MALE TRAITS, MATING TACTICS AND REPRODUCTIVE SUCCESS IN THE BUFF-BREASTED SANDPIPER, TRYNGITES SUBRUFICOLLIS

Buff-breasted sandpipers use a variety of mating tactics to acquire ma tes, including remaining at a single lek for most of the breeding seas on, attending multiple leks during the season, displaying solitarily o r displaying both on leks and solitarily. We found that differences in body size, body condition, fluctuating asymmetry Scores, lying colora tion, territory location and-behaviour (attraction, solicitation and a gonistic) did not explain the observed variation in mating tactics use d by males. Which males abandoned versus returned to leks was also not related to morphology or behaviour, and there was no tendency for mal es to join leks that were larger or smaller than the lek they abandone d. These results suggest that male desertion of leks was not dependent on a male's characteristics nor On the size. of the lek he was presen tly attending. Males did join leks with larger males than their previo us lek, perhaps to mate with females attracted to these larger 'hotsho t' males. Males at both leks and solitary sites successfully mated. Le k tenure did not affect mating success, although lekking a males appea red to mate more frequently-than solitary males. Courtship disruption and to a lesser extent, female mimicry, were effective at preventing f emales from mating at leks, and may offer a partial explanation for fe male mating off leks. Our analysis that combined all males together wi thin a year(regardless of mating tactic) indicated that males that att ended leks for longer periods of time and that had fewer wing spots we re significantly more likely to mate. Given some evidence that wing sp otting declines with age; and that females inspect male underwings dur ing courtship, the latter result suggests that:female choice may play some role in determining male success. We suggest that male buff-breas ted sandpipers may use alternative mating tactics more readily than ma les in other 'classic' lek-breeding species because: (1) unpredictable breeding:conditions in this species' high arctic breeding range leads to low lek stability, which in turn hinders mate selection mechanisms mediated by male dominance and female choice; and (2) males are not c onstrained by morphological markings that indicate;status or sex. Both -characteristics may reduce the reproductive benefits associated with males adopting one mating tactic and result in a sort of scramble comp etition in which males switch between tactics as local conditions chan ge. (C) 1998 The Association for the Study of Animal Behaviour.