Resources related to Status

Parasitism, Population Dynamics And Hybridization In Cavity- Nesting Seaducks

Intraspecific and interspecific brood parasitism occur frequently in waterfowl. We examine the consequences of these behaviors to the population dynamics of Barrow's and Common Goldeneyes during a 10 year study period in central British Columbia. The frequency of parasitism was significantly related to population density and to the availability of nest sites. High levels of parasitism, in turn, resulted in reduced reproductive success of females.

Philopatry In Nesting Adult Female Spectacled Eiders At Kigigak Island, Yukon Delta National Wildlife Refuge, Alaska

In response to the dramatic decline of the species (early 1970's to 1990's) on the Yukon-Kuskokwim Delta, I conducted a nesting ecology study on spectacled eiders (Somateria fischeri) at Kigigak Island from 1992-1996. The Kigigak Island population has had relatively high nest success between 1992-1996 (92%, 63%, 70%, 64%, and 82%, respectively). More than 50% of the nesting females have been marked (n=161). Preliminary results show that 70% of the marked females have returned to nest at least once following their banding year and that 52% returned at least two consecutive years.

Population Dynamics Of Spectacled Eiders On The Yukon- Kuskokwim Delta, Alaska

Spectacled Eider (Somateria fischeri) populations in western Alaska have declined precipitously since the late 1970's. Subsequently, the species was listed as threatened in 1993. To investigate the potential causes of the decline, we developed a deterministic model of Spectacled Eider population dynamics based on demographic data we collected on the Yukon-Kuskokwim Delta, Alaska, from 1991-1996. The model incorporated estimates of nest success, clutch size at hatch, duckling survival, age of first reproduction, and adult female survival collected at a two locations.

Mitochondrial DNA control region sequence variation in Common Eiders reveals extensive mixing of subspecies

We sequenced a hypervariable 319 bp portion of the control region of mitochondrial DNA in five subspecies of Common Eiders (Somateria mollissima) and an outgroup sample of King Eiders (S. spectabilis). Variation was found at 71 sites (22%), which defined 56 haplotypes in the total sample. A genealogical tree relating the haplotypes revealed three major clades, but with the exception of Common Eiders (S. v-nigra) from Alaska, they did not correspond with putative subspecies identities.

Evidence of Population Declines among Common Eiders Breeding in the Belcher Islands, Northwest Territories

Information regarding the status of common eiders Somateria mollissima breeding in the Canadian Arctic is lacking. In 1997, we surveyed five island archipelagoes in the Belcher Islands in Hudson Bay (56 00'-57 30'N, 79 30'-80 00'W) from 3 - 23 July 1997. Our results were compared with eider surveys of the same islands completed between 1985-89 using a standard protocol. This study represents the first population trend data of any common eider population breeding in the eastern Canadian Arctic. 1416 nests were found on 431 islands; most (94.1%) while the female was still incubating.

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