The impact of several environmental factors on density of woodcocks (Scolopax rusticola) wintering in a southern European region

Abstract

Knowledge of spatio-temporal animal distribution patterns is one of the main chapters of wildlife research, not only due to its biological and ecological importance but also its usefulness in the conservation and management of animal populations. Iberia is a target wintering region for the Eurasian woodcock (Scolopax rusticola). The aim of the present work is to determine which factors shape woodcock distribution patterns during the winter period. To ascertain this, we used data collected over three consecutive years (winter of 2010/2011–2012/2013) in a region from northern Iberia (Gipuzkoa). Woodcock numbers (W) were modeled using generalized linear mixed models. The models that best fitted our data included a significant effect of latitude, land uses, sampling year, and type of meadow on W (once weighted for the number of visits and the area of each meadow). Overall, W tended to be lower in sites from southern Gipuzkoa, in those areas where there was a higher proportion of tree plantations, in grazed mountain pastures, and during the winters of 2011 and 2012 in relation to 2010 (mean ± SD values in 2010, 0.4 ± 0.5 woodcocks/ha; 2011, 0.2 ± 0.3 woodcocks/ha; 2012, 0.2 ± 0.4 woodcocks/ha). Part of the observed variance was due to the “year” effect, which could include several potential explanatory variables. Future research should try to add variables such as year-associated meteorological conditions, at both breeding and non-breeding quarters. Locally, a mosaic of some forest/woodland with abundant meadows would allow numbers of woodcocks to reach an optimum within the region. Moreover, the species was more abundant in the north; hence, the zones close to the coast had more importance from a conservation standpoint.