The late spring and slimmer diet of blue grouse on lowland breeding ranges on Vancouver Island was determined by examination of the contents of 875 crops taken from birds collected on 3 study areas in the years 1950 through 1952 and 1957 through 1966. The spring and early summer diet of males was mostly conifer needles, while adult females ate mainly leaf material and flowers during the same period. The food of chicks was mainly invertebrates until the birds reached the age of approximately three weeks, at which time plant material formed the greater portion of the diet. In late summer the diet of both adult and juvenile grouse was primarily fruits and seeds of trailing blackberry, salal, huckleberry, and other plants. Selection of plant foods occurred at the time of ovulation and moult. As a result, the protein and mineral content of the diet was highest during periods of greatest need. No apparent differences in the spring diet of females were found which could be related to poor early survival of chicks, or to a delayed hatch in 1962. The various food types were eaten in similar relative proportions by adult and yearling grouse, and differences in reproductive performance of these two age classes could not be related to the diet of the grouse. The altitudinal migration of blue grouse in late summer and autumn does not appear to be related to the availability or condition of the food supply at the time of departure of the birds. / Science, Faculty of / Zoology, Department of / Graduate

The dispersion of a population of blue grouse was analyzed using data from a breeding range on east-central Vancouver Island. During the summers of 1959-1962, the locations, densities, habitat preferences, and behaviour of grouse were studied using several habitats with varying densities of vegetation. A removal experiment was performed in different habitats to test the effect of interaction and selection of habitat on the dispersion of males. All adult males and a few yearling males were territorial, and territories were spaced in a near-uniform pattern. Within a given season, males removed from their territories were seldom replaced by other adults, suggesting that no surplus of non-territorial adults was present. About half of the yearling males were prevented from establishing territory by the presence of adults, and these yearlings were attracted to the vicinity of territorial males. The location of territories by newly-adult males did not depend significantly on the number of territories already present, even though the tendency toward uniform spacing was preserved. Comparison with other studies indicated that territory size and possibly the fraction of yearling males in the population were inversely related to the density of males. Females restricted their movements while on the breeding range but were not territorial. No pair-bonds were observed but females stayed near territorial males prior to nesting. After the hatch, the locations of females and broods bore no relation to each other or to the positions of males. Interaction apparently had no effect on breeding numbers. All birds preferred sparse vegetation to dense. When compared to randomly-chosen points, territories were found more often in areas with sparse vegetation, elevated points, and patches of open ground. Within open habitats, nests were usually located where cover by logs, stumps, and ground-level vegetation was high, and cover by dead plants and litter was low. Broods were associated with moist areas and other areas having heavy cover by vegetation at the ground level. Chicks apparently dispersed widely between their first and second summers. In their third summer, males usually returned within one-half mile of the positions they used as yearlings. Once territories were established, the owners returned to them in succeeding summers. Females one year and older showed a fairly accurate return to their previous locations. The dispersion was described somewhat theoretically by considering the summer population to be grouped into two types of aggregations. The first, found in the earlier half of the summer, was caused by the attraction of yearling males and lone females to territorial males. Later, hens with their broods were the dominant groupings. The spacing, movements, and habitat preferences seemed to be adaptations allowing such populations to rapidly exploit new habitats. / Science, Faculty of / Zoology, Department of / Graduate

I studied the dispersion of winter wrens in 100-year-old, second-growth, coastal western hemlock forest at the University of British Columbia Research Forest in southwestern British Columbia from 1978-81. Male winter wrens were territorial on non-overlapping territories at an average density of 60 per km2. An average of 8% were polygamous. Females occupied generally non-overlapping home ranges at least during the breeding period, but were not shown territorial, although this possibility could not be excluded. Winter wrens were not uniformly distributed but showed differential use of various individual ecosystems (as mapped by Klinka 1976) and ecosystems grouped by forest floor habitats. Surplus, potentially territorial males were available during the breeding period which could have occupied the empty or sparsely occupied areas. Invertebrate food was more abundant in habitats used by winter wrens as compared to avoided habitats, and, food is proposed as a factor in habitat selection by winter wrens. I propose that winter wrens are spaced by territoriality and clumped by suitable habitat, and suggest that these two factors influence the patterns of dispersion of winter wrens in coastal western hemlock forest, and perhaps elsewhere as well. Klinka's ecosystems and grouped ecosystems were proposed as indicative of the distribution of winter wrens, and perhaps of other wildlife species generally. If so, ecosystems can arid should be used as the base for the study and management of wildlife in the province of British Columbia, and perhaps elsewhere as well. / Forestry, Faculty of / Graduate

This study was conducted to evaluate waterfowl harvests on the Delta Marsh, Manitoba, under a variety of options utilizing a modified predator-prey model. The study involved monitoring of ducks and hunters to examine key components of waterfowl mortality. Seven hypotheses were formulated involving the relationships between duck vulnerability by species and hunter effort, factors determining effective bag size, hunter effort, effects of weather on kill, and whether or not hunters are selective. Aerial surveys and experimental hunts were conducted and kill statistics gathered on the Pasquia and Delta Marshes in Manitoba to evaluate predictions from the hypotheses. The analysis of field data revealed that duck vulnerability is negatively proportional to hunting effort and that ducks are most wary when hunter effort is greatest. Hunters were afield in largest numbers during periods of high duck density. Hunters did not shoot selectively and crippling losses approximated one-third of the birds shot. Weather had little influence on the kill; bird population size and hunter effort were more important determinants of hunter success. Distribution patterns of ducks were clumped relative to hunting areas, and the probability of mortality for an individual duck was observed to decrease with increasing flock size. Handling time per bird downed did not limit achieved bag size whereas time between encounters was found to be independent of population size and resulted in a non-linear, kill-density relationship. Field results were incorporated into the predator-prey model and management schemes involving population size, hunter effort, and season length were evaluated. Simulation results revealed that Mallard and Lesser Scaup harvest are not greatly affected by increased hunter effort and that season length and population size strongly influence harvest. Shortened seasons are recommended if kill reductions are desired for Mallard. Lesser Scaup require no special regulations whereas Canvasbacks require short seasons (less than 2 weeks) during times when populations exceed 5000. The predator-prey model is recommended for in-depth analysis of local regulations whereas multi-variate statistical models may be more useful in forecasting yields on a regional level. / Science, Faculty of / Zoology, Department of / Graduate

Our California Bird Friends is an attempt to interest children in birds, by presenting a group of factual stories describing the habits and characteristics, the courage and cleverness of various birds. It is hoped that it will fill a definite need in nature study. The stories are limited to proven facts, presented in a manner which the elementary school child of the fourth, firth, and sixth grades may readily read and understand. The element of reality in the thesis is greatly enhanced by the nature of the illustrations, which are photographs and sketches or real birds in true-to-fact situations. It is hoped that the thesis will be found valuable either for oral or silent reading. The stories are intended to stimulate oral reading, but are simple enough and of suitable length for rapid independent silent reading. The tests which follow the stories provide definite comprehensive checks.

Systematic ornithology has been woefully neglected in Utah. While this state has a number of men who know her birds and who have aroused interest in them, they have produced no published record of what we have. So far as the writer knows there is no adequate, representative, or systematic collection of Utah species within the state. Utah has, however, been fortunate in having a nuraber of expert ornithologists collect and study the bird life of different sections of bar territory.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

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