Natal Dens Research Articles

Survivorship of a Nonharvested Raccoon Population in South Texas

To fully understand the effects of harvest and other anthropogenic factors on raccoon (Procyon lotor) populations, information is needed on survival of raccoons that are protected from these types of mortality. We monitored raccoons in South Texas during 1990-93 to determine age- and sex-specific survivorship of a raccoon population protected from legal harvest. Juvenile survivorship was low (S = 0.65) during the nestling stage but increased as young matured and began traveling with mothers. Nestling survival was related to natal den type. Monthly survival distributions differed (P 0.05) between adult males and females. Our annual survival estimates for males and females (S = 0.84) were higher than those reported for a harvested population in Iowa. Our comparison of survival estimates from Iowa and Texas suggests harvest may be additive for raccoons or, if harvest is compensatory, raccoons in Iowa may have lower survival than raccoons in Texas, regardless of harvest.

Distribution and density estimates for urban foxes (Vulpes vulpes) in Melbourne: implications for rabies control

The distribution and density of red fox populations was investigated in metropolitan Melbourne from 1990 to 1993. Distribution data were collected from sightings reported by members of the public, from spotlight and active den surveys, and from trapping and road kills. Archival data suggested that resident populations of foxes have been present within the inner metropolitan area since the early 1940s. Contemporary fox populations were found to be extensively distributed throughout the urban area, with few 1-km 2 grids within a 5-km radius of the Central Business District not containing foxes. Density estimates were based on nearest-neighbour analysis of active natal dens in four field sites. Observations of cubs over a 4-year period at 17 dens within the field sites revealed a mean litter size of 4.36 cubs. Mean 4-year density estimates for each field site, immediately after the breeding season, were 0.47–2.55 dens km −2, which was estimated to represent 3–16 foxes km −2. Density estimates may be conservative, as family groups may contain more than one non-breeding adult. The implications of these data are discussed with respect to the potential role of the urban fox in the epidemiology of rabies. It was concluded that fox populations at the field sites were of sufficient density to maintain a sylvatic epizootic of rabies.

Construction of a natal den by an introduced River Otter, Lutra canadensis, in Indiana

Construction of a natal den by an introduced River Otter, Lutra canadensis, in Indiana

Selection of natal dens by the swift fox (<i>Vulpes velox</i>) on the Canadian prairies

Selection of natal dens by the swift fox (<i>Vulpes velox</i>) on the Canadian prairies

Characteristics of Wolverine Reproductive Den Sites

Successful wolverine (Gulo gulo) reproduction may be linked to the availability and quality of reproductive dens sites, but little is known about wolverine reproductive dens, especially in North America. We present descriptions of wolverine dens in Idaho and Alaska, compare them to dens in other regions, and propose factors that may influence den-site selection. Our study includes 8 den sites used by 3 females over 4 years in northwestern Alaska and 7 sites used by 2 females over 4 years in central Idaho. We categorized reproductive dens of wolverines as either natal (used during parturition) or maternal (used subsequent to the natal den and before weaning). Dens in Alaska were usually long, complex snow tunnels with no associated trees or boulders. In contrast, dens in Idaho were always associated with fallen trees or boulders. All dens were covered with at least 1 m of snow. With few exceptions, wolverine dens described to date have been located in alpine, subalpine, taiga, or tundra habitat. Reports of dens in low elevation, densely forested habitats are rare. Factors which may have influenced selection of den sites included thermoregulatory advantages, protection from predators, suitability of the site during the spring thaw, and location of rearing habitat. We recommend managers consider limiting wolverine harvests and reducing human disturbance in wolverine denning g habitat.

