Do Tengmalm's Owls alter parental feeding effort under varying conditions of main prey availability?

Abstract

We studied the diet composition and behavioural responses to variable food conditions in Tengmalm´s Owls (Aegolius funereus). The abundance of main prey (voles and mice) of owls was higher in the Ore Mountains, Czech Republic, than in the Kauhava region, Finland. on average smaller prey items were brought to nestlings at the Finnish site.

However, both absolute and relative (per one nestling) feeding frequency was higher in the Kauhava region, and the biomass available to individual nestlings did not differ between the two areas.

Keywords

• Fluctuating food conditions
• short-eared owls
• aegolius-funereus
• falco-tinnunculus
• eurasian kestrel
• population fluctuations
• reproductive success
• functional-responses
• breeding performance
• alternative prey