THE TREE SWALLOW (Tachycineta bicolor) has been the focus of a diversity of research that is rivaled by few other bird species. A quick search through the Science Citation Index reveals over 400 manuscripts either focusing on or involving...
Rainbow smelt (Osmerus mordax) is a recent invader to the lakes of the Hudson Bay drainage in northwestern Ontario, Canada. In some systems, the invasion has been linked to an increase in mercury (Hg) concentration in native predatory...
Sperm competition is a major force in sexual selection, but its implications for mating–system and life–history evolution are only beginning to be understood. The well–known sneak–guard model predicts that sneaks will win in sperm competition. We now provide empirical confirmation...
We examined habitat selection by breeding Cerulean Warblers (Dendroica cerulea) at three spatial scales in eastern Ontario over three years (1997–1999). Territories were characterized by well-spaced large trees, with high canopies and dense foliage cover at heights between...
We studied the effects of catch‐and‐release angling on rock bass Ambloplites rupestris a small but common centrarchid species in North America. A field study of hooking injury and mortality was conducted in Lake Erie at a water temperature of 16°C...
A general model in thermal ecology predicts that ectotherms should stop thermoregulating when the costs outweigh the benefits. Support for this model comes from studies of warm‐temperate species, but the extent to which the model can be extrapolated to species...
We used more than 326 000 observations of temperature collected by radio telemetry from 38 individuals over three years to investigate thermoregulation and thermal relations of northern water snakes (Nerodia sipedon) near the northern limit of their distribution in...
Data from five pumpkinseed sunfish (Lepomis gibbosus) populations were used to generate age‐specific survival rates and to test the prediction of life history theory that early maturity and high annual reproductive effort are favored by low adult survival...
In this study, we examined the constraints of nestbox size on nestling growth and survival while controlling for variation in clutch size and parental quality.
Current management strategies for black bass Micropterus spp.—specifically, largemouth bass M. salmoidesand smallmouth bass M. dolomieu—sometimes incorporate regulations with closed fishing seasons during reproductive activities. Our field study investigated how well anglers were complying with Ontario's closed black...
Current management strategies for black bass Micropterus spp.—specifically, largemouth bass M. salmoides and smallmouth bass M. dolomieu—sometimes incorporate regulations with closed fishing seasons during reproductive activities. Our field study investigated how well anglers were complying with Ontario's closed black...
To determine the factors that influence a female's decision of whether or not to re-lay, we removed first clutches from 17 marked female Tree Swallows (Tachycineta bicolor) in a nest-box population in eastern Ontario, Canada. Females and nests...
The effects of temporary male absence during egg laying on the production of extra-pair young by female eastern bluebirds,Sialia sialis, were examined. Females whose mates were removed for 2 days during egg laying produced more extra-pair young than...
Damage to the shoot apex commonly causes release of lateral meristems from apical dominance in plants. This has been shown in some species to promote increased seed and/or biomass production (i.e. overcompensation) by stimulating lateral branching, primarily in plants growing...
The dogbane tiger moth, Cycnia tenera, emits ultrasonic sounds by rhythmically buckling a pair of tymbals when stimulated by pulsed sounds resembling bat echolocation. We monitored the central pattern generator governing this response by recording the motor output of the...
We assessed the frequency of extra-pair paternity (percentage of broods with a least one extra-pair young) in 25 families of tree swallows nesting in natural cavities and compared it to that in a nestbox.
Pairs of captive male brown-headed cowbirds (Molothrus ater) housed with a female formed clear dominance relationships, and when an older male was housed with a yearling male, the adult was usually dominant.
The purpose of the experiments presented here was to determine the location within the central nervous system (CNS) of the proposed tymbal central pattern generator (CPG) in Cycnia tenera. Motor neuron impulses that underlie tymbal activation were recorded extracellularly from...
We used a laboratory experiment to determine effects of a predator (other than straightforward prey consumption) and food availability, during the larval stage, on adult size, age at emergence and fecundity of Chironomus tentans.
Many fish species are protracted spawners, producing fry over a several-week breeding season. We demonstrate that this time dimension has important implications for recruitment by relating the body size and survival of yearlings to the day that they were born.
We report here an estimate of the time of day of egg laying in Eastern Bluebirds using the method developed by Scott (1993) to analyze data we collected during a study of mate guarding (Meek and Robertson 1994).
It has recently become apparent that females of many species of birds often copulate with, and produce young sired by, males other than their social mates. Understanding the adaptive significance of this behaviour requires knowing whether extra-pair matings entail any...
The life cycle of Hepatozoon sipedon sp. nov. was studied in two snake species, the Northern water snake and the Eastern garter snake, in its mosquito hosts Culex pipiens and C. territans, and in the Northern leopard frog. Gametogenesis, fertilization...
Predation risk may have a profound impact upon foraging behaviour. I studied how potential exposure to predation affected the foraging behaviour of eastern chipmunks.
This study empirically tests the prediction that the echolocation calls of gleaning insectivorous bats (short duration, high frequency, low intensity) are acoustically mismatched to the ears of noctuid moths and are less detectable than those of aerially hawking bats.
I propose that the tymbal response in modern arctiids evolved from either flight or walking CPGs and that preadaptive circuitry ancestral to tymbal movements still exists in modern silent Lepidoptera.
In an E Ontario population of northern water snakes basking activity peaked at 09:00 then declined steadily until 14:00 before increasing again. In the field, temperatures of basking snakes averaged (±SE) 26.3 ± 0.7°C, while captive snakes in a thermal...
We examined the influence of body temperature on swimming speed of northern water snakes (Nerodia sipedon) and determined how variation in water temperature influenced their escape response.
