SINGING FOR YOUR SUPPER - ACOUSTICAL LURING OF AVIAN PREY BY NORTHERNSHRIKES

Northern Shrikes (Lanius excubitor) are predatory songbirds in which b oth sexes sing much of the year. I experimentally tested the hypothesi s that winter singing by Northern Shrikes serves the purpose of attrac ting small passerines to be captured as prey. I broadcast Northern Shr ike 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 migrato rius) were controls. Treatment effect was significant for number of pa sserines observed, time taken for approach, and nearest approach, but not for the number of call notes given by each passerine. More small p asserines were observed during the Northern Shrike song and these song birds responded more quickly and approached more closely than during t he control and robin treatments. These results support the hypothesis that Northern Shrikes acoustically lure prey.