题目选项分析

Unable to build nests or care for their young, female cowbirds lay up to 40 eggs a year in the nests of other birds, including warblers, vireos, flycatchers, and thrushes.

Unable to build nests or care for their young, female cowbirds use the nests of other birds to lay up to 40 eggs a year, including those of warblers, vireos, flycatchers, and thrushes.