Active wolverineGulo gulodens as a minimum population estimator in Scandinavia

Minimum numbers of wolverinesGulo gulowere estimated for Scandinavia, based on the average number of active dens recorded in 1995–1997. To estimate the proportion of females active at dens, we followed individual females using radio‐telemetry in northern Sweden, northern Norway and south‐central Norway. The sex and age structure of the population was estimated based on a sample of wolverines harvested before the introduction of protective measures and harvest restrictions. Our results are compared with those found in other published wolverine studies, mostly from North America. The Scandinavian population of one‐year‐old and older wolverines was estimated at 413 ± 71 (SD) individuals (265 ± 55 in Sweden and 147 ± 25 in Norway). This method gave a lower population estimate than those found in earlier surveys based on summation of local (municipality) estimates (Troms) and on local tracking surveys (Nordland). The differences may be explained by the existence of a large number of undiscovered natal dens in the two counties mentioned above, but the previous estimates were based on methodologies with sources of error that could inflate estimates. The population size in south‐central Norway (the Snøhetta plateau, Trollheimen, Reinheimen and Rondane), based on the average number of active natal dens during 1995–1997, was estimated to be 26 ± 7 individuals. This was in concordance with the 23–30 individuals estimated from intensive tracking and radio‐telemetry in spring 1995. Monitoring wolverine reproduction as a basis for population estimates could provide an important management tool. Based on our results, we recommend that the management authorities in Norway closely monitor the presently high harvest rate of wolverines in parts of the country, and establish population monitoring methods that allow continuous evaluation of management strategies.

Denning ecology of the striped skunk in the Canadian prairies: implications for waterfowl nest predation

1. From 1993 to 1995, we studied the summer denning ecology of 40 radio‐collared striped skunks Mephitis mephitis (32 females, eight males) during the waterfowl nesting season in Saskatchewan, Canada. 2. Forty‐seven natal dens were used by 30 females. Natal den sites were either underground burrows (55%) or holes underneath buildings (45%), and were preferably located in farmsteads. 3. Male and female striped skunks used similar resting sites which consisted of above‐ground retreats (57%), underground burrows (23%), buildings (17%) and culverts (3%). 4. Habitat preferences for resting sites did not differ between males and females: both sexes preferred farmsteads and wetlands, whereas managed waterfowl nesting areas, woodland and miscellanous habitats were avoided. Cropland was avoided for both natal dens and resting sites. 5. Females did not simultaneously share natal dens or resting sites, but both types of retreats were occupied by different females over time. Natal dens were occupied for 47 ± 3 days for females using a single den vs. 60 ± 3 days for females using >1 natal dens. Den switching may have been induced by a build‐up of faeces. 6. Management of natal den sites such as abandoned farmsteads and buildings may provide an avenue of non‐destructive predator management that is less expensive and controversial than exclusion or control.

Characteristics of American Marten Den Sites in Wyoming

We examined characteristics of den structures and den sites used by female American marten (Martes americana) for natal and maternal dens in the Sierra Madre Range, Wyoming. During 1988-95, we located 18 natal dens (parturition sites) and 97 maternal dens (sites where kits were present exclusive of parturition) used by 10 female marten. Important den structures included rock crevices (28%), snags (25%), red squirrel (Tamiasciurus hudsonicus) middens (19%), and logs (16%). Resource selection function (RSF) analysis showed that an individual selection model provided a significantly better fit than a null model or pooled selection model, indicating that the sample of marten selected maternal den sites that differed from random sites, and that individual animals did not select maternal den sites in the same manner. Six marten individually exhibited significant selection for maternal den sites within home ranges. Overall selection coefficients for maternal dens indicated the number of squirrel middens was the most important variable, followed by number of snags 20-40 em diameter at breast height (dbh), number of snags 2:41 em dbh, and number of hard logs 2:41 em in diameter. Selection of natal den sites was also significant via comparison between selection and no-selection models, with number of middens, number of Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) >20 em dbh, and number of hard logs 2:41 em in diameter the most important variables in descending order of importance. Large logs, large snags, and large, live spruce and fir trees are important characteristics for marten den sites in the central Rocky Mountains. The prominence of middens at den sites suggests red squirrels provide important denning structures as well as prey for marten.

Importance of Tree Cavities as Natal Dens for Fishers

Abstract We determined characteristics of natal dens used by radio-collared fishers in southcentral Maine. Twelve adult (≥2 yr old) females were monitored for periods of 1-5 yr each during 1984-1989. Estimated whelping dates of 12 litters were March 3-April 1, and females used 1-5 natal dens each until denning ended in early June. All 33 natal dens were in tree cavities on upland sites. Hardwoods composed 94% of the den trees, with aspens accounting for 52%. We recommend that forestry practices allow for a continued supply of mature and decadent hardwoods > 40 cm dbh to replace cavity trees that fall. Where cavity trees must be removed, cutting should be done outside the March-June denning period to avoid disturbance or mortality of fisher litters. North. J. Appl. For. 13(2): 79-83.