This study investigated the effect of exogenous 11-ketotestosterone (11KT) and testosterone (T), two important androgens involved in fish reproduction, as well as cyproterone acetate (CYA), an antiandrogen, on behaviors of male bluegill (Lepomis macrochirus) during prespawning and parental care periods.
Using field observations and laboratory experiments we examined the role of temperature in microhabitat selection by an eastern Ontario population of northern water snakes (Nerodia sipedon).
3-Chlorobenzoate (3Cba)-degrading bacteria were isolated from the waters and sediments of flowthrough mesocosms dosed with various concentrations of 3Cba and inoculated with a 3Cba-degrading Alcaligenes sp., strain BR60. Bacteria capable of 3Cba degradation which were distinct from BR60 were isolated...
We investigated habituation in killifish (Fundulus diaphanus) to repeated exposure of predator models of varying shades in two positions (above and below) against backgrounds of varying shades. Killifish that had habituated to a model of a given shade...
We examined the effects of variation in prey abundance on foraging site selection by juvenile bluegill sunfish, in the absence and presence of a predator. Groups of bluegills chose between two plots of artificial vegetation differing in plant stem density...
Food webs for 15 freshwater ecosystems in North America are reconstructed, based upon fish feeding habits in these ecosystems and established trophic categorizations for aquatic invertebrates. My own research in Goose Creek, Virginia, as well as literature data, provided the...
1. Most studies examining interactions between insectivorous bats and tympanate prey use the echolocation calls of aerially-feeding bats in their analyses. We examined the auditory responses of noctuid (Eurois astricta) and notodontid (Pheosia rimosa) moth to...
Radio telemetry was used to determine the time of emergence from and entry into communal hibernacula by black rat snakes (Elaphe obsoleta obsoleta) and to gain insight into the proximate factors involved in these behaviours. Emergence in mid-April...
Male parental care generally is assumed to improve survival of nestlings and increase female reproductive success (fitness). Consequently, the need for male assistance is considered by some to be responsible for the evolution of monogamy when the investment of the...
Temporal changes in the composition of the pollinator fauna of the tristylous aquatic plant Pontederia cordata were documented during the flowering seasons of 1982 and 1983. A total of 18 species of insects, mainly bumblebees, and a single species of...
This study examines the compromise between predator avoidance and foraging in bluntnose minnows, Pimephales notatus, in shoals of different sizes and at three levels of hunger: 5, 24 or 72 h of deprivation. Trials were carried out in the...
The hypothesis that naive shoal members begin to feed more quickly on a food, novel in type, location and required foraging technique, when informed group members are present was tested with bluntnose minnows (Pimephales notatus) foraging in shoals...
The simple ears of months have responded evolutionarily to the varied levels of selection pressure exerted upon them by insectivorous bats. While frequency-matched (syntonic) bats exert the primary pressure that determines where a sympatric moth's best frequency (BF) lies, there...
Shoals of 3, 5, 7, 10, 15, and 20 bluntnose minnows, Pimephales notatus, were allowed to forage in the absence and presence of a fish predator, which was separated from the shoal by a clear plexiglass partition. A typical...
Studies of brown-headed cowbirds (Molothrus ater) suggest that yearling males are as successful at acquiring mates as adult males. Our aim in this study was to determine if dominance status of males was also independent of age when...
We present data on two methods of sexing adult Tree Swallows before they develop a brood patch or cloacal protuberance. Based on measurements of 219 adults, 100% of the birds with a brown forehead (N = 85) were females. Among...
Handling time for prey of different sizes and morphological types was studied in the largemouth bass (Micropterus salmoides). Prey ranged in size from about 1/10 to 2/3 the length of the bass. Handling time increased rapidly with prey...
Whip-poor-wills (Caprimulgus vociferus) showed significantly higher levels of locomotory, vocal, and nest activity during twilight and bright moonlight than under moonless conditions. Field observations and nest record card data indicated that Caprimulgus species usually synchronize their reproductive cycle...
Studies on the ontogeny of behaviour in fish have seldom considered the adaptive significance of the order of appearance of the behaviours. Results of laboratory studies and field observations on the ontogeny of feeding, predator-avoidance, and agonistic behaviour in largemouth...
The growth and feeding behaviour of individually held underyearling largemouth bass (Micropterus salmoides) exposed to 50 μg/l pentachlorophenol (PCP) was monitored over a 7-day period which followed a 7-day acclimation period to the experimental conditions. Exposure to PCP...
Analysis of the piscivore guild in fish species-rich lake and stream systems in eastern Ontario showed the co-occurrence of three types: (1) specialists that became piscivorous at the age of a few weeks (Esox, Micropterus); (2) ‘secondary’ piscivores...
Male Nannothemis bella (Uhler) dragonflies are territorial at the breeding site. On the basis of the male behavioural time budgets, the species can be regarded as a territorial percher. Those acts involved in territorial maintenance (patrolling and fighting) are more...
The exotic macrophyte Myriophyllum spicatum spread widely in Lake Opinicon, Ontario, after 1974, dominating the 2.0- to 3.5-m depth zone which had previously been largely open water. In the shallows it formed beds within the species-rich native Potamogeton–Vallisneria...
Relatively little work has been done on the ontogeny of feeding behaviour in fish. One of the aims of this study was to compare the ontogeny of feeding behaviour in four species of centrarchid fish of diverse feeding guilds. A...
A mass encystment of Mallomonas pseudocoronata cells was observed in a polymictic lake from Southern Ontario, Canada. Scanning electron microscopy was used to describe its statospore, which is oval in shape, covered by short spines, and has a short cylindrical collar.
The effect of plant size on reproductive characteristics was examined in a natural population of Erythronium americanum Ker. The number of ovules, fertilized ovules, unfertilized ovules, aborted seeds, and seeds and the fruit weight were found to be correlated positively...
