In fickle environments where capricious weather—erratic rainfall and fluctuating temperatures—made food sources iffy, mockingbirds not only had a bigger repertoire but were better at copying the songs and calls of other species, with truer notes and more consistency. Perhaps a male’s singing skills signal to females that he’s clever enough to cope with unpredictable environments, says Botero. This adds weight to the idea that some aspects of birdsong may provide information about a male bird’s general cognitive skill—and that sexual selection is acting on these signals of intelligence.
