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The Marbled Murrelet Brachyramphus marmoratus is a threatened seabird that relies on old-growth forest for nesting. We compare marine space use between breeding and non-breeding birds, and how marine home range locations and overlap vary with respect to nesting location and breeding status. We collected very high frequency (VHF) radio-telemetry data in southern British Columbia from Clayoquot Sound (190 birds; 2000–2002) and Desolation Sound (206 birds; 1998–2001). The sites differ strongly in their oceanic exposure and surrounding terrestrial features. Kernel utilization distribution-based estimates showed that breeders and non-breeders had similar overall distributions, but breeders were more spatially aggregated. Pooled home ranges of non-breeders were larger than those of breeders, but the distributions of individual home range sizes did not differ significantly by breeding status. However, compared with non-breeders, breeding murrelets were more likely to share their home range with other breeders. Home range sizes were larger and commuting distances were longer at Desolation Sound than at Clayoquot Sound; the average home range size for individuals was 241 ± 6.7 km² at Clayoquot Sound and 330 ± 8.8 km² at Desolation Sound. Individuals that nested closer together were more likely to share their marine home range in Desolation Sound, but not at Clayoquot Sound. Commuting distance to a nest site was not related to home range size at either site. Our results support the hypothesis that, at a local scale, breeding murrelets congregate at specific foraging areas and are not strongly constrained by commuting distance to nesting locations. Our results also support the concept that home range size may be indicative of the overall habitat quality of an area. We quantify connectivity between terrestrial and marine habitats and highlight important historical foraging locations. [ABSTRACT FROM AUTHOR]

We applied a capture–mark–resight (CMR) method to estimate the population size of the Galápagos PenguinSpheniscus mendiculus. In 1999, we estimated 1198 individuals, with lower and upper 95% confidence limits of 1054 and 1403 individuals, respectively, and estimated that approximately 57% of the total population was counted in an annual census. Applying this estimate to the 2003 census, we estimated that the population size for the whole archipelago was 1351 individuals. We also applied the correction factor derived from the 1999 CMR data to other censuses carried out between 1970 and 2003 and estimated a maximum population of about 4000 individuals in 1971 when the highest numbers of Penguins were counted. Although the Penguin population size has fluctuated in the last 33 years, the overall trend shows larger populations in 1970–80 followed by relatively smaller populations and a slow recovery rate in 1983–2003. The data set also shows two major population declines (in 1983 and 1998), which are coincident with El Niño episodes. [ABSTRACT FROM AUTHOR]