Considered to be one of the most attractive are the blue eggs laid by birds. Why do birds lay blue eggs? Well, the blue color has biliverdin to thank for that. Biliverdin is a bile pigment that ...

Eastern Bluebird: Similar to the American Robin, Eastern Bluebirds lay bright blue eggs that are quite striking. Bowerbird: Males of this species collect colorful objects to attract females, and their ...