- Marine Ecology: Political, Economic and Environmental Implications
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How large an area of sea do Helgoland seabirds use for foraging during the breeding season?
Helgoländer Meeresuntersuchungen volume 49, pages 603–604 (1995)
Conclusions
Of the species examined, only the guillemot remained within the study area, while other species ranged much further from the colony to forage. The number of guillemots present at sea was 2943±222 birds as calculated by Ordinary Kriging method (van der Meer & Leopold, in prep.). This corresponds to the number expected from the size of the colony and the attendance patterns of the birds (2889: Grunsky, 1992).
Based on (1) metabolism of adults, (2) cost of egg production, (3) amount of food delivered to chicks, and (4) population parameters according to Grunsky (1992), we calculated the total energy consumption during the breeding season (cf. Cairns et al., 1992). The length of the breeding season was taken from 1st April (10 days before the first egg) to 16th June (mean day of leaving). In total, the guillemots used 1015 million kJ of energy to complete the 1991 breeding season. The diet (Grunsky, 1992) consisted, for 68.6%, of sandeel (7.8 kJ/g wet mass) and for 31.4%, of clupeoids (10.8 kJ/g), so in total 81 tonnes of sandeel and 37 tonnes of clupeoids were needed to support the colony of guillemots.
Literature Cited
Cairns, D. K., Montevicchi, W. A., Birt-Friesen, V. L. & Macko, S. A., 1992. Energy expenditures, activity budgets, and prey harvest of breeding Common Murres. — Stud. Avian Biol.14, 84–92.
Grunsky, B., 1992. Anwesenheit adulter Trottellummen (Uria aalge) in der Brutkolonie auf Helgoland, Bestandsermittlung und Nahrungsökologie ihrer Jungen. Dipl.Arb., Univ. Bonn, 98 pp.
Leopold, M. F., Wolf, P. A. & Hüppop, O., 1992. Food of young and colony-attendance of adult GuillemotsUria aalge on Helgoland. — Helgoländer Meeresunters.46, 237–249.
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Leopold, M.F., Grunsky, B., Hüppop, O. et al. How large an area of sea do Helgoland seabirds use for foraging during the breeding season?. Helgolander Meeresunters 49, 603–604 (1995). https://doi.org/10.1007/BF02368385
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DOI: https://doi.org/10.1007/BF02368385