Most men like to make themselves bigger than they are. This is also true for the frigatebird, but which colour is its heart-shaped balloon?

Explanation

Male frigatebirds have a gular pouch that is inflatable. It is hard work and can take up to 20 minutes, but then it's also a large, red, heart-shaped balloon. The male shakes his head quickly from side to side, moves his wings and calls the females so they can check him out. A female frigatebird wants to mate with the male with the largest and most shiny balloon. Whilst mating, the male places his wings over the female's eyes so she doesn't get distracted by other males with even more impressive balloons.