New paper on the foraging ecology of Brown boobies

New paper on the foraging ecology of Brown boobies Sula leucogaster from Tinhosas Islands, Gulf of Guinea

The foraging distribution (through GPS tracking) and diet of Brown boobies from Tinhosa Grande island (São Tomé and Príncipe) were explored during the breeding season of last year.

This study showed that Brown boobies forage up to 200 km from the colony, and that females performed the longest trips. Both sexes foraged preferentially over deep oceanic waters (deeper than 2000 m). The diet of Brown boobies included juvenile fish and squid (Sthenoteuthis pteropus), comprising mostly fish species whose juvenile phases live in the pelagic environment, and only migrate to coastal waters when adults. The most frequent of those prey found was Flying gurnard (Dactylopterus volitans). The relevance of such prey shows that Brown booby conservation depends not only on the management of their foraging areas and breeding sites but also on the correct management of the coastal adjacent areas that support the adult individuals of some of their prey.

The Tinhosas islands, located ca. 20 km south of Príncipe Island in the Democratic Republic of São Tomé and Príncipe, host one of the largest colonies of seabirds in the east tropical Atlantic. Here an estimate of 738 pairs of Brown boobies nest among over than 140 000 breeding pairs of Sooty terns (Onychoprion fuscatus), and smaller numbers of Brown noddies (Anous stolidus), and Black noddies (A. minutus). Brown boobies have declined by 60% over the last 20 years, most likely due to human persecution of birds in the colony, for consumption and trade and virtually nothing is known on the foraging ecology of this population.

This work was carried out by members of Fundação Príncipe; Fauna & Flora International; MARE- ISPA Instituto Universitário and CESAM, Universidade de Lisboa, as part of the project “Establishing a network of marine protected areas across São Tomé and Príncipe through a co-management approach” (https://www.blueactionfund.org/wp-content/uploads/2018/10/Factsheet_FFI.pdf).

The paper can be read here https://doi.org/10.1007/s00227-021-03904-0