FIELD NOTES: Seen by Claire and Mary Curry in Greenwood, Texas on October 23, 2001.  On November 3, we asked David Sibley and he confirmed that it was either Henslow's, Vesper, or Savannah sparrow from just looking at the photos below.  The very flat head (see sketch) rules out both Vesper and Savannah Sparrows.  This is a very rare bird for this area (see Birds of North-Central Texas, by Warren Pulich.)