SYNCHRONY OF ESTRUS IN COMMON SHREWS

Timing of first estrus was recorded for female common shrews (Sorer ar aneus) in a dense population near Oxford, England. Time of estrus coul d be identified to within 24 h for eight of 13 females captured regula rly on the study site. Six of these females became sexually receptive within 26 h of one another, and seven within 48 h. The number of males captured in each female's range increased significantly around the ti me of first estrus. The number captured in the range of a female withi n 24 h of estrus varied between five and eight (mean +/- SE = 6.1 +/- 0.4), and the minimum number of females in estrus visited by each male varied from zero to four (mean +/- SE = 1.6 +/- 0.2). Synchrony of es trus may facilitate opportunities for choice of mates or multiple mati ng by females.