Diet of Starling Sturnus vulgaris nestlings on farmland: the importance of Tipulidae larvae

Capsule Tipulidae larvae are a key resource for adult Starlings provisioning their young on lowland farmland. Aims (i) To describe Starling nestling diet on lowland farmland. (ii) To examine the effects of brood size variation and nestling age on Starling parental food provisioning. Methods Over 4 years, we observed parental food provisioning at 42 nests across 4 sites on lowland farmland in Oxfordshire, UK using nestbox video recorders. Results Tipulidae larvae were the most frequent prey item recorded in provisioning loads (52%), the next most frequent were winged insects (11%), then Coleoptera larvae (6%), Lepidoptera larvae (5%) and Lumbricidae (5%), with 21% of prey unidentified. Estimates of prey lengths, dry mass and total energy content also confirmed that Tipulidae larvae were the key prey source. Generalized linear mixed-effects models showed that larger broods received fewer Tipulidae larvae per nestling per day and that the proportion of Tipulidae larvae in the diet did not vary with brood size or nestling age. Conclusion Our results support the idea that Tipulidae larvae are the primary dietary item for nestling Starlings on lowland farmland.