Alexander K. Prichard

PIGEON GUILLEMOTS AS A SENTINEL SPECIES: A DOSE-RESPONSE EXPERIMENT WITH WEATHERED OIL IN THE FIELD

Nests of pigeon guillemots (Cepphus columba) were located along the south shore of Kachemak Bay, Alaska, and monitored during the breeding seasons of 1994 and 1995. Rates of nestling growth were measured and blood samples were collected for measurements of serum biomarkers. Haptoglobin, total protein, alanine aminotransferase, aspartate aminotransferase, and sodium in sera were measured as potential biomarkers of oil ingestion. Differences in mean levels of biomarkers were observed between years, and between nestlings and adults, as well as among locations within Kachemak Bay. During summer 1995, a controlled dose-response experiment was conducted with weathered Prudhoe Bay Crude Oil. Fifty-one nestlings were divided into three groups: controls, nestlings fed 0.05 ml of oil, and nestlings fed 0.20 ml of oil. Each experimental nestling was fed the dose of weathered oil twice: once at approximately day 20, and again 5 days later at approximately day 25 post-hatching. Blood samples were collected immediately before dosing on days 20, 25, and again on day 30 post-hatching. Site-specific differences in some blood variables were observed among treatments. These results suggest that the doses of weathered oil administered to guillemot nestlings were not sufficient to induce a persistent inflammatory response.

Conflicts between reindeer herding and an expanding caribou herd in Alaska

The reindeer industry has existed in Alaska since 1892. This industry has largely been concentrated on the Seward Peninsula, Alaska because suitable habitat has been available and caribou have been absent here for over 100 years. Until recently, reindeer meat and velvet antler production consistently generated millions of dollars in revenue critical to the economies of rural Alaskan communities. From 1976 to 1996 the Western Arctic Caribou Herd (WACH) increased from about 75 000 to 463 000 animals. Concurrently, seasonal range use of the WACH shifted westward onto traditional reindeer ranges of the Seward Peninsula. Reindeer herders lost 75-100% of their herds through commingling and out¬migration with wild caribou. This loss of over 12 000 reindeer represents a potential economic value of 13 million dollars. Sustainable meat and velvet antler production and the economies of western Alaskan are likely to be affected by these changes.

Growth and body weight of free-range reindeer in western Alaska

Total body weight of 9749 reindeer calves and 4798 adult reindeer were measured from 1984 to 1999 on the Seward Peninsula, western Alaska, USA. Growth rates of male and female calves, and annual growth patterns of adults were determined. Male calves grew faster than female calves. Reproductive females were lighter than non-reproductive females during summer but there was no effect of reproduction on average body weights the following winter. Adult males age 3-5 were heavier during summer than winter. Castrated males weighed the same as uncastrated males in summer, but were significantly heavier in winter, and did not display the large annual fluctuations in weight typical of reproductive males and females. Growth rates were higher and body weights greater in this herd than many other cir-cumpolar reindeer populations. We suggest these kinds of physiological indices should be used to monitor the possible effects of spatial and temporal variation in population density and to evaluate changes in herding practices.

Summer resource selection and identification of important habitat prior to industrial development for the Teshekpuk Caribou Herd in northern Alaska.

Many caribou (Rangifer tarandus) populations are declining worldwide in part due to disturbance from human development. Prior to human development, important areas of habitat should be identified to help managers minimize adverse effects. Resource selection functions can help identify these areas by providing a link between space use and landscape attributes. We estimated resource selection during five summer periods at two spatial scales for the Teshekpuk Caribou Herd in northern Alaska prior to industrial development to identify areas of high predicted use for the herd. Additionally, given the strong influence parturition and insect harassment have on space use, we determined how selection differed between parturient and non-parturient females, and between periods with and without insect harassment. We used location data acquired between 2004–2010 for 41 female caribou to estimate resource selection functions. Patterns of selection varied through summer but caribou consistently avoided patches of flooded vegetation and selected areas with a high density of sedge-grass meadow. Predicted use by parturient females during calving was almost entirely restricted to the area surrounding Teshekpuk Lake presumably due to high concentration of sedge-grass meadows, whereas selection for this area by non-parturient females was less strong. When insect harassment was low, caribou primarily selected the areas around Teshekpuk Lake but when it was high, caribou used areas having climates where insect abundance would be lower (i.e., coastal margins, gravel bars). Areas with a high probability of use were predominately restricted to the area surrounding Teshekpuk Lake except during late summer when high use areas were less aggregated because of more general patterns of resource selection. Planning is currently underway for establishing where oil and gas development can occur in the herd’s range, so our results provide land managers with information that can help predict and minimize impacts of development on the herd.

