Birds Hunting Marine Invertebrates

In structural complexity, adaptation to all sorts of environments, and development of a remarkable social organization among some, the arthropods are judged to represent the peak of evolutionary advancement attained by invertebrates.—Moore, Lalicker, and Fischer, Invertebrate Fossils (1952)

Spotted Sandpiper (non breeding) with Isopod, Surfside Jetty Park, Texas
Spotted Sandpiper (Nonbreeding) with Isopod (Sea Slater), Surfside Jetty Park, Texas. Man-Made structures like jetties provide unusual habitat for birds and marine invertebrates alike along the muddy Texas coast. At Surfside, large blocks of hard, igneous rock provide substrate for the attachment of encrusting organisms like barnacles and algae. Foraging birds take maximum advantage of this synthetic habitat and climb around picking off edibles. Canon EOS 7DII/600mm f/4L IS (+1.4x TC). Natural light.

It’s almost time to get back into one of our spring birding habits: A road trip to the Smith Oaks Rookery on High Island in the afternoon (for the best light), followed by the night in Winnie, and a trip down the Bolivar Peninsula the next morning. The highlight of Bolivar is usually Frenchtown Road, where shorebirds and waders can often be seen hunting for invertebrates, especially arthropods, on the tidal flats, in the shallow tidal channels, and from among the exposed oyster patch reefs.

Black-bellied Plover with Ghost Shrimp, Frenchtown Road, Bolivar Peninsula, Texas
Black-bellied Plover with Ghost Shrimp, near Frenchtown Road, Bolivar Peninsula, Texas. Ghost shrimp are infaunal, meaning that they live in burrows within the sediment. Canon EOS 7D/600mm f/4L IS (+1.4x TC). Natural light.

Another spring tradition is travel to Bryan Beach (or Surfside Jetty Park or Quintana Neotropical Bird Sanctuary), followed by a trip up Follett’s Island, across to Galveston Island, ending at Lafitte’s Cove. These trips have the best of both worlds, littoral marine habitats and songbird migrant traps among mighty hardwoods.

Whimbrel with Crab, Frenchtown Road, Bolivar Peninsula, Texas
Whimbrel with Crab, near Frenchtown Road, Bolivar Peninsula, Texas. Elisa caught this bird as it fished a crab from its burrow. Canon EOS 7D/500mm f/4L IS (+1.4x TC). Natural light.

This time of year reminds the birder of the fact that birds are governed by the never-ending search for food. As avian migrants follow the sun’s energy north, they are mostly following the the exploding biomass of terrestrial invertebrates, primarily arthropods. Birds lucky enough to be able the tap the perennial invertebrate bounty of the sea can overwinter along the coast. Those dependent on terrestrial and aquatic arthropods like insects must wait for the inevitable return of the summer swelter.

American Avocets among Oysters, Frenchtown Road, Bolivar Peninsula, Texas
American Avocets Hunting among Oysters, near Frenchtown Road, Bolivar Peninsula, Texas. In this marine setting, these birds are likely looking for shrimp and other small crustaceans. In a freshwater setting, they would be primarily after insects. Canon EOS 7DII/600mm f/4L IS (+1.4x TC). Natural light.

©2016 Christopher R. Cunningham and Elisa D. Lewis. All rights reserved. No text or images may be duplicated or distributed without permission.