How do birds use their colors and songs to communicate?

Kara Belinsky is a recent PhD graduate in OEB who studies the way birds communicate using their colors and songs. The type of birds she studies are tiny birds called chestnut-sided warblers. These birds are called "chestnut-sided" because they have reddish stripes on their sides. They're called warblers because they sing pretty, warbling, whistle-like songs. Biologists hypothesize that birds use their songs and their colors to attract mates and to defend their territories against other birds, but they don't know exactly how they do this. Kara watches wild chestnut-sided warblers to see which birds attract mates (and raise baby birds) and which birds win fights over territories. To do this, she catches the birds in nets and measures the color of each bird's feathers, then lets them go and records the songs that they sing. Then she compares the color and singing of each bird with how many babies they raise and how well they compete in fights.