Population dynamics of Wolves Canis lupus in Bialowieża Primeval Forest (Poland and Belarus) in relation to hunting by humans, 1847–1993

AbstractPopulation dynamics and demography of the WolfCanis lupuswere studied in Bialowieza Primeval Forest (BPF, 1250 km2), the best preserved mixed and deciduous forest in the lowlands of Europe; 40% of BPF belongs to Poland and 60% to the Belarus Republic. Polish and Belarussian game departments' inventories of Wolf numbers (1946‐93), archival hunting statistics (1847–1993), observations, snowtracking and reports on shot Wolves (1980‐93) are presented. In BPF, Wolves coexist with five species of ungulates: European BisonBison bonasus.MooseAlces alces, Red DeerCervus elaphus, Roe DeerCapreolus capreolusand Wild BoarSus scrofa.During the last 150 years, there were four periods with high numbers of Wolves in BPF: around 1820‐40, 1870‐80, 1925‐30 and 1945‐48, always after uprisings and wars. Maximally, from 7.2 to 9.1 ind./100 km2were recorded. Declines and prolonged periods of low numbers of Wolves (due to persecution by humans) were recorded in 1882–1915 and 1958‐72 (0–1 ind./100 km2).In recent years (1980‐93), there were on average 33 Wolves in BPF (2.6 ind./lOO km2) and their numbers were slowly increasing. Data from this period were subject to a demographic analysis of the Wolf population. In the Polish part of BPF (on average, 13 Wolves recorded every year), negligible hunting occurred in 1980‐89, and since 1989 Wolves have been protected. In the Belarussian part, Wolves were treated as pests, and every year 16 Wolves were shot out of the mean number of 20 individuals recorded (80%). Most of the killed Wolves (70% of harvest) were shot in December, January and February, during traditional snowtracking‐driving hunts with ‘fladry’ (lines of flags).Hunting in the Belarussian part of BPF caused a decline in pack size from an average of 4.0 (SD 2.0) in late autumn, to 3.6 (SD 1.6) in mid winter, to 2.3 (SD 1.5) in late winter. In the Polish part (no hunting), the pack size varied from 4.2 (SD 1.7) in the late autumn, 4.3 (SD 2.2) in mid winter, to 3.6 (SD 1.9) in the late winter. Among Wolves shot, 44% were females and 56% were males (ratio 1: 1.3). The age of 63 shot Wolves was estimated by external features; 35% were juveniles < 1 year, 43% were 2–3 years old, and 22% were 4–5 years' old. In 1980‐93, in the whole BPF, legal hunting accounted for 78% of Wolf mortality, taking pups from their natal dens by humans 16%, poaching 4%, traffic accidents < 1%, and unknown causes 1%. Sarcoptic mange was recorded in several shot Wolves.On average, 6.25 pups per litter were born (range 3–8). If only natural factors of mortality are considered, 3 months after birth the mean litter size was 3.1 (50% mortality), and 2.2 pups per litter would reach 1 year of age (65% of mortality). However, 29% of all recorded pups were taken by humans for pets (in both the Polish and Belarussian parts of BPF) or to receive a bounty (in the Belarussian part). As early as November, juveniles along with adults are subject to hunting in the Belarussian part. Thus, if both natural and human‐caused mortality is considered, 2.2 pups per litter survived 3 months (65% mortality) and only 0.9 pup per litter reached 1 year of age (85% mortality).In 1980‐93, the Bialowieia population of Wolves survived and increased, most probably due to a constant immigration of Wolves (on average, two immigrants per year) from the vast forests adjoining BPF to the east.

