The males of species that form long-lasting pair-bonds, like many birds, often continue to make elaborate displays of plumage, colors and dances after they mate with a female. While their time and energy might be better spent taking care of their offspring, these displays also encourage the female to invest more of their energy into the brood.
Click here for original story, Investing in love and affection pays off for species that mate for life
Source: Phys.org