Fitness is at the core of evolutionary theory, but it is difficult to measure accurately. One way
to measure long-term fitness is by calculating the individual's reproductive value, which …

Evolutionary theory predicts that females seek extra‐pair fertilizations from high‐quality
males. In socially monogamous bird species, it is often old males that are most successful in …

The question of why females engage in extra-pair behaviors is long-standing in evolutionary
biology. One suggestion is that these behaviors are maintained through pleiotropic effects …

Few empirical studies have quantified relationships between changing weather and
migratory songbirds, but such studies are vital in a time of rapid climate change. Climate …

Animal sociality, an individual's propensity to associate with others, has fitness
consequences through mate choice, for example, directly, by increasing the pool of …

Mist netting is the most commonly used method for catching birds for scientific ringing, but
despite decades of use, there have been few attempts to quantify the associated potential …

Human‐induced biological invasions are common worldwide and often have negative
impacts on wildlife and human societies. Several studies have shown evidence for selection …

The question of why socially monogamous females engage in extra‐pair behaviour is long‐
standing in evolutionary biology. Due to a lack of empirical support among passerine birds …

In species with biparental care, behavioral coordination in the provisioning of the progeny is
hypothesized to increase the number of offspring that survive to independence …

Highlights•Within years, male house sparrows invested in social or extrapair offspring, or
both.•Within a year, reproductive strategy depended on the environmental context.•Males …