Aggression decreases as play emerges in infant spotted hyaenas: preparation for joining the clan

The early social development of spotted hyaenas, Crocuta crocuta, is marked by a dramatic transition at 2–3 weeks of age, when infants are taken from the isolation of their natal den, where they are intensely aggressive, to the communal den, where they meet most clan members for the first time. This study examined behaviour patterns in eight sets of captive twins during the first month of life to document the changes that prepare young hyaenas for social integration at the communal den. Bite shakes, the most extreme aggressive behaviour, declined markedly within the first week of life, but other forms of aggression remained constant. During week 1, low-intensity prosocial behaviour occurred primarily between mother and cub. By week 2, higher-intensity social play emerged, occurring mainly between siblings. In weeks 3 and 4, cub interactive play was most frequent, lasted longer and was more vigorous. Locomotor and object play did not emerge until weeks 3 and 4, respectively. Dominance relations between siblings were operationally defined by submissive withdrawals. Accordingly, aggression was unidirectional, with dominants initiating most interactions. By contrast, play was reciprocal and equally initiated by dominant and subordinate cubs. Maternal interruption of cub behaviour mainly occurred during extreme aggressive interactions, but rarely during vigorous play. Results showed that prosocial behaviour emerged in captive hyaena cubs following a decline in severe aggression and before the time wild cubs are taken from the natal to the communal den. It is suggested that play may modulate aggression, following the establishment of a dominance relationship, and may serve an immediate prosocial function to prepare aggressive infant hyaenas for integration into the clan.

Preliminary Field Assessment of a Cabergoline Baiting Campaign for Reproductive Control of the Red Fox (Vulpes Vulpes).

The use of poison baiting in Australia to control foxes is impractical in urban areas and some wildlife reserves because of hazards to non-target animals. More acceptable methods of fox control in such environments are needed. Cabergoline is a dopamine agonist that has previously been demonstrated to have an abortifacient effect in cats (Felis catus) and dogs (Canis familiaris). The prolactin-inhibiting action of cabergoline may also result in cessation of lactation. Cabergoline has been shown to be completely palatable to foxes and is easily incorporated into a non-poisonous bait. The ability of bait-delivered cabergoline to effect the birth of viable fox cubs was tested in urban Melbourne and rural Bendigo, Victoria. A sample of 51 natal dens were chosen for this study on the basis that they had been active for 3 consecutive years (1991-93). 30 treatment dens were randomly selected and each treated once during August and again during September 1994 with 8 non-poisonous Foxoff baits containing 170 micro g of cabergoline and 200 mg of tetracycline to act as a biomarker. The remaining 21 dens were used as controls. Baits were randomly placed by burial within a 50-m radius of the den. Activity of all dens was assessed until December 1994 for direct/indirect signs of fox cubs. Bait uptake was >88% overall for the treatment dens. The resulting incidence of cubs was significantly lower in the treatment dens than in the controls. The potential for cabergoline to be used in urban areas and island populations as an adjunct to conventional control methods is discussed.

Denning behaviour and activity of arctic fox Alopex lagopus pups: Implications of food availability

The behaviour of arctic fox Alopex lagopus pups was studied in 51 in two regions of southern Scandinavia (60 and 63°N) and in 51 on the western coast of Svalbard (79°N). In Scandinavia, observations were made both in years of high and low abundance of food (i.e. voles and lemmings). No rodents live on the western coast of Svalbard, where foxes depend mainly on sea birds. Pups were on average lying nearly half the time, with explore and play fight next in frequency. Pups in a year of decreasing or low lemming abundance rested more outside the den, rested more overall, and less frequently indulged in exploration or play fighting than pups in years of higher abundance of voles and lemmings. They also began following adults at an early age and abandoned their natal den earlier. Svalbard pups were intermediate in several respects, but they regularly abandoned their natal den at the age of about 1 1/2 months. Pups at dens were active 24% of daytime hours (08.00–20.00) and 31% of nighttime hours (20.00–08.00).

