Population size and factors affecting at-sea distributions of four endangered procellariids in the tropical pacific
Article Abstract:
An estimate of the size of the population of four taxa of procellarids in the eastern tropical Pacific was made. The census was done at-sea. The pelagic population on the basis of breeder and non-breeder was 10,600(p. a. auricularis), 18,000-19,000(P. a. newelli), 3,750-4,500(Pt. p. sandwichensis) and 20,000(Pt. p. phaeopygi) pairs. The maximal and minimal estimate calculations showed breeding populations larger than earlier thought for first three subspecies and similar for Pt. p. phaeopygia. The range of birds commuting from colonies varied from 650 km(p. a. auricularis) to 13,000 km (P. a. newelli and Pt. p. sandwichensis). Foraging behavior is in consonance with wing morphology of each group.
Publication Name: The Condor
Subject: Biological sciences
ISSN: 0010-5422
Year: 1995
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The effects of weather and lunar cycle on nocturnal migration of landbirds at Southeast Farallon Island, California
Article Abstract:
Multivariate and univariate statistics were used to study the effects of climate and lunar cycles on the nocturnal migration of birds at Southeast Farallon Island (SEFI), CA. Results revealed that arrival at SEFI increased with low wind speeds, low visibility, full cloud cover and lack of fog, while departure and migration volume increased with low wind speeds, low but rising pressure, clear skies, increased visibility and reduced moonlight. Arrival and departure was only minimally affected by wind direction and air temperature. A convergent evolution of weather-migration strategy selection is suggested.
Publication Name: The Condor
Subject: Biological sciences
ISSN: 0010-5422
Year: 1993
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Status and trends of the ashy storm-petrel on southeast Farallon Island, California, based upon capture-recapture analyses
Article Abstract:
Capture-recapture technique was used in the investigation of the ashy storm-petrel, Oceanodroma homochroa, population size and dynamics in the southeast area of Farallon Islands, CA. Taped vocalization playbacks were used to lure the birds to fixed sampling locations. Results reveal that the population of the storm-petrel declined by 34% in the area in 20 years. The number of breeding birds also dropped by 42% in the same period.
Publication Name: The Condor
Subject: Biological sciences
ISSN: 0010-5422
Year: 1998
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