Diet of the Lesser Kestrel, Falco naumanni, in Israel

Abstract

The food of the Lesser Kestrel (Falco naumanni) was studied by means of pellet contents analysis. A total of 645 entire pellets was collected, 550 pellets from the urban area of Jerusalem, 71 pellets from a rural area (a farmland) in Alona Region, 12 pellets from a natural area in the Judean Desert and 12 pellets from a quarry near Rosh Hain. Grasshoppers (Orthoptera), beetles (Coleoptera) and sun spiders (Solifugae) constituted the bulk of the diet. Numerically, grasshoppers and beetles were almost equally important (38.5% and 42.2% respectively), while sun spiders were much less numerous (11.7%). However, in terms of biomass, grasshoppers (54.7%) were far more important than beetles (18.8%) and sun spiders (20.6%). Four beetle families, viz. Carabidae, Scarabaeidae, Curculionidae and Tenebrionidae, comprised together 76.8% of all beetle prey items and 81.6% of beetle biomass. Among grasshoppers, the most important family (64.6% by numbers of prey items, 70.4% by grasshopper biomass) was the locusts (Acrididae). Significant month-to-month variations in the proportion of the main prey groups have been recorded. From February to April the Lesser Kestrel fed mainly on beetles, while from May to July it fed mainly on grasshoppers and sun spiders. Beetles and sun spiders comprised a much lower proportion of prey in 1998 (low rainfall) than in 1999 (high rainfall), while the proportion of grasshoppers and other invertebrates (altogether) was higher in 1998 than in 1999.