Spacing, movements, and habitat selection of the river otter in boreal Alberta

1994 ◽  
Vol 72 (7) ◽  
pp. 1314-1324 ◽  
Author(s):  
D. G. Reid ◽  
T. E. Code ◽  
A. C. H. Reid ◽  
S. M. Herrero

Seasonal spacing patterns, home ranges, and movements of river otters (Lontra canadensis) were studied in boreal Alberta by means of radiotelemetry. Adult males occupied significantly larger annual home ranges than adult females. Males' ranges overlapped those of females and also each other's. In winter, home ranges of males shrank and showed less overlap. Otters often associated in groups, the core members typically being adult females with young, or adult males. Otters tended to be more solitary in winter. In winter, movement rates of all sex and age classes were similar, and much reduced for males compared with those in other seasons. These data indicated a strong limiting effect of winter ice on behaviour and dispersion. We tested the hypothesis that otters select water bodies in winter on the basis of the suitability of shoreline substrate and morphology for dens with access both to air and to water under ice. Intensity of selection was greatest in winter, with avoidance of gradually sloping shorelines of sand or gravel. Adults selected bog lakes with banked shores containing semi-aquatic mammal burrows, and lakes with beaver lodges. Subadults selected beaver-impounded streams. Apart from human harvest, winter habitats and food availability in such habitats are likely the two factors most strongly limiting otter density in boreal Alberta.

1964 ◽  
Vol 42 (2) ◽  
pp. 295-304 ◽  
Author(s):  
U. Paim ◽  
W. E. Beckel

Adult males and mated and unmated adult females of O. brunneum (a wood-boring beetle) were tested in situations where they could select CO2 of different concentrations. Oviposition by the beetles in relation to different concentrations of CO2 was also observed. The males did not respond to CO2. The unmated females occurred most frequently in places containing decaying wood or CO2 of a higher concentration than is present in air. The mated females oviposited most frequently in places where the concentration of CO2 was highest. Carbon dioxide probably plays a role in the selection of sites for oviposition by adult beetles in nature.


2000 ◽  
Vol 78 (8) ◽  
pp. 1380-1390 ◽  
Author(s):  
M Ben-David ◽  
T M Williams ◽  
O A Ormseth

Following the Exxon Valdez oil spill (EVOS), river otters (Lontra canadensis) on oiled shores had lower body mass, selected different habitat characters, and had larger home ranges and less diverse diets than did otters living in non-oiled areas. We explored the possibility that these changes were due to the effect of crude oil contamination on physiological and behavioral processes in otters. Fifteen otters were exposed to two levels of oil contamination under captive controlled conditions at the Alaska Sealife Center in Seward, Alaska, U.S.A. We collected blood samples for hematological examinations and measured oxygen consumption in otters exercising on a motorized treadmill. We also observed diving and foraging behavior of otters offered live fish. Otters exposed to oil became anemic relative to controls. While oxygen consumption of resting river otters was not related to changes in hemoglobin concentration, exercising river otters with decreased hemoglobin levels displayed significantly increased oxygen consumption (P = 0.042). Oiled otters also performed fewer dives when chasing fish (P = 0.04), representing a potential decrease of 64% in the capture rate of prey. Our data strongly support the hypothesis that changes in prey types and home-range utilization by oiled river otters following EVOS were influenced by hematological changes, associated increases in energetic costs, and reduced diving ability.


2000 ◽  
Vol 78 (12) ◽  
pp. 2087-2095 ◽  
Author(s):  
Michael J Chamberlain ◽  
Charles D Lovell ◽  
Bruce D Leopold

Recently, coyotes (Canis latrans) have expanded their range to include most areas of the southeastern United States. However, most research on coyotes has been conducted in western and northern regions of North America. We radio-monitored 38 adult coyotes from 1993 to 1997 in central Mississippi. Home-range sizes (P = 0.681) and core-area (area of concentrated use) sizes (P = 0.736) were similar across seasons, but females maintained larger home ranges (P = 0.006) and core areas (P < 0.001) than males. Male-male, female-female, and male-female home-range overlap was greatest during whelping and pup rearing. Except for mated pairs, core-area overlap was negligible across all seasons for adults maintaining neighboring home ranges. Coyote habitat selection varied across spatial scales, though selection was similar between males and females at all scales. Coyote movement rates differed (P < 0.001) temporally, being highest during nocturnal periods. Overall, the highest movement rates for the monitored population were observed for females during summer. Two males and 2 females were suspected of forming pair bonds and frequently traveled together within shared home ranges, as did 2 adult males. Our data indicate that interactions among individual adults are influenced by sex, as most confirmed instances of direct contact occurred between pairs or suspected social groups. In our study area, neighboring adult coyotes exhibited territoriality at the core-area level.


