Abstract
Male white-backed woodpeckers (Dendrocopos leucotos) in a 250-km2 study area in western Norway are significantly larger than females in bill length and depth, wing and tarsus lengths, and bodyweight. During the winters (October–March 1985–2002), most pairs were observed within their breeding territory where both sexes foraged mainly in grey alder and birch trees, and visited trees of the same tree height and stem width. However, males foraged more frequently on dead trees and on trees broken by storms. Males also used more trees with less bark cover, foraged nearer the ground and used foraging sites of larger diameter. Furthermore, males practised more deep wood-pecking and less bark-pecking than females. Unlike in other sexually dimorphic woodpecker species, the foraging niche breadth in wintering white-backed woodpeckers showed only minor sexual differences, and the sexes overlapped significantly in all parameters examined. Since previous studies in the area have shown that the sexes overlap considerably in use of their territory, it was expected, as found in other size dimorphic woodpeckers, that the larger male would displace the supposedly socially subordinate female to suboptimal feeding sites. In our area, the sexes were rarely seen together, and no sign of aggression between the sexes was observed. Despite the sex-specific differences found in the foraging behaviour of the birds, it is not obvious how the differences should be related to size dimorphism.
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References
Andersson M (1994) Sexual selection. Princeton University Press, Princeton, N.J.
Aulén G (1988) Ecology and distribution history of the white-backed woodpecker Dendrocopos leucotos in Sweden. Swedish Univ Agricult Sci Dept Wildlife Ecology, Rep 14. Uppsala, Sweden
Aulén G, Lundberg A (1991) Sexual dimorphism and patterns of territory use by the white-backed woodpecker Dendrocopos leucotos. Ornis Scand 22:60–64
Austin GT (1976) Sexual and seasonal differences in foraging of Ladder-backed Woodpeckers. Condor 78:317–323
Carlson A (2000) The effect of habitat loss on a deciduous forest specialist species: the white-backed woodpecker (Dendrocopos leucotos). Forest Ecol Manage 131:215–221
Cramp S (ed) (1985) The birds of the western Palearctic, vol 4. Oxford University Press, Oxford
Hogstad O (1976) Sexual dimorphism and divergence in winter foraging behaviour of three-toed woodpeckers Picoides tridactylus. Ibis 118:41–50
Hogstad O (1977) Seasonal change in intersexual niche differentiation of the three-toed woodpecker Picoides tridactylus. Ornis Scand 8:101–111
Hogstad O (1978) Sexual dimorphism in relation to winter foraging and territorial behaviour of the three-toed woodpecker Picoides tridactylus and three Dendrocopos species. Ibis 120:198–203
Hogstad O (1991) The effect of social dominance on foraging by the three-toed woodpecker Picoides tridactylus. Ibis 133:271–276
Hogstad O, Stenberg I (1994) Habitat selection of a viable population of white-backed woodpeckers Dendrocopos leucotos. Cinclus 17:75–94
Hogstad O, Stenberg I (1997) Breeding success, nestling diet and parental care in the white-backed woodpecker Dendrocopos leucotos. J Ornithol 138:25–38
Jackson JA (1970) A quantitative study of the foraging ecology of downy woodpeckers. Ecology 51:318–323
Kilham L (1970) Feeding behavior of downy woodpeckers. Condor 64:126–133
Ligon JD (1968) Sexual differences in foraging behavior in two species of Dendrocopos woodpeckers. Auk 85:203–215
Matthysen E, Grubb TC Jr, Cimprich D (1991) Social control of sex-specific foraging behaviour in downy woodpeckers, Picoides pubescens. Anim Behav 42:515–517
Pavlik S (1999) Breeding ecology of the white-backed woodpecker Dendrocopos leucotos in an oak forest. Biol Bratislava 54:187–194
Peters WD, Grubb TC Jr (1983) An experimental analysis of sex-specific foraging in the downy woodpecker, Picoides pubescens. Ecology 64:1437–1443
Price PW (1975) Insect ecology. Wiley, New York
Schoener T (1968) The Anolis lizards of Bimini: resource partitioning in a complex fauna. Ecology 49:704–726
Selander RK (1966) Sexual dimorphism and differential niche utilization in birds. Condor 68:113–151
Shine R (1989) Ecological causes for the evolution of sexual dimorphism: a review of the evidence. Q Rev Biol 64:419–461
Slatkin M (1984) Ecological causes of sexual dimorphism. Evolution 38:622–630
Svensson L (1992) Identification guide to European passerines. Svensson, Stockholm
Virkkala R, Alanko T, Laine T, Tiainen J (1993) Population contraction of the white-backed woodpecker Dendrocopos leucotos in Finland as a consequence of habitat alteration. Biol Conserv 66:47–53
Wallace RK Jr (1981) An assessment of diet-overlap indexes. Trans Am Fish Soc 110:72–76
Wilson DS (1975) The adequacy of body size as a niche difference. Am Nat 109:769–784
Winkler H, Christie DA, Nurney D (1995) Woodpeckers. Helm, Sussex
Acknowledgements
We thank J. Heggset for help in the field, T. Grubb and an anonymous referee for comments on the manuscript. The birds were caught under a licence from the Directorate of Nature Management. Financial support was provided by the Directorate for Nature Management, the Regional Commisioner for Møre og Romsdal, the World Wildlife Foundation, the Norwegian Ornithological Society, the Nansen Foundation and The Royal Norwegian Society of Sciences and Letters.
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Stenberg, I., Hogstad, O. Sexual dimorphism in relation to winter foraging in the white-backed woodpecker (Dendrocopos leucotos). J Ornithol 145, 321–326 (2004). https://doi.org/10.1007/s10336-004-0045-6
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DOI: https://doi.org/10.1007/s10336-004-0045-6