Migratory Movements and Activity Patterns of White-Faced Storm-Petrels Pelagodroma marina Breeding in Cabo Verde

Abstract

SummarySeabirds spend most of the year offshore, out of human sight, covering great distances while migrating and foraging for food often in remote areas of the high seas. Several small seabirds that anthropogenic activities might threaten have hitherto remained untracked. One such species is the anti-tropical White-faced Storm-petrel Pelagodroma marina. Indeed, its movements and activity patterns are largely unknown, although often regarded as dispersive. In this study, we aimed to identify the post-breeding movements and the daily activity patterns of White-faced Storm-petrels breeding in Cabo Verde (P. m. eadesorum). We tracked five adults with geolocators (GLS) between 2019 and 2022 and modelled their routes using Satellite Geolocation for Animal Tracking (SGAT). We programmed geolocators to record when the bird was dry or on the water to understand their daily activity patterns during the non-breeding period. Results showed that the White-faced Storm-petrels breeding in Cabo Verde are truly migratory, heading towards the northwest Atlantic in May-June and returning in October-November through the northeast towards Cabo Verde, following a clockwise movement. Birds spent the non-breeding period in areas associated with seamounts along the mid-Atlantic Ridge and south of the Azores. In addition, we found that the species is mainly active at night during the non-breeding season, suggesting that it takes advantage of the diel vertical migration of zooplankton and nekton associated with seamounts. The time spent on the water increased before returning to the colony, probably due to reduced flying ability during the moulting period. Our data add to the growing evidence that the North-central Atlantic is a crucial location for the conservation of pelagic seabirds and highlights the need to protect these remote areas from the increasing human impact on the high seas.—Medrano, F., Repullés, K., Militão, T., Leal, A. & González-Solís, J. (2024). Migratory movements and activity patterns of White-faced Storm-petrels Pelagodroma marina breeding in Cabo Verde. Ardeola, 71: 101-118.