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Article Excerpt
ABSTRACT. The northern fulmar (Fulmarus glacialis) is a common seabird of the North Atlantic Ocean and marine areas of eastern Nunavut. We studied attendance patterns of fulmars at two colonies in the Canadian High Arctic to assess variation in attendance at high latitudes, to compare these patterns to those found for fulmars breeding at colonies to the south, and to determine how weather conditions and breeding status might influence attendance. Colony attendance patterns shared similarities across the species' range, although local variation in the timing of food supplies may explain differences in the seasonal timing of peak counts at colonies. Stronger winds and extreme inclement weather resulted in lower counts of birds at colonies. Seasonal and daily variation in attendance was attributable to differences in the numbers of failed breeders or non-breeding birds. Changes toward earlier breakup and reduced extent of sea ice should lead to earlier peaks and continued short periodicities in colony attendance cycles of Arctic fulmars.
Key words: colony attendance, Fulmarus glacialis, marine production, northern fulmar, weather
RESUME. Le fulmar boreal (Fulmarus glacialis) est un oiseau marin courant du nord de l'ocean Atlantique et des regions marines de Test du Nunavut. Nous avons etudie les tendances de frequentation des fulmars a deux colonies situees dans l'Extreme-Arctique canadien dans le but d'evaluer les variations de frequentation en hautes latitudes, de comparer ces tendances a celles caracterisant les fulmars se reproduisant aux colonies se trouvant plus au sud et de determiner en quoi les conditions meteorologiques et le statut de reproduction peuvent exercer une influence sur la frequentation. II existait des similarites entre la repartition des especes sur le plan des tendances de frequentation au sein des colonies, bien que les variations locales en matiere de disponibilite des approvisionnements alimentaires puissent expliquer les differences entre les denombrements saisonniers de pointe aux colonies. Les vents violents et le temps des plus inclements se sont traduits par des denombrements d'oiseaux moins grands aux colonies. Les variations de frequentation saisonnieres et quotidiennes etaient attribuables aux differences sur le plan du nombre de reproducteurs manques ou d'oiseaux ne se reproduisant pas. Les changements qui se manifestent, tels que l'avancement de la debacle et une moins grande surface de glace de mer, devraient entrainer des pointes plus natives et des periodicites continuellement courtes pour ce qui est des cycles de frequentation des colonies de fulmars boreaux.
Mots cles: frequentation des colonies, Fulmarus glacialis, production marine, fulmar boreal, conditions meteorologiques
Traduit pour la revue Arctic par Nicole Giguere.
INTRODUCTION
Among broadly distributed bird species, reproductive traits (e.g., phenology, egg or clutch size, breeding success) may vary significantly in response to differing local environ\mental conditions within the breeding range (e.g., Robertson et al., 2006). Hence, proper management of such species requires knowledge of regional variation in these traits and of the factors that might lead to local adaptations. The northern fulmar (Fulmarus glacialis) is a petrel with a circumpolar distribution, breeding across 35[degrees] of latitude (to 80[degrees] N; Hatch and Nettleship, 1998). This seabird is a long-lived predator and scavenger that lays a single egg annually (Mallory, 2006). Its highly efficient flight is enhanced during windier conditions (Furness and Bryant, 1996). Most northern fulmars are year-round inhabitants of the low Arctic and Boreal oceanographic zones (Salomonsen, 1965), where the birds are ubiquitous on the open ocean. However, fulmars from High Arctic colonies are found in the low Arctic or Boreal zone only over the winter; each May, they migrate north to their breeding colonies, where they remain through September (Mallory et al., 2008a).
Fulmars breeding in the High Arctic experience environmental constraints (lower temperatures, near-constant daylight, snow, and sea ice) not experienced by fulmars elsewhere in the breeding range (Hatch and Nettleship, 1998; Mallory and Forbes, 2007). Thus, we were interested in determining the variation in colony attendance by birds at different High Arctic colonies, and how their attendance patterns compared to attendance by conspecifics nesting in the Boreal zone, where wind and weather are known to influence fulmar attendance (Coulson and Horobin, 1972; Hatch, 1989; Furness and Bryant, 1996). An assessment of factors influencing Arctic fulmar breeding ecology is timely, as environmental conditions are changing rapidly in this region (ACIA, 2005).
We monitored colony attendance by fulmars at two colonies in the Canadian High Arctic: Prince Leopold Island and Cape Vera (Fig. 1). While some aspects of fulmar attendance at Prince Leopold Island have been described (Hatch and Nettleship, 1998; Gaston et al., 2006), we provide the first description of colony attendance at Cape Vera, the northernmost fulmar colony in Canada. We compared our observations to attendance patterns observed elsewhere and analyzed how weather affected attendance at High Arctic colonies. Although fulmars exhibit strong diurnal patterns in colony attendance at lower latitudes, Falk and Moller (1997) found no such trends at a colony in Greenland located only 4[degrees] farther north than Cape Vera, so we expected that fulmars in High Arctic Canada would exhibit weak diurnal trends in attendance. However, we predicted that their colony attendance would be consistent with the pattern observed at southern colonies; that is, attendance would be lower during stronger winds or storms, particularly for nonbreeding birds or failed breeders.
METHODS
Research was conducted at two northern fulmar colonies in the Canadian High Arctic oceanographic zone (Salomonsen, 1965; Fig. 1). Breeding phenology, behavior, and success at both colonies are influenced by...
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