PSG 2012 Hawaii abstracts - Pacific Seabird Group

ARTIFICIAL LIGHTS IN FISHING PORT AFFECT PREY DENSITY AND NOCTURNAL
FORAGING BEHAVIOR OF GULLS
Kazuhiko Hirata, Yutaka Watanuki, Laboratory of Marine Ecology, Graduate School of Fisheries
Sciences, Hokkaido University, 3-1-1, Minato-cho, Hakodate, Hokkaido, 041-8611, Japan,
khirata@fish.hokudai.ac.jp
Artificial lights provide nocturnal foraging opportunities for usually diurnal predators. The density of
diurnal seabird can be affected by artificial light (fish collecting lamps and outdoor lamps along the coast)
since these lights change the behavior of their prey species (zooplankton and small fish). Empirical field
studies covering multiple trophic levels, however, have not been carried out. We observed nocturnal
foraging behavior of gulls in 12 fishing ports in Hakodate, Hokkaido, and also measured seasonal changes
in the number of gulls and density of zooplankton under an artificial light at Hiura port. More nocturnal
foraging gulls were observed in ports with more lights. The percentage of nocturnal foraging individuals
and the density of zooplankton (oviferous amphipods) were higher under the light than the surrounding
surface water. More nocturnal foraging gulls were observed in January-May when the density of
zooplankton was higher than July-December. These indicate that the lights in port attract zooplankton and
enhance nocturnal foraging gulls.
CONSERVATION STATUS OF TROPICAL SEABIRDS AND GUIDING REMOVAL OF INVASIVE
VERTEBRATES ON ISLANDS
Nick D. Holmes* 1 , Dena Spatz 2 , Don Croll 2 , Bernie Tershy 2 and Stuart Butchart 3 1 Island Conservation,
100 Shaffer Rd., Santa Cruz, CA 95060 USA; nick.holmes@islandconservation.org ; 2 Coastal and
Conservation Action Laboratory, University of California at Santa Cruz, 100 Shaffer Rd., Santa Cruz, CA
95060 USA; 3 BirdLife International, Wellbrook Court, Girton Road, Cambridge, CB3 0NA, United
Kingdom
Seabirds are the most foremost threatened group of birds, with 28% of species identified at risk of
extinction. An estimated 70% of seabirds are exposed to terrestrial threats on their breeding islands, with
invasive vertebrates widely documented as a critical threatening process. We worked with numerous
partners to build a database of island populations of IUCN Threatened seabirds and other vertebrates, with
an overall of goal of identifying and prioritizing islands where removal of invasive vertebrates can
maximize recovery potential of threatened species. We collated information for Critically Endangered,
Endangered and Vulnerable seabird species, recommended conservation actions for each species by
Birdlife, the number and location of breeding islands for each species, and presence of invasive
vertebrates on these breeding islands. A total of 30 species breed on islands between the tropics of
Capricorn and Cancer, with Procellaridae representing 16 of these species, highlighting this family as
conservation concern in the tropics. A total of 157 breeding islands were identified, with invasive
vertebrates were recorded on at least 75% of islands. Threatened tropical seabird breeding islands were
geographically and politically clustered, with the five species recorded in both the Galápagos Archipelago