the birds they see. Researchers then compile and analyze this data.
The second source comes from surveys of 143 radar stations that detect the masses of birds quite finely during their migration at night. More than half of the birds in North America migrate south.
Ducks and geese are the big exception: their populations, after being threatened, have increased since 1970. It is thanks to the awareness of hunters who have supported protective measures, says a co-author of the study, Ornithologist Ken Rosenberg of Cornell University.
CAUSES INCORRECTLY INCLUDED
The causes are poorly understood, but ornithologists mention other factors, such as cats left outside and windows of houses in which birds are smashed, a cause of mortality far from innocuous: the number of birds killed in these conditions were estimated in 2014 between 365 million and 1 billion per year in the United States.
F I N.
North America has lost 3 billion birds since 1970.
September 20, 2019.
Goldfinch and blackbirds among the most affected.
WASHINGTON (AFP) The bird population in North America has collapsed by a quarter since 1970, nearly 3 billion fewer birds in the wild, according to a study published yesterday by the journal Science.
Yellow Goldfinch
Rural birds are the most affected, probably due to the reduction of meadows and meadows and the extension of farmland, as well as the use of pesticides that, by killing insects, affect the entire food chain. But forest birds and generalists are also in decline.
However, 90% of the losses occur in 12 bird families, including sparrows, warblers, blackbirds, and goldfinch (species that live in the United States and Canada are not the same). than in other parts of the globe).
American Robin
These figures correspond to the decline observed elsewhere, particularly in France, where the National Observatory of Biodiversity has estimated that the decline of field birds between 1989 and 2017 was 30%.
SOURCES
The US study combines two data sources.
The first comes from the annual surveys carried out each spring at the time of the breeding season by thousands of volunteers, using an identical method, since 1970. On a 40-kilometer country road route, these observers stop every kilometer 3 minutes and count all the birds they see. Researchers then compile and analyze this data.
The second source comes from surveys of 143 radar stations that detect the masses of birds quite finely during their migration at night. More than half of the birds in North America migrate south.
Ducks and geese are the big exception: their populations, after being threatened, have increased since 1970. It is thanks to the awareness of hunters who have supported protective measures, says a co-author of the study, Ornithologist Ken Rosenberg of Cornell University.
CAUSES INCORRECTLY INCLUDED
The causes are poorly understood, but ornithologists mention other factors, such as cats left outside and windows of houses in which birds are smashed, a cause of mortality far from innocuous: the number of birds killed in these conditions were estimated in 2014 between 365 million and 1 billion per year in the United States.
F I N.
