Along the CA and AZ southern borders, the whitewings head south into Mexico as the weather changes in the fall. The early departures seem to be related more to rain (monsoon season in Yuma can be spectacular) than to temps. If we get a big storm with temps still over 100F, the whitewings are gone. The mourning doves hang around longer and are usually still abundant in November and December, but they flock up because they are migratory. I'm pretty sure the doves remember fields from year to year because they live a long time if predators or hunters don't get them. I think I read that the oldest dove in captivity lasted something like 24 years. The farmers in the Imperial Valley and around Yuma who plant small plots specifically for doves seem to favor milo.
PS: from
http://www.ehow.com/info_8374317_long-life-span-mourning-dove.html"The average lifespan of a mourning dove is approximately a year and a half. According to the Wild Bird Watching website, mourning doves in their first year of life have a mortality rate of up to 75 percent, while adult mourning doves have a mortality rate of up to 60 percent. Following the survival of the first year, which is the hardest, mourning doves can live up to five years. The All About Birds website states that
the oldest known mourning dove lived to be more than 31 years old."
