Date of this Version
Erforschung biologischer Ressourcen der Mongolei (2012) 12: 193-201.
The quality and size of nestling food of the Desert Wheatear Oenanthe deserti ssp. atrogularis were investigated in the spring of 2001 in the Dzungarian Gobi in Mongolia. Data are based on observations of nine pairs. Nestling food consisted of several taxa caught on the ground and in the air. Diptera, Coleoptera larvae, and Hymenoptera were the most frequent prey, that is, they contributed 17 to 30% of all food items each. The food composition changed with nestling age and season.
Food item size decreased with date. A higher proportion of multiple prey loadings were brought to nestlings in the second half of the season than in the first half. Prey items were significantly smaller in multiple prey loadings than in single prey loadings, but as a whole, multiple prey loadings were larger than single prey loadings. Despite the increase of the proportion of multiple prey loadings in the second half of the season compared with the first half, the loading size decreased with time. Presumably, large, profitable prey became rarer with the ongoing season. This may have caused the parents’ feeding effort to increase and prevented them from starting regular second broods.