I took a walk across Central Park Wednesday morning. Spring migration is in full swing, and in the hundred yards or so from Azalea Pond to Laupot Bridge in the Ramble I saw, among other birds, two Louisiana Waterthrushes, a bunch of Ruby-Crowned Kinglets, a Swamp Sparrow, a very dapper Yellow-Bellied Sapsucker stepping out, and a Palm Warbler.