As people flock to the shore to live, work, and recreate, coastal birds are exposed to different types and increasing amounts of human disturbance.  Colonially-nesting birds, such as gulls, terns and skimmers, have been forced to nest on saltmarsh islands because many of the suitable sandy beaches are either used by people or exposed to predators that have followed people to the barrier islands.   Barnegat Bay has more than 200 saltmarsh islands, but only a few are suitable for nesting: most are so low that either they flood during storm tides, or they are so high that they can harbor rats, foxes and other predators.  The birds thus have a very narrow range of islands that they can use for nesting.  Recently there has been an increase in the number of personal watercraft (PWC) on Barnegat Bay, and many operators of them are unaware of the effect of PWCs on birds nesting on salt marsh islands. While the birds can cope to some extent with flood tides and predators, they do not need the added stress of increased human disturbance which PWCs bring close to their shores.

I have been studying nesting gulls, terns, and skimmers on Barnegat Bay since 1976, and have noticed a decline in the reproductive success of some species, notably Common Terns, nesting in areas with increased PWC activity.  In 1997 I studied the effect of all boats (including PWCs) on nesting terns in Little Mike's Island in Barnegat Bay. We recorded the type, speed and location (distance from the nesting island, location around the island), and the resulting altered behavior of the terns. Speed was noted as slow (no wake), moderately fast, or racing. We sat on a nearby dock, and watched the boats and the birds through binoculars. The channel between little Mike's Island and the barrier island is posted as a "No Wake" zone.

Both motor boat and PWC activity in the vicinity of the tern nesting island was highest around midday, and again in the late afternoon and early evening.  Motor boats were restricted to the channel, while some PWC's traveled all around the island, often passing very close to or even over its shores.

 Most motor boats followed maritime law and passed slowly through the appropriate channel.  Less than 8% of the PWCs however, moved slowly.  The rest either ran fast of raced through the channel.

Common Terns nest densely on Little Mike's Island, and when disturbed, nearby birds fly into the air and circle over the colony.  Since the island is small, and hundreds of pairs nest on the island, when a few fly up from the nest,  they are joined by the others. This pattern allowed us to examine disturbances by counting the number of birds flying above the colony during and immediately after the passage of a boat.

The Common Terns altered their behavior as a result of the type of boat,  location of a boat, and the speed of the boat.  Significantly more birds flew up from their nests when a PWC went by than when a motor boat went by,   and more terns flew up when the PWC went close to the island than when when they were in the boat channel. Boats that raced elicited the strongest response, as did boats that were outside of the regular boat channel.

 There are several problems when birds are constantly disturbed,   and leave their nests: the eggs and chicks can be knocked out of the nest, eggs or chicks that are not incubated or covered can be exposed to predators such as Herring Gulls that swoop down and eat them.  On very hot days it takes only a few minutes for the searing sun to kill delicate embryos or chicks that are too young to find shade. All of these problems result in lowered reproductive success for the terns, and ultimately, lower  populations of terns on Barnegat Bay.

In most cases the problems caused by PWCs are a result of people being unaware of the dire consequences of their behavior. Many of these problems can be reduced by PWCs slowing down whenever they pass an island with nesting birds of when they are in a "No Wake" zone, and by staying 100 feet from the edge of a nesting island whenever it is possible. Birds readily adapt to boats moving through an established channel as long as they move slowly and quietly. Nesting birds can coexist on Barnegat Bay with many different types of boats, as long as we learn to avoid moving quickly, loudly, or too close to their nesting islands.