[billybobsky]

Or migratory birds even?

The fact that there are no bee corpses doesn't mean that they are leaving, it just means they are dying outside of the hive. Viruses and parasites have been known to cause behavior changes of animals as large as mice (humans are probably affected as well, we just aren't smart enough to recognize that people with epstein-barr are just a little more insane than those without).

This collapse has only been observed (this time) in commercial hives, IIRC, suggesting a contained biological cause as the last time bee hives collapsed it was the natural hives that disappeared and not the commercial ones... They are two independent populations...