I took a 1 hour walk this morning at Lake Roland. Had one yellow-crowned night heron (adult) below the dam. Otherwise, it was very quiet... except for a singing white-throated sparrow! The sparrow was heard from the east side of the lake, in a swampy area about ten minutes' walk from the main entrance. It sang once, and I wondered if I was imagining things. After 10-15 minutes, it sang three more times. The bird was in an overgrown thicket, and well off the path. I chose not to go in after it. So this is a heard-only bird. I did not hear mockingbird or other mimics in the area. My guess is that this was a very early migrant- white throats are not expected until late September! Peter Lev Towson, MD