Arctic Hare Research Articles

GYRFALCON DIET IN CENTRAL WEST GREENLAND DURING THE NESTING PERIOD

Abstract We studied food habits of Gyrfalcons (Falco rusticolus) nesting in central west Greenland in 2000 and 2001 using three sources of data: time-lapse video (3 nests), prey remains (22 nests), and regurgitated pellets (19 nests). These sources provided different information describing the diet during the nesting period. Gyrfalcons relied heavily on Rock Ptarmigan (Lagopus mutus) and arctic hares (Lepus arcticus). Combined, these species contributed 79–91% of the total diet, depending on the data used. Passerines were the third most important group. Prey less common in the diet included waterfowl, arctic fox pups (Alopex lagopus), shorebirds, gulls, alcids, and falcons. All Rock Ptarmigan were adults, and all but one arctic hare were young of the year. Most passerines were fledglings. We observed two diet shifts, first from a preponderance of ptarmigan to hares in mid-June, and second to passerines in late June. The video-monitored Gyrfalcons consumed 94–110 kg of food per nest during the nestling per...

Gyrfalcon Feeding Behaviour during the Nestling Period in Central West Greenland

We studied gyrfalcon (Falco rusticolus) food delivery and feeding behavior during the nestling period in central West Greenland during the 2000 and 2001 field seasons. We used time-lapse video cameras installed at three nests to record 2677.25 hours of nestling video. Ptarmigan delivered to nests were usually plucked prior to delivery and included the breast and superior thoracic vertebrae. Arctic hare leverets were rarely plucked and often delivered in parts. The most commonly delivered leveret part was the hind legs attached to the lower back. Passerines were rarely plucked and usually delivered whole. After feeding the young, adults removed 20.9% of prey items from the nest, which included items both with and without obvious muscle still attached. Prey delivery rates were similar among nests and increased as nestlings aged. Prey delivery frequency peaked in the morning and evening, with a distinct lull in the late evening and early morning hours. Male and female adults delivered a similar number of prey, though males typically delivered smaller prey than females. Gyrfalcons cached and re-delivered at least 9.1% of all items delivered, and one item was cached and retrieved three times.

Holocene environmental reconstruction from deltaic deposits in northeast Greenland

AbstractTerraces of different age in the Zackenberg delta, located at 74°N in northeast Greenland, have provided the opportunity for an interdisciplinary approach to the investigation of Holocene glacial, periglacial, pedological, biological and archaeological conditions that existed during and after delta deposition.The raised Zackenberg delta accumulated mainly during the Holocene Climatic Optimum, starting slightly prior to 9500 cal. yr BP (30 m a.s.l.) and continued until at least 6300 cal. yr BP (0.5 m a.s.l.). Evidence of sea‐level change is based on conventional14C dates of shells from the marine delta bottomsets,14C AMS dating of macroscopic plant material from the foresets and of fluvial deposits. Arthropod and plant remains from 7960 cal. yr BP in the delta foresets include the oldest evidence of the arctic hare in Greenland and evidence of a rich herb flora slightly different from the modern flora.Empetrum nigrumandSalix herbacearemains indicate a summer temperature at least as high as today during delta deposition. Post‐depositional nivation activity, dated by luminescence, lichenometry and Schmidt Hammer measurements indicate mainly late Holocene activity, at least since 2900 yr BP, including Little Ice Age (LIA) avalanche activity. Pedological analyses of fossil podsols in the Zackenberg delta, including14C AMS dating of selected organic rich B‐horizons, show continued podsol development during the Holocene Climatic Optimum and into the subsequent colder period of the late Holocene, until 3000–2400 yr BP. A Neo‐Eskimo house ruin found on the lower part of the delta, presently being eroded by the sea, is dated toAD1800. It presumably was abandoned prior toAD1869, and suggests that some of the last Eskimos that lived in northeast Greenland might have occupied the Zackenberg delta. Copyright © 2002 John Wiley & Sons, Ltd.

The Biting Midge Culicoides impunctatus Goetghebuer, 1920 (Diptera: Ceratopogonidae) recorded from the Faroes

The biting midge, Culicoides impunctatus, not hitherto recorded from the Faroes, was collected in light traps operated at Gerðinum, Mýrarnar, and Hoyvfk, Streymoy. The species is widespread, occurring in Asia and Europe, e.g. in Britain (including Orkney), Denmark and Norway, but it is not known from lceland and Greenland. C. impunctatus, which is associated with bogland, was particularly abundant at Mýrarnar. The mean antennal ratios (the ratio of the sum of the length of the apicalfive segments of the antennal flagellum to the sum of the basal segments) of Faroese female specimens was significantlylower than mean ratios recorded from Britain and Denmark, indicating smaller absolute body size. The species is an extremely persistent biter, feeding on man and large mammals. In the Faroes man, cattle, sheep and possibly the arctic hare are potential hosts. The feeding on livestock may cause considerable distress, in cattle hypersensitivity to the bites may develop and in horses the biting may give rise to an allergic dermatitis. The record of C impunctatus adds a troublesome biting fly to the Faroese fauna.

