Attraction of Hoopoe Upupa epops females and males by means of song playback in the field: influence of strophe length

Experimental Hoopoe Upupa epops songs prepared with synthetic sound to diff er in strophe length were used to test whether Hoopoe females prefer long s trophes. The songs were broadcast simultaneously in the field from two loud speakers situated 100 m apart, in early spring, when females actively searc h for mates. The playbacks attracted a total of 87 individuals, both males and females, with a maximum of five individuals (three males and two female s) per trial. A female was considered to have been attracted by the song br oadcast From a loudspeaker when she approached unaccompanied by a male. and when there was no male nearby. A total of 15 females chose one of the song s and significantly more were attracted by the one with long strophes. Thes e results suggest that in the Hoopoe, male song attracts females, and that strophe length is a sexually selected song cue. There were no differences i n the number or kind of males (classified according to strophe length) attr acted by each playback. Frequently the experiment attracted more than one m ale simultaneously. These aggregations cannot be explained as territorial r esponses, and their significance is discussed together with that of natural spontaneous groupings of displaying males. Apparently males aggregate wher e they expect to find females.