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

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

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

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

Effects of Gas Flaring on the Behavior of Night-migrating Birds at an Artificial Oil-production Island, Arctic Alaska

We studied movement rates and the general flight behavior of bird flocks seen on radar and recorded visually at Northstar Island, Arctic Alaska, from 13 to 27 September 2002. Most of this period (13 – 19 and 21 – 27 September) had no gas-flaring events, but a major gas-flaring event occurred on the night of 20 September. Movement rates of targets on radar and of bird flocks recorded visually in the first ~50% – 60% of the night were much lower during the non-flaring period than during the night of flaring, whereas rates in the last ~40% – 50% of the night were similar in all periods. The general flight behavior of birds also differed significantly, with higher percentages of both radar targets and bird flocks exhibiting straight-line (directional) flight behaviors during the non-flaring periods and higher percentages of radar targets and bird flocks exhibiting non-straight-line (erratic and circling) flight behaviors during the gas-flaring period. During the night of gas flaring, the bright illumination appeared to have an effect only after sunset, when flocks of birds circled the island after being drawn in from what appeared to be a substantial distance from the island. On both radar and visual sampling, the number of bird flocks approaching the island declined over the evening, and the attractiveness of the light from flaring appeared to decline. The visibility of the moon appeared to have little effect on the behavior of birds. Because illumination from extensive gas-flaring is such a strong attractant to migrating birds and because most bird flocks fly at low altitudes over the water, flaring booms on coastal and offshore oil-production platforms in Arctic Alaska should be positioned higher than the mean flight altitudes of migrating birds to reduce the chances of incineration.Nous avons étudié les taux de déplacement et le comportement de vol général des troupeaux d’oiseaux captés par radar ou consignés visuellement à l’île Northstar, dans l’Alaska de l’Arctique, du 13 au 27 septembre 2002. Pendant presque toute cette période (du 13 au 19 et du 21 au 27 septembre), il n’y a pas eu de brûlage de gaz à la torche, mais la nuit du 20 septembre, il y a eu un important brûlage de gaz à la torche. Les taux de déplacement des cibles radar et des troupeaux d’oiseaux consignés visuellement pendant la première tranche d’environ 50 % à 60 % de la nuit étaient beaucoup moins élevés pendant la période où il n’y avait pas de brûlage à la torche que pendant la nuit où il y a eu brûlage à la torche, tandis que pendant la deuxième tranche d’environ 40 % à 50 % de la nuit, les taux de déplacement étaient semblables pendant toutes les périodes. Le comportement de vol général des oiseaux a également affiché une différence considérable. De plus grands pourcentages de cibles radar et de troupeaux d’oiseaux adoptaient un comportement de vol rectiligne (direct) pendant les périodes où il n’y avait pas de brûlage à la torche, et de plus grands pourcentages de cibles radar et de troupeaux d’oiseaux affichaient un comportement de vol non rectiligne (erratique et indirect) pendant la période où il y a eu brûlage à la torche. La nuit du brûlage à la torche, la vive illumination n’a semblé avoir un effet qu’après le coucher du soleil, quand les troupeaux d’oiseaux encerclaient l’île après avoir été attirés depuis un endroit qui semblait très lointain. Tant pour l’échantillonnage prélevé par radar que par consignation visuelle, le nombre de troupeaux d’oiseaux s’approchant de l’île diminuait dans le courant de la soirée, et l’attrait de la lumière émanant du brûlage à la torche semblait également diminuer. La visibilité de la lune semblait avoir peu d’effet sur le comportement des oiseaux. Puisque l’illumination provenant du brûlage prolongé à la torche exerce une si grande force d’attraction chez les oiseaux migrateurs, et puisque la plupart des troupeaux d’oiseaux volent en basse altitude au-dessus de l’eau, le torchage effectué sur les plateformes pétrolières côtières et extracôtières dans l’Alaska de l’Arctique devrait être positionné plus haut que les altitudes moyennes de vol des oiseaux migrateurs afin de réduire les risques d’incinération

An Ongoing Shift in Mammalian Nest Predators of Yellow-billed Loons in Arctic Alaska

