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Analysis of 531 nest cards (Polish Nest Record Scheme) of the Great Spotted Woodpecker, obtained in the years 1970–2003 is presented here. The data is derived from almost the whole of Poland, except for the Białowieża National Park. From the material processed for the purpose of this study, the Great Spotted Woodpeckers appear to nest in various types of wooded habitats, especially in forests and they are very flexible in their choice of nesting sites, both in terms of age of tree stands and intensity of human penetration. As a rule, woodpeckers breed mostly in holes made in deciduous trees (oak, birch, and alder). More than 95% of nests were excavated in tree trunks, primarily in dead or weakened trees. Woodpeckers excavated their nest in the range of 0.5–19 m above the ground, with more than 75% of them found in the narrower range from 1–7 m. The height of cavity above the ground did not depend on tree species or vegetation type and was also weakly correlated with the height of tree stands. The openings of cavities showed no statistically significant differences in their geographical orientation. Although the information about woodpecker nests, gathered in the Nest Record Scheme does contain certain errors (such as “habitat preferences” of observers), the obtained results provided a better insight into the nesting ecology of this species in Poland.
Riparian forests provide important roosting habitat, abundant prey and access to drinking water for many bat species but to date there has been little research on the differential quality of habitats within riparian areas. We quantified the density of potential roost cavities in three age classes (i.e., young: ca. 20 years, mature: ca. 60 years, and old: ca. 100 years) of riparian cottonwood (Populus deltoides) forest stands. Bat activity was also sampled using acoustic detectors in one representative stand of each age class. Stands were situated along an 80 km stretch of the Missouri River in southeastern South Dakota and northwestern Iowa, USA. We predicted the highest density of potential roosts and the highest activity of bats to occur in the oldest age class. Contrary to our predictions, and previous work in aspen dominated upland sites, we found that the density of potential roosts was not significantly different between mature and old stands. However, there were no potential roosts in young stands. Data from guano traps verified the use of a number of cavities in both mature and old stands. Both commuting and foraging activities were highest in the mature, relative to the old and young stand. In total, our data indicate that mature and old stands represent high quality roosting habitat, with the mature being used preferentially for commuting and foraging. Trees in the oldest stands, however, are nearing the end of their lifespan and falling. Younger cohorts must therefore be retained for future recruitment of natural cavities.
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