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 new feeding technique for experimental and routine culturing of the insect Rhodnius prolixus

1994 ◽  
Vol 72 (12) ◽  
pp. 2244-2247 ◽  
Author(s):  
Erwin Huebner ◽  
Rene Harrison ◽  
Karen Yeow
Keyword(s):  
Cost Effective ◽  
Rhodnius Prolixus ◽  
Wire Mesh ◽  
Artificial Membrane ◽  
Egg Hatchability ◽  
Rabbit Blood ◽  
Adult Females ◽  
Feeding Technique ◽  
Heat Sealing ◽  
Membrane Envelope

We report a method for artificially feeding the reduviid insect Rhodnius prolixus that utilizes heparinized rabbit blood enclosed in an artificial-membrane envelope. Envelopes of Parafilm M® or Nescofilm® are made by heat sealing two pieces, one of which is stretched first, on three sides. Blood is then put into the envelope, the air expelled, and the fourth side sealed with a bag sealer. The blood-filled envelopes are then placed on a standard slide warmer set at 37 °C and insects in jars with wire-mesh tops are allowed to feed. Normal gorging and subsequent molting of instars were attained. Adult females show normal fecundity (the E value was 0.19 for mated females) and egg hatchability was also normal. The method is simple, cost effective, and easy to implement. It is especially suited for experimental feedings.

scholarly journals Breeding Biology and Success of a Reintroduced Population of the Critically Endangered Puaiohi (Myadestes Palmeri)

The Auk ◽  
2006 ◽  
Vol 123 (3) ◽  
pp. 753-763 ◽  
Author(s):  
Erik J. Tweed ◽  
Jeffrey T. Foster ◽  
Bethany L. Woodworth ◽  
William B. Monahan ◽  
Jherime L. Kellerman ◽  
...  
Keyword(s):  
First Record ◽  
Nesting Success ◽  
Breeding Biology ◽  
Rodent Control ◽  
Breeding Behavior ◽  
Adult Females ◽  
In The Wild ◽  
Daily Nest Survival ◽  
High Predation ◽  
Reintroduced Population

Abstract The ultimate success of reintroduction programs for endangered species depends on the ability of reintroduced animals to breed in the wild. We studied the nesting success and breeding biology of a reintroduced population of Puaiohi (Myadestes palmeri) on the island of Kaua'i, Hawaii. Thirty-four captive-bred Puaiohi were released into the Alaka'i Swamp in 1999-2001 and monitored using radiotelemetry. Ten females and two males paired with wild and other released birds, including one polygynous trio. From March to September, 31 nests were built. Mean clutch size was 2.0 eggs, daily nest survival was 0.97 ± 0.01 (mean ± SE) and overall nest success was 0.40 ± 0.02. We confirmed predation, most probably by rats (Rattus spp.), as the greatest cause of nest failure, occurring at 38% of active nests with known fates, and causing the death of two nesting adult females. Ground-based rodent control proved ineffective at protecting nest attempts. Successful nests fledged an average of 1.4 young each (n = 10), and 85% of fledglings survived at least two weeks. Importantly, breeding behavior and success were comparable to those of wild Puaiohi. This is the first record of breeding in the wild from captive-bred endangered Hawaiian passerines. The ability of captive-bred Puaiohi to survive and breed successfully in the wild bodes well for future releases of this and other endangered passerines, but high predation rates on nests and nesting females highlights the importance of maintaining and restoring safe habitat for recovery. Biología y Éxito Reproductivo de una Población Reintroducida de Myadestes palmeri, una Especie en Peligro Crítico

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.

Clutch Size and Nesting Success in Red-Winged Blackbirds

The Auk ◽  
1975 ◽  
Vol 92 (4) ◽  
pp. 815-817
Author(s):  
William J. Francis
Keyword(s):  
Clutch Size ◽  
Nesting Success

BIONOMICS OF ENOCLERUS BARRI (COLEOPTERA: CLERIDAE)

1969 ◽  
Vol 101 (4) ◽  
pp. 382-386 ◽  
Author(s):  
Richard E. Rice
Keyword(s):  
British Columbia ◽  
Life Cycle ◽  
North America ◽  
Sex Ratio ◽  
Rocky Mountain ◽  
Mountain Region ◽  
Western North America ◽  
Adult Females ◽  
Rocky Mountain Region ◽  
Life Cycle Stages

AbstractEnoclerus barri Knull occurs in western North America from British Columbia south to Mexico and throughout the Rocky Mountain region. Adults were collected at Grass Valley, Calif., from May to September at traps baited with beetle attractants. Collections occurred at temperatures ranging from 22.5° to 31 °C; the sex ratio of trapped beetles was 4.5 females to 1 male. Duration of life cycle stages at 24 ± 2 °C were: egg, 9 days; larva, first iastar, 14 days; second instar, 12 days; third instar feeding stage, 14 days. All larvae reared to third instar failed to pupate in the laboratory. Adult females of unknown age when collected lived from 10 to 131 days and produced an average of 389 eggs per female. Enoclerus barri utilized six species of Scolytidae as hosts in the laboratory.

