DISEASE AS A CONTROL OF A POPULATION OF BLUE GROUSE, DENDRAGAPUS OBSCURUS FULIGINOSUS (RIDGWAY)

J. F. Bendell

doi:10.1139/z55-014

DISEASE AS A CONTROL OF A POPULATION OF BLUE GROUSE, DENDRAGAPUS OBSCURUS FULIGINOSUS (RIDGWAY)

Canadian Journal of Zoology ◽

10.1139/z55-014 ◽

1955 ◽

Vol 33 (3) ◽

pp. 195-223 ◽

Cited By ~ 11

Author(s):

J. F. Bendell

Keyword(s):

New Records ◽

Population Control ◽

Mortality Factor ◽

First Year ◽

Population Stability ◽

Adult Males ◽

Age Classes ◽

Dendragapus Obscurus ◽

Summer Range ◽

First Year Of Life

A population of blue grouse was studied on its summer range at Quinsam Lake, Vancouver Island, to determine the factors of importance in population control. The population is stable with a density of 0.40 adult males and 0.78 yearling and adult females to the acre. A life table is constructed on the basis of a stable population, the death of 80% of the chicks in the first three months after hatch, and the death of 31% of the adults each year, as calculated from banding returns. The survivorship curve is negatively "J"-shaped. Mortality rates appear constant and independent of age after the first year of life. Space, weather, food, predators, and disease are considered as factors capable of population control. Six parasites are new records in this host. Two of the six, Plagiorhynchus formosus and Dispharynx nasuta occur commonly and almost exclusively in the chicks, where they cause extreme damage to the tissues of the gut. It is concluded that parasitism by these helminths is an important mortality factor in the chicks and a major cause of population stability—an equilibrium between death in the older age classes and replacement by surviving young.

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Aspects of survival in juvenile polar bears

Canadian Journal of Zoology ◽

10.1139/z96-138 ◽

1996 ◽

Vol 74 (7) ◽

pp. 1246-1252 ◽

Cited By ~ 64

Author(s):

Andrew E. Derocher ◽

Ian Stirling

Keyword(s):

Maternal Age ◽

Polar Bear ◽

Survival Rates ◽

Mortality Factor ◽

First Year ◽

Hudson Bay ◽

Maternal Condition ◽

Sampling Regime ◽

Fat Stores ◽

First Year Of Life

We captured, weighed, tagged, and monitored polar bear (Ursus maritimus) cubs and yearlings in western Hudson Bay to examine survival rates and correlates with survival. Cub survival between spring and autumn increased with cub mass and maternal mass, but was not related to maternal age or maternal condition. Cub survival between spring and autumn varied annually between 39.0 and 100.0% and averaged 53.2%. Whole-litter loss between spring and autumn was 30.8%, and only 38.0% of the females did not lose any cubs. Survival of spring twins was similar regardless of size, but in triplet litters, survival between spring and autumn varied according to cub size. Minimum cub survival from one autumn to the next was 34.7% and was related to cub mass, maternal mass, and maternal condition. Cub survival during autumn was estimated at 83.0%. Survival during the first year of life was no more than 44.0% but we could not estimate an annual survival rate because of the sampling regime. Possibly because harvesting was the major mortality factor for yearlings (19.4% of the yearlings were removed from the population per year), no factors examined correlated with survival of yearlings. We found no sex-related differences in survival of cubs or yearlings in any period. Relationships between survival in polar bear cubs and their condition suggest that lack of food availability, sometimes due to low maternal fat stores for lactation, leads to starvation and may be the main cause of mortality.

