We studied the spring emergence of red-sided gartersnakes (Thamnophis sirtalis parietalis) from a large communal den in Manitoba to clarify the context in which courtship and mating occur. In particular, is the mating system in such a massive aggregation (> 20,000 snakes) substantially different from that at smaller dens? Radio-tracked female snakes stayed near the den for a few days postemergence, apparently waiting until they recovered locomotor ability after the long hibernation period, before setting out for their summer ranges. Females dispersed from the den in all directions, rather than following distinct migration corridors. Male snakes moved frequently and spent much of their time far from the den in surrounding woodland. Most males remained near the den for only a small proportion of the entire mating season, apparently because of high rates of energy expenditure during mate-searching and courtship. Courting groups contained from 1-62 males and were largest close to the den. Most courting and mating occurred in groups of less than five males, often more than 20 m from the den. These small group sizes resulted from the females' dispersal prior to mating. Larger groups did not induce female cooperation (mating) more quickly than small groups. Despite the spectacular aggregations of courting snakes within the den, most reproductive activity in this population (as in other gartersnake populations) occurs in small groups, widely dispersed over a broad area.
|Number of pages||10|
|Publication status||Published - Feb 2001|