The blue-footed boobies' red blowing sac is important, as it is used to display the bird's health and fitness. A male with a brighter and redder sac is considered healthier, making them more attractive to potential mates. By inflating and deflating his sac during the mating dance, the male tries to attract the female's attention. The brighter and redder the sac, the higher the likelihood that the female will choose the male as a mate. Show more