Spring migration begins in April
By DON MORROW
Around half of St. Marks National Wildlife Refuge’s Spring migrants pass through in April, when about 5-million warblers, thrushes, tanagers, vireos, swallows, and sandpipers cross the refuge, mostly at night. Migration proceeds in fits and starts. Birds are moving every night, but most of April’s migrants will fly on a half dozen nights during the month, on some of which, up to a half million birds will cross the refuge. A small percentage of these birds will drop in to rest, delighting local birders with views of almost fifty species that occur here only in migration.
These migrant birds lead lives that span continents. Their brief presence here ties us to places far distant from the refuge. In April, we may see Rose-breasted Grosbeaks that wintered in Central America headed to the slopes of the Appalachian Mountains in Virginia, Blackpoll Warblers from the Amazonian jungles of Brazil headed to the boreal forests of Yukon Territory, or Pectoral Sandpipers that spent the winter in Uruguay headed to coastal tundra along the shores of the Beaufort Sea. Protected lands like St. Marks are critically important migration stopover sites for these birds.
By the time April begins, leaf out is complete and the hammock forest near the Double Bridges is painted in shades of green. It’s a good place to look for newly-returned Great-crested Flycatchers, Red-eyed Vireos, Yellow-throated Vireos, Northern Parulas and Prothonotary Warblers.
There are still a few leftover ducks. Blue-winged Teal continue to move through and April sees a pulse of late Northern Shovelers, likely birds that wintered in Cuba or Hispaniola. The Common Loons that wintered on the Gulf finish moving early in the month. They’ll make several hops on their way to the Northwoods.
Shorebirds are on the move too. Our summer-breeding Willets have begun to return. They are similar enough to the winter Willets that, except for a seasonal increase in Willet numbers, their arrival can be hard to discern. Our winter Willets will soon begin to leave for the Canadian Prairies where they breed.
April is the time to begin watching for the uncommon migrant shorebirds; American Golden Plover and Wilson’s Phalarope, along with Pectoral, White-rumped, Solitary, and Stilt Sandpipers. All of these birds are making long, continent-hopping journeys.
A lot happens at the refuge this month. Listen for the dull roar of bull gators echoing across Headquarters Pond in late morning, as gator courtship season begins. Watch there for newly hatched Common Gallinules, small black fuzzballs following their parents.
April at St. Marks is the month with the highest avian diversity, when over two hundred species may be recorded at the refuge; an eclectic mix of leftover winter birds, newly-arrived summer breeders, year-round residents, and transmigrants.
There are April days at St. Marks when the stars and the weather align and the woods are suddenly full of colorful migrants. It’s like a love affair when you’re young; sudden, exciting, and too soon over.
Don Morrow can be reached at donaldcmorrow@gmail.com.