A scientist studies a species of bird. The males and females look very similar in color but the are much larger than females. What can conclude about these birds?

Sexual Dimorphism is the phenomenon where organisms of the same species have distinct differences in physical appearance. In the case of this bird species, the males are larger than the females, This is a common form of sexual dimorphism known as "size dimorphism."

The scientist can conclude that the birds exhibit size-related sexual dimorphism. This means that the males and females of the species have different average body sizes, with males being larger. This size difference may have evolved due to various reasons, including natural selection pressures related to survival, reproduction, or both.