Tichodroma (Dec 2022)
On food composition and foraging ecology of the Western Yellow Wagtail (Motacilla flava) in Western Slovakia
Abstract
The Western Yellow Wagtail (Motacilla flava) is typical species of agricultural landscapes, where the food supply is significantly limited. The nestling diet composition and its foraging ecology are little known in the entire range. Therefore, we studied the composition of the nestlings’ food and some aspects of its foraging ecology by photos from the shelter, in a population on abandoned agricultural land (17 ha) in Western Slovakia near Piešťany town (48,55098° N, 17,805612° E, 150 m asl.) in April–July 2017–2022. Analyzing 177 photos/feedings of young (1–12 days old) by a male and a female in 9 nests, was found a total of 361 prey items (2.7% of them unidentified). The food consisted of invertebrates from 12 orders, 33 families, and approximately 86 species. Spiders (Araneida, 19.4%), crickets and grasshoppers (Orthoptera, 18.6%), and moths (Lepidoptera) and dipterans (Diptera) with the same proportion 15.2%, belonged to the eudominant prey groups. Among the dominant and frequent species were, e. g., the aposematically coloured spider Argiope bruenichii, the mayfly Ephemera danica, the bush-crickets Leptophyes albovittata, Bicolorana bicolor, from other taxa there were significantly represented Noctuidae and Geometridae caterpillars, cicadas (Cicadellidae) and flies from the suborder Nematocera. The prey body length varied between 2 mm (snail Vallonia pulchella) and 50 mm (dragonfly of the genus Sympetrum) (average 17.1±8.6 mm, n = 361), i.e. it was on average longer than the average bill length (11–12 mm). Parents brought 1–10 prey items per feeding (mean = 2.0±1.5 items/ feeding, ca. 50% >1 object/ feeding, n = 177), the species thus belongs to the group of the “multiple prey loaders”. The size of foraging territories and the role of the parents in chick feeding was studied in one nest in 2022.
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