Royal Terns are found only on isolated beaches of small barrier islands and sandbars

Seabirds Attracted to Louisiana Coast

Their Habitats Are Affected by Forces of Nature and Man

By Dr. Jenneke M. Visser
Photographs by C. C. Lockwood

The Louisiana coast is used extensively by a variety of seabirds, ranging from the majestic Brown Pelican the state bird - to the tiny Least Tern.

A significant percentage of the U.S. population of many seabird species breeds along the Louisiana coast. The same nesting sites tend to be used year after year by some species, while shifts in colony sites are not unusual for others.

The habitats favored by seabirds in Louisiana can be divided into marsh islands, barrier islands, sandbars, and beach sites.

"Seabirds are seriously threatened by the continued erosion of the Louisiana coast."

Forster's Terns are restricted to marsh islands. The colonies in marsh habitat are generally small -- two to 500 nesting adults -- and the habitat usually consists of small islands on the edge of large bays. In such locations, there is an accumulation of wrack, or dead vegetation, such as oyster grass.

These islands are unstable because of their susceptibility to over-wash during storms and erosion due to wave action. However, they protect the birds from being preyed upon by raccoon and mink and are, therefore, preferred over similar areas connected to the mainland.

The Brown Pelican and Laughing Gull use both marsh and barrier islands. Three species of tern -- Royal, Caspian, and Sandwich -- are found only on isolated beaches of small barrier islands and sandbars, where the birds are protected from disturbance by humans and predators.

A stunning photo reveals Royal and Sandwich Terns nesting on a beach, with many shown in flight. Click for full-size photo -- 121K.

Other species -- Black Skimmer, Least Tern, and Gull-billed Tern -- can be found on any type of beach, as well as on sandbars.

Seabirds are seriously threatened by the continued erosion of the Louisiana coast. However, there are a few success stories showing how effective forts by the state and federal government have restored habitat for these birds.

These successes include the restoration of Queen Bess and Raccoon Point -- the major Brown Pelican colonies west of the Mississippi River -- as well as Wine Island, which is currently used for nesting by other species -- Black Skimmer, Royal Tern, and Sandwich Tern, and occasionally Caspian Tern.

Queen Bess was restored with sand, plants, and an earthen-shell dike in 1990 and rocks in 1992. Wine Island was renewed with dredged materials and rocks in 1991. Raccoon Point was restored with dredged material and plants in 1993 after the island seriously eroded due to Hurricane Andrew, which struck in the previous year.

A Brown Pelican, Louisiana's state bird, is one of a growing species. After their extinction in Louisiana in the early 1960's, Brown Pelicans were reintroduced from Florida. The breeding population has increased dramatically in the past two decades.

A dramatic increase in the breeding population of Brown Pelicans has been observed in Louisiana in the past two decades. After their local extinction in the early 1960's, Brown Pelicans were reintroduced from Florida and have nested at Queen Bess since 1971.

From there, Brown Pelicans decolonized or attempted breeding in areas that were historically important colony sites, such as Raccoon Point, Chandelier Islands, the mouth of the Mississippi River, and the sandbar in East Timbalier Pass.

In contrast, the total number of breeding Black Shimmers appears to be declining in Louisiana. This decline may be due to the diminishing use of the wash over areas at Fourchon in Lafourche Parish - because of human disturbance as well as the erosion of previously important sand spits, small points of land. Fortunately, the colony at Wine Island has increased dramatically since the island was restored.

Tern populations seem to be relatively stable, with large variations in breeding population from year to year. These variations are due to the vulnerability of tern nesting habitats to storms. Hurricanes and winter storms can alter the quality and quantity of available habitat as well as destroy nests in the summer.

This happened in 1989 when Hurricane Chantal hit the Louisiana coast during the first week of August. Although not a major hurricane, Chantal caused above-normal tides that washed over many of the beaches used by terns and shimmers.

A colony of birds at East Timbalier Pass was surveyed both before and after the storm, and an estimated 50-percent reduction in numbers of breeding adults at the site was reported. However, some flightless young among the Black Skimmer, Royal Tern, and Sandwich Tern survived the storm.

In addition to being impacted by storms, Least Terns, which nest mostly along the beach at Fourchon, are frequently bothered by humans. Nests and aggressive adult birds have been seen there in areas disturbed by vehicle traffic, with no eggs or young observed. In contrast, the relatively undisturbed colonies all had nests with eggs.

This illustrates the importance of leaving these nesting birds alone.

The Raccoon Point colonial bird rookery marks the site of one of Louisiana's rapidly eroding islands. Click for full-size photo -- 69K.

Seabird colonies can be recognized in areas where more than ten birds fly up when a human approaches. The birds will often stage mock attacks or try to divert a person's attention by pretending they are injured. This is common behavior for a Black Skimmer.

The nests of seabirds are difficult to distinguish because they are often nothing more than a small depression in the sand. The eggs are camouflaged, so as not to be detected by predators.

Young seabirds defend themselves by avoiding detection. They sit still pressed to the sand to blend in with the background.

When the parents leave the nest due to a disturbance, eggs and young can quickly overheat. Therefore, nature lovers are asked to observe the birds from a distance and let them take care of their young.

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