Table 1. Parameters of foraging trips of Dolphin Gulls Leucophaeus scoresbii.

	n			Trip length	Maximum distance from colony	Trip duration (min)	N° of trips per day
Mussel feeders	6			21.6±3.6 (17−26.3)	9.6±1.4 (7.8−11.5)	476±238 (255−930)	1.5±0.6 (1−2)
Colony feeders	10			18.2±10.7 (3.2−41.4)	7.8±4.9 (1.3−18.7)	357±165 (90−638)	2±0.5 (1−3)
t-test for Equality of Means				t = 0.7	t = 0.9	t = 1.2	t = -1.8
				P = 0.47	P = 0.40	P = 0.25	P = 0.09
Males	8			17.4±7.1 (3.2−24.3)	7.8±3.4 (1.3−10.7)	332±152 (90−533)	1.9±0.7 (1−3)
Females	8			21.5±10.0 (8.4−41.3)	9.1±4.7 (4.1−18.7)	472±220 (240−930)	1.8±0.5 (1−2)
t-test for Equality of Means				t = 0.9	t = 0.7	t = 1.5	t = -0.4
				P = 0.37	P = 0.53	P = 0.16	P = 0.73

Parameters were determined using GPS loggers during the incubation period at New Island (51°43′S, 61°18′W), Falkland Islands/Islas Malvinas, in the southwestern Atlantic Ocean. Median data for each individual were compared, i.e. one data point per individual was used to determine means, standard deviations and ranges, and to test for differences between mussel and colony feeders. One-Sample Kolmogorov-Smirnov Test (all P>0.2) and visual inspection of histograms revealed that the parameters were normally distributed. Distances are given in kilometers.