Warbler Guy, how do I know if warbler migration is strong? Migrating warblers are more dense on some spring days than other ones?

Fine question, Caren (in Austin).

I often use online radar to note spring migration trends.

One that is good: Birdcast

See:

http://birdcast.info/forecast/24-april-1-may-2015-forecast-and-thats-a-cold-shot-baby/

At this link, you'll read about the current week's presence of migrators and predictions.

It is a great resource, given the BirdCast forecast highlights migrant species that you can expect to see in each of several regions: Upper Midwest and Northeast; Gulf Coast and Southeast; Great Plains; and West.