We recently had a talk by Lindsay Addison, Audibon Coastal Biologist. One of the topics she covered was the influence of humans on bird habitat along the shore. Lindsay has agreed to help CFAS develop an educational web page on this topic. However, during the summer Lindsay is busy montoring bird nesting sites; so until time permits, this web page is UNDER CONSTRUCTION!.
Coastal inlets let fresh water enter into the ocean from rivers and streams, and during incoming tides these same inlets let salt water enter in the reverse direction. From a bird's point-of-view, this is like a conveyor belt serving and all-you-can-eat buffet. As a result, inlets are very important for birds; modifying coastal inlets can be detrimental to bird populations.
Terminal groins are jetties built at inlets - at the terminus of islands. Their purpose is to control the movement of sand - perhaps to keep boating channels open, or perhaps to protect shoreline dwellings. But preventing the natural movement of sand destoys habitat that is necessary for birds. See material from the North Carolina Coastal Federation
A Terminal Groin has been proposed for Rich Inlet near Wilmington. Read why NC Audubon thinks this is a bad idea