The flexibility of an intermediate feeder: dietary selection by mountain hares measured using faecal n-alkanes.

Herbivores with an intermediate feeding strategy either vary their diet between a grazing (bulk roughage feeders) or browsing (concentrate selectors) strategy on a seasonal basis or select a mixed diet at any one time. The underlying ecological causes of the seasonal dietary shift in a small non-ruminant intermediate feeder - the mountain or arctic hare (Lepus timidus L.) were determined. Diet composition and selection relative to availability were investigated for 41 individual free-ranging mountain hares (of which 18 female hares were radio-collared) occupying an upland mosaic landscape in north-east Scotland. Diet composition was determined using faecal n-alkane analysis. Radio-collared hares were designated as pasture, woodland or moorland hares according to the habitat that predominated their home-range. In common with previous studies, mountain hares switched from a browse-dominated diet during winter to a Gramineae-dominated diet in summer, although it was only significant for reproductively active females during the peak breeding season. Diet composition remained consistent regardless of habitat occupied. However, the diet of radio-tracked hares differed significantly from the biomass available in the individual home-ranges; Gramineae were preferentially selected over browse species throughout the year. During winter and in particular during the early breeding season, intermediate feeders, such as mountain hares, ate browse material when the availability of higher quality was restricted. The ability to browse or graze represents a flexible foraging strategy permitting survival and production through periods of changing or unpredictable forage quality and availability.

Lack of Reproduction in Muskoxen and Arctic Hares Caused by Early Winter?

A lack of young muskoxen (Ovibos moschatus) and arctic hares (Lepus arcticus) in the Eureka area of Ellesmere Island, Northwest Territories (now Nunavut), Canada, was observed during summer 1998, in contrast to most other years since 1986. Evidence of malnourished muskoxen was also found. Early winter weather and a consequent 50% reduction of the 1997 summer replenishment period appeared to be the most likely cause, giving rise to a new hypothesis about conditions that might cause adverse demographic effects in arctic herbivores.Key words: arctic hare, Lepus arcticus, Ellesmere Island, malnutrition, muskox, Ovibos moschatus, population, reproduction, snow, weather, winter severity

Arctic Fox (<i>Alopex lagopus</i>) Diet in Karupelv Valley, East Greenland, during a Summer eith Low Lemming Density

We investigated the diet of arctic foxes (Alopex lagopus) in the Karupelv valley, East Greenland, during the summer of 1997. Despite a low density, lemmings were the most utilized prey, comprising 65.3% of dry fecal weight in fresh feces. This demonstrates the importance of lemming species as prey for arctic foxes all through a lemming cycle. Birds, arctic hare (Lepus arcticus), and insects also contributed to the diet. Arctic fox remains suggested that the foxes had scavenged their own species. Vegetation, muskoxen (Ovibos moschatus), and seal (Phocidae) were found in small amounts. We compared estimates of prey availability and diets of arctic foxes for a coastal area (<10 km from the shore) and an inland area (>10 km from the shore). Abundance of avian prey tended to be higher in the coastal area. Fresh feces indicated a significant overall difference in arctic fox diets between the coastal and inland areas. Within prey categories, lemmings were significantly more represented in the inland area, while the coastal area had a more diverse diet overall. We also suggest that the existence of arctic foxes in East Greenland is dependent on regular peak years in lemming density.

Seasonal changes in Arctic Hare, Lepus arcticus, diet composition and differential digestibility

Seasonal changes in Arctic Hare, Lepus arcticus, diet composition and differential digestibility

Food Habits of Arctic Wolves in Greenland

Analysis of feces was used to determine natural prey of arctic wolves ( Canis lupus ) in Nansen Land, North Greenland (83°N, 43°W), and Hold with Hope, East Greenland (74°N, 22°W). A total of 461 feces was collected during summers 1991–1995. In Nansen Land ( n = 110), muskox ( Ovibos moschatus ) was the major food of wolves with a frequency of occurrence of 79.4%. Lemmings ( Dicrostonyx groenlandicus ) were the next most-important group with a frequency of 19.6%, followed by arctic hares ( Lepus arcticus ) at 7.5%, wolves at 0.9%, and arctic foxes ( Alopex lagopus ) at 0.9%. Plastic and nylon rope occurred in three feces, suggesting scavenging on garbage. In Hold with Hope ( n = 351), muskoxen also were the predominant prey with a frequency of 65.4%, followed by geese and other birds at 35.5%, lemmings at 10.2%, arctic hares at 2.3%, and beetles at 0.3%. Remains of garbage (paper and paint chips) occurred in one fece. Differences in availability of regional prey may best explain dissimilarity in food habits between areas, but seasonal differences in contents of feces also may be important.