Lactation in yearling Alaskan reindeer: Implications for growth, reproduction, and survival

Unlike most Rangifer herds, free-ranging female reindeer {Rangifer tarandus) on the Seward Peninsula, Alaska frequently give birth as yearlings (12 months). In other reindeer herds this early reproduction has led to negative effects such as decreased future weight gain and reproduction. We analyzed reindeer data collected on the Seward Peninsula between 1987 and 1997 to determine what effect lactating as yearlings had on future weight gain, reproductive rates, and survival. Reindeer were rounded up during June and early July. Individual ear tag numbers were recorded, females were visually inspected for the presence of a distended udder, and some animals were weighed. Females with distended udders as yearlings had subsequent recapture rates, survival rates, weight gain, and future reproductive success comparable to females that did not have distended udders as yearlings. These findings suggest that the beneficial effects of increased calf weight gain outweigh potential negative effects of early reproduction in these reindeer. This may be due to high quality range leading to heavy calves and the ability of females to maintain body reserves during lactation.

Factors affecting velvet antler weights in free-ranging reindeer in Alaska

Free-ranging reindeer on the Seward Peninsula in western Alaska are rounded up from late May to early July and antlers are removed. We used data collected from 1987 to 1997 to determine how velvet antler weights of males and females varied with age, year, reproductive status, Julian date, and body weight. Male antler weights increased with age up to age five years, and were lower in castrates than in bulls. There was a significant positive relationship between body weight and antler weight in both sexes. Female antler weights increased with age until at least age nine. Lactating females had lower antler weights than non-lactating females, but this effect is better explained by differences in body weight. Antler weight of individual reindeer at age two years was better predicted by their antler weights as yearlings than their body weight as yearlings.

Rapid Growth of a Nesting Colony of Lesser Snow Geese (Chen caerulescens caerulescens) on the Ikpikpuk River Delta, North Slope, Alaska, USA

Abstract. A small colony of nesting Lesser Snow Geese (Chen caerulescens caerulescens) was discovered on the Ikpikpuk River delta in 1992. The number of nesting pairs averaged 35 (Range = 0–60) from 1992 to 1998, then increased dramatically from 176 in 1999 to 12,373 in 2015, for a λ of 1.40 (SE = 0.138). Concomitant with this dramatic population increase, the geographic extent of the colony expanded annually from three small islands in the northwestern portion of the delta during 1992–1999 to all vegetated deltaic islands in 2001 and farther inland on the mainland from 2006 onward. When colony growth was most rapid (2001–2008), nesting success averaged 79% (Range = 48–97%). Low nesting success during 2009–2014 (< 50% in all years except one), primarily caused by brown bears (Ursus arctos), was followed in 2015 by 96.6% success. In 2015, ∼22,000 adults (in both brood-rearing and adult-only flocks) were accompanied by more than 25,000 goslings in July and August. These numbers represent a remarkable increase in the abundance of Snow Geese west of the Colville River, where only 15 years previously fewer than 500 birds nested. Both immigration and high productivity probably have contributed to colony growth, although the relative importance of effects of the two factors in this growth has not been determined. Further analyses may provide insights into population relationships and the management implications of rapid local and regional growth of Snow Goose populations in northern Alaska.

Use of satellite telemetry to evaluate movements of caribou within subsistence hunting areas in northern Alaska

Caribou from the Teshekpuk Herd (TH) are an important subsistence resource for residents of Inupiaq villages in northern Alaska. In recent years the use of satellite telemetry has increased the understanding of the herds annual movements and interactions with other herds. Most caribou of the TH are within the National Petroleum Reserve—Alaska (NPRA) throughout the year. The northeastern portion of NPRA has undergone two lease sales for oil and gas exploration, and lease sales are tentatively scheduled for the central/northwest portion of the NPRA in 2004. During 1990—1999, the movements of 27 caribou from the TH were tracked using satellite collars. We evaluated the proportion of time caribou were available to Inupiaq hunters by incorporating maps depicting subsistence-use areas for each of seven Inupiaq villages, and then examining seasonal and annual movements of caribou relative to those areas. By combining caribou locations with subsistence hunting areas, we were able to explore spatial and temporal patterns in caribou availability to subsistence hunters. This information is useful for managers to set appropriate hunting regulations and for devising sensible alternatives and mitigation of likely petroleum development in NPRA.

Use of satellite telemetry data, GIS, and HTML to create an interactive display of caribou movements

The use of animation clearly reveals the large annual variation in wintering areas and large differences in daily movement rates for this herd. This interactive display can be adapted for school groups, subsistence hunters, the general public, or scientists.