Nesting Common Eider (<i>Somateria mollissima</i>) Population Quintuples in Northwest Greenland

Abstract

ABSTRACT. Common eider (Somateria mollissima) populations in Greenland severely declined throughout the 20th century. As a result, in 2001, harvest regulations were changed and the length of the hunting season was reduced. Recent data suggest that these changes have been successful, and population regrowth is occurring. In the Avanersuaq District, northwest Greenland, only one systematic survey quantifying the number of nesting eiders had previously been conducted, in 1997 and 1998. Although this district had historically been identified as having the largest number of breeding eiders in Greenland, the 1997 -98 survey results showed a relatively small estimated population of 5000 pairs. However, it is not known to what extent changes in hunting regulations have affected nesting abundance in this area. Therefore, the Avanersuaq District was systematically resurveyed during the 2009 breeding season, approximately 11 years after the previous survey. These results showed that the population had increased to 5.4 times its 1997 -98 size, with an annual compounded growth rate of 15.3%. On a single island, nearly 4500 active nests were observed. Five islands had more than 2600 nests each and comprised 75% of the total nests counted. Along with historical information to account for additional nesting habitat not surveyed, the observed population growth rate from this study suggests that the overall Avanersuaq common eider breeding population size ranges from 25 000 to 30 000 pairs, or roughly half of the total estimated West Greenland breeding population. Despite the significance of the Avanersuaq District as a breeding area for common eiders, we have only limited information about this population. The effects of recent extensions of the hunting season on this population are also unknown, and the only wintering location information is based on a few individuals banded in the 1920s and 1940s. Additional research on migratory movements is suggested before any further changes are made to hunting regulations.Key words: common eider, Somateria mollissima, population growth, Greenland, Avanersuaq District RÉSUMÉ. Au cours du XX e siècle, les populations d'eiders à duvet (Somateria mollissima) ont connu un déclin considérable au Groenland. C'est pourquoi en 2001, le règlement relatif à la chasse a été modifié et la saison de chasse a été raccourcie. Selon des données récentes, ces changements ont porté fruits en ce sens que la population s'est accrue. Dans le district d'Avanersuaq, dans le nord-ouest du Groenland, seulement un relevé systématique ayant pour but de quantifier le nombre d'eiders nicheurs a été fait, et c'était en 1997-1998. Bien qu'au fil des ans, ce district a compté le plus grand nombre d'eiders reproducteurs du Groenland, le relevé de 1997-1998 avait établi que la population était relativement petite, avec une estimation de 5 000 paires. On ne sait toutefois pas dans quelle mesure la modification du règlement sur la chasse a eu des effets sur l'abondance d'eiders nichant dans la région. Par conséquent, le dist...

New species records and changes in abundance of waterfowl in northwest Greenland

“…Within our study area in the Avanersuaq District, an ameliorating climate has been suggested as a contributing factor to recent increases in both local common eider and peregrine falcon populations, and earlier nest initiation dates for gyrfalcon (Burnham and Burnham 2011;Burnham et al 2012a, b). As daily temperatures increase, the number of days available to breed and successfully raise offspring also increases, thereby allowing for a northward expansion among many species.…”

“…Wolstenholme and Saunders Islands are generally unsuitable for nesting waterfowl (i.e., cliffs and talus slopes) and were surveyed by boat with the exception of the large flat on the southwest side of Saunders Island, which was surveyed by foot. For information on specific island survey methodology, see Burnham et al (2012a). When applicable, five digit codes from the Greenland seabird colony database (Boertmann et al 1996) were used to identify specific islands.…”

“…Results of waterfowl surveys of the Carey Islands ( Fig. 1; 50 km off the coast) and common eider nest counts have been published elsewhere (Burnham and Burnham 2010;Burnham et al 2012a). Islands and coastlines were visited in years other than 2009, and while systematic surveys were not done, data were recorded, which provide useful information and have been included here.…”

“…1) is home to tens-of-millions of seabirds and the largest population of common eiders (Somateria mollissima) and snow geese (Chen caerulescens) in Greenland (Boertmann 1994(Boertmann , 1996Burnham et al 2012a). Six waterfowl species are known to breed in the area: common eiders, king eiders (Somateria spectabilis), long-tailed ducks (Clangula hyemalis), snow geese, Canada geese (Branta canadensis), and brent geese (Branta bernicla) (Salomonsen 1950;Boertmann 1994).…”

“…Six waterfowl species are known to breed in the area: common eiders, king eiders (Somateria spectabilis), long-tailed ducks (Clangula hyemalis), snow geese, Canada geese (Branta canadensis), and brent geese (Branta bernicla) (Salomonsen 1950;Boertmann 1994). Of these, the common eider occurs in the greatest numbers, with an estimated 25,000-30,000 breeding pairs based on a survey conducted in 2009 (Burnham et al 2012a). Information on the other five species is limited to Salomonsen's (1950) Birds of Greenland, a 1959 snow goose survey by Røen (1960), and general species observations collected during both historical and contemporary expeditions and brief visits to the area or anecdotal field notes (e.g., Chapman 1899;Gibson 1922;Thing 1976;Vaughan 1988;Best and Higgs 1990).…”