Quaternary vertebrates from Greenland: A review

Remains of fishes, birds and mammals are rarely reported from Quaternary deposits in Greenland. The oldest remains come from Late Pliocene and Early Pleistocene deposits and comprise Atlantic cod, hare, rabbit and ringed seal. Interglacial and interstadial deposits have yielded remains of cod, little auk, collared lemming, ringed seal, reindeer and bowhead whale. Early and Mid-Holocene finds include capelin, polar cod, red fish, sculpin, three-spined stickleback, Lapland longspur, Arctic hare, collared lemming, wolf, walrus, ringed seal, reindeer and bowhead whale. It is considered unlikely that vertebrates could survive in Greenland during the peak of the last glaciation, but many species had probably already immigrated in the Early Holocene.

96/06570 Brown coal mining and water resource management in the Rhenish district. Protection of water supply in a heavy strained area

Compared to agricultural lands, forests are complex ecosystems as they can involve diverse plant species associations, several vegetative strata (overstorey, shrubs, herbaceous and other annual plant layer) and multi-layered soil profiles (forest floor, hemi-organic and mineral layers). A high degree of variability is thus generally observed in radionuclide transfers and redistribution patterns in contaminated forests. In the long term, the soil compartment represents the major reservoir of radionuclides which can give rise to long-term plant and hence food contamination. For practical reasons, the contamination of various specific forest products has commonly been quantified using the aggregated transfer factor (Tag in m2 kg−1) which integrates various environmental parameters including soil and plant type, root distribution as well as nature and vertical distribution of the deposits. Long lasting availability of some radionuclides was shown to be the source of much higher transfer in forest ecosystems than in agricultural lands. This study aimed at reviewing the most relevant quantitative information on radionuclide transfers to forest biota including trees, understorey vegetation, mushrooms, berries and game animals. For both radiocaesium and radiostrontium in trees, the order of magnitude of mean Tag values was 10−3 m2 kg−1 (dry weight). Tree foliage was usually 2–12 times more contaminated than trunk wood. Maximum contamination of tree components with radiocaesium was associated with (semi-)hydromorphic areas with thick humus layers. The transfer of radionuclides to mushrooms and berries is high, in comparison with foodstuffs grown in agricultural systems. Concerning caesium uptake by mushrooms, the transfer is characterized by a very large variability of Tag, from 10−3 to 101 m2 kg−1 (dry weight). For berries, typical values are around 0.01–0.1 m2 kg−1 (dry weight). Transfer of radioactive caesium to game animals and reindeer and the rate of activity reduction, quantified as an ecological half-life, reflect the soil and pasture conditions at individual locations. Forests in temperate and boreal regions differ with respect to soil type and vegetation, and a faster decline of muscle activity concentrations in deer occurs in the temperate zone. However, in wild boar the caesium activity concentration shows no decline because of its special feeding habits. In the late phase, i.e. at least a few months since the external radionuclide contamination on feed plants has been removed, a Tag value of 0.01 m2 kg−1 (fresh weight) is common for 137Cs in the muscles of adult moose and terrestrial birds living in boreal forests, and 0.03 m2 kg−1 (fresh weight) for arctic hare. Radiocaesium concentrations in reindeer muscle in winter may exceed the summer content by a factor of more than two, the mean Tag values for winter ranging from 0.02 to 0.8 m2 kg−1 (fresh weight), and in summer from 0.04 to 0.4 m2 kg−1. The highest values are found in the year of initial contamination, followed by a gradual reduction. In waterfowl a relatively fast decline in uptake of 137Cs has been found, with Tag values changing from 0.01 to 0.002 m2 kg−1 (fresh weight) in the three years after the contaminating event, the rate being determined by the dynamics of 137Cs in aquatic ecosystems.