1992 ◽  
Vol 19 (2) ◽  
pp. 137 ◽  
Author(s):  
GW Arnold ◽  
DE Steven ◽  
A Grassia ◽  
J Weeldenburg

The home ranges were studied from 1977 to 1981 of western grey kangaroos (Macropus fuliginosus) living in a 300-ha remnant of wandoo [Eucalyptus wandoo] surrounded by farmland at Baker's Hill, Western Australia. The M. fuliginosus population varied from 140 to 200 animals during the study. In 1979, four females (>30 kg) and 2 adult males (31 kg and 47 kg) were fitted with radio-transmitters and their movements recorded. The home ranges of these animals varied from 39 to 70 ha; the average overlap in the area used during the day and that used at night was 16.4%. Many of the kangaroos fed on farmland at night. The night ranges of 51 marked kangaroos were recorded using a spotlight. The animals showed a strong fidelity to their home ranges. Only 3 males (about 5-yr-old) shifted their night ranges; the centres of the ranges moved only 600-800 m. Older males had significantly larger night ranges than younger males and females. Individual females and the younger males showed preferences for using particular access points to get onto farmland; the older males showed no preferences. The core areas of the night ranges of many adult females overlapped closely in 'groups', but there was no evidence of 'mob' home ranges that were socially separated.


1999 ◽  
Vol 59 (1) ◽  
pp. 125-130 ◽  
Author(s):  
C. F. D. ROCHA

The home range of the Tropidurid lizard Liolaemus lutzae, an endemic species of the costal sand dune habitats of Rio de Janeiro State, was studied in the beach habitat of Barra de Maricá restinga, Maricá County. Home ranges were studied using a mark-recapture technique in a delimited area at the beach habitat. I considered for estimates and analysis the home ranges of those lizards with a minimum of four positions. The size of L. lutzae home ranges varied according to the segment of the population. The mean home range size of adult males (x = 59.8 ± 33.7 m²) was significantly larger than that of adult females (x = 22.3 ± 16.1 m²). Juvenile mean home range size was significantly smaller than that of adult males, but did not differ from that of adult females (t = 1.058; p = 0.149). The overlap between male home ranges was usually low (3.6%), being in general only peripheral. Conversely, there was a considerable overlap between home ranges of adult females with those of adult males, the home range areas of two or three females being enclosed in the home range of one adult male. The small overlap between home ranges of adult males suggested mutual exclusion. The observed between-sex differences in the size of L. lutzae home range may be explained by the sexual dimorphism in body size in this species, and by the need of adult males to establish larger areas so as to include many females in their areas, during the reproductive season. The differences in home range along ontogeny probably result from differences in body size of the different segments of the population, due to trophic differences (carnivory and herbivory levels), and the dispersal of young after birth. Because L. lutzae is omnivorous, but primarily herbivorous when adult, and due to its sit-and-wait foraging behavior (mainly on arthropods), it does not need to move around over large areas to find food, which in turn reduces the area necessary for it to live.


2008 ◽  
Vol 4 (3) ◽  
pp. 243-245 ◽  
Author(s):  
A.R Martin ◽  
V.M.F da Silva ◽  
P Rothery

Amazon river dolphins or botos ( Inia geoffrensis Blainville) were observed carrying objects in 221 social groups over a 3-year study period. Sticks, branches and clumps of grass were taken from the water surface and often repeatedly thrashed or thrown. Lumps of hard clay were collected from the river bed and held in the mouth while the carrier rose slowly above the surface and submerged again. Carriers were predominantly adult males and less often subadult males. Adult females and young dolphins rarely carried objects. Groups of dolphins in which object carrying occurred were differentially large and comprised a greater proportion of adult males and adult females. Aggression, mostly between adult males, was significantly associated with object carrying. The behaviour occurred year-round, with peaks in March and July. A plausible explanation of the results is that object carrying by adult males is aimed at females and is stimulated by the number of females in the group, while aggression is targeted at adult males and is stimulated by object carrying in the group. We infer that object carrying in this sexually dimorphic species is socio-sexual display. It is either of ancient origin or has evolved independently in several geographically isolated populations.


