A metallic sheen attracts mates but warms easily, possibly making it harder to keep cool
For sunbirds, all that shimmers is piping hot.
The birds’ flashy, iridescent feathers heat up more than other types of feathers, possibly making it harder to stay cool in hot, sunny conditions.
Many studies on the thermal properties of animal color have previously focused on differences between how dark and light colors derived from pigments react to light and heat, says Svana Rogalla, a biophysicist at the Biofisika Institute in Bilbao, Spain. Less attention has been paid to how heat interacts with structural color — often vibrant, iridescent hues created by light refracting off of microscopic structures.
In the new study, Rogalla and colleagues turned to sunbirds, nectar-feeding birds typically smaller than sparrows that are native to Africa, Asia and Australia. Sunbirds have feather colors that come from a mix of sources, including pigments like fiery carotenoids and dark melanin as well as iridescent structural color.
For sunbirds, all that shimmers is piping hot.
The birds’ flashy, iridescent feathers heat up more than other types of feathers, possibly making it harder to stay cool in hot, sunny conditions.
Many studies on the thermal properties of animal color have previously focused on differences between how dark and light colors derived from pigments react to light and heat, says Svana Rogalla, a biophysicist at the Biofisika Institute in Bilbao, Spain. Less attention has been paid to how heat interacts with structural color — often vibrant, iridescent hues created by light refracting off of microscopic structures.
In the new study, Rogalla and colleagues turned to sunbirds, nectar-feeding birds typically smaller than sparrows that are native to Africa, Asia and Australia. Sunbirds have feather colors that come from a mix of sources, including pigments like fiery carotenoids and dark melanin as well as iridescent structural color.
