TY - GEN N1 - Bibliogr. p. 13-14 N1 - p. [9]-14 : ill. ; 27 cm N1 - Abstract. pol. N2 - A Great Grey Shrike population was studied in two large plots (220 km2 and 176 km2) in western Poland in 1999 - 2003. During the study period densities varied from 11.4 to 14.1 breeding pairs/100 km2 but numbers were stable. In all, 180 Great Grey Shrike nests were found - 114 (63.3%) in conifers, 66 (36.7%) in deciduous trees. This population’s reproductive parameters were relatively high in comparison to those of other European populations: mean clutch size - 6.6, hatching success - 92.5%, mean brood size - 5.72, mean number of fledglings per pair - 4.1, mean number of fledged young per successful pair - 5.25. Eggs (mean 27.1 x 19.9 mm) were found to be larger than reported in the literature. Nesting success was similar in both study plots, but there was slight seasonal variability: 52.6% - 41.0% from 99 nesting attempts in the first plot, 43.7% - 42.1% from 37 nests in the second. Predation was the main cause of nest losses. Plastic string used as nesting material appeared to be the most important cause of partial failures: 13 (8.2%) of a total of 147 nestlings surviving to fledging perished as a result of becoming tangled up in it. Nestlings rarely starved. Nests in linear habitats suffered significantly higher breeding losses (78.6%, N = 28) than those in non-linear habitats (50%, N = 90). The high fitness values obtained from this population were probably due to traditional farming practices, the sparing use of pesticides and the good potential food base. M3 - Text J2 - Acta Ornithologica, vol. 39, no. 1 J2 - Biologia rozrodu srokosza w zachodniej Polsce J2 - Great grey shrike biology PY - 2004 IS - 1 EP - 14 KW - Great Grey Shrike KW - Lanius excubitor KW - breeding biology KW - farmland KW - nest location A1 - Antczak, Marcin A1 - Hromada Martin A1 - Grzybek Jerzy A1 - Tryjanowski Piotr A1 - Polska Akademia Nauk. Muzeum i Instytut Zoologii A2 - Museum and Institute of Zoology, Polish Academy of Sciences PB - Museum & Institute of Zoology VL - 39 CY - Warszawa SP - 9 T1 - Breeding biology of the great grey shrike Lanius excubitor in W Poland UR - http://rcin.org.pl/dlibra/publication/edition/54203 ER -