No description available.

Thesis (Ph. D.)--Illinois State University, 1990. / Title from title page screen, viewed November 4, 2005. Dissertation Committee: Charles F. Thompson (chair), Dale E. Birkenholz, Angelo Capparella, Steven A. Juliano, Scott K. Sakaluk. Includes bibliographical references (leaves 61-67) and abstract. Also available in print.

This study was restricted to birds using tree-holes as nest-sites. Of a total of 20 species in the study area, only 13 were sufficiently abundant to merit consideration. These fell into three natural groups on the basis of hole size, with only one euryoecious species (Iridoprocne bicolor) nesting in all three groups. Only the group based on holes made by the Colaptes woodpeckers (Flickers) can presently be construed as showing evidence of nest-site competition. Physical and ecological characteristics of nest-sites are analyzed in terms of intensification or amelioration of nest-site competition. The competing species, all using holes made by Colaptes cafer, are Sturnus vulgaris, Sialia currucoides, Bucephala albeola, Iridoprocne bicolor and Falco sparverius. The data suggest that although competition is now present in this group, it may have been absent before the advent of Sturnus in the avifauna. Neither selection for different sites nor competitive exclusion seem to have occurred before the appearance of Sturnus, which now occupies roughly 25% of all available nests, but one or both of these may now be going on. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

This study relates the species composition, numbers, and habits of a hole-nesting avifauna to its environment in successional stages of a coniferous forest in southwestern British Columbia. Emphasis is placed upon explaining an observed presence or absence of nest-site competition. In two breeding seasons, the hole-nesting avifauna was found to be low in numbers of both species and individuals. Most of these birds were able to excavate their own nesting cavities, and commonly did so, for which activity the habitat generally provided ample opportunity. As the species present often differed widely from one another in the type and placement of their preferred nest cavities, there was usually a surplus of different cavity types present. Secondary hole-nesters either concentrated their activities around the buildings in the nearby town, neglecting the more "natural" sites available; were not obligated to use cavities when nesting; or occurred in such low densities, and were so positioned in the available suitable habitat, as to suggest that nest-site competition had no effect upon the populations. Only scattered indications of nest-site competition were observed in wooded areas. Four species nested in crevices in buildings and in bird boxes in a small town, where their breeding population densities were much higher than in the surrounding countryside. Nest-sites were judged to be present in excess, and nest-site competition, observed infrequently, was so rare, and apparently without significant harmful effects, that it was judged to be of negligible importance as a population-regulating factor. The overall absence of nest-site competition is contributed to not only by the preferences of the species regarding their nest-sites, but also by the fact that the results of their habitat selection processes, and their living habits within these habitats, tend to keep them ecologically distinct. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Call number: LD2668 .T4 1985 K343 / Master of Science

The doubly labelled water technique was validated for captive-bred, laying Japanese quail (Coturnix coturnix), and used to measure the energy expenditure of free-living laying swallows (Hirundo rustica). Swallows had a slightly higher energy expenditure during laying than during incubation or nestling-rearing. Energy expenditure and the net cost of incubation increased sharply for female dippers (Cinclus cinclus) when clutches were enlarged to 6 eggs. Lipophilic dyes were used to determine the rate of ovarian follicular growth and the volume of yolk deposjted in a 24 h period by captive quail and free-living swallows. Rates of yolk deposition were related to daily energy expenditure in quail, but not in swallows. Balances placed under swallow nests recorded an increase in female mass from 5 d before the first egg was laid. Female mass peaked on the evening before the first egg and declined as eggs were laid. Mass changes during laying were equal to the mass of the oviduct and developing ova. However, body composition also changed, as a lipid reserve was built up in the final 4 d before the first egg was laid, whilst body water content declined. This substantially increased the peak energy requirement for biosynthesis in a laying swallow. The lipid reserve was catabolized during the remainder of the laying period. The lipid reserve was likely to serve as an insurance against a drop in food intake during laying. Shortage of food on the day before the first egg was laid led to a reduction in clutch size for some swallows. There was no evidence for use of a protein reserve by laying swallows. A model was developed from which it was predicted that egg production by swallows, and probably all other insectivorous birds, would be constrained by energy rather than crude lipid or protein requirements. It was concluded that laying patterns and clutch sizes were sometimes constrained by food availability during egg-laying, and that an upper limit to clutch size could be set by the capacity of an incubating bird to cover the eggs.