Shoaling is an evolved behavior in fishes that has several adaptive advantages, including allowing individuals to avoid predation through risk dilution. However, factors such as size disparity and the presence of heterospecifics may influence the behavior of individual fish within...
Many populations have intraspecific diversity in phenotype and ecological strategy, but the mechanisms maintaining such diversity are not fully understood. Multiple behaviors can be maintained either as a conditional strategy, where fitness depends on an individual’s phenotype, or as a...
Chemical signalling is widespread across animal taxa. Even birds, once thought to have little or no sense of smell, are now known to possess a fully functional olfactory system and may thus respond to conspecific and heterospecific chemical signals. In...
Larger numbers of colonists can be more likely to establish and spread due to the benefits provided by either more individuals (quantity) or a greater diversity of genotypes or phenotypes (genetic diversity). However, the value of higher colonist quantity or...
The major histocompatibility complex (MHC) plays a key role in vertebrate immunity, and pathogen-mediated selection often favours certain allelic combinations. Assessing potential mates' MHC profiles may provide receivers with genetic benefits (identifying MHC-compatible mates and producing optimally diverse offspring) and/or...
Bycatch, the incidental capture of non‐target organisms, occurs in most commercial fisheries. Although immediate bycatch mortality is frequently documented in fisheries, detrimental sub‐lethal effects and potential post‐release mortality remain largely unknown despite the potential population‐level consequences. Turtles are captured as...
Bluegill sunfish (Lepomis macrochirus) are one of the classic systems for studying male alternative reproductive tactics (ARTs) in teleost fishes. In this species, there are two distinct life histories: parental and cuckolder, encompassing three reproductive tactics, parental, satellite...
According to traditional theory, success in competition between plant species generally involves a ‘size-advantage’. We predicted therefore that plants with larger body size should impose greater limits on the number of species — especially relatively small ones — that can...
Bycatch of non‐target species in commercial fishing nets can have adverse impacts on their populations. Freshwater turtle populations are particularly susceptible to increases in adult mortality, and freshwater turtles are among the most threatened vertebrates.
Localized antipredator behaviors have been observed in a wide variety of taxa. Recent work has also shown that animals that provide parental care adjust their behavior when faced with variation in offspring predation pressure. This variation in offspring predation pressure...
Proximate mediators of reproductive behaviors in vertebrates have a long history of study. In fishes, relatively few studies have focused on hormonal control of parental care, despite a comprehensive background on the general physiology of fishes, and the frequent occurrence of parental care behaviors. Studies on...
The dawn chorus of songbirds provides an ideal opportunity to study communication networks because multiple singers are within signalling range of each other, permitting eavesdropping by both males and females. Using an Acoustic Location System, we examined the dawn chorus...
The ability to discriminate among signallers and to respond to them on an individual basis provides receivers with substantial benefits. For example, discriminating among signallers allows receivers to ignore unreliable individuals or to focus their territorial defence on unfamiliar intruders...
Predation is considered one of the main costs to reproduction but is rarely examined from a physiological perspective. In particular, little is known about the influence of brood predation pressure on the physiology of parents engaged in care. Brood defense...
Theoretical models predict that individual males will increase their investment in ejaculates when there is a risk of sperm competition. Because the production of ejaculates is assumed to be energetically costly, only those males in good physical condition should be...
Two of the major stressors associated with the catch-and-release of recreationally angled fish are exercise and air exposure. This study investigated the combined effects of exercise and air exposure duration on the congeneric largemouth bass Micropterus salmoides and smallmouth bass ...
The behaviour and survival of pike, Esox lucius L., released with a retained lure in the mouth was studied relative to control fish, which simulated line breakage prior to landing. Behaviour was monitored during the first hour post‐release with the...
In dominance-structured animal societies, variation in individual fitness is often related to social status. Like many passerine birds, Black-capped Chickadees (Poecile atricapillus) have a short average adult life-expectancy (∼2 years); however, the maximum recorded life span is >5×...
The current biodiversity crisis is characterized by the decline and extinction of numerous animal populations and species world-wide. To aid in understanding the threats and causes of population decline and the assessment of endangerment status of a species, conservation scientists...
During live‐release angling tournaments in North America, fish are typically retained in livewells onboard boats during the angling day. Mortality of fish occurs at some tournaments, and wave intensities and livewell conditions may influence mortality levels. This study used two...
