We tested the hypothesis that the basis of the variation in reproductive strategy among male yellow warblers (Dendroica petechia) is a tradeoff in the allocation of reproductive effort to intrasexual competition (territorial effort) and to parental care (parental...
Field observations were conducted on four species of nesting male centrarchids to determine if guarding males discriminate intruders with respect to their potential threat to the brood, their size or position in the water column, or by the stage of...
The order in which females settle on territories likely reflects patterns of female choice of territory and/or mates. Yet in most studies of female choice, settlement dates are usually only inferred from dates of nest initiation or first egg date...
Patterns of food use and food availability were analysed in a species rich summer weedbed community of juvenile lake fish to elucidate ontogenetic and ecological adaptations facilitating species co-existence and rapid growth. It was found that: (a) the community was...
Seventy-two plants of Vaccinium angustifolium, 24 from Newfoundland, 24 from Nova Scotia and 24 from Ontario, were set out in equal numbers on the Nova Scotian mainland and eastern Ontario in order to monitor differences in vegetative and reproductive...
We monitored the time spent at the nest and following behavior of mated tree swallows to determine if males were guarding their mates. The proportion of time spent together at the nest did not decrease significantly between fertile and postfertile...
The present paper examines how singing is used in territorial communication between neighboring male song sparrows, Melospiza melodia. We concentrate upon the "dynamics" of song behavior, in which shortterm variations in patterns of singing are analyzed from two perspectives...
A comparative study of the diets of five year classes of perch in Lake Opinicon showed Year class 0 to be mainly Cladocera feeders, the Year class II to take a diversified range of insect larvae, whereas from Year class...
The submerged macrophyte community of Lake Opinicon was sampled by a combination of quadrats and line transects in 1972 and 1973. Mean organic biomass was 248 g -m2 with a range of 1 to 1 154 g -m2 ...
Measurements made in shallow lakes and tanks have shown that temperatures near and at the surface of substrates respond significantly to changes in solar radiation, water circulation and substrate color. Temperature differences between light and dark colored natural and artificial...
Changes in aggressive responsiveness to 5 stimulus dummies (Normal, Aggressive, and Subordinate sunfish, Pike, and Minnow) over the 4 periods (Nesting, Spawning, Brooding, and Vacating) of the reproductive phase were studied in 49 ♂ ♂ over two seasons in the...
The effects of interspecific competitive encounters have traditionally been viewed in terms of species replacement, but recent workershave recognised the importance of weak or diffuse competition, which leads only to reduced niche volume. Evidence of such niche restriction...
The feeding periodicities of five common cohabiting fish species in Lake Opinicon, Ontario, were defined for the early summer period of accelerated feeding by determining the mean weights of stomach contents per gram of body weight at intervals of 2–3 hr...
