Measurements of Diving Depth in Dovekies (Alle alle)

Falk, Knud; Pedersen, Carsten Egevang; Kampp, Kaj

doi:10.1642/0004-8038(2000)117[0522:moddid]2.0.co;2

Cited by 25 publications

(8 citation statements)

References 10 publications

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“…The chick is brooded for the first 3–5 d, after which it is left mostly alone in the nest with parents only visiting briefly to feed (Stempniewicz 2001). During the post‐brooding period, parents spend most of their time foraging at sea, diving up to 35 m deep to feed themselves and collect food for the chick (Falk et al 2000). The chick meal is brought back to the colony in an expandable gular pouch which can contain up to 4,000 prey items (Karnovsky et al 2003).…”

Section: Methodsmentioning

confidence: 99%

Flexibility in the bimodal foraging strategy of a high Arctic alcid, the little aukAlle alle

Welcker¹,

Harding²,

Karnovsky³

et al. 2009

Journal of Avian Biology

126

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A bimodal foraging strategy has previously been described for procellariiform seabird species and is thought to have evolved in response to local resource availability being too low for adult birds to meet chick requirements and simultaneously maintain their own body condition. Here, we examine the dual foraging trip pattern of an alcid, the little auk Alle alle, at five colonies with contrasting oceanographic conditions. In spite of large variation in local conditions, little auks at all colonies showed the same general pattern of alternating a single long‐trip with several consecutive short‐trips. However, we found that the foraging pattern was flexible and could be adjusted at three levels: (1) the length of long‐trips, (2) the frequency of short‐trips, and (3) the total time spent foraging. Birds facing unfavorable conditions increased the duration of long‐trips and reduced the number of short‐trips. These adjustments resulted in reduced provisioning rates of chicks despite the fact that birds also increased the time allocated to foraging. Travel times during foraging trips were positively correlated to the total duration of the trip suggesting that differences in trip length among colonies were partly driven by variation in the distance to foraging areas. Most birds spent substantially more time traveling during long compared to short‐trips, indicating that they accessed distant foraging areas during long‐trips but remained close to the colony during short‐trips. However, the difference in travel times was small at the site with the most favorable conditions suggesting that bimodal foraging in the little auk may be independent of the existence of high‐quality areas at distance from the breeding ground.

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Section: Methodsmentioning

confidence: 99%

Flexibility in the bimodal foraging strategy of a high Arctic alcid, the little aukAlle alle

Welcker¹,

Harding²,

Karnovsky³

et al. 2009

Journal of Avian Biology

126

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“…1) with two consecutive replicate standard WP‐2 plankton net hauls (0.25 m 2 in area, mesh size 180 µm) at each of the four stations on 27 July 2005. As little auks only dive to 35 m (Falk et al. 2000) the nets were towed vertically from a depth of 50 m up to the surface.…”

Section: Methodsmentioning

confidence: 99%

Little auks (Alle alle) breeding in a High Arctic fjord system: bimodal foraging strategies as a response to poor food quality?

Steen

Vogedes²,

Broms

et al. 2007

Polar Research

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The foraging behaviour of little auks ( Alle alle ) in the Bjørndalen colony on the western coast of Spitsbergen was studied during the breeding season 2005. The duration of foraging trips and contents of gular pouches were analysed. Quantitative zooplankton samples procured in the vicinity of the colony facilitated a comparison between gular pouch contents and the availability of prey species. Zooplankton and gular pouch samples were all sampled within a time window of approximately one week. Using the Bray-Curtis similarity index, we determined that little auks in this colony have a bimodal foraging strategy consisting of long and short foraging trips with two corresponding distinct diets. Short trips are most likely to be centred on areas within the Isfjorden complex, whereas the birds are most likely to use the long trips (of typically more than 10 hours) to reach areas off the continental slope where they are able to feed selectively on large, energy-rich food items such as Calanus hyperboreus . This bimodal foraging strategy may be a response to the low availability of nutrientrich food close to the colony, which is insufficient to sustain both parents and chicks. Bimodal foraging trip strategies are well documented in many species in the Southern Ocean. This is the first study to show a similar feeding pattern in an Alcidae species in the Northern Hemisphere.

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“…The diving depth capacity in these birds is related to body size. The largest of these species, the Brünnich's guillemot, makes the deepest dives (> 200 m; Croll et al 1992), whereas the smallest, the little auk (zooplankton feeder), dives to rather shallow (< 30 m) depths (Falk et al 2000). Mehlum et al (2001) found that Brünnich's guillemots in Kongsfjorden dive as deeply as 136 m, although mean dive depth was 45 m. The common eider is mainly a benthic feeder that forages in shallow waters, down to depths of 15 m (Frimer 1995).…”

Section: Seabirdsmentioning

confidence: 99%

The marine ecosystem of Kongsfjorden, Svalbard

Hop¹,

Pearson²,

Hegseth³

et al. 2002

Polar Research

503

337

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Kongsfjorden is a glacial fjord in the Arctic (Svalbard) that is influenced by both Atlantic and Arctic water masses and harbours a mixture of boreal and Arctic flora and fauna. Inputs from large tidal glaciers create steep environmental gradients in sedimentation and salinity along the length of this fjord. The glacial inputs cause reduced biomass and diversity in the benthic community in the inner fjord. Zooplankton suffers direct mortality from the glacial outflow and primary production is reduced because of limited light levels in the turbid, mixed inner waters. The magnitude of the glacial effects diminishes towards the outer fjord. Kongsfjorden is an important feeding ground for marine mammals and seabirds. Even though the fjord contains some boreal fauna, the prey consumed by upper trophic levels is mainly Arctic organisms. Marine mammals constitute the largest top‐predator biomass, but seabirds have the largest energy intake and also export nutrients and energy out of the marine environment. Kongsfjorden has received a lot of research attention in the recent past. The current interest in the fjord is primarily based on the fact that Kongsfjorden is particularly suitable as a site for exploring the impacts of possible climate changes, with Atlantic water influx and melting of tidal glaciers both being linked to climate variability. The pelagic ecosystem is likely to be most sensitive to the Atlantic versus Arctic influence, whereas the benthic ecosystem is more affected by long‐term changes in hydrography as well as changes in glacial runoff and sedimentation. Kongsfjorden will be an important Arctic monitoring site over the coming decades and a review of the current knowledge, and a gap analysis, are therefore warranted. Important knowledge gaps include a lack of quantitative data on production, abundance of key prey species, and the role of advection on the biological communities in the fjord.

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Measurements of Diving Depth in Dovekies (Alle alle)

Cited by 25 publications

References 10 publications

Flexibility in the bimodal foraging strategy of a high Arctic alcid, the little aukAlle alle

Flexibility in the bimodal foraging strategy of a high Arctic alcid, the little aukAlle alle

Little auks (Alle alle) breeding in a High Arctic fjord system: bimodal foraging strategies as a response to poor food quality?

The marine ecosystem of Kongsfjorden, Svalbard

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