The behavioural ecology of dingoes in north-western Australia. II. Activity patterns, breeding season and pup rearing

This paper reports aspects of a long-term study (1975-84) of the ecology, social organisation and behaviour of dingoes, Canis familiaris dingo, on the lower Fortescue River in Western Australia. In all, 170 dingoes were fitted with radio-collars and tracked from aircraft. Dingoes were sighted during 59% of the 13 618 occasions that they were being radio-tracked during the day. Radio-tracking yielded 31 229 daytime and 3016 night-time locations of radio-collared dingoes. The average duration of radio contact with 146 dingoes was 9 months (range 1-35 months). Dingoes were most active around sunrise and sunset, moderately active during the night, and least active during the heat of the day. Travelling (local meandering and more purposeful movement) was the most commonly witnessed activity. Levels of scent-marking (raised-leg urination and ground-scratching), howling and general activity increased over the 2-3 months prior to the mating period, suggesting that dingoes may have a long pro-oestrus (1-2 months). Whelping took place from mid-May to mid-August (mean date 18 July). The characteristics of natal dens are described. The pattern of activities associated with pup-rearing, including alloparental behaviour, closely followed that of related canids.

A record of an otter (Lutra lutra) natal den

Journal of ZoologyVolume 222, Issue 4 p. 689-692 A record of an otter (Lutra lutra) natal den P.S. Taylor, P.S. Taylor Department of Zoology, University of Aberdeen, ScotlandSearch for more papers by this authorH. Kruuk, H. Kruuk Institute of Terrestrial Ecology, Banchory, ScotlandSearch for more papers by this author P.S. Taylor, P.S. Taylor Department of Zoology, University of Aberdeen, ScotlandSearch for more papers by this authorH. Kruuk, H. Kruuk Institute of Terrestrial Ecology, Banchory, ScotlandSearch for more papers by this author First published: December 1990 https://doi.org/10.1111/j.1469-7998.1990.tb06024.xCitations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume222, Issue4December 1990Pages 689-692 RelatedInformation

First Wolf Den in Western U.S. in Recent History

Gray wolves (Canis lupus), once common throughout the conterminous United States, were exterminated everywhere except northeastern Minnesota by the 1930's (Mech 1970). The last wolf taken in Montana by a government trapper was in 1936 (Ream and Mattson 1982). In the northern Rocky Mountains, wolves have been observed and killed occasionally during the past 50 years, but no reproduction or dens have been documented (Brittan 1953; Day 1981; Ream and Mattson 1982; Singer 1979; Weaver 1978). This note describes a wolf den in Glacier National Park (GNP), Montana in 1986 and reports 5 additional dens in GNP and adjacent British Columbia (BC) in 1982, 1985, and 1987. The study area was in the North Fork Flathead River drainage and adjacent Wigwam River drainage immediately to the west and covered approximately 5000 km2. The North Fork originates in BC and flows 50 km southeast where it crosses into the U.S. and forms the west boundary of GNP for 70 km. Wolf surveys in Montana from 1972 to 1979 yielded no evidence of wolf reproduction, and an adult female wolf radio-collared 7 km northwest of GNP in 1979 did not den in 1979 or 1980 (Ream and Mattson 1982). The closest known breeding population to Montana prior to 1982 was approximately 100 km north of GNP in Alberta (Ream and Harris 1986). In 1982, a litter of 7 pups was discovered at a rendezvous site 10 km northeast of GNP (B. McLellan, pers. comm.). On 18 May 1985, McLellan captured a lactating female wolf (W8550) in a grizzly bear (Ursus arctos) leg hold snare, radio-collared and released her, and she returned to her den 12 km north-northwest of GNP within 24 hours. Seven black pups were observed near this den on 8 July 1985. W8550, another gray adult, 3 black adults and the 7 black pups (Magic Pack), moved south into GNP in November 1985, where it remained for most of the time thereafter. The size of the pack was reduced to 8 when 4 members of the pack disappeared in March, 1986. W8550 initiated denning activity 20 km south-southeast of the Canadian border in GNP on 15 April 1986, and remained at the den until 20 May when she began to move short distances. On 31 July she was observed from a fixed-wing aircraft at this den, with 5 pups and 7 other adults. The pack remained at the den and rendezvous site until 29 July when they moved 15 km north to another rendezvous site in GNP. On 6 August the authors hiked in to examine the den. The 1986 den consisted of 5 den openings dug into a flat-topped, heavily forested knoll that rose 3 m above an adjacent 2 ha meadow. Scats and trampled vegetation, and earlier aerial observations, indicated that the meadow was used as a rendezvous site after the pups left the den. The den openings were located within an area of 400 m2 extending 40 m along the edge of the knoll. Den openings were well hidden in Engelmann spruce (Picea engelmanni), Douglas-fir (Pseudotsuga menziesii), and lodgepole pine (Pinus contort) forest, with Engelmann spruce dominating at the immediate den openings. When visited in August, most of the meadow was dry, although wet meadow vegetation dominated the lower portions and the intermittent creek that meandered through the meadow. Three openings were dug down into the flat top surface of the knoll and 2 were dug into the steep, north-facing side. By wriggling in as far as possible and reaching with a 3 m wood stick, we could not reach the end of 1 north-facing den hole, probably the natal den. The other 4 holes were 1, 2, 2, and 3 m in depth. The entrance holes averaged 30 cm in width and 50 cm in height. Another den hole had been dug to a depth of 1 m, 400 m northwest of the den area described above. It probably was dug in the early spring and and not used much as there were only 2 old (>2 months) scats found near the entrance. It was in lodgepole pine, 5 m northwest of a 40 ha meadow and was more conspicuous than the other den holes. W8550 was apparently displaced as the alpha female of the Magic Pack in late January 1987 and was seen alone for several months thereafter north of the border. Later, 4 other members from the Magic Pack joined her and she denned in BC during late May. Remaining members of the Magic Pack denned in GNP in late April but we never found what we were sure was the natal den. Radiocollared male W8401, alone for 2 years, found a mate and denned in late April,40 km west-northwest of GNP in BC, 7 km north of Montana.

