Birds-of-paradise are sending secret color signals invisible to human eyes, scientists say

Birds-of-paradise are even colorful in the dark, with feathers and body parts that glow a brilliant yellow-green under ultraviolet (UV) light, a new study found.

​ Birds-of-paradise are even colorful in the dark, with feathers and body parts that glow a brilliant yellow-green under ultraviolet (UV) light, a new study found. Read More Breaking News, Latest News and Videos | CNN