I don't think they communicate in any way with respect to migration. Lots of birds migrate in flocks, but hummingbirds are solitary. They are driven forward by hormonal urges, which I assume are connected with things like day length, food availability, weather, etc.

The longest known lifespan of a wild Ruby-throated hummingbird according to my friends at Powdermill (a banding station east of here) is 5 years for a male, and 9 years for a female. Mortality is higher in males, presumably because they take more chances by migrating earlier in the spring, and also because they expend a lot of energy establishing a territory and fighting with other males. Mortality is high for all hummingbirds, of both sexes,and easily half don't even survive their first migration.

When I worked in an aviary, some years ago, seems to me we had a Costa's hummingbird that lived into its teens. I can't remember for sure, but I know it was a very old bird. Birds in general are much longer lived than mammals of equivalent size. So, even though they have high metabolisms, hummingbirds can live way longer than tiny mammals like shrews, which I don't think live longer than a year or two!