Something you don't hear every day

While doing this morning's bird observations and putting the seedings out for the day (they're hardening off nicely), I heard the usual twitterings and chippings of warblers and goldfinches at the feeders and starlings trilling and chittering from the phone lines.

Then I heard a wolf whistle. Twice. Then three and four times. Then the wolf whistle was interrupted by starling noises. Then more wolf whistling. And a pretty good imitation of the lesser goldfinches. And more starling chitters.

I wonder if they think they're clever.