A field test of food information transfer in communally roosting greenfinches Carduelis chloris

Abstract

We tested whether communally roosting greenfinches Carduelis chloris obtained information from conspecifics on the distribution of unpredictable food sources (sunflower seeds, Helianthus sp.) during a severe winter. Seeds were provided at randomly chosen sites in the afternoon and the numbers of greenfinches at these bait sites in the afternoon and the following morning were compared. Numbers did not increase from the afternoon to the morning in eight out of nine trials where greenfinches turned up at the bait sites. Attraction to the bait decreased with increasing ambient temperatures, more birds turning up during severe frost. Subordinate females were attracted to the bait more frequently than dominant male greenfinches.