Large-scale sampling of potential breeding sites in male ruffs.

The traditional narrative of the life cycle of migratory birds is that individuals perform long-distance movements between a breeding and a wintering site, but are largely resident at those sites. Although this pattern may apply to socially monogamous species with biparental care, in polygamous systems, the sex that only provides gametes may benefit from continuing to move and sample several potential breeding sites during a single breeding season. Such behaviour would blur the distinction between migration and breeding.

What drives our aesthetic attraction to birds?

In the Anthropocene, the era when the imprint of humans on nature is pervasive across the planet, it is of utmost importance to understand human relationships with other species. The aesthetics of nature, and of species, is one of the values that plays a role in shaping human-nature relationships. Birds are ubiquitous across the world.

Semelparous marsupials reduce sleep for sex.

Sleep is a prominent, seemingly universal animal behavior. Although sleep maintains optimal waking performance, the biological drive to sleep may be incompatible with the life history of some species. In a multi-year study on semelparous marsupials in Australia, we provide the first direct evidence of ecological sleep restriction in a terrestrial mammal.

Mutual mate guarding with limited sexual conflict in a sex-role-reversed shorebird.

Mate guarding is typically considered a male strategy to protect paternity. However, under some circumstances, females might also benefit from guarding their mate. Female mate guarding might be particularly important in socially polyandrous species in which females compete for access to care-giving males.

Sexual selection for extreme physical performance in a polygynous bird is associated with exceptional sex differences in oxygen carrying capacity.

In many animals, males compete for access to fertile females. The resulting sexual selection leads to sex differences in morphology and behaviour, but may also have consequences for physiology. Pectoral sandpipers are an arctic-breeding polygynous shorebird in which males perform elaborate displays around-the-clock and move over long distances to sample potential breeding sites, implying the need for physiological adaptations to cope with extreme endurance.