Today at Rancho San Rafael Park (Reno), I heard a Killdeer on the large lawn area. However, there was also a flock of European Starlings about, and since they can do an excellent rendition of a Killdeer call, I made sure I saw the bird before counting it.
I thought I should remind new birders who might be taking part in the Great Backyard Bird Count this weekend that, when you are in an area where starlings are common (such as along the river or in a park), an ID of a bird by sound only should be carefully considered. There was a recent discussion on the Oregon bird list, mentioning that starlings do great imitations of Ash-throated Flycatchers and Western Wood Pewees. Starlings can not only imitate many different birds, but can also imitate inanimate objects. The best imitation I ever heard was a few months ago, when I heard an "American Avocet" calling from the top of a mature cottonwood. I was so impressed with the imitation that I sat and listened for a while. It was a really perfect call.