Spatial Patterns of Yearling Male Blue Grouse and Their Relation to Recruitment into the Breeding Population

The Auk ◽  
1983 ◽  
Vol 100 (3) ◽  
pp. 653-657 ◽  
Author(s):  
Ian G. Jamieson ◽  
Fred C. Zwickel
Keyword(s):  
British Columbia ◽  
Spatial Patterns ◽  
Radio Telemetry ◽  
Breeding Population ◽  
Adult Males ◽  
Costs And Benefits ◽  
Breeding Range ◽  
Dendragapus Obscurus ◽  
Different Types ◽  
Occupied Territories

Abstract Movements of yearling male Blue Grouse (Dendragapus obscurus) were monitored by radio telemetry during the springs of 1980 and 1981, on Hardwicke Island, British Columbia. The locations of the birds were clumped around territories of adult males. Most birds were associated with a few occupied territories, others settled near vacant sites that had been used as territories in previous years, and a few moved widely over the breeding range. Some territories attracted more yearlings than others. Presumed costs and benefits that may be associated with different types of spatial patterns of yearling males are discussed.

Breeding Biology of the Savannah Sparrow on Kent Island

The Auk ◽  
1978 ◽  
Vol 95 (2) ◽  
pp. 235-246 ◽  
Author(s):  
Clara L. Dixon
Keyword(s):  
New Brunswick ◽  
Clutch Size ◽  
Breeding Season ◽  
Breeding Population ◽  
Nesting Success ◽  
Breeding Biology ◽  
Passerculus Sandwichensis ◽  
Herring Gulls ◽  
Savannah Sparrow ◽  
The Mean

Abstract I studied the breeding biology of the Savannah Sparrow (Passerculus sandwichensis) on Kent Island, New Brunswick, Canada from 1964 through 1968. I estimated the breeding population to be 125-135 pairs $(412-445\ \text{individuals}/{\rm km}^{2})$. The mean number of nests produced per female, including those destroyed by predators, was 2.97. Clutch size ranged from 2 to 5. The mean clutch size based on 1,142 eggs in 284 nests of known clutch size was 4.02. Not only was the four-egg clutch most numerous but a greater percentage of eggs in the four-egg clutches hatched and the mean number of young fledged per nest was also highest. The mean incubation period was 12.2 days, the mean duration of nestling life was 9 days, and the approximate length of the breeding season as 52 days. The daily mortality rate of eggs was 11.9% and of nestlings 2.1%. Predation was the major factor affecting reproductive success; 50.5% of all nests located were destroyed by predators. The main nest predators were Common Crows and Herring Gulls. Of the nests destroyed by predators, 87.8% contained eggs rather than nestlings. The intense predation necessitated high nest replacement. The mean interval between the termination of one nest and the appearance of the first egg in the succeeding nest was 6.3 days. If successive nests are destroyed on the day incubation begins, it is hypothetically possible for a pair to produce four nests during a single breeding season; many birds in the population produce at least three. Although enough time was available for birds to fledge two broods in a season, few of them fledged more than one. Thus, the nesting success was low (success from egg to hatching 18.1%). High nest replacement compensated for high egg mortality, and an average of 2.16 young per pair were fledged per season.

Auditory Monitoring of up to Eight Simultaneous Sources

1994 ◽  
Vol 38 (9) ◽  
pp. 505-509 ◽  
Author(s):  
Dennis J. Folds ◽  
Jeffrey M. Gerth
Keyword(s):  
Visual Search ◽  
Response Times ◽  
Search Time ◽  
Auditory Signal ◽  
Significant Group ◽  
Amount Of Information ◽  
Moderate Density ◽  
Auditory Monitoring ◽  
Launch Event ◽  
Very High

The present research examined visual and auditory monitoring of independent, concurrent sources. Subjects monitored from one to eight concurrent visual indicators for the occurrence of a “launch” event. Five between-groups conditions were studied: a visual-only group, plus four audiovisual groups that differed in the amount of information provided over the auditory channel. Accuracy scores were very high for all groups. Response times showed an overall increase with display density (number of concurrent sources). A significant group x density interaction revealed an advantage of one of the audiovisual conditions compared to the visual-only group at moderate density levels (5 or 6 concurrent sources), but not at lower or higher density levels. This finding probably indicates the value of an auditory signal to reduce visual search time.

THE GEOGRAPHIC RANGE OF IXODES SORICIS Gregson.

1946 ◽  
Vol 78 (11-12) ◽  
pp. 200-200 ◽  
Author(s):  
E. W. Jameson
Keyword(s):  
British Columbia ◽  
Geographic Range ◽  
Type Series ◽  
Marin County ◽  
Adult Females ◽  
Sorex Vagrans

Ixodes soricis Gregson is known from the type series of adult females, nymphs, and larvae collected by Gregson from long-tailed shrews (Sorex vagrans and S. setosus) in southwestern British Columbia, and from one female collected by Robert Holdenried from Sorex trowbridgii in Marin County, California (Cooley and Kohls, Nat. Inst. Health Bull. No. 184, 1945).

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