Habitat requirements of the Lesser Spotted Woodpecker (Dendrocopos minor) in forests of northeastern Switzerland

Despite the widespread distribution of the Lesser Spotted Woodpecker. many aspects of the species' biology are poorly known, particularly regarding it s habitat requirements in central European forests. Recent studies suggest population declines in many areas of its range, making the need for appropr iate management guidelines urgent. In 1997, we examined which habitat facto rs affect the presence of the Lesser Spotted Woodpecker in deciduous lowlan d, non-riverine forests of northeastern Switzerland and evaluated the usefu lness of playback tapes for censusing the species. Selected on the basis of prior knowledge of the species' distribution, 27 forests were searched for Lesser Spotted Woodpeckers using playbacks from March to early May. The sp ecies was still present in 17 of these formerly occupied forests, while 5 n ew registrations were made in previously unoccupied forests. Ninety percent of the registrations occurred between 16 March and 24 April, and the woodp eckers responded to the playbacks most often with call series. The habitat structure of forests with Lesser Spotted Woodpeckers was compared with that of forests where the species had been absent both during previous censuses and in 1997, and which had a similar tree species composition, forest stru cture and elevation to the occupied forests. Logistic regression analysis i dentified four habitat variables as significant predictors of the species' presence/absence. Accordingly, forests were most likely occupied by the Les ser Spotted Woodpecker if more softwoods, but fewer snags (with a DBH great er than or equal to 15 cm) per area were available, if the distance to lake s and rivers was small, and the elevation was low. Therefore, the distribut ion of the Lesser Spotted Woodpecker seems to be affected by variables refl ecting both forest structure and relative position of the forests within th e landscape. We conclude that the Lesser Spotted Woodpecker will benefit fr om protection and promotion of softwood in all forest types, resulting in i ncreased habitat connectivity. Moreover, censuses using playbacks can be ef ficiently conducted during a short period in March/April.