Rozšíření a biologie jestřába lesního (Accipiter gentilis L.) v Chřibech

Abstract

In 2002–2006, mapping the goshawk (Accipiter gentilis L.) population was carried out at the SE edge of the Chřiby Upland, the Czech Republic. At the same time, the food spectrum of the predator was determined in detail in 2004. The studied area amounted to about 30 km2. In the area, 5 nest localities occurred. Each year five occupied nests were observed. The food spectrum was analysed according to leftovers of food in nests and in the vicinity of the nests. In total, 387 leftovers of food were found. Birds represented 52%, mammals 42% and other animals (insect, reptiles etc.) 6% of prey. The population of goshawk was monitored from the period of a wedding flight to a period when young birds left their nest during the period of five years. The number of eggs was on average 2.9 per one nest. The total number of laid eggs was 73 during five years. The number of brood was on average 2.7 per one nest. Sex ratio was 47/53 per cent in favour of males. The total number of hatched birds was 68 during five years, out of the number 32 females and 36 males. Moreover, dimensions of nests at particular localities were also determined. The diameter of nests was on average 72.2 cm and the mean height of the actual nest was 48 cm. Nests occurred at an average height of 21.3 m.