Comparison of Microstructure of White Winter Fur and Brown Summer Fur of Some Arctic Mammals

Abstract Several species of Arctic mammals have brown hair in the summer and molt into a white pelage in the winter. It is unknown whether characteristics other than color of the hair also change during the color transition between seasons. We borrowed guard hair samples from museums to represent summer and winter pelages of five species: Alopex lagopus (Arctic fox), Lepus americanus (snowshoe hare), Lepus Arcticus (Arctic hare), Mustela erminea (ermine) and Mustela nivalis (least weasel). Micro‐structural differences exist between the brown and white hairs. In general, white winter hairs had larger upper shaft medullas comprising more air‐filled cells and smaller lower shafts. These structural changes may function in conservation of heat or in increasing light reflection to whiten the fur and aid as camouflage. © 1997 Published by Elsevier Science Ltd on behalf of The Royal Swedish Academy of Sciences.

Comparative Winter Habitat Use and Associations among Herbivores in the High Arctic

We studied winter habitat use and interspecific associations among large- and medium-sized herbivores on southeastern Victoria Island, Arctic Canada, by documenting the deposition of feces in relation to vegetation. Associations between ptarmigan ( Lagopus spp.), arctic hares ( Lepus arcticus ), caribou ( Rangifer tarandus ), and muskoxen ( Ovibos moschatus ) were assessed using the Jaccard Index (JI) and chi² at two scales, i.e., with 1 m² and 1 ha as sampling units. JI values for species pairs were greater at the larger scale, but chi² revealed significant (positive) associations only at the smaller scale and only between arctic hares and caribou and between arctic hares and ptarmigan. Comparative use of habitats was described with respect to vegetation by canonical correspondence analysis (CCA). Ptarmigan and muskoxen were most strongly correlated with lowland vegetation and caribou with upland vegetation; arctic hares were intermediate. CCA also indicated rather wide separation in the multivariate space, further suggesting distinct patterns of habitat use. The results imply that these species were segregated in their use of resources in this High Arctic environment. Key words: arctic hare, caribou, habitat selection, interspecific relationships, multivariate, muskox, niche, ptarmigan, spatial scale

Digestibility of forage types by arctic hares

Abstract:We examined the composition of plant tissues in the stomach and the feces of arctic hares (Lepus arcticus Ross) to obtain an index to digestibility of dietary components. The monocotyledonous sedges and to lesser extent grasses were over-represented in the feces as compared to the stomach, reflecting their lower digestibility in contrast to dicotyledonous willow (Salix arctica Pall.), forbs, and mountain avens (Dryas integrifolia M. Vahl.). Arctic hares are similar to collared lemmings (Dicrostonyx groenlandicus Traill) and mountain hares (Lepus timidus Linnaeus) in this pattern of digestibility of plants available to them as forage.

Resource partitioning by mammalian herbivores in the high Arctic.

Willow (Salix arctica) and sedges (Carex stans and Eriophorum triste) were the dominant plants available as forage for herbivores in the high Arctic of Greenland. Willow leaves were of high quality as forage in early stages, of phenology, but crude protein and digestibility declined markedly by late stages whereas sedges, remained high in forage quality throughout the growing season. Densities of fecal pellets indicated that muskoxen (Ovibos moschatus) made heaviest use of sedge-dominated vegetation types in both winter and summer, although increased use of willow communities was observed in early summer. Hares (Lepus arcticus) favored willow-dominated communities in both winter and summer. Evidence of collared lemming (Dicrostonyx groenlandicus) winter use was mainly in willow-dominated communities where snow had accumulated, whereas in summer they were present in drier habitas dominated by willows, but with greater plant diversity. Analyses of plant tissues in feces indicated that graminoids composed over 60% of the diet of muskoxen in winter and over 40% in summer. Willows were of nearly equal importance in the muskox diet in summer, and forbs, Dryas integrifolia, and moss collectively composed over 20% of the diet in both summer and winter. Grass accounted for nearly 50% of the diet of hares in both summer and winter, with willows, forbs, and moss accounting for most of the remainder. Willows and graminoids dominated the diet of lemmings, with willows being somewhat more important in summer and graminoids in winter. Moss was a noteworthy dietary component of lemmings. Differences in body and digestive-tract morphology among the three mammalian herbivores account for differences in locomotive efficiency, predator avoidance, and foraging efficiency which interact with vegetation quality, density, and patchiness. The resulting patterns of use of the landscape result in minimal overlap in use of forage resources and help to explain the distribution and co-existence of high Arctic herbivores.

THE LATEGLACIAL FAUNA FROM THE ROBIN HOOD CAVE, CRESWELL CRAGS: A RE‐ASSESSMENT

Summary. Re‐study of the fauna recovered in 1969 during excavations by John Campbell in front of the West Entrance to Robin Hood Cave, Creswell Crags, Derbyshire, England, shows it to include components of different ages. Arctic hare is the only species certainly exploited by humans and it is suggested that the position and character of cut‐marks preserved on bone surfaces documents the processing and possible consumption of uncooked meat. It has not been possible to identify the time(s) of year when these hares died. Radiocarbon results for cut‐marked bones are important for dating the Creswellian.

