Final answer:
Female house finches prefer brightly colored males as it signifies health and potential for good parental care. The bright plumage can indicate an energy surplus, which could mean the male is capable of aiding with the offspring. Sexual selection, seen in studies like Endler's work on guppies, shows that females often choose more colorful males.
Step-by-step explanation:
Female house finches tend to choose brightly colored males as mates because this feature can be an indicator of the male's health and fitness for parental care. Bright plumage can suggest that the male has an excess energy budget, which, according to some hypotheses, could indicate the potential for participation in parental care. However, it is also suggested that the expenditure of energy on elaborate courtship displays could preclude a male from assisting with parental care. The reproductive strategies of birds can vary widely; some species with males who perform courtship rituals might not assist in parental care, whereas in others, the presence of colorful plumage implies that the male has the energy available to assist with the offspring. In the case of the peacock, a male's large and bright tail is deemed attractive by females as it signifies good health, which in turn implies that he could produce healthy offspring. Meanwhile, a study by Endler on guppies suggested that sexual selection favors brighter coloration in environments with less predation, as females prefer more vividly colored males.