Recent threads have discussed how certain migrating species call and display
long before they get to their breeding grounds. Does such behavior depend on
whether they're already en route vs. still on their wintering grounds, or on
the bird's age, or some other general factors? Also, is there such a thing
as a "pack your bags, we're all gonna migrate soon" flock call for spring
and/or fall? Thanks for any info.

Janet Millenson
Potomac, MD (Montgomery County)

----------------------------------------------------------------
"Look at the birds!" -- Pascal the parrot