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Bird predation on gypsy moth Lymantria dispar L. (Lepidoptera Erebidae) egg masses may have a significant role in the gypsy moth population regulation; therefore the understanding of this process is a key issue to prevent large scale damage. In this paper, we aimed to quantify the winter predation of egg masses by birds and to reveal what factors affect its efficiency in three types of Central European hardwood forests. We detected a predation frequency of 20%, i.e. every fifth egg masses was destroyed at some extent by birds, while the mean percentage of removed surface per attacked egg masses was 35%. We measured the size of egg masses, their location on the trunk and environmental variables. Factors affecting predation frequency as well as the removed surface differed among forest stands characterized by different tree species composition. In beech dominated forest, egg masses located on the north and northeast side of trees were more frequently attacked than egg masses located in any other directions. In hornbeam forests, the predation frequency increased with the height on the trunk, while in Turkey oak forests, only the size of egg masses had a significant positive effect on egg mass predation rate. Egg mass size also affected the percentage of removed surface. Tree species, tree diameter and shrub cover had no significant effect on egg mass predation. Thus, we can conclude that egg mass predation is influenced rather by egg mass location or size than by other habitat characteristics. [ABSTRACT FROM AUTHOR]

Bird predation on gypsy moth Lymantria dispar L. (Lepidoptera Erebidae) egg masses may have a significant role in the gypsy moth population regulation; therefore the understanding of this process is a key issue to prevent large scale damage. In this paper, we aimed to quantify the winter predation of egg masses by birds and to reveal what factors affect its efficiency in three types of Central European hardwood forests. We detected a predation frequency of 20%, i.e. every fifth egg masses was destroyed at some extent by birds, while the mean percentage of removed surface per attacked egg masses was 35%. We measured the size of egg masses, their location on the trunk and environmental variables. Factors affecting predation frequency as well as the removed surface differed among forest stands characterized by different tree species composition. In beech dominated forest, egg masses located on the north and northeast side of trees were more frequently attacked than egg masses located in any other directions. In hornbeam forests, the predation frequency increased with the height on the trunk, while in Turkey oak forests, only the size of egg masses had a significant positive effect on egg mass predation rate. Egg mass size also affected the percentage of removed surface. Tree species, tree diameter and shrub cover had no significant effect on egg mass predation. Thus, we can conclude that egg mass predation is influenced rather by egg mass location or size than by other habitat characteristics. [ABSTRACT FROM AUTHOR]