G. Vernon Byrd

ASSESSING THE EFFECTS OF INTRODUCED NORWAY RATS (RATTUS NORVEGICUS) ON SURVIVAL AND PRODUCTIVITY OF LEAST AUKLETS (AETHIA PUSILLA)

Abstract We assessed potential effects of introduced Norway rats (Rattus norvegicus) on Least Auklets (Aethia pusilla) breeding at Sirius Point on Kiska Island, the largest auklet colony in the Aleutian Islands, Alaska. We compared productivity, chick growth, and adult survival of Least Auklets during 2001-2003 at Kiska and two nearby, rat-free Least Auklet colonies on Buldir and Kasatochi islands. During 2001 and 2002 (when rats were abundant), productivity at Kiska was the lowest ever recorded for this species (0.09–0.16 chicks fledged per eggs laid), primarily because of high mortality of newly hatched chicks. Growth rates and mean fledging mass were both lower on Kiska than on rat-free islands, though there were some interannual differences in these patterns. Adult survival rates were highly variable among years but strongly concordant among colonies, and survival from 2001 to 2002 on Kiska (0.881 ± 0.033) did not differ significantly from long-term averages on either Buldir (0.853 ± 0.014, 1990-2003) or Kasatochi (0.893 ± 0.027, 1996-2003) islands. Although we found little evidence at nesting crevices of predation on adults, eggs, or chicks, low productivity and slow chick growth were both consistent with disturbance caused by rats, particularly through disruption of adults attempting to brood or provision young chicks. Breeding failure may have been exacerbated by low prey availability for chick provisioning, but the lack of concordance in either productivity or chick growth rates between Kiska Island and nearby rat-free Buldir Island cast doubt on this possibility. Évaluer les Effets de Rattus norvegicus Introduits sur la Survie et la Productivité de Aethia pusilla

The Birds of Adak Island Alaska

Adak Island lies between 51”35’ and 52”Ol’ N. and 176”25’ and 176”59’ W, in the Andreanof Group, Aleutian Islands. Although Taber (1946) provides an annotated list of birds he observed at Adak in winter, year-round observations have not been previously published. Since Adak lies near the middle of the axis formed by the Alaska Peninsula and the Aleutian and Commander islands (fig. l), which links North America and Asia, its avifauna is composed of species with varied geographic origins. Closely paralleling the findings of Emison et al. (1971), who discuss the geographic origins of 100 species of birds known from Amchitka Island, 65% (81 species) of the birds recorded at Adak have contemporary breeding distributions in both North America and Asia (vs. 68% at Amchitka) ; 19% (24 spp.) have affinities only to Asia (vs. 15%); 12% (15 spp.) have affinities only to North America (vs. 13%); and 3% (4 spp.) breed only on midand south Pacific islands (vs. 4%). Of the 124 species included in the following annotated list, two, Anas poecilorhyncha zonorhyncha and Cuculus canorus canorus, are new to North America. Seventeen additional forms are represented by few North American records, and well over half of the species listed have not been previously recorded on Adak.

Food habits of the Whiskered Auklets at Buldir Island, Alaska

We studied the food habits of Whiskered Auklets (Aethia pygmaea) at Buldir Island, western Aleutian Islands, Alaska, during the summer of 1976. At Buldir, these birds fed primarily in and near convergent tidal fronts in the passes between three islets just offshore; feeding occurred throughout the day. Whiskered Auklets ate at least 10 different species of zooplanktonic prey, of which the copepod Neocalanus plumchrus was the most important. Next in importance were chaetognaths (probably Sagitta elegans), the amphipod Parathemisto pacifica, megalopae of the crab Erimacrus isenbeckii, and an unidentified amphipod. Pteropods (probably Limacina helicina), larval cephalopods, and a larval fish occurred in trace amounts. During most of the summer, Whiskered Auklets were nearly monophagous on N. plumchrus; we do not consider a difference in prey during late incubation/early chick rearing to represent a biologically-significant trend. We collected Least (A. pusilla), Crested (A. cristatella), and Parakeet (Cyclorrhynchus psittacula) auklets during late chick rearing, to compare their food habits with those of Whiskered Auklets. At this time, both Least and Whiskered auklets were monophagous on smaller N. plumchrus, whereas Crested and Parakeet auklets mainly ate larger N. cristatus and P. pacifica; Parakeet Auklets ate the widest diversity of zooplankton. Selection of prey by the four auklet species appeared to occur in relation to size, with the smaller auklets eating smaller zooplankters.

