For decades, ornithologists have debated the primary evolutionary purpose behind the complex, energetic songs of male songbirds during the spring breeding season. A traditional hypothesis suggests that these vocalizations function primarily as territorial defense mechanisms, warning rival males to stay away from established nesting sites. However, a recent study focusing on the behavioral patterns of the northern mockingbird (Mimus polyglottos) challenges this long-held assumption. Researchers tracked male mockingbirds upon their arrival at breeding grounds, noting that their singing frequency and acoustic variation peaked significantly prior to the arrival of females. Crucially, immediately after a male successfully paired with a female, his singing rate plummeted by over eighty percent, remaining minimal for the rest of the season. Based on this dramatic post-pairing decline, the study's authors concluded that the primary function of the mockingbird's elaborate spring song is to attract mates rather than to defend territory.
Based on the passage, the researchers' conclusion that the primary function of the mockingbird's spring song is to attract mates rather than to defend territory depends on which of the following unstated assumptions?
- AFemale mockingbirds choose mates based solely on the complexity and variation of the songs they hear.
- BMale mockingbirds sing with the greatest frequency and variation before the females arrive at the breeding grounds.
- The necessity of defending territory against rival males does not drop significantly after a male mockingbird pairs with a female.Cevap
- DRival male mockingbirds only attempt to invade established territories before nesting pairs are formed.