It's so encouraging to read this thread tonight! During today's inspection, i heard a faint "quacking duck" sound coming from one of the hives. Could this have been a worker bee? Why would she have made that noise? Was it a sign of distress?
I was under the impression (apparently the misimpression) that only queens and/or virgin queens could pipe. But i was so certain there was just one queen in the hive. My husband and i inspect every two weeks, and while we saw two queen cups VERY early on in the Spring, they were never laid in and were quickly torn down. Just now, i poured over our inspection photographs to see if i might have missed any elongated peanut shaped cells (though i couldn't fathom how i might have missed something so obvious). Nothing. So i was really perplexed! Well, i still am, really.
I have so much to learn (about beekeeping, among other things) ...
PS: A Google search revealed it may be a forage-related communication, or a signal of hive disturbance (the latter of which makes perfect sense since today was the first time we sugar dusted the hives - quite an experience for us, and apparently for the bees as well).