Friday, March 21, 2008

Loose Feathers #142

Dicksissel / Photo by Steve Maslowski (USFWS)

Birds news and links
  • What causes birds to start singing in spring? The answer seems to be an increase in photoperiod. In Japanese Quail (Coturnix japonica), longer days activate genes on the surface of the brain. The genes release a hormone associated with growth and metabolism, which trigger the release of gonadotrophins. These, in turn, stimulate the bird's testes and cause it to sing.
  • Dupont's Lark (Chersophilus duponti), a threatened songbird, occurs only in Spain. A recent study found that as its population has declined, male larks' vocal performance has declined as well. With fewer other singing males to learn from (and compete with), male larks are losing the upper portions of their singing range.
  • Male Zebra Finches (Taeniopygia guttata) sing a slightly different song when actively courting a female than when singing alone. Female finches can detect the small differences and prefer the directed song to an undirected one. The effect is particularly strong when the singer is familiar to the listener.
  • Urban Peregrine Falcons (Falco peregrinus) in England use artificial light for nocturnal hunting. Prey remains at urban peregrine sites include snipe, rails, and grebes - all rather shy species that stay under cover by day but sometimes migrate through cities at night. Scientists suspect that the falcons catch these species at night. (I have observed behavior this in DC, where peregrines will sometimes hunt in the lights around the Washington Memorial.)
  • A federal judge ordered the US Fish and Wildlife Service to list the Bald Eagle as endangered within Arizona. Conservationists had argued that the desert eagles are a distinct population and need protection.
  • Governor Corzine plans to sign the horseshoe crab moratorium bill on Tuesday.
  • As we produce and use more biodiesel, we can expect to see more biodiesel spills, which kill any birds or fish that encounter it.
  • Scientific American has a podcast interview with Jeffrey Wells of the Boreal Birdsong Initiative.
  • Audubon and National Geographic have a live crane cam set up to track migration at Rowe Sanctuary in Nebraska.
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