Simultaneous GPS-tracking of parents reveals a similar parental investment within pairs, but no immediate co-adjustment on a trip-to-trip basis

Table 3 Outcome of a Multiple Response Permutation Procedure (MRPP) that was used to calculate the dissimilarities in offspring investment (trip duration, total distance travelled, flying and foraging) and self-maintenance (time allocated to resting outside the colony) within and between pairs

Trip parameters	Within pairs	Between pairs	Observed delta	Expected delta
VL
Total distance (km)	0.223	0.252	7.133	7.895
Trip duration (h)	0.296	0.368	91.980	108.800
Resting (h)	0.231	0.266	3.117	3.481
Flying (h)	0.300	0.356	2.998	3.435
Foraging (h)	0.454	0.528	2.699	3.273
ZB
Total distance (km)	0.281	0.301	8.468	9.123
Trip duration (h)	0.349	0.404	96.820	112.000
Resting (h)	0.274	0.292	3.479	3.719
Flying (h)	0.352	0.403	3.264	3.754
Foraging (h)	0.490	0.538	3.395	3.849

Dissimilarities are calculated separately for the two colonies [Vlissingen: VL (N = 12 pairs), Zeebrugge: ZB (N = 13 pairs)]. Observed delta is the overall weighted mean of group mean distances. Expected delta is the mean of original dissimilarities, under the null hypothesis of no group structure. Significance of delta is < 0.001 for all parameters

ISSN: 2051-3933