Abstract: Identifying important foraging areas is fundamental to detecting the
demographic drivers of a species and ultimately to plan conservation
measures. For some species, such as small pelagic seabirds, foraging
grounds are difficult to locate and remain largely unknown. We used
miniaturised GPS devices (∼0.95g) to study foraging movements of
Mediterranean Storm-petrels
Hydrobates pelagicus melitensis during the
incubation period. A total of 43 individuals at Benidorm colony
(southwestern Mediterranean Sea) were tracked during a single foraging
trip. We first assessed potential negative effects of the tracking
devices.
We recorded 22 complete foraging trips and measured home-range,
foraging areas and the degree of overlap among individuals. We used
first passage time analyses (FPT) to differentiate foraging/resting from
flying/travelling activities and to infer potential foraging areas. All
tracked birds returned to the colony. On average, individual body
weight slightly decreased after foraging trips, suggesting a small
immediate negative effect of the device. Tracked birds had high breeding
success (0.71). Foraging trips lasted between 1 and 4.5 days with the
total distance travelled ranging between 303.14 and 1,726.53km. The
visited areas covered the whole south-western part of the Mediterranean
Sea. Tracked individuals shared more than 50% of their home-range areas.
Foraging areas were located further from the colony than previously
thought (from 240 to 469km away) on deep sea areas of the Alboran Sea
and Cartagena Canyons. Further studies are needed to locate foraging
grounds during other life-cycle periods and to evaluate repeatability
yearly, in order to determine the important marine areas for the
species.—Rotger, A., Sola, A., Tavecchia, G. & Sanz-Aguilar, A.
(2021). Foraging far from home: GPS-tracking of Mediterranean
Storm-petrels
Hydrobates pelagicus melitensis reveals long-distance foraging movements.
Ardeola, 68: 3-16.
