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New hummingbird discovered, bird flu, backyard-bird counts, Arctic shorebirds, rare-bird sightings, and picky female brush-turkeys
New hummingbird discovered, bird flu, backyard-bird counts, Arctic shorebirds, rare-bird sightings, and picky female brush-turkeysBirding Briefs -- August 2007
Published: June 22, 2007 Hummingbird discovered in Colombia
One of the world's largest bird families -- Trochilidae, the hummingbirds -- just added a new member. A newly discovered 329th species joins 18 hummingbirds in the United States and Canada, 36 in Mexico, and more than 240 in South America.
The Gorgeted Puffleg (Eriocnemis isabellae) was discovered in the Serrania del Pinche mountains in southwestern Colombia in 2005. The news was announced in May. The 3.9-inch-long bird has an iridescent violet-blue and green gorget, or throat patch, a black tail, and like most other pufflegs, white tufts above its legs.
The ornithologists who discovered the bird say it has a small and unprotected range. They have recommended that the species be classified as critically endangered.
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Don't blame wild birds for flu spread
Scientists, public-health agencies, and the media routinely blame migratory birds for the spread of the highly pathogenic avian influenza virus H5N1 and often predict that birds will carry the disease from Asia into Alaska.
But three French ecologists, writing in The Ibis, the British Ornithologists' Union journal, say wild birds are not at fault. Rather, the shipping of poultry throughout Asia and Europe has caused the disease to spread.
Michel Gauthier-Clerc, Camille Lebarbenchon, and Frédéric Thomas write: "The westward road and railway links from areas of infection in China provide the most obvious routes for the initial spread of the virus if the main agent of dispersal was human movement of birds."
In addition, they say, wild birds have not been dying en masse in breeding areas and along migration routes, as would be expected if they carried the virus commonly.
The paper is the latest piece of evidence that migratory birds have been scapegoats for the dispersal of H5N1. In March, after seven years of tests did not find the virus, the U.S. Department of Agriculture said that transmission via Alaska is unlikely.
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Four-decade study finds that migrants are faring better than resident birds
The North American Breeding Bird Survey (BBS) has recorded an 18 percent decline in total bird numbers since 1966. But the downward trend has not been uniform. Species that fly south of the United States for winter are doing much better, on average, than resident species.
The findings, based on nearly 40 years of BBS data from the Atlantic and Mississippi flyways, were published in the April 2007 issue of BioScience.
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van Valiela, a biologist at Boston University and the Woods Hole Marine Biological Laboratory in Massachusetts, and Paulina Martinetto, a researcher from Argentina, found that birds that live in the United States and Canada year-round decreased 19 percent and those that migrate within the two countries declined 30 percent.
In contrast, species that breed in North America and winter in Mexico and central and southern South America showed little change, and most notably, birds that winter in Central America and northern South America increased 20 percent.
Sorting the data further, Valiela and Martinetto concluded that birds of open, edge, and wetland habitats declined while forest-dwelling species increased. Bird abundance, they conclude, reflects the expansion of North American forests in recent decades and the loss of open space.
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New research reveals international importance of disputed Alaskan area
The first-ever comprehensive survey of breeding shorebirds in a disputed portion of the coastal plain of Alaska's Arctic National Wildlife Refuge has found that the number is easily large enough to qualify the area as a site of international importance.
Led by Stephen Brown, director of shorebird research and conservation at the Manomet Center for Conservation Science, researchers estimated the number of shorebirds in the so-called 1002 Area to be about 230,000.
The total is more than twice the biological criterion for classification in the Western Hemisphere Shorebird Reserve Network (WHSRN) as a Site of International Importance (100,000 birds) and more than 10 times the threshold for qualification as a Ramsar Wetland of International Importance (20,000 birds).
The percentage of North America's population of Pectoral Sandpipers breeding in the area, more than 13 percent, also exceeds the standard WHSRN uses to define sites of international importance (10 percent).
Whether to develop oil and gas reserves in the 1002 Area has been a subject of intense debate for years. Yet until this survey, conducted in 2002 and 2004, the population sizes and distributions of nesting shorebirds was unknown.
The area occupies 1.6 million acres between the Beaufort Sea and the foothills of the Brooks Range at the northern edge of the 19 million-acre Arctic refuge. It is bounded by the Canning River to the west and the Aichilik River to the east.
"Our data indicate that nesting shorebirds tend to associate with wetland and riparian habitats that are unevenly distributed on the coastal plain," the researchers wrote in the February 2007 issue of The Condor, the journal of the Cooper Ornithological Society.
"The importance of these habitats for breeding shorebirds, many of which have declining populations, should be considered when making management decisions. Any future changes occurring in these habitats would have disproportionate effects on breeding shorebirds."
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What female brush-turkeys want
The megapodes are the only birds in the world that do not use their own body heat to incubate eggs. Instead, they lay their eggs in nest mounds, which generate the warmth required for incubation.
The Australian Brush-turkey's one-meter-tall nest mound is considered one of the most remarkable structures built by any bird. Males build the mounds and tend to them alone after females lay their eggs. Females mate with several males during the breeding season and lay eggs in many different mounds.
Researchers have known for many years that females appear to assess a mound's quality before deciding to mate with its owner. Recently, Ann Goth, a brush-turkey expert in Sydney, found that mounds with internal temperatures ranging from 32-35°C (90-95°F) received more eggs than colder or hotter mounds. Females also laid larger eggs, which produce the healthiest chicks, in mounds with the optimum temperature range.
In the January 2007 issue of The Auk, she said "this observation appears to suggest that females choose mounds rather than males."
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