Renesting in adult and yearling blue grouse

1983 ◽  
Vol 61 (2) ◽  
pp. 289-291 ◽  
Author(s):  
Lennart G. Sopuck ◽  
Fred C. Zwickel
Keyword(s):  
Home Ranges ◽  
Adult Females ◽  
Dendragapus Obscurus ◽  
Average Size ◽  
Second Clutch

Eight of 31 radio-tagged female blue grouse (Dendragapus obscurus) that had first nests terminated before hatch produced second clutches. Significantly more adult than yearling hens renested. All yearling hens that produced a second clutch had first nests terminated during laying or early incubation; but most yearlings did not renest. Adult females renested independently of the stage of incubation when nests were terminated. Average size of second clutches of adults are likely larger than those of yearlings and average size of second clutches of all females are likely smaller than those of first clutches. Most prenesting home ranges used during second nesting attempts were in the same general areas and of the same sizes as those used during initial nesting attempts.

Density, movements, and breeding success of female blue grouse in an area of reduced male density

1984 ◽  
Vol 62 (8) ◽  
pp. 1556-1560 ◽  
Author(s):  
Richard A. Lewis
Keyword(s):  
Home Range ◽  
Breeding Success ◽  
Control Area ◽  
Home Ranges ◽  
Low Density ◽  
Timing Of Breeding ◽  
Apparent Effect ◽  
Adult Females ◽  
Male Density ◽  
Dendragapus Obscurus

The density of male blue grouse (Dendragapus obscurus) on a 95-ha area was reduced artificially by approximately 75% in 1982. Density, movements, and breeding success of females on this area in that year were compared with those of females on the same area in 1981 (when density of males was undisturbed) and of females on an unmanipulated control area in 1981 and 1982. A reduction in male density had no apparent effect on the density of either yearling (potential recruits) or adult females, or the daily movements, timing of breeding, and breeding success of females. Home ranges of females were largest when male density was artificially reduced, but not significantly so. The larger home range sizes of females residing in an area with a very low density of males did not seem to result entirely from females searching for males with which to breed. Results of this study suggest that densities of male blue grouse have no apparent effect on densities of females or production of young, and support the hypothesis that densities of females in this species are regulated independently of males.

POPULATION ATTRIBUTES OF BLUE GROUSE IN SOUTHWESTERN ALBERTA

1966 ◽  
Vol 44 (5) ◽  
pp. 799-814 ◽  
Author(s):  
D. A. Boag
Keyword(s):  
Mortality Rate ◽  
Adult Male ◽  
Age Distribution ◽  
Older Age ◽  
Home Ranges ◽  
Adult Males ◽  
Age Classes ◽  
Adult Females ◽  
Dendragapus Obscurus ◽  
Breeding Grounds

A population of blue grouse (Dendragapus obscurus) was studied over a 10-year period in southwestern Alberta. During this time a number of population attributes were documented. Density declined from a maximum of 47 adult males in 1955 to a minimum of 6 in 1964 on the 620-acre study area. Dispersion of adult male blue grouse on the breeding grounds was accomplished by establishing territories which averaged 1.5 ac. Adult females inhabited overlapping home ranges which averaged 43 ac in size. The age distribution among marked birds on the breeding grounds in May and June indicated 75% adult (2 years and older) and 25% subadult (1 year of age). Of the adults, approximately one-half were 2-year-olds with decreasing proportions in older age classes until none remained after they were 9 years old. Juveniles formed 40% of the fall population each year. The average hatch was 5.1 chicks per breeding female. Recruitment to the population has been inadequate to maintain numbers. Excessive mortality or dispersal rates must account for this. Minimum recorded loss of chicks during their first summer averaged 27%. Mortality rate of birds more than 1 year old averaged 56% per annum. Dispersal to other breeding ranges was recorded only in juvenile grouse.

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
Keyword(s):  
Lontra Canadensis ◽  
Home Ranges ◽  
Adult Males ◽  
Movement Rates ◽  
River Otters ◽  
Aquatic Mammal ◽  
Adult Females ◽  
Two Factors ◽  
Bog Lakes ◽  
Selection Of

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.

Home-Range Size and Fidelity of Western Grey Kangaroos (Macropus Fuliginosus) Living in Remnants of Wandoo Woodland and Adjacent Farmland.

1992 ◽  
Vol 19 (2) ◽  
pp. 137 ◽  
Author(s):  
GW Arnold ◽  
DE Steven ◽  
A Grassia ◽  
J Weeldenburg
Keyword(s):  
Home Range Size ◽  
Home Ranges ◽  
Adult Males ◽  
The Core ◽  
Adult Females ◽  
Radio Transmitters ◽  
Core Areas ◽  
Males And Females ◽  
Eucalyptus Wandoo ◽  
Older Males

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.

scholarly journals Habitat changes reduce the carrying capacity of Hluhluwe-Umfolozi Park, South Africa, for Critically Endangered black rhinoceros Diceros bicornis

Oryx ◽  
2007 ◽  
Vol 41 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Caroline Reid ◽  
Rob Slotow ◽  
Owen Howison ◽  
Dave Balfour
Keyword(s):  
South Africa ◽  
Carrying Capacity ◽  
Critically Endangered ◽  
Home Ranges ◽  
Source Population ◽  
Black Rhinoceros ◽  
Habitat Changes ◽  
Diceros Bicornis ◽  
Average Size ◽  
Stocking Rates

