In boreal owls, the level of investment provided by the male is directly related to the level of parental care effort in brooding by the female.Zárybnická, M., & Vojar, J. (2013). Effect of male provisioning on the parental behavior of female Boreal Owls Aegolius funereus. Zoological Studies, 52(1), 36. Increased resources (i.e. food) provided by the male during the nesting stage increases female effort in brooding of the offspring. This is similar to the differential allocation hypothesis, which suggests that females increase their reproductive effort overall when offspring are the result of ideal mates. Brooding behavior is key to the success of owl fledglings, so when males provide adequate food, females provide adequate care.Sheldon, B. C. (2000). Differential allocation: tests, mechanisms and implications. Trends in Ecology & Evolution, 15(10), 397-402. Fewer or lighter individual fledglings are produced as polygamy rate increases and the amount of male effort becomes increasingly important in predicting female brooding effort.Korpimäki, E. (1991). Poor reproductive success of polygynously mated female Tengmalm's owls: are better options available?. Animal Behaviour, 41(1), 37-47.