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Primary molt of blue grouse (Dendragapus obscurus) and its relation to reproductive activity and migration

Canadian Journal of Zoology ◽

10.1139/z77-232 ◽

1977 ◽

Vol 55 (11) ◽

pp. 1782-1787

Author(s):

Fred C. Zwickel ◽

Jane A. Dake

Keyword(s):

Rank Order ◽

Reproductive Activity ◽

Adult Males ◽

Age Classes ◽

East Central ◽

Dendragapus Obscurus ◽

Close Relationship ◽

And Migration ◽

Late Starters ◽

Reproductive Activities

A total of 906 blue grouse (Dendragapus obscurus fuliginosus) were examined for primary molt from 1969 to 1976 on east-central Vancouver Island. First birds to molt were yearling males, followed by adult males, lone (broodless) females, and brood females, in that order. General reproductive activity of the different sex–age classes followed the same rank order (least to greatest). No brood hens molted until after their chicks were hatched, with adult females molting earliest, in relation to yearling females. The rates of molt of yearling males, adult males, and lone females were all linear but brood females, which began their molt latest, had an accelerated, curvilinear rate of molt. Our data most closely fit the hypothesis that molt is inhibited by reproductive activities. The close relationship between initiation of molt and reproductive activity agrees with data for most other species of north-temperate birds.There was no separation of molt and summer–autumn migration. The most likely explanation for an accelerated rate of molt in late starters is a preparation for winter.

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POPULATION ATTRIBUTES OF BLUE GROUSE IN SOUTHWESTERN ALBERTA

Canadian Journal of Zoology ◽

10.1139/z66-081 ◽

1966 ◽

Vol 44 (5) ◽

pp. 799-814 ◽

Cited By ~ 4

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.

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Development of Steelhead Trout (Salmo gairdneri) Otoliths and Their Use for Age Analysis and for Separating Summer from Winter Races and Wild from Hatchery Stocks

Journal of the Fisheries Research Board of Canada ◽

10.1139/f74-171 ◽

1974 ◽

Vol 31 (8) ◽

pp. 1420-1426 ◽

Cited By ~ 9

Author(s):

J. L. McKern ◽

H. F. Horton ◽

K V. Koski

Keyword(s):

Growth Characteristics ◽

Salmo Gairdneri ◽

First Year ◽

Steelhead Trout ◽

Subsequent Growth ◽

Otolith Growth ◽

Age Classes ◽

X Ray ◽

Life History Patterns ◽

First Year Of Life

In steelhead trout (Salmo gairdneri) the first pair of otoliths (sagittae) appeared in X-ray photographs of embryos 14 days before hatching and were the first calcified structures visible. Subsequent growth characteristics of otoliths were used in identifying as freshwater and ocean annuli and spawning checks, and indicated seven age-classes and 26 life history patterns among 434 specimens. Diameters of otolith nuclei were smaller (P ≤ 0.01) in summer steelhead (mean = 0.348 mm) than in winter steelhead (mean = 0.436 mm), and diagonally measured otolith growth representing the first year of life was larger (P ≤ 0.01) in hatchery-reared (1.291 mm) than in wild steelhead (0.868 mm for 2/fish and 0.769 mm for 3/fish). Absence of changes in density in the freshwater growth of otoliths from hatchery-reared steelhead and presence of such changes in the otoliths from wild steelhead served as a subjective means of accurately separating the two stocks.

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Age, growth and condition of the Perth herring, Nematolosa vlaminghi (Munro) (Dorosomatinae), in the Swan Estuary, south-western Australia

Marine and Freshwater Research ◽

10.1071/mf9860105 ◽

1986 ◽

Vol 37 (1) ◽

pp. 105 ◽

Cited By ~ 11

Author(s):

CF Chubb ◽

IC Potter

Keyword(s):

Western Australia ◽

Condition Factor ◽

First Year ◽

Growth Equation ◽

Age Classes ◽

Beach Seine ◽

Gill Net ◽

The Mean ◽

Von Bertalanffy Growth Equation ◽

First Year Of Life

The size, age and condition of Perth herring, N. vlaminghi, in the Swan Estuary in south-western Australia, were investigated between February 1977 and January 1980 using samples collected by beach seine and gill net. An examination of scale annuli showed that the population consisted predominantly of age classes 0+ to 4 +. By the end of their first year of life, Perth herring had reached mean lengths of 105 mm (= 9.8 g) in 1977, 105 mm (= 10.0 g) in 1978, and 95 mm (= 7.9 g) in 1979. The von Bertalanffy growth equation was calculated to be Lt = 381{1 -exp[- O.17(t + 0.6S)]}. During winter, the growth rate declined markedly and the mean condition factor fell to its lowest level. Perth herring started to make a major contribution to the important commercial fishery for this species during their third year of life.