Den distribution and den use by the red fox Vulpes vulpes japonica in Kyushu

AbstractThe distribution of dens and den use by the red fox was studied in Kumamoto Prefecture between 1968 and 1982. A total of 80 dens were classified into natal, residential, and temporarily‐visited dens. Natal dens comprised 12.4% of all dens. Relative proportions were quite stable for a long period. This indicates a constant number of reproducing females in the area for a considerable length of time. Seasonally the utilization of den showed three peaks in February, May and October. The peaks coincided well with the peaks of reproductive activity of female foxes. The results of multiple regression analysis of distribution of dens with respect to selected environmental parameters around densites indicated that the fox selectively utilize open land, rather than densely vegetated areas. The persistence of dens, the selective utilization by foxes of open land and the sizes of dens were all related to the breeding activities of female foxes inhabiting the area. Reproductive females usually used plural dens (“den group”) in one reproductive season. The numbers of those females occuring in the area were maintained at a steady level for fairy long periods. These indicate that the existence of a stable social relationship between females mediated through occupancy of “den groups.”

Black Bear Cub Mortality Due to Flooding of Natal Dens

Statistiques effectuees dans le nord-est de la Pennsylvanie de 1973 a 1983 (5,2% de mortalite des jeunes dans le terrier)

Social organization and movement patterns of Black‐backed jackals Canis mesomelas in South Africa*

Black‐backed jackals Canis mesomelas were studied in three areas in Southern Africa, by means of radio tracking, visual observations and ear tagging. Jackal pups moved from the close proximity of their natal dens at 3 months of age, but stayed in the vicinity of the dens for at least 6 months. Dispersal often occurred at an age of about 2 years, mainly during the winter. Adult jackals had smaller home ranges than younger animals. Adult home ranges were inhabited by mated pairs. These ranges were mutually exclusive and differed in size between study areas. The home ranges of immature jackals overlapped extensively with those of the adult jackals. Some young jackals acted as helpers in rearing the pups at natal dens, while others roamed over large areas. Adult jackals move over longer daily distances than did younger animals. The significance of the division of Black‐backed jackal populations into breeding and non‐breeding components is discussed as well as the similarities among the social systems of Canis mesomelas. C. aureus and C. latrans.

Natural selection and the communal rearing of pups in African wild dogs (Lycaon pictus)

The contributions of adult (>18 months) and yearling (10–18 months) African wild dogs (Lycaon pictus), to raising pups were quantified at eight natal dens, where pups remain for their first three months of life.