Only Some Ectoparasite Populations are Affected by Nest Re-Use: an Experimental Study on Pied Flycatchers

Abstract

Summary. Nest re-use in birds is rare but since appropriate cavities may be scarce, cavity-nesting birds may often re-use those that were occupied in previous seasons. Old nest material may contain and/or attract more ectoparasites than fresh material. Therefore it is important to understand the effects of nest re-use on the abundance of different ectoparasite species of different virulence and their impli cation for breeding parameters and nestling condition. We studied the consequences of nest re-use in a population of pied flycatchers Ficedula hypoleuca breeding in central Spain by offering them both nest-boxes with old nest material and cleaned nest-boxes. We monitored breeding activity from the early stages of nest construction until fledging, and then finally removed nests to estimate ectoparasite abun dances. Occupation rates were similar for both treatments. We found that blowfly and flea abundances were significantly higher in old nests than in new nests, but the abundance of mites, the most viru...