Singing for Your Supper: Acoustical Luring of Avian Prey by Northern Shrikes

Abstract

Northern Shrikes (Lanius excubitor) are predatory songbirds in which both sexes sing much of the year. I experimentally tested the hypothesis that winter singing by Northern Shrikes serves the purpose of attracting small passerines to be captured as prey. I broadcast Northern Shrike song for 5 min while recording the number of small passerines that approached the tape player, time taken for approach to occur, nearest approach, and mean number of call notes given by each small passerine observed. A blank tape and the song of American Robin (Turdus migratorius) were controls. Treatment effect was significant for number of passerines observed, time taken for approach, and nearest approach, but not for the number of call notes given by each passerine. More small passerines were observed during the Northern Shrike song and these songbirds responded more quickly and approached more closely than during the control and robin treatments. These results support the hypothesis that Northern Shrikes acoustically lure prey.