Phantom rivers filter birds and bats by acoustic niche.

Natural sensory environments, despite strong potential for structuring systems, have been neglected in ecological theory. Here, we test the hypothesis that intense natural acoustic environments shape animal distributions and behavior by broadcasting whitewater river noise in montane riparian zones for two summers. Additionally, we use spectrally-altered river noise to explicitly test the effects of masking as a mechanism driving patterns. Using data from abundance and activity surveys across 60 locations, over two full breeding seasons, we find that both birds and bats avoid areas with high sound levels, while birds avoid frequencies that overlap with birdsong, and bats avoid higher frequencies more generally. We place 720 clay caterpillars in willows, and find that intense sound levels decrease foraging behavior in birds. For bats, we deploy foraging tests across 144 nights, consisting of robotic insect-wing mimics, and speakers broadcasting bat prey sounds, and find that bats appear to switch hunting strategies from passive listening to aerial hawking as sound levels increase. Natural acoustic environments are an underappreciated niche axis, a conclusion that serves to escalate the urgency of mitigating human-created noise.

Patterns of gender-role behaviour in children attending traditional and non-traditional day-care centres.

Using a sex-typed free-play task and the Draw-a-Person test, the gender-role behaviour of children attending a day-care centre whose staff adhered to a "non-sexist" child-rearing philosophy was compared to the gender-role behaviour of children attending a more traditional day-care center. Parental provision of sex-typed and neutral toys and approval of cross-sex role behaviour was also assessed. On both measures, the two groups of children showed culturally typical patterns of gender-role behaviour. The parents of the two groups of children were generally similar in terms of the kinds of toys they provided and in their attitudes toward the expression of cross-sex role behaviour. Potential explanations for the inability to demonstrate effects of the "non-sexist" child-rearing philosophy were discussed.