Introduction—The Impacts of the 2008 Eruption of Kasatochi Volcano on Terrestrial and Marine Ecosystems in the Aleutian Islands, Alaska

*Corresponding author: U.S. Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, U.S.A. tdegange@usgs.gov {U.S. Fish and Wildlife Service, Alaska Maritime National Wildlife Refuge, 95 Sterling Highway, Suite 1, MS 505, Homer, Alaska 99603, U.S.A. {School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada 89154-4004, U.S.A. 1U.S. Geological Survey, Alaska Volcano Observatory, 4210 University Drive, Anchorage, Alaska 99508, U.S.A.

BREEDING BIOLOGY OF CRESTED AUKLETS AT BULDIR AND KASATOCHI ISLANDS, ALASKA

We quantified breeding parameters of Crested Auklets (Aethia cristatella) at Buldir and Kasatochi islands in the Aleutian Islands, Alaska, in 1996 and 1997. Crested Auk- lets incubated their eggs for about 36 days and chicks weighed about 35 g within the first three days of hatching (14% of adult mass; Buldir, n = 58). Growth rates averaged about 9.9 g per day during the linear phase (Buldir, n = 58; Kasatochi, n = 17), and chicks fledged at an average mass of 248 g (95% of adult mass; Buldir, n = 63) and a wing length of 123 mm (88% of adult wing length; Buldir, n = 37) at 34 days after hatching. We found no differences in intraisland and intrayear chick growth for Buldir and Kasatochi. Productivity (the product of hatching success and fledging success) averaged more than 60% for the two years at Ka- satochi and for eight years (1990 to 1997) at Buldir. Intercolony comparisons of productivity parameters revealed differences in hatching date, age of chicks at fledging, and hatching and fledging success. Adult mass differed significantly between the sexes (267 g for males, 253 g for females) and among years. At Buldir, we observed no effect of various levels of inves- tigator disturbance on hatching and fledging success or on other breeding parameters. We found no negative relationships between hatching date and fledging age, hatching date and fledging mass, or fledging mass and fledging age, contrary to the predictions of Ydenbergs (1989) model of intraspecific variation in timing of fledging of alcid chicks. Crested Auklet chicks, like those of other diurnally active species of auklets, grow relatively fast and depart at a younger age compared with chicks of two nocturnal species of auklets. Received 24 April

COLONY MAPPING: A NEW TECHNIQUE FOR MONITORING CREVICE-NESTING SEABIRDS

Abstract Monitoring populations of auklets and other crevice-nesting seabirds remains problematic, although numerous methods have been attempted since the mid-1960s. Anecdotal evidence suggests several large auklet colonies have recently decreased in both abundance and extent, concurrently with vegetation encroachment and succession. Quantifying changes in the geographical extent of auklet colonies may be a useful alternative to monitoring population size directly. We propose a standardized method for colony mapping using a randomized systematic grid survey with two components: a simple presence/absence survey and an auklet evidence density survey. A quantitative auklet evidence density index was derived from the frequency of droppings and feathers. This new method was used to map the colony on St. George Island in the southeastern Bering Sea and results were compared to previous colony mapping efforts. Auklet presence was detected in 62 of 201 grid cells (each grid cell  =  2500 m2) by sampling a randomly placed 16 m2 plot in each cell; estimated colony area  =  155 000 m2. The auklet evidence density index varied by two orders of magnitude across the colony and was strongly correlated with means of replicated counts of birds socializing on the colony surface. Quantitatively mapping all large auklet colonies is logistically feasible using this method and would provide an important baseline for monitoring colony status. Regularly monitoring select colonies using this method may be the best means of detecting changes in distribution and population size of crevice-nesting seabirds.

Trends in populations of Red-legged Kittiwake Rissa brevirostris , a Bering Sea endemic

Summary The Red-legged Kittiwake Rissa brevirostris is a small gull which is restricted to four breeding locations, all in the Bering Sea (Pribilof Islands, Bogoslof Island, Buldir Island, and the Commander Islands). In the mid-1970s, when the earliest counts were made at most sites, approximately 260,000 birds were present at breeding colonies. Subsequent counts indicated that populations at Bogoslof and Buldir had increased by the early 1990s. Data for the Commander Islands were inadequate to make strong conclusions about trends but there were no indications of substantial change between the 1970s and 1990s. In contrast, Red-legged Kittiwakes have declined in the Pribilof Islands by approximately 50% since the mid-1970s, a matter of concern because this island group once contained more than 80% of the worlds population. Research is needed to determine causes for declines in Red-legged Kittiwakes and population monitoring should continue to provide a basis for conservation measures.