Tweets,

The definitions of Neotropical migrant that has surfaced on Tweeters this
week seems to be based on political boundaries if I read them correctly. If
a breeding species from north of Mexico ("North America") migrates south to
Mexico or farther south, then we're calling it a Neotropical migrant.

However, for those who have been south of the US/Mexico border know, the
temperate zone extends well south into tropical latitudes. Many, many North
American breeding species (especially sparrows, longspurs...) do indeed
spend the winter in Mexico, but not in the tropical zone at low elevations
but, rather in the temperate zone at high elevations (>1,000 m) on the
Mexican plateau. Are these Neotropical migrants? I haven't seen this issue
raised, or, if it has been resolved, I've missed discussion on it.

Besides sparrows and longspurs, a good number of warblers never or rarely
visit the true tropical zone, though they may winter as far south as
Central America. Of western North American warblers, Townsend's, Hermit,
Yellow-rumped, Black-throated Gray are rare or absent below temperate zone
habitats, though most winter well within the Neotropics in terms of
latitude. The same goes for flycatchers like Dusky, Gray and Hammond's.

Orioles and tanagers are true Neotropical migrants, along with a bunch of
species like swallows, other vireos and warblers, etc.

A good exercise in becoming acquainted with the wintering distribution and
habitats of "our" birds is to sift through Howell and Webb's "A Guide to
the Birds of Mexico and northern Central America." Fair to excellent maps
for most North American species are presented along with discussion on
habitats each species favors while south of the border.

Andy Stepniewski
Wapato WA