Behavioural Adaptations to Arctic Winter: Shelter Seeking by Arctic Hare (<i>Lepus arcticus</i>)

Behavioural modifications used by arctic hares, Lepus arcticus, to maintain their normal body temperature in late winter, including posture, orientation, the use of natural shelter, and the digging of snow dens, were studied on Ellesmere Island, N.W.T., between 1985 and 1992 and on Bathurst Island, N.W.T., between 1968 and 1992. Hares adopted a near-spherical shape while resting with only the thick pads of the hind feet touching the snow. Hares typically rested together in closely spaced winter groups of up to 28 hares. Huddling did not occur, except in young littermates in summer. Hares in groups did not usually seek shelter, but solitary hares normally groomed, rested, and reingested in the shelter of large rocks. When wind speeds dropped below 10 km/h, resting hares shifted from facing away from wind to an orientation towards the sun. As daily mean temperatures increased in April-May, the usual resting posture changed from the tightly curled resting sphere to crouching and sprawling. Hares used natural shelter, especially rocks and snowdrifts, and man-made structures. They also modified snowdrifts by digging snow dens up to 188 cm in length. Thirty-seven dens were seen in 8 of 15 years of observations at Bathurst Island, and seven were seen on Ellesmere Island in 1 of 5 seasons. Snow dens were not used for feeding and their value as safety from predators is likely secondary to their value as shelter.Key words: arctic hare, shelter seeking, sheltering, winter adaptations, posture

An experimental study of red fox predation on arctic and snowshoe hares

We tested the relative vulnerability of arctic (Lepus arcticus) and snowshoe (Lepus americanus) hares to predation by red foxes (Vulpes vulpes) in experimental trials on three islands off Newfoundland's southwest coast. Arctic hares were significantly more vulnerable than snowshoe hares to fox predation: they were killed at a higher rate, and though the probability of death increased slightly for arctic hares over a trial period, it decreased for snowshoe hares. Rates of fox predation on arctic hares were inversely related to home-range size and nutritional status, whereas predation on snowshoe hares was inversely related to the percentage of home-range core areas with dense understory cover. We believe the arctic hare's greater vulnerability to fox predation, found in this study, coupled with its apparent inability to utilize food resources in forested areas that support snowshoe hares, which we found in an earlier study, largely accounts for the current restriction of arctic hares in Newfoundland to certain mountain and coastal barrens. The status of arctic hare populations before the introduction of snowshoe hares is unclear. However, distribution and abundance likely decreased as red foxes and lynx (Lynx canadensis) increased and began to cycle with snowshoe hares. Dispersal of foxes, and perhaps of lynx, from forested areas following snowshoe hare declines would have periodically intensified predation on the barrens.

Demographic responses of arctic hares Lepus arcticus placed on two predominantly forested islands in Newfoundland

During January‐April 1989. we monitored survival, reproduction, and body condition of 19 radio‐collared arctic haresLepus areticusintroduced to two predominantly (80%) forested islands. Merchant (66 1 ha) and Burke (82 6 ha), in Placentia Bay, Newfoundland By late April, bone‐marrow fat (42 7%) and kidney fat indices were lower than found in populations on the mountain barrens of western Newfoundland However, most island hares gained weight overwinter, and litter sizes (mean. 4 2 in utero) and testis weights (mean, 8 3 g) were as large or larger than recorded from other introduced and natural populations in Newfoundland The distribution of telemetry locations, tracks and feeding sites indicated that hares frequented the scattered barrens (totalling c 30 ha) on both islands in greater proportion than available These results suggest that, in the absence of snowshoe hares and mammalian predators, forested regions interspersed with small patches of barrens can sustain arctic hares

Dispersion of introduced arctic hares (Lepus arcticus) on islands off Newfoundland's south coast

We describe dispersion of radio-collared arctic hares (Lepus arcticus) introduced to three islands off Newfoundland's south coast. Nearest-neighbor analyses indicated that home-range activity centers were aggregated during both summer and winter. Mean distances between activity centers were significantly less during winter than during summer, with the greatest aggregation observed when rates of fox predation were least and snow depth and persistence were greatest. Arctic hares apparently lack a rigid social-dominance system; hence, environmental factors such as availability of food sources, snow conditions, and presence of predators may primarily influence dispersion.