Evolution of Monogamy
Genuine love and affection between a mating pair of animals is a behavior that occurs very rarely in nature. For a long time, humans believed they were the only creatures on Earth capable of experiencing love. Biologically speaking, monogamous behavior can only hold back the evolution of a species, limiting the abundance and diversity of the offspring. What do birds stand to gain by falling in love with one another?
Many ornithologists believe that monogamy in birds evolved in response to the needs of their offspring. Being a bird parent is such a demanding job, it literally takes two to do it. One bird would have such a difficult time keeping her eggs warm, keeping herself fed, and keeping an eye out for predators all at the same time… she’d never get any sleep.
Birds take shifts incubating eggs, gathering food, and keeping watch to make the job go smoother. Within most species of large, predator birds, the female stays with the nest during the whole of incubation while the male gathers food for the both of them. In many species of songbirds, the male takes his turn at the nest approximately every twelve hours, giving the female a chance to stretch her wings.
Hungry baby birds are very vocal about their needs, and can’t be left alone for very long. It takes two parents to gather food and supplies and keep new babies warm and safe from predators without neglecting their own needs in the process.
Regardless of the reasoning behind it, bird behavior is very different from many other animal species in how they interact with each other and with their young. Birds live to love and many form strong, life-long unions with their partners even after mating season has come and gone.