A recent study (“Evolution of sexual cooperation from sexual conflict”)* seeks to explain what evolutionary mechanisms may be behind mate fidelity and the long-lasting pair-bonds of some animals. While the research mentions songbird examples such as zebra finches, many raptors, such as Southern California’s local Bald & Golden eagles, are known to invest in long-lasting pair-bonds as well.
“In contrast to theories of sexual selection that predict males have the most to gain by seeking out as many mates as possible, evolutionary explanations for the opposite kinds of behavior—loyalty to one mate, teamwork and private displays between pairs—have been harder to explain. The new paper shows how these behaviors often inevitably evolve in species that form pair bonds.”
View the full article here:
https://news.uchicago.edu/story/investing-love-and-affection-pays-species-mate-life
*Servedio, M. R., Powers, J. M., Lande, R., & Price, T. D. (2019). Evolution of sexual cooperation from sexual conflict. Proceedings of the National Academy of Sciences, 116(46), 23225-23231.