Warbler migration and diversity

Greetings,
Warbler report in Mexico...
We recently had an outing of our Veracruz birding club in the southern part of the state, in the Catemaco/Los Tuxtlas area. Although the peak warbler migration has passed, we still had many lovely Chestnut-sided Warblers, a few male Bay-breasted Warblers, several Black-and-White Warblers, lingering Yellows and Wilson's, and other migrants such as 2 or 3 male Scarlet Tanagers (a transient and not common here), and many Empidonax sp. flycatchers. This is now the peak of the Empidonax migration.

This brings up a question: Where is the highest diversity of warbler species found?

For many years I have been curious if anyone has the number of species we have here in Central Veracruz. I once counted warbler species for what we call Central Veracruz (found in eastern Mexico), and I came up with a list of 53 species of warbler. We generally define central Veracruz as a narrow east-west swath from the Gulf of Mexico coast (near Veracruz City) up into the Sierra Madre Oriental  (near Xalapa), from sea level to over 2,000 meters (over 7,000 feet), and about 100 km (60 miles long). Obviously this includes several habitat types, but it also includes eastern NA migrant species as well as western species, sometimes in the same flock (39 of the species are true migrants), in addition to resident species, many endemic to Mexico. I compared our 53 species with the Yucatan Peninsula's 38 species, all of Mexico's 66 species, Costa Rica's 52 species, and North America's (US and Canada) 46 species (correct me if I am wrong with any numbers,
 please).

Anyone else have numbers they wish to share? It will be difficult to compare lists within our various defined areas, but we could include geographic and political areas, for example a state's list, a region of a state or country, a park, etc.

Regards,
Robert Straub
Xalapa, Veracruz, Mexico
straub_robert@...

P.S. I came up with this warbler list for a small article of mine "The Amazing Birds of Central Veracruz, Especially the Warblers!"

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