Remote measurement of the physiology, behaviour and energetic status of free-living animals is made possible by a variety of techniques that we refer to collectively as ‘biotelemetry’. This set of tools ranges from transmitters that send their signals to receivers...
We present behavioural data demonstrating that the little brown bat, Myotis lucifugus, and the northern long-eared bat, M. septentrionalis, can glean prey from surfaces and take prey on the wing. Our data were collected in a large outdoor flight...
Leptocerid caddisflies have a wide variety of case forms, and therefore it might seem difficult to establish behavioral homologies at the family or generic levels. We videotaped case building in representatives of 9 genera in 8 leptocerid tribes and compared...
Retene (7‐isopropyl‐1‐methylphenanthrene) is a naturally formed polycyclic aromatic hydrocarbon (PAH) that causes teratogenicity in fish larvae and induction of cytochrome P450 (CYP1A) enzymes. Retene occurs at high concentrations (≤3,300 μg/g dry wt) in surface sediments contaminated by resin acids from...
Three previous studies have disagreed on whether breeding synchrony increases nest success through reduced nest predation in Red‐winged Blackbirds (Agelaius phoeniceus) in eastern North America. We used data from an 11‐yr study of redwings in eastern Ontario, Canada...
here has been much recent interest in subtle departures from perfect symmetry in bilaterally paired morphological characters, and the extent to which such departures reflect aspects of individual quality. We used data from aviary contests involving pairs of wild-caught male...
Recent evidence suggests that in many animal taxa, males characterized by low levels of bilateral asymmetry realize a mating advantage. The mechanisms responsible are poorly understood, but there is much interest in the possibility that symmetry reflect, aspects of underlying...
Using data from a 6-year paternity study of red-winged blackbirds, I tested the hypotheses that increased nesting synchrony should either promote extra-pair mating by increasing the advantage of extra-pair mating to females, or decrease extra-pair mating by constraining males from...
Little is known about the breeding biology of the Cerulean Warbler (Dendroica cerulea), a species declining throughout much of its range. However, life history information can provide important insight into the vulnerability of a rare species to habitat disturbance. We...
Evidence of the pathogenicity of haematozoa in wild bird populations is limited, possibly because infected birds alter their behavior to avoid the costs of being parasitized. We tested this hypothesis by examining dominance relationships relative to parasite status in captive...
These results support the hypothesis that sibling relatedness influences begging behaviour in birds, and suggests that increased intensity of begging can evolve whenever female promiscuity or brood parasitism lowers the coefficient of relatedness among nestmates.
Male red-winged blackbirds (Agelaius phoeniceus) vary substantially in how much they sing. We tested whether song rate reflected the male’s quality, the quality of his territory, or his frequency of interaction with potential competitors. Song rate declined with...
We present a model and an experimental test for a nonshareable parental-investment behavior (fanning of eggs) using parental male bluegill sunfish. The model predicts that as brood size increases, nonshareable investment into the brood should increase if a parent is...
The behavioural response of juvenile bluegill sunfish (Lepomis macrochirus ) to predation risk when selecting between patches of artificial vegetation differing in food and stem density was investigated. Bluegill foraging activity was significantly affected by all three factors. Regardless...
Parental care of nestling and fledgling American robins, Turdus migratorius, was studied in eastern Ontario. There was no evidence of brood division prior to fledging but brood division was the predominant pattern after fledging. Females initiating second nests reduced...
There are large numbers of reproductively mature female tree swallows (Tachycineta bicolor) which do not breed due to limits of suitable nesting cavities. Many of these floaters are one-year-old females that have a distinctive subadult plumage. This study...
The auditory characteristics of the arctiid moth, Cycnia tenera were examined using two behavioral criteria, sound production and flight cessation. The majority of the individuals tested indicated a maximum sensitivity to frequencies between 30 and 50 kHz although there is...
A description is given of a rare soil disease, called "barren ring", which occurs in some old, deserted pastures. It is an expanding ring-shaped area of diameter up to 17 meters in which the vegetation is killed. Regeneration of normal...
Quantitative data are presented on ninhydrin-reacting substances in hydrolysates and extracts of Recent sediments, sedimentary rocks, and fossils, as determined by column chromatography. The recovery of amino acids added in small amounts to a concentrated calcium chloride solution was found...
