Adult Survival of Leach’s Storm Petrels Nesting in Distinct Oceanographic Domains of BC
Project Reference Number: 2006-05
Project Status: Complete
Led by: Anne Harfenist, Seabird Biologist, SmithersJanet Gray, Queen Charlottes
Funder: Private Funding - Anne Harfenist
As upper trophic level predators, marine birds are considered useful indicators of changes in marine ecosystems (eg. Furness and Camphuysen 1997; Boyd and Murray 2001). Much seabird research has examined reproductive parameters and population trends of species representing a range of feeding guilds in relation to oceanographic conditions (eg. Ainley et al. 1995). Over the last decade, the emphasis has shifted to incorporate adult survival estimates (eg. Bertram et al. 2005; Sandvik et al. 2005) – a key demographic parameter for long-lived species with low annual reproductive output such as seabirds.
Storm-petrels (Oceanodroma sp.) comprise approximately 27% of British Columbia’s total population of nesting seabirds (Rodway 1991). Their feeding habitat and primary prey species differ from those of other seabird species in the province: they forage over the shelf break and open ocean on prey items caught on the surface including myctophids and amphipods (Vermeer 1992). Despite their abundance and significance as indicators of conditions in portions of the marine ecosystem that are difficult to otherwise study, population trends and demography of storm-petrels in B.C. remain poorly described. Furthermore, their feeding habits render storm-petrels especially vulnerable to offshore oil and gas development. Baseline survival estimates will be required for impact assessment if offshore exploration proceeds in the future.
This study will determine annual adult survival estimates for Leach’s Storm-petrel (O. leucorhoa), the more abundant of the two storm-petrel species nesting in British Columbia. As comparisons of demographic parameters of Cassin’s Auklets (Ptychoramphus aleuticus) nesting in different oceanic current systems has aided our understanding of the relationship between ocean conditions and seabird populations (Bertram et al. 2005), the present study will be conducted at two geographically dispersed sites along the B.C. coast.