Year-round movements of sympatric Fork-tailed (Oceanodroma furcata) and Leach's (O. leucorhoa) storm-petrels

Abstract

Long-distance movements are characteristic of most seabirds in the order Procellariiformes. However, little is known about the migration and foraging ranges of many of the smaller species in this order, especially storm-petrels (Hydrobatidae). We used Global Location Sensors to document the year-round movements of sympatrically breeding Fork-tailed Storm-Petrels (Oceanodroma furcata) and Leach's Storm-Petrels (O. leucorhoa) from the Gillam Islands located northwest of Vancouver Island, British Columbia, Canada. In 2016, breeding Fork-tailed (N = 5) and Leach's (N = 2) storm-petrels traveled maximum distances of~1550-1600 km from their colony to a region that has a wide shelf with major canyons creating a highly productive foraging area. After the breeding season, Fork-tailed Storm-Petrels (N = 2) traveled to similar areas west of the Gillam Islands, a maximum distance of~3600 km from the breeding colony, and remained in the North Pacific Ocean and north of the Subarctic Boundary for an average of 5.4 mo. Postbreeding Leach's Storm-Petrels (N = 2) moved south to the Eastern Tropical Pacific, west of central Mexico, Ecuador, and northern Peru, an estimated maximum distance of~6700 km from their breeding colony, and remained there for an average of 7.2 mo. Carbon (d 13 C) and nitrogen (d 15 N) stable isotope analyses of feathers revealed niche separation between Fork-tailed (N = 21) and Leach's (N = 53) storm-petrels. The wide range of d 15 N values in the feathers of Leach's Storm-Petrels (N = 53) suggests that they foraged at a variety of trophic levels during the non-breeding season. Our results demonstrate that storm-petrels have large core foraging areas and occupy vast oceanic areas in the Pacific during their annual cycle. However, given the coarse precision of Global Location Sensors, additional study is needed to identify the specific areas used by each species during both breeding and non-breeding periods.RESUMEN. Movimientos anuales de los simp atricos Pa ıño rabihorcado (Oceanodroma furcata) y Pa ıño boreal (O. leucorhoa) Los moviemientos a larga distancia son caracter ısticos de la mayor ıa de las aves marinas del orden Procellariiformes. Aun as ı, poco se sabe de la migraci on y los rangos de forrajeo de las especies m as pequeñas del orden, especialmente los petreles de las tormentas o pa ıños (Hydrobatidae). Usamos Sensores de Ubicaci on Global para documentar los movimientos durante todo el año de dos especies que cr ıan simp atricamente, el Pa ıño rabihorcado (Oceanodroma furcata) y el Pa ıño boreal (O. leucorhoa), desde las Islas Gillam ubicadas al noroeste de la Isla de Vancouver, Columbia Brit anica, Canad a. En 2016, los pa ıños rabihorcados (N = 5) y boreales (N = 2) reproductivamente activos viajaron distancias m aximas de~1550-1600 km desde su colonia a una regi on que tiene una placa ancha con grandes cañones que crean un area de forrajeo altamente productiva. Luego de la temporada reproductiva, los pa ıño rabihorcados (N = 2) viajaron a areas similares al oeste de las Islas Gillam, una dis...

Double‐tagging scores of seabirds reveals that light‐level geolocator accuracy is limited by species idiosyncrasies and equatorial solar profiles

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Metabarcoding, stables isotopes, and tracking: unraveling the trophic ecology of a winter-breeding storm petrel (Hydrobates castro) with a multimethod approach

“…Although the combination of these techniques shows a strong potential to study the trophic ecology of seabirds, it has only been used for a small number of storm-petrel species (e.g. Pollet et al 2014a;Halpin et al 2018;Paiva et al 2018).…”

Birds of a feather moult together: Differences in moulting distribution of four species of storm-petrels

“…Studying the non-breeding distribution of small pelagic seabirds, such as storm-petrels, is still a challenge, resulting in a considerable knowledge gap. Although progress is being made with the miniaturisation of devices enabling whole year tracking [ 15 – 17 ], sample sizes remain relatively small due to low retrieval rates and incomplete tracks [ 15 – 17 ]. Additionally, these devices, while not proven detrimental [ 15 – 17 ], may be considered a relatively invasive method to study year-round movements.…”

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