Jan J Wijmenga

• Master of Science
• Technician at University of Alberta

The timing and amount of foraging in birds are shaped by many of the same extrinsic factors, including temperature and daylength, as well as intrinsic factors, such as sex and age. Here, we investigate co-variation between these traits. We observed a population of 143 individually marked black-capped chickadees (Poecile atricapillus) over a 90 day...

Spatial ecology tends to focus on average movement patterns within animal groups; however, recent studies highlight the value of considering movement decisions both within and among individuals. We used a marked population of black-capped chickadees (Poecile atricapillus), to assess the causes and consequences of within- and among-individual differ...

Historically, spatial ecology studies have focused on average movement patterns within animal groups; however, recent studies highlight the value of considering movement decisions both within- and among-individuals. Using a marked population of black-capped chickadees (Poecile atricapillus), we used the number of unique feeders an individual visits...

Sampling, investing time or energy to learn about the environment, allows organisms to track changes in resource distribution and quality. The use of sampling is predicted to change as a function of energy expenditure, food availability, and starvation risk, all of which can vary both within and among individuals. We studied sampling behavior in a...

Within species, individuals often show repeatable differences in behaviours, called ‘animal personality’. One behaviour that has been widely studied is how quickly an individual resumes feeding after a disturbance, referred to as boldness or risk-taking. Depending on the mechanism(s) shaping risk-taking behaviour, risk-taking could be positively, n...

Foragers rely on various cues to assess predation risk. Information theory predicts that high certainty cues should be valued more than low certainty cues. We measured the latency of black-capped chickadees (Poecile atricapillus) to resume feeding during winter in response to cues that conferred different degrees of certainty about current predatio...

Parental provisioning behavior is a major determinant of offspring growth and survival, but high provisioning rates might come at the cost of increased predation threat. Parents should thus adjust provisioning activity according to current predation threat levels. Moreover, life-history theory predicts that response to predation threat should be co...

Males of socially monogamous species can increase their siring success via within-pair and extra-pair fertilizations. In this study, we focused on the different sources of (co)variation between these siring routes, and asked how each contributes to total siring success. We quantified the fertilization routes to siring success, as well as behaviors...

A number of studies have suggested that avian brood size is individually optimized. Yet, optimal reproductive decisions likely vary owing to among-individual differences in environmental sensitivity. Specifically, 'proactive' individuals who do not track environmental changes may be less able to produce optimal brood sizes than 'reactive' individua...

Sampling bias is a key issue to consider when designing studies to address biological questions and its importance has been widely discussed in the literature. However, some forms of bias remain underestimated. We investigated the roosting decisions of free-living great tits utilizing nest-boxes in response to the installation of a novel object (a...

Seasonal bird migration involves long flights, but most time is actually spent at intermediate staging areas. The duration of stay at these sites can be evaluated with mark—recapture methods that employ day-to-day local encounters of individually marked birds. Estimates of staging duration are based on two probabilities: the immigration probability...

Seasonal bird migration involves long flights, but most time is actually spent at intermediate staging areas. The duration of stay at these sites can be evaluated with mark–recapture methods that employ day-to-day local encounters of individually marked birds. Estimates of staging duration are based on two probabilities: the immigration probability...

The importance of extrapair paternity (EPP) as an aspect of mixed reproductive strategies is currently the focus of many studies. Since females have at least some control over the occurrence of inseminations, they are expected to engage in extrapair copulations only if they benefit, for instance through gaining high-quality or compatible genes for...

In most migrant birds, young perform their first migration independently of adults. The presumed dearth of learning opportunities has been linked to a lack of fast adaptive change in migration routes. Here we describe the first example of an adaptive route change within a generation of a migratory bird. Ruffs (Philomachus pugnax) migrating from Wes...