Foraging behavior and at-sea distribution of White-Tailed Tropicbirds in tropical ocean

Abstract

We used miniaturized GPS loggers and site observations to access foraging patterns and nest behaviour of the White-tailed Tropicbird Phaethon lepturus (WTTB), an endangered species at its South Atlantic breeding colony. Dual foraging pattern was observed with alternation between long and short foraging trips. Birds responsible for nest attendance engaged in short foraging trips with mean distance from colony of 25 ± 17 km, total distance covered of 79 ± 65 km and mean duration of 4.02 ± 5.28 hours. Birds flew by dawn and returned before dusk while partners were at sea for long foraging trips that ranged from four to 11 days, with mean maximum distance from colony of 105 ± 47.48 km. Chicks were usually left alone for hours and chick predation by Land Crab Johngartia lagostroma, egg consumption by Goniopsis cruentata and intra-specific competition are suspected to be responsible for high chick mortality rates.Keywords: Tropicbird, GPS, dual foraging, behavior. Comportamento de forrageio e distribuição no mar doRabo-de-palha-de-bico-laranja em oceano tropical ResumoUtilizamos aparelhos de GPS miniaturizados e observações de campo para determinar padrões de forrageio e comportamento em ninho da espécie ameaçada Rabos-de-palha-de-bico-laranja Phaethon lepturus em sua colônia reprodutiva do Atlântico Sul. Padrão dual de forrageio foi observado, com alternância entre viagens longas e curtas. Aves responsáveis por cuidado parental efetuaram viagens curtas de forrageio com em média 25 ± 17 km de distância da colônia, distância total percorrida média de 79 ± 65 km e duração média de 4.02 ± 5.28 horas. As aves saíram da colônia entre o amanhecer e o entardecer, enquanto seus parceiros estavam em alto-mar em viagens longas de quatro a 11 dias de duração, com média de distância máxima da colônia de 105 ± 47.48 km. Filhotes foram constantemente deixados sozinhos por várias horas, e predação por Johngartia lagostroma, consumo de ovos por Goniopsis cruentata e competição intra-específica possivelmente foram responsáveis por sua morte.Palavras-chave: Rabos-de-palha, GPS, estratégia dual de forrageio, comportamento.

Raking the ocean surface: new patterns of coordinated motion in seabirds

“…Among these, pelagic species such as tropicbirds, noddies and terns display different foraging modes. White‐tailed tropicbirds mainly forage solitary (Jaquemet et al , Campos et al ), and occasionally associate with feeding dolphins (Jaquemet et al , Spear and Ainley ). Comparatively, sooty terns, brown and black noddies are highly gregarious and are often found in multi‐specific feeding assemblages (Evans , Au and Pitman , Jaquemet et al , Hebshi et al , Goyert et al ).…”

Genetic structuring among colonies of a pantropical seabird: Implication for subspecies validation and conservation

“…None of the tracked birds crossed the equator and reached the southern Atlantic Ocean. Campos, Andrade, Bertrand, and Efe (2018) and Santos, Campos, and Efe (2019) tracked the movement of white‐tailed tropicbirds ( P. l. ascensionis ) during chick‐rearing from Fernando de Noronha archipelago and showed that long foraging trips reached an average distance from the breeding colony of 105 ± 48 km. This reinforces the hypothesis of a lack of connectivity between northern and southern populations of the Atlantic Ocean.…”

Foraging habitat choice of White-tailed Tropicbirds revealed by fine-scale GPS tracking and remote sensing

“…Ecologically, they share with boobies, gannets and terns the ability of plunge diving, but unlike these species, they avoid foraging in large multi-species flocks (Spear & Ainley, 2005). They are also unusual in that although they fly long distances (comparable to procellariids), they lack the ability to soar (Spear & Ainley, 1997; Mannocci et al, 2014; Campos et al, 2018). This flight behaviour seems to be possible because they rest for long periods on the water between periods of flight (Spear & Ainley, 2005; Mejias et al, 2017).…”

“…This flight behaviour seems to be possible because they rest for long periods on the water between periods of flight (Spear & Ainley, 2005; Mejias et al, 2017). Despite these unusual characteristics, tropicbirds have only been tracked in a few studies (Pennycuick et al, 1990; Le Corre et al, 2012; Soanes et al, 2016; Mejias et al, 2017; Campos et al, 2018), which greatly limits our understanding of their foraging ecology.…”