Answer:
The two forms interbreed often in nature, and their offspring have good survival and reproduction.
Explanation:
Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. The two forms interbreed often in nature, and their offspring have good survival and reproduction would be cause for this reclassification of the myrtle warbler and Audubon's warbler
