Temporal and spatial patterns in the diet of northern fulmars Fulmarus glacialis in the Canadian High Arctic

Abstract

The northern fulmar Fulmarus glacialis is a medium-sized seabird with a broad, circumpolar range in the northern hemisphere, and is the only petrel that inhabits the High Arctic. We used stomach analysis and stable isotopes (δ 15 N, δ 13 C) of muscles to examine the diet of 179 fulmars during the breeding season at 4 locations in Arctic Canada, to compare diet to those from studies conducted in these regions > 2 decades earlier. Across sampling locations, cephalopods, polychaetes and crustaceans dominated dietary remains in fulmars, although there was some regional variation. Both stable isotopes and stomach dissections showed that a seasonal shift in diet occurred in May, after which fulmars fed at a higher trophic level, suggesting a difference in winter/migration diet and breeding season diet. After migration, fulmar digestive organs decreased markedly in size, and by the time chicks were hatching, these organs were still 17 to 39% smaller than their size when birds arrived at the colony. Despite ongoing changes in the marine environment in much of the Arctic due to global warming, recent fulmar diet samples were similar to samples collected in the 1970s and 1980s, except that a higher proportion of recent collections contained fish. KEY WORDS: Arctic · Cephalopod · Crustacean · Procellariiformes · Reproduction Resale or republication not permitted without written consent of the publisherAquat Biol 10: [181][182][183][184][185][186][187][188][189][190][191] 2010 fulmar diet in the High Arctic, although it appears to rely more on invertebrates in this region, particularly early in the breeding season, than farther south (Hatch & Nettleship 1998, Mallory 2006.We examined the diet of fulmars at several locations in the Canadian High Arctic. This region is experiencing environmental changes, including less extensive and thinner sea ice cover, earlier ice breakup, later ice formation and in some cases warmer sea surface temperatures (ACIA 2005). Most High Arctic marine birds use ice edges, leads and polynyas as important foraging locations because these sites are often highly productive and provide the only open water areas where prey are accessible (Brown & Nettleship 1981, Stirling 1997. In fact, in the Canadian Arctic, most polynyas and recurrent ice leads have been identified as key marine habitat sites for migratory birds (Mallory & Fontaine 2004). Thus, long-term changes in marine environmental conditions may influence the timing and availability of prey for breeding marine birds. For example, Gaston et al. (2003) found that the diet of thick-billed murres Uria lomvia at one Arctic colony switched from ice-associated Arctic cod Boreogadus saida to warmer-water capelin Mallotus villosus over a 20 yr period. Such changes in marine food webs could potentially influence reproduction of marine birds through changes in prey availability or diet quality. Consequently, our study sought to: (1) establish a baseline of dietary information for fulmars at locations where this had not been investigated previ...

Foraging movements of Leach's storm‐petrels Oceanodroma leucorhoa during incubation

“…Miniaturisation of archival light loggers (geolocators) has enabled researchers to gain valuable knowledge about foraging and migratory movements of an increasing number of seabird species that weigh less than 500 g (Rayner et al , Navarro et al ). Stable isotope analysis has also been used to study geographic movements (Cherel et al ) and changes in diet associated with movements for many birds, including seabirds (Mallory et al , González‐Solís et al ). For instance, 13 C tends to be depleted towards the poles (Cherel and Hobson , Quillfeldt et al ), so differences in carbon signature can provide information about north–south movement.…”

Changes in organ size and nutrient reserves of arctic terns (Sterna paradisaea) breeding near a High Arctic polynya

“…Extensive evidence shows that marine environments in many regions are changing rapidly due to anthropogenic activities (e.g., Watson and Tidd 2018), pollution (e.g., Bustnes et al 2010;Clayden et al 2015;Provencher et al 2019), and broad-scale climatic shifts (e.g., Bryndum-Buchholz et al 2019). Seabirds are important indicators of marine ecosystem health because they feed at upper trophic levels; thus, their ecology and behavior are sensitive to changes in the marine environment (Furness and Camphuysen 1997;Parsons et al 2008;Mallory, Karnovsky et al 2010). For example, in the Arctic, poor seabird body condition and delayed breeding phenology can indicate low food availability, often due to late or extensive sea ice concentrations (Gaston, Gilchrist, and Mallory 2005;Moe et al 2009).…”

Seabird predation on Arctic cod during summer in the Canadian Arctic

“…Only fulmars fed on prey other than cod, including zooplankton and food scraps from hunters (cf. Mallory et al 2010).…”

“…Only fulmars fed on prey other than cod, including zooplankton and food scraps from hunters (cf. Mallory et al 2010).Fulmars successfully captured cod 24 and 19% of the time when diving from air (21 attempts) and the water's surface (32 attempts), respectively (Fig. 3b).…”