AbstractThe Critically Endangered black rhinoceros Diceros bicornis occurs mainly in protected areas. Hluhluwe-Umfolozi Park, South Africa, contains a key source population for black rhino conservation, and declining population productivity has been attributed to negative habitat changes and a reduction in carrying capacity. As home range increase may be an index of declining habitat quality we determined the home ranges of the black rhino in the Park and compared these ranges with previous estimates. The average size of the home ranges during 1991–2001 was 23.07 ± SE 0.81 km2, which is 54% greater than in the 1980s. Sex and the availability of water did not influence home ranges. Home ranges decreased in winter. Female:male ratios varied across the Park, indicating that one or both sexes may prefer specific areas. Changes in vegetation structure and composition may have caused rhino to maintain larger ranges in order to meet their nutritional requirements. Ongoing review of stocking rates, population performance (including indicators such as range size), and intervention strategies are necessary to manage black rhino in dynamic savannah ecosystems.

scholarly journals Home range of the Tropidurid lizard Liolaemus lutzae: sexual and body size differences

1999 ◽  
Vol 59 (1) ◽  
pp. 125-130 ◽  
Author(s):  
C. F. D. ROCHA
Keyword(s):  
Body Size ◽  
Home Range ◽  
Mutual Exclusion ◽  
Home Range Size ◽  
Range Size ◽  
Home Ranges ◽  
Adult Males ◽  
Adult Females ◽  
The Mean ◽  
Janeiro State

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.

Reintroduction of the greater bilby, Macrotis lagotis (Reid) (Marsupialia : Thylacomyidae), to northern South Australia: survival, ecology and notes on reintroduction protocols

2003 ◽  
Vol 30 (1) ◽  
pp. 15 ◽  
Author(s):  
K. E. Moseby ◽  
E. O'Donnell
Keyword(s):  
Site Fidelity ◽  
South Australia ◽  
Home Range Size ◽  
Home Ranges ◽  
Radio Tracking ◽  
Significant Preference ◽  
Adult Females ◽  
Males And Females ◽  
Food Reserves

Nine bilbies were reintroduced to a 14-km2 reserve free of rabbits, cats and foxes in South Australia in April 2000. The survival, growth and ecology of the population were studied for 17 months after release by means of radio-tracking and trapping. Reproduction was continuous over the study period, with juveniles successfully recruited into the population. Home-range size of female bilbies averaged 0.18 km2 and was significantly smaller than home ranges of males, which averaged 3.16 km2. Wild-born subadults had smaller home ranges than adults. While male home ranges, and male and female home ranges overlapped considerably, females appeared to maintain areas discrete from other adult females. Bilbies showed a significant preference for dune habitat. As swale habitat appears too hard for burrow construction and males moved greater distances from diurnal burrows than females, males are likely to access food reserves that are under-used by females. Both males and females reused at least 30% of their burrows, and females displayed long-term site fidelity. The release was considered successful and suggests that despite historical damage from rabbits and stock, bilbies are able to successfully recolonise parts of their former range in arid South Australia once rabbits, cats and foxes are removed.

Nesting parameters in a high density, declining population of blue grouse

1988 ◽  
Vol 66 (8) ◽  
pp. 1736-1741 ◽  
Author(s):  
Fred. C. Zwickel ◽  
Richard A. Lewis ◽  
Donald T. McKinnon
Keyword(s):  
British Columbia ◽  
Clutch Size ◽  
Nesting Success ◽  
Moderate Density ◽  
Egg Hatchability ◽  
General Region ◽  
Adult Females ◽  
Dendragapus Obscurus ◽  
Very High ◽  
Egg Fertility

Of four nesting parameters (clutch size, egg fertility, egg hatchability, and nesting success) in a population of blue grouse, Dendragapus obscurus fuliginosus, at Hardwicke Island, British Columbia, only clutch size differed between yearling and adult females. There was no difference among years for any of the parameters considered. This population declined from very high to moderate density during the studies reported here, and clutch size, egg fertility, and hatchability were significantly lower than reported for a more stable population (Comox Burn) in the same general region. Nesting success at Hardwicke Island, however, was higher than at Comox Burn. Collectively, the parameters examined do not, by themselves, explain the observed decline. Nevertheless, they suggest that the population at Hardwicke Island differed from that at Comox Burn in some fundamental aspects of reproduction that may be symptomatic of other factors possibly involved in its decline, e.g., the survival of chicks.

A live-trapping of Australian brush-tailed possums, Trichosurus vulpecula (Kerr), in the Orongorongo Valley, Wellington, New Zealand

1973 ◽  
Vol 21 (1) ◽  
pp. 75 ◽  
Author(s):  
MC Crawley
Keyword(s):  
New Zealand ◽  
Home Ranges ◽  
Trichosurus Vulpecula ◽  
Adult Males ◽  
Adult Females ◽  
Capture Site ◽  
Live Trapping ◽  
Indigenous Forest ◽  
Autumn And Winter ◽  
Initial Capture

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.

The proximate causes of male-biased natal emigration in Columbian ground squirrels

1993 ◽  
Vol 71 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Darwin R. Wiggett ◽  
David A. Boag
Keyword(s):  
Ground Squirrels ◽  
Home Ranges ◽  
Adult Males ◽  
Spermophilus Columbianus ◽  
Adult Females ◽  
Study Support ◽  
Proximate Causes ◽  
Natal Home ◽  
And Behavior ◽  
Columbian Ground Squirrels

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.

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