Scott A. Hatch 1987 <p><span>I studied the timing and frequency of copulation in mated pairs and the occurrence of extra-pair copulation (EPC) among Northern Fulmars (</span><i>Fulmarus glacialis</i><span>) for 2 yr. Copulation peaked 24 days before laying, a few days before females departed on a prelaying exodus of about 3 weeks. I estimated that females were inseminated at least 34 times each season. A total of 44 EPC attempts was seen, 9 (20%) of which apparently resulted in insemination. Five successful EPCs were solicitated by females visiting neighboring males. Multiple copulations during a single mounting were rare within pairs but occurred in nearly half of the successful EPCs. Both sexes visited neighbors during the prelaying period, and males employed a special behavioral display to gain acceptance by unattended females. Males invested time in nest-site attendance during the prelaying period to guard their mates and pursue EPC. However, the occurrence of EPC in fulmars was largely a matter of female choice.</span></p> application/pdf 10.2307/4087544 en American Ornithological Society Copulation and mate guarding in the Northern Fulmar article