The Coastal Plain of northern Alaska is an important nesting area for a variety of avian species, where the productivity of ground-nesting species can be strongly influenced by nest predators. Recently, the density of red foxes (Vulpes vulpes) has increased in many areas of the Arctic, likely because of climate warming as well as the availability of anthropogenic food sources during winter. In areas where they occur sympatrically, red foxes can outcompete and kill the smaller Arctic fox (Vulpes lagopus). There is considerable dietary overlap between the fox species, but if the red fox is a more successful nest predator, this ongoing shift in canid species could have important implications for ground-nesting species like the Yellow-billed Loon (Gavia adamsii). We examined time-lapse photographs from 186 nests of Yellow-billed Loons in northern Alaska during the years 2008 – 15 and 2019 for the presence of foxes and other nest predators and quantified nest predation by species. Although both Arctic and red foxes were photographed near nests, we found that all successful predation of Yellow-billed Loon nests by foxes was attributable to red foxes, which were the second most frequent predator of Yellow-billed Loon nests after Glaucous Gulls (Larus hyperboreus). Arctic foxes photographed at Yellow-billed Loon nests were unsuccessful at displacing incubating loons. Several data sources suggest that the prevalence of red foxes has increased in Arctic Alaska over the last three decades, a change that is likely to have negative impacts on the nesting success of Yellow-billed Loons and possibly other large waterbirds. La plaine côtière du nord de l’Alaska est une aire de nidification importante pour une variété d’espèces aviaires, où la productivité des espèces nichant au sol peut être grandement influencée par les prédateurs de nids. Récemment, la densité de renards roux (Vulpes vulpes) a augmenté en maint endroit de l’Arctique, vraisemblablement en raison du réchauffement climatique et de la disponibilité de sources alimentaires anthropiques en hiver. Là où ils se retrouvent de manière sympatrique, les renards roux peuvent l’emporter sur les renards arctiques (Vulpes lagopus) plus petits et réussir à les tuer. Il existe un chevauchement alimentaire considérable entre les espèces de renards, mais si le renard roux est un prédateur de nids plus prolifique, le virage caractérisant les espèces de canidés pourrait avoir d’importantes incidences sur les espèces nichant au sol, comme le plongeon à bec blanc (Gavia adamsii). Nous avons examiné les photographies accélérées de 186 nids de plongeons à bec blanc du nord de l’Alaska prises entre les années 2008 et 2015 ainsi qu’en 2019 afin de repérer la présence de renards et d’autres prédateurs de nids, en plus de quantifier la prédation des nids en fonction des espèces. Même s’il y a des photographies de renards roux et de renards arctiques à proximité de nids, nous avons pu constater que toutes les prédations réussies de nids de plongeons à bec blanc étaient attribuables au renard roux, le deuxième plus grand prédateur de nids de plongeons à bec blanc après le goéland bourgmestre (Larus hyperboreus). Les renards arctiques photographiés aux nids de plongeons à bec blanc n’ont pas réussi à déplacer les plongeons en période d’incubation. Plusieurs sources de données suggèrent que la prédominance des renards roux a augmenté dans l’Arctique alaskien au cours des trois dernières décennies, un changement qui est susceptible d’avoir des incidences négatives sur le succès de la nidification des plongeons à bec blanc, voire d’autres oiseaux aquatiques plus volumineux.

Aerial survey and telemetry data analysis of a peripheral caribou calving area in northwestern Alaska

With industrial development expanding in the Arctic, there is increasing interest in quantifying the impacts of development projects on barren ground caribou (Rangifer tarandus granti). The primary data source to assess caribou distribution and predict impacts in remote areas of Alaska has shifted in recent decades from aerial survey data to telemetry data, but these techniques have different strengths and weaknesses. The ranges of two caribou herds, the Western Arctic Herd and the Teshekpuk Herd, overlap in northwest Alaska between Wainwright and Atqasuk, Alaska. Based on long-term telemetry data sets, this region was thought to be outside of the core calving ranges of both herds. Calving has long been reported to occur in this general area, but early reports assumed caribou were from the Western Arctic Herd and only one systematic aerial survey of caribou density and distribution during calving has been conducted in this area in recent decades. Following interest in industrial development in this area, we conducted aerial strip-transect surveys during early to mid-June 2013–2015 to directly assess the density and distribution of caribou in the area and we used existing telemetry data to compare our results to the seasonal distribution of both herds. Total caribou densities varied between 0.36 and 1.06 caribou/km² among years, and calf densities varied 0.04 and 0.25 calves/km² among years. Contrary to assumptions by early researchers in the area, telemetry data indicated that caribou in this area during early to mid-June were from the Teshekpuk Herd. The use of telemetry data alone underestimated the importance of this area for calving, but the combination of aerial surveys and telemetry data provided complementary information on caribou use of this area showing the importance of collecting the appropriate types of data for assessing potential impacts of development on caribou

