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Intensity of plumage colour may advertise individual condition, health and parasite resistance of birds. Although numerous studies confirmed such function of ornaments in songbirds, still very little is known about signalling properties of colour feathers in woodpeckers. We test whether the size and colour of a red cap displayed by both male and female Middle Spotted Woodpeckers are related to mass and length of tarsus, wing, tail and beak. We found that body mass was correlated with cap width and brightness in woodpeckers of both sexes. At the same time body mass affected reproductive success of individuals. This suggests that both cap width and brightness has the potential to signal individual condition in the studied species.
Three species of cavity nesters potentially competitive with the Starling — the Great Spotted Woodpecker Dendrocopos major, Middle Spotted Woodpecker D. medius and Nuthatch Sitta europaea were studied in the years 1997-1999. The number of suitable nest sites for Starlings and competitive pressure were manipulated by increasing or decreasing the availability of nest boxes. Increased nest-site competition did not lead to significant changes in number among the studied species. The Starling was found to take over up to 25% of holes chosen by Nuthatches for breeding. Increased availability of nest sites did not protect Nuthatches from cavity losses, but reduced their frequency. Only 20% of Nuthatch pairs that lost their holes renested successfully in the same breeding season. No impact of Starlings on breeding woodpeckers was noted.
Woodpeckers are a very good indicators of forest naturalness. The fact that many species of these birds are in decline in central and western Europe resulted from changes in forest management (e.g. favouring coniferous forest, removal of dead trees). The aim of this research was to evaluate the importance of patches of deciduous species for the occurrence of some specialized woodpeckers in the conditions of Scots pine dominated stands. The study focused on species associated with deciduous forest, i.e. middle spotted woodpecker Leiopicus medius (L.), white−backed woodpecker Dendrocopos leucotos (Bechstein) and grey−headed woodpecker Picus canus (Gmelin). Statistical analyses were performed for the woodpeckers, which occurred in more than 10 territories. The studies were performed in 2015−2017 in the southern part of the Sandomierz Basin in three study areas (52,6−59 km²). Two plots were dominated by black alder Alnus glutinosa and oak Quercus sp., while the third one was characterized by the highest share of black alder, followed by silver birch Betula pendula and oak. Deciduous trees at the age over 80 years accounted for less than 2% of the total area of each plot. The most abundant bird species in patches of deciduous forest was the middle spotted woodpecker (25 territories), while the rarest was white−backed woodpecker (1 territory). Grey−headed woodpecker appeared in 12 territories. The density of woodpeckers in deciduous forest areas ranged from 0.45 territories/100 ha for grey−headed woodpecker to 1.54 territories/100 ha for the middle spotted woodpecker. In the alder patches we found all territories of grey−headed woodpecker, 24% territories of the middle spotted woodpecker and single territories of white−backed woodpecker. The patches dominated by oak accounted for about 76% of territories of middle spotted woodpecker. The average area of the patches with presence of middle spotted woodpecker and grey woodpecker was significantly higher than the patches where woodpeckers were absent. The middle spotted woodpecker occurred in the forest patches with the highest average age. Redundancy Analysis (RDA) demonstrated that the occurrence of middle spotted woodpecker was most strongly associated with the area of the patches over 10 ha, while the grey−headed woodpecker preferred mature forest stands of alder. These species abundance was negatively correlated with a patch area less than 10 ha.
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