Predation on artificial nests in post-mining recultivated area and forest edge:contrasting the use of plasticine and quail eggs

摘要

Intensive opencast coal mining has been in effect in the northeastern outskirts of Pecs (south Hungary) since 1968.The covering layer of the northern,recultivated area extending over 15 ha is overgrown by herbaceous vegetation.Oleaster (Elaeagnus angustifolia) was planted in rows on the hillsides.The recultivated open areas are bordered by turkey oak forests (Potentillo micranthae-Quercetum daleschampii Horvat A.O.1981) from the east,north,and westthus it forms a wedge of a clearing in the wood.Our studies have aimed at determining whether nest predation is greater in the forest edge or in the rows of oleaster in the recultivated area.First a plasticine egg,then a quail egg was put in each of the 50-50 artificial nests mounted on trees in the two habitat types.After a week it was found that predation to nests with only one plasticine or one quail egg in each was significantly higher in forest edge trees than in the rows of oleaster.There was no significant difference between predation to plasticine and quail eggs in either of the habitats.Irrespective of where the nests were,predators (mostly jays,tits,and once a small mammal) attempted to "consume" the plasticine eggs in the nest,whereas quail eggs were usually taken away.The rate of disappearance of eggs from the nests (plasticine 24%,quail 60%) differed significantly from the rate of pecking or gnawing at them and from in situ consumption (plasticine 76%,quail 40%).Nests located in tree rows in the recultivated areas are safer than those in the forest edge.