Scientific Journal of the BirdLife Hungary

A Magyar Madártani és Természetvédelmi Egyesület tudományos folyóirata

Ornis Hungarica. vol.8-9. (1999) p.39-55.

A fészekaljpredáció jelentősége, valamint kísérletes vizsgálatának előnyei, hátrányai és módszertana
Báldi András

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Nest predation is one of the most important factors influencing reproductive success and community composition of birds. Recent studies also showed that nest predation increases after habitat fragmentation. Therefore, there is a strong interest of conservation biologists to describe and understand patterns of nest predation. However, studying nest predation have some problems, such as observer's disturbance, habitat destruction, and methodological problems. The conduction of nest predation experiments with artificial nests has no such problems, but there are several other ones. The most important of such difficulties is the relation between nest predation rates of actual and dummy nests. A recent concensus seems to be that artificial nests are useful to compare nest predation rates between areas or experimental treatments, but they are inappropriate to estimate absolute predation rate. A cheap and easy way of constructing a nest is to form it using chicken wire, and line it with dead vegetation. Quail eggs are used most commonly in these experiments, although quail eggs are larger than the eggs of most passerines. This could potentially bias predation rates, since predators with small gapes are unlikely to take these eggs. The identification of the predators requires an automatic camera systems, imprint eggs, or other devices to record tracks or feather/hair of the predators. To evaluate whether there are any differences between two or more areas, or treatments, a test of homogeneity is recommended, such as the G-test. A common shortcoming of nest predation experiments is the spatial scale of studies, which are usually within the home range of only a few potential predators. Therefore, local effects may significantly influences the results, which makes generalisation difficult.