Artur GOŁAWSKI 1 *, Zbigniew KASPRZYKOWSKI 2 , Marek JOBDA 3 , Irena DUER 4 1 Department of Zoology, Siedlce University of Natural Sciences and Humanities, Prusa 12, 08–110 Siedlce, Poland, *e-mail: artgo1@uph.edu.pl (corresponding author) 2 Department of Ecology and Nature Protection, Siedlce University of Natural Sciences and Humanities, Prusa 12, 08–110 Siedlce, Poland, e-mail: zbykas@uph.edu.pl 3 Polish Society for the Protection of Birds, Odrowąża 24, 05–270 Marki, Poland, e-mail: marek.jobda@otop.org.pl 4 State Research Institute of Soil Science and Plant Cultivation, Czartoryskich 8, 24–100 Puławy, Poland e-mail: iduer@iung.pulawy.pl THE IMPORTANCE OF WINTER CATCH CROPS COMPARED WITH OTHER FARMLAND HABITATS TO BIRDS WINTERING IN POLAND POLISH JOURNAL OF ECOLOGY (Pol. J. Ecol.) 61 2 357–364 2013 Regular research paper ABSTRACT: The study examined the im- portance of winter catch crops (intercrops) to wintering birds in a low-intensity farming area of Poland. Birds were counted on two occasions between November 2009 and January 2010 in 514 research plots in two different parts of the country. During the two counts 28 species were recorded. Yellowhammer Emberiza citrinella, Corn Bunting Emberiza calandra, Tree Sparrow Passer montanus and Shorelark Eremophila alp- estris were the most numerous species. The sta- tistical analysis (GLZ) of the influence of survey, location and habitat types on the occurrence of birds in the farmland did not reflect the signifi- cant effect on any variables. Significant differ- ences in densities of birds between the habitats analysed (GLM) were noted. The stubbles sup- ported a relatively greater density of birds than the mustard winter catch crop and ploughed fields. Increasing the area of winter catch crops at the expense of ploughed fields may favour birds, but when winter crops are sown in fields that would otherwise be left as stubble, winter- ing conditions for birds deteriorate, especially for buntings. KEY WORDS: cover crops, habitat use, low- intensity farmland, agricultural landscape, bird assemblages 1. INTRODUCTION The decline of many breeding popula- tions of some farmland bird species in west- ern Europe has been related to increased winter mortality caused by reduced food availability (Wilson et al. 1996, Donald et al. 2001, Vickery et al. 2002). One of the most important reasons has been the switch from spring to autumn tillage and the associ- ated loss of over-winter stubbles that are the source of seed for many granivorous species (Evans 1997). Farmland in eastern Poland is less intensively managed than in other Eu- ropean countries (Tryjanowski et al. 2009, Goławski and Kasprzykowski 2010, Tryjanowski et al. 2011), but since Poland’s accession to the EU there has been a gradual change in the utilization of arable fields. Agro- environmental programmes have encouraged the re-farming of fallow land in the whole country: this has been the most spectacular habitat change in farmland (Tr y j a n ow s - ki et al. 2009). The second most important change in agricultural practices has been the expansion in the acreage of winter catch crops as a result of EU farm subsidies. The aim of this is to maintain the plant cover during the winter in order to prevent wind erosion of the journal 34.indb 357 2013-07-09 14:47:58