closed today, thur and fri; "chirping", swallow spectacle

We are closed today (wed), tomorrow and friday. There are still some hummingbirds around and we might open at the weekend if the conditions are favorable.
Many of you (but not I) have heard the "chirping" sound that hummers use to communicate with each other (often to say "get out of my flowers"). Note that I say "sound" not "noise": someone recently asked me about the noises they make, and I replied that only humans make noise, and birds make sounds. The chirping is rather high frequency, so I cannot hear it. On this link (at the very useful website of NY Stare bird song recordings made by my Stony Brook  University colleague Tony Phillips) you can listen to the chirping (but again I can barely hear it). A much louder sound is recorded here:

http://macaulaylibrary.org/search?taxon=Trochilidae&taxon_rank_id=55&taxon_id=12022457&tab=audio-list&page=2

So I don't know what to beleive: my ears or my lying eyes.

Yesterday evening between 6 and 7 there were thousands of swallows mostly moving west (though a few were circling, or going briefly east), and all seemed to be catching insects as they flew). The were over the bluff and slightly over the Sound, both above and belwo me. They did not have forked tails so were not barn swallows, and were probably tree or cliff swallows. Over a 1 hour period I sat mesmerized by the spectacle; tens of thousands must have passed over that period.

Today's photo is by Linda Sullivan. The hummer is feeding at rosebay sage.