New World wood-warblers {that are not closely related to the various Old World warblers in the Eastern Hemisphere (e.g., Europe, Asia)} are often identified to number as 112-115 species, occurring among 24-26 genera. The centers (or “epicenters”) of their breeding areas occur in eastern North America, the West Indies, Mexico and Central America, and Andean South America.

The majority of northern-latitude breeding species migrate, but many island and tropical species are sedentary. Many of these latter species remain close to their birthing areas or perform short-distance, post-breeding altitudinal/elevation migrations. As for myself, I often see 20-30 wood-warbler species during early May when I return to homecoming birding forays in the Midwest (and, concurrently, attend the annual Wisconsin Society For Ornithology conference).

Last year, for example, I was lucky to visit Wisconsin to attend the conference during the peak of neotropical songbird migration, so I tallied more than 25 wood-warbler species. Then, when I returned in August, I began seeing southbound migrants in the northern portion of the state. Milwaukee County (in s. WI) was nearly devoid of warbler detections, except for probable nesting species such as American Redstart and Yellow Warbler.

In contrast, my n. CA residency, yields more warbler species during the breeding season — a result that surprises many people because the West is thought to host far fewer warbler species. For example, in Marin County (Bay Area) where I live, I often detect at least eight warbler species annually and, in the Sierra Nevada Mountains (near Yuba Pass and/or amid the Gold Lakes country off of Highway 49 near Bassetts), I sometimes successfully sleuth out nine warbler species.