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Partial Characterization of Circulating Inhibin-B and Pro-αC During Development in the Male Rhesus Monkey1

Endocrinology ◽

10.1210/endo.140.12.7167 ◽

1999 ◽

Vol 140 (12) ◽

pp. 5497-5504 ◽

Cited By ~ 10

Author(s):

Stephen J. Winters ◽

Tony M. Plant

Keyword(s):

Gel Filtration ◽

Cell Number ◽

Inhibin B ◽

First Year ◽

Adult Males ◽

Mean Values ◽

Multiple Blood ◽

A Minor ◽

First Year Of Life ◽

Male Rhesus

Abstract Gel filtration chromatography and ELISAs for inhibin-B and pro-αC were used to examine the circulating forms of inhibin in the neonatal (age 2–6 weeks), juvenile (age 1–2 yr), and adult male rhesus monkey. In all samples, isoforms of inhibin-B of 26–36K and 150K were found. Both forms were significantly greater in the adult. Theα -subunit assay detected major peaks at 45–60 and 29–31K, and a minor peak of greater than 100K. As for inhibin-B, the major forms of inhibin pro-αC were highest in adulthood. Inhibin-B and pro-αC were measurable in peripheral plasma at age 1 week, increased with the neonatal rise in plasma FSH, and then decreased but remained detectable through age 1 yr. Values in adult males were higher than at any time during the first year of life. Finally, mean values of plasma inhibin-B and pro-αC in five monkeys, based on multiple blood samples drawn between age 1 week and 1 yr, were rank ordered and were found to be highly positively correlated (r = 0.96), suggesting that inhibin levels in the first year of life may be a marker of Sertoli cell number, and may predict the spermatogenic capacity of the testis in adulthood.

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The Development of Swallowing Respiratory Coordination

Perspectives on Swallowing and Swallowing Disorders (Dysphagia) ◽

10.1044/sasd18.1.19 ◽

2009 ◽

Vol 18 (1) ◽

pp. 19-24

Author(s):

Maggie-Lee Huckabee

Keyword(s):

Cortical Activation ◽

First Year ◽

Healthy Children ◽

Nasal Airflow ◽

Single Session ◽

Primary Finding ◽

Patterns Of Behavior ◽

Cortical Modulation ◽

First Year Of Life ◽

Swallowing Apnea

Abstract Research exists that evaluates the mechanics of swallowing respiratory coordination in healthy children and adults as well and individuals with swallowing impairment. The research program summarized in this article represents a systematic examination of swallowing respiratory coordination across the lifespan as a means of behaviorally investigating mechanisms of cortical modulation. Using time-locked recordings of submental surface electromyography, nasal airflow, and thyroid acoustics, three conditions of swallowing were evaluated in 20 adults in a single session and 10 infants in 10 sessions across the first year of life. The three swallowing conditions were selected to represent a continuum of volitional through nonvolitional swallowing control on the basis of a decreasing level of cortical activation. Our primary finding is that, across the lifespan, brainstem control strongly dictates the duration of swallowing apnea and is heavily involved in organizing the integration of swallowing and respiration, even in very early infancy. However, there is evidence that cortical modulation increases across the first 12 months of life to approximate more adult-like patterns of behavior. This modulation influences primarily conditions of volitional swallowing; sleep and naïve swallows appear to not be easily adapted by cortical regulation. Thus, it is attention, not arousal that engages cortical mechanisms.

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