Effects of a Hazing-Light System on Migration and Collision Avoidance of Eiders at an Artificial Oil-Production Island, Arctic Alaska

During migration, Common and King Eiders (Somateria mollissima and S. spectabilis) cross the Beaufort and Chukchi Seas of Arctic Alaska. Because they may become attracted to lights, eiders are susceptible to collision with structures, including offshore oil facilities. We used ornithological radar in 2001 – 04 to characterize the behavior of eiders migrating past Northstar Island, an oil-production island near Prudhoe Bay, Alaska, and to assess the effects of a hazing-light system on migrating eiders. “Eider” radar targets exhibited pulsed, irregular periods of movement; movement rates were higher when sea ice was present, without precipitation, and during tailwinds and crosswinds but were not affected by lights. Velocities (ground speeds) were higher when ice was present and with strong tailwinds. They were lower at night when the lights were on, but higher during the day when the lights were on. Radar targets exhibited little variation in flight behavior as they passed the island; the proportion of non-directional behavior was larger when ice was present, with tailwinds, with weak winds, and near the full moon when it was not visible. Lights had no effect on flight behavior. Birds tended to exhibit more course changes as they approached the island, greater angular changes when they changed course, and larger net increases in passing distance as a result of those course changes when the lights were on; however, none of these differences were statistically significant. Overall, the hazing lights at Northstar did not disrupt the birds’ migratory movements but resulted in increased avoidance of the island.En période de migration, l’eider à duvet et l’eider à tête grise (Somateria mollissima et S. spectabilis) survolent la mer de Beaufort et la mer des Tchouktches dans l’Alaska de l’Arctique. Comme ils sont attirés par les lumières, les eiders risquent d’entrer en collision avec des structures, y compris les installations pétrolières au large. De 2001 à 2004, nous avons utilisé un radar ornithologique pour caractériser le comportement des eiders qui migrent au-delà de l’île Northstar, une île de production pétrolière près de Prudhoe Bay, en Alaska, et pour évaluer les effets d’un système d’éclairage de dispersion sur les eiders en migration. Les « eiders » ciblés par le radar présentaient des périodes de mouvement pulsées et irrégulières; les taux de mouvement étaient plus importants en présence de glace marine, en l’absence de précipitation et en présence de vent arrière et de vent latéral, mais n’étaient pas touchés par les lumières. Les vélocités (vitesses au sol) étaient plus élevées en présence de glace et de forts vents arrière. Elles étaient plus basses la nuit lorsque les lumières étaient allumées, mais plus élevées le jour lorsque les lumières étaient allumées. Nous avons observé peu de variation quant au comportement de vol des cibles atteintes par le radar pendant qu’elles survolaient l’île; la proportion de comportements de vol non directionnels était plus importante en présence de glace, de vent arrière, de vent faible et lorsque la pleine lune n’était pas visible. Les lumières n’ont pas eu d’impact sur le comportement de vol. Lorsque les lumières étaient allumées, les oiseaux avaient tendance à changer de direction plus souvent durant leur vol à l’approche de l’île et à effectuer de plus grandes variations angulaires lorsqu’ils changeaient de direction, puis présentaient une nette augmentation de la distance de passage à la suite de ces changements de direction. Toutefois, aucune de ces différences n’était statistiquement importante. En général, les lumières de dispersion de l’île Northstar n’ont pas nui aux mouvements migratoires des oiseaux, mais ces derniers ont davantage évité de voler près de l’île

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 herd's 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