OK, so there's still a possibility it could snow again, but spring is officially here and the birds know it.  After a long, cold, snowy winter, it is welcome relief to hear American Robins and Northern Cardinals singing from almost anywhere in Central Iowa in the morning.  Eastern Meadowlarks are claiming their territories in the prairies, and Red-winged Blackbirds are spread out along the highways.  Turkey Vultures are being seen, there are reports of Eastern Phoebes and Tree Swallows arriving, and waterfowl have been migrating through for a few weeks.  From now through early June there will be new species coming through weekly.  Some will be returning to nest in Iowa, while others continue on to breed north of us.  A few species, such as American Tree Sparrows, Lapland Longspurs, Snow Buntings, and Northern Saw-whet Owls, actually choose to winter here in Iowa and will be returning north to nest, so we will soon bid them farewell.  Resident species are thinking about nesting.  Cavity nesters like woodpeckers, chickadees, and nuthatches can get an earlier start due to the extra protection they get from the weather in their sturdy nest sites.  Tough birds like Bald Eagles and Great Horned Owls begin nesting in the dead of winter and are fully involved in nesting now.  Spring doesn't last, so get out there and experience it throughout the season!