1973 ◽  
Vol 21 (1) ◽  
pp. 75 ◽  
Author(s):  
MC Crawley

A live-trapping study of a population of Australian brush-tailed possums, Trichosurus vulpecula (Kerr), in indigenous forest of the Orongorongo Valley, Wellington, N.Z., was carried out from March 1966 to November 1968. In 14 ha of podocarp-mixed broadleaf forest, 301 possums (150; 151) were individually marked and repeatedly captured in a series of trapping periods. The population comprised residents and transients of both sexes with sub- adults forming the bulk of the latter, particularly in spring. The estimated population density varied from 10.6 per ha in November 1966 to 6.4 per ha in August 1968. There was one well-defined season of births each autumn and a few births in winter. On average, 73% (67-92%) of mature females produced pouch young each year. Females resident throughout the study had the highest breeding success (79%). Achievement of sexual maturity was delayed; no females bred until they were 2 yr old, and some not even at 3 yr. Losses occurred at all stages of the life history and averaged 62% between the pouch young and subadult stages; thus only 28 subadults per 100 females were recruited. Adult losses averaged 26% per annum. Adult males (mean weight 2.46 kg) were heavier than adult females (2.33 kg). Weights varied seasonally, with males heaviest in summer and lightest in spring, and females heaviest in winter and lightest in summer. Possums of both sexes were rather sedentary, with males (95% of captures within 115 m of the initial capture site) being less so than females (95 % of captures within 90 m of the initial capture site). More than half of the captures (55% for males, 62% for females) were made within 30 m of the site of initial capture. Males moved farther in autumn and summer than in other seasons, while females did so in autumn and winter. Subadults were apparently more sedentary than adults. Home ranges of adult males (mean 0.81 ha) were significantly larger than those of adult females (0.46 ha). Considerable overlapping of the ranges of both sexes occurred, and territorial behaviour was not conspicuous. The dispersion of the population remained the same throughout the study although the component individuals changed. The results of the present study are compared with those of similar studies in New Zealand and Australia, and the dynamics of the Orongorongo Valley possum population are discussed with reference to variable rates of reproduction and mortality.


1993 ◽  
Vol 71 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Darwin R. Wiggett ◽  
David A. Boag

The results of this study support the hypothesis that male-biased emigration of yearling male Columbian ground squirrels (Spermophilus columbianus) is socially induced. The likelihood of emigration from both the natal site and the natal colony was correlated with parameters of social structure and behavior. Agonism by the mother and (or) neighboring adult females, in association with parturition and lactation, apparently caused the initial shifts of yearling males away from their natal home ranges. After these shifts, yearling males that lived in areas where the number of neighboring males (both adult and yearling) was high relative to the number of females emigrated to areas within the natal colony that were more female-biased (intracolony emigration), or emigrated from the natal colony (intercolony emigration). Reduced numbers of adult males apparently resulted in lower rates of emigration by yearling males. Among the latter, emigrants appeared to be subordinate to non-emigrants. We discuss these findings in light of current hypotheses concerning the proximate and ultimate causes of emigration in ground-dwelling sciurids.


2002 ◽  
Vol 80 (5) ◽  
pp. 951-955 ◽  
Author(s):  
Nancy G Solomon ◽  
Joseph J Jacquot

Many studies have documented intraspecific differences in the behavior of males or females. In some species, many adults are territorial while others have larger home ranges encompassing multiple territories. Although these two types of behavior have been documented, they are not well understood in mammals. Therefore, in the mono gamous prairie vole (Microtus ochrogaster) we characterized individuals that engage in these two behavior patterns as residents and wanderers. We monitored populations enclosed in 0.1-ha. enclosures at Miami University's Ecology Research Center. As many as 26% of animals were wanderers: animals captured frequently, but less than 75% of the time, at one nest. As expected, wanderers had larger home ranges than residents. Wanderers were primarily adult males (70%) but included some adult females. This behavior pattern was not fixed, since some wanderers previously had been residents and at least 31% of males and 57% of adult female wanderers became residents during the same field season. Wanderers were not in worse physical condition, as estimated by body mass, and survived for slightly longer than residents. Thus, it does not appear that wanderers are making the best of a bad situation, but analysis of parentage is critical to validate this conclusion.


1999 ◽  
Vol 26 (3) ◽  
pp. 263 ◽  
Author(s):  
Jane Melville ◽  
Roy Swain

We studied the home ranges of the alpine skink, Niveoscincus microlepidotus, in an alpine transition zone on Mt Wellington, Tasmania, over a 5-month period to examine seasonal patterns in the home-range characteristics of four male, four female and two sub-adult juvenile lizards. Home-range sizes and activity patterns within these were quantified. Adult males had significantly larger home ranges with more activity centres than adult females; most activity centres were clearly synonymous with basking sites and were defended by overt aggressive behaviour. Home ranges of males showed little overlap and no seasonal variation while those of femals were unusual amongst reptiles in showing extensive overlap and seasonal change in size. Ranges were smallest in spring when all females were pregnant and were smallest in summer when only one female was pregnant. Range overlap ensured that all females studied had potential access to at least two males. Juveniles had no defined home ranges and appeared to be transients.


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