Foraging strategy of the little auk Alle alle throughout breeding season – switch from unimodal to bimodal pattern

Abstract

Energy and time allocation differs between incubation and chick‐rearing periods, which may lead to an adjustment in the foraging behaviour of parent birds. Here, we investigated the foraging behaviour of a small alcid, the little auk Alle alle during incubation and compared it with the chick‐rearing period in West Spitsbergen, using the miniature GPS (in Hornsund) and temperature loggers (in Magdalenefjorden). GPS‐tracking of 11 individuals revealed that during incubation little auks foraged 8–55 (median 46) km from the colony covering 19–239 (median 120) km during one foraging trip. Distance from the colony to foraging areas was similar during incubation and chick‐rearing period. During incubation 89% of foraging positions were located in the zone over shallower parts of the shelf (isobaths up to 200–300 m) with sea surface temperature below 2.5°C. Those environmental conditions are preferred by Arctic zooplankton community. Thus, little auks in the Hornsund area restrict their foraging (both during the incubation and chick‐rearing period) to the area under influence of cold, Arctic‐origin water masses where its most preferred prey, copepod Calanus glacialis is most abundant. The temperature logger data (from 4 individuals) indicate that in contrast to the chick‐rearing period, when parent birds alternated short and long trips, during the incubation they performed only long trips. Adopting such a flexible foraging strategy allows little auks to alter their foraging strategy to meet different energy and time demands during the two main stages of the breeding.

Marine birds and mammals foraging in the rapidly deglaciating Arctic fjord - numbers, distribution and habitat preferences

“…data). Such an opportunity for emergency feeding close to the colony when weather conditions beyond the fjord are bad may increase the breeding success of birds (Jakubas et al , 2014Kidawa et al 2015;Hilde et al 2016) and buffer the adverse consequences of climatic and oceanographic changes (Grémillet et al , 2015.…”

“…Being short-distance foragers (Cairns 1987), they do not leave the fjord to feed. The pursuit-diving little auk, with a huge local breeding population (c. half million pairs) exploits the outer feeding grounds (Jakubas et al 2012(Jakubas et al , 2014; only a small number of them forage in the fjord, presumably during bad weather. The least numerous were king eider and ivory gull, species of special conservation concern.…”

Intra-seasonal variation in zooplankton availability, chick diet and breeding performance of a high Arctic planktivorous seabird

“…The two fjords are the main breeding areas of the little auk on Svalbard (Isaksen 1995). We studied the zooplankton community composition on known foraging grounds of little auks breeding in Hornsund (fjord and shelf zone) and Magdalenefjorden areas (fjord and shelf zone close to Magdalenefjorden and Smeerenburgfjorden) , 2014Stempniewicz et al 2013;Hovinen et al 2014a) (Fig. 1).…”

Parental Coordination of Chick Provisioning in a Planktivorous Arctic Seabird Under Divergent Conditions on Foraging Grounds

“…Thus, examining the provisioning schemes in these two locations expands the range of environmental conditions. The sea shelf in the vicinity of Hornsund constitutes the main foraging area of the Little Auks from this colony (Jakubas et al, 2013(Jakubas et al, , 2014; and see Figure 1). This area is typically under the influence of two currents: the coastal Sørkapp Current, which carries cold, less saline Arctic water, and the West Spitsbergen Current (an extension of the Norwegian Atlantic Current), which transports warmer, more saline Atlantic water (Piechura et al, 2001;Cottier et al, 2005).…”