An introduction to the ‘Big Four’ marine shorebirds in St. Johns County

For many ecological reasons, we are fortunate to live between the Atlantic Ocean beaches, the Intracoastal Waterway marshes and the St. Johns River estuarine blueway corridor.


We have some of the best aquatic (freshwater) and marine (salt water) shorebird habitat in the state, possibly in the coastal Southeast.

This area provides prime habitat for dozens of bird species, but I will focus on what I refer to as the “big four” of shorebirds — black skimmer, least tern, Wilson’s plover and American oystercatcher.

The big four, like many uncommon birds, are imperiled and protected by federal and state regulations. It’s very important for us to be aware of these birds and the habitats they use, so we can help keep their populations healthy.

During the summer, these four birds normally nest on beaches, islands in the Intracoastal Waterway, causeways and even temporary sandbars or dredge islands in our region.

Locally, in the confluence of the St. Augustine Inlet and Matanzas Bay is one such island known as Julia’s Island. It is important nesting site for the big four because it is protected from predators like domestic dogs, raccoon and fox.

However, Julia’s Island is also a popular recreation area for fishermen and boaters, who sometimes are not aware that many imperiled birds nest on the island.

Habitat loss from coastal development has reduced the number of suitable colony nesting areas for these birds. Their camouflaged eggs are laid in nests that are simple, relatively unsheltered scrapes in the sand and are very hard to see.

Fun Facts About the Big 4

1. Black skimmer has a striking plumage combination of black above and white feathers below, making them easy to spot and identify as they glide over water or relax on the beach. Black skimmers “skim” the surface of the water with black-tipped, bright red bills. The lower half of the bill is longer than the upper, allowing it to slice through the water and dip down to grab small fish encountered near the surface.

2. Least tern is the smallest tern in North America growing to only about 8 to 9 inches long. Least terns have long, pointed wings and a deeply forked tail. Other physical characteristics include a yellow beak, gray back, white belly and black cap. Preferring a natural coastal nesting site, this small tern will also build nests on flat gravel rooftops. They can also be seen over the St. Johns River. The least tern’s diet primarily consists of fish, but they will also feed on small invertebrates.

3. Wilson’s plover is named for early Scottish-American ornithologist Alexander Wilson, who first collected a specimen in May 1813. It’s stout, black bill and flesh-colored legs distinguish this species from other small plovers. They will resort to faking injury, such as a broken wing, to distract potential predators, especially from a nest or chicks. They will defend their territory with ground and aerial chases. This plover forages for food on beaches, usually by sight, moving slowly across the beach. They have a liking for crabs but will also eat insects and marine worms.

4. American oystercatcher is one of the largest and heaviest of Florida’s shorebirds. The oystercatcher is unmistakable with a striking appearance. They are dark-brown, black and white, with a bright red bill. When in flight, a diagonal white stripe in each wing forms a V-pattern. Oystercatchers get their name from their habit of snatching oysters from slightly open shells. They also use their powerful bills to open mollusks and to sort through heavy shells in search of food.

There are many organizations a volunteer citizen scientist can get involved with such as the local Audubon chapter,, Shorebird Alliance and the Florida Fish and Wildlife Conservation Commission. Bird stewardship, hands-on conservation and community outreach are all important elements provided by these organizations. The common goal of these groups is public education, and to improve the conservation status and stability of the big four as well as all imperiled bird species.

To contact Mike Adams, email