Texas Parks & Wildlife Magazine   


May 2010 cover image 12 Vulnerable Nursery

Vulnerable Nursery

Colonies of coastal birds need protection to raise their young, and Audubon volunteers have been standing guard.

By David Newstead

As the sun peeks through the marsh on a calm, quiet morning in the bay, legions of feathered residents are already in their places and ready to work.

A black skimmer draws a thin, gray line in the shallow water with its lower beak, hoping to snap up a killifish; a white ibis stalks through the cordgrass probing for a meal; a roseate spoonbill swishes its bill back and forth through the soft mud to sift out tiny worms and crustaceans; and a reddish egret performs its erratic dance in pursuit of prey.

Photo by Kathy Adams Clark

It happens every morning, and it is a scene that is as invigorating and as emblematic of our state’s shorelines as the sight of a tailing redfish. The birds’ job is to raise a family, and from February through August, they are working not just to feed themselves but also a mate and a few hungry mouths at the nest.

All counted, more than 30 species of colonial water birds nest on the Texas coast, including pelicans, herons, ibises, spoonbills, terns, skimmers and gulls. The birds are called “colonial” because of their habit of nesting in dense aggregations called rookeries — think of it as a nursery, with tens, hundreds and sometimes even thousands of birds crammed into a small area busily tending to their duties in order to bring new life into the world. There’s a cacophony of screeching and squawking, and the distinct aroma of ammonia.

If all goes well, after a couple months the downy young will mature and leave the island as elegantly dressed fledglings — and populations will remain healthy. If it doesn’t go so well, few if any young birds are added to the flocks. With too many of these bad years, populations can be in real trouble.

It seems difficult to imagine a time when water birds were not a conspicuous presence on the Texas coast, but at one time they were persecuted almost to the point of extirpation from the state. Toward the end of the 19th century, many of the rookeries were raided by market hunters who shotgunned as many birds as they could for sale to the fashion markets of New York, where their feathers would adorn the hats of fashionable women on Fifth Avenue. Ounce for ounce, their feathers were worth more than gold. In response to the slaughter, the Audubon Society was formed just over 100 years ago by citizens who realized that the birds could not sustain this grim harvest. When one of the first Audubon wardens — Guy Bradley — was shot and killed while protecting an island in South Florida, conservationists rallied to urge legislative protection for critical nesting areas, and for the birds themselves. The Migratory Bird Treaty Act of 1918 made it illegal to harm or kill native nongame birds, and this law continues to be the primary federal legal protection for birds even today. The great egret was selected as the emblem of what is now the National Audubon Society, and those folks with the bird emblem on their hats are still working to protect nesting water birds.

In Texas, the Audubon group’s early conservation work began in 1906 when Henry P. Attwater (after whom the Attwater’s prairie-chicken was named) was appointed to direct activities to conserve the state’s diverse bird life. Among other accomplishments, he was a strong and successful advocate for the licensing of hunting activities and for ensuring that revenue raised was used for protection and propagation of game, providing the basis of what later became the Texas Parks and Wildlife Department. In 1923, Audubon’s coastal conservation efforts got in full swing with the lease of Green Island in the Lower Laguna Madre from the Texas General Land Office — literally “paying rent” for the birds. This strategy of leasing islands from the state and managing them for water birds has expanded through the years, and today Audubon manages more than 80 islands along the Texas coast, totaling more than 13,000 acres.

Photo by Kathy Adams Clark

Fortunately, the birds are no longer under threat from shotgun-wielding market hunters. However, many of the birds never fully recovered from those early losses, and over the years a new set of perils emerged that are in many ways more challenging to address.

As human habitation and development of the Texas coast spread over the 20th century, the physical and ecological character of the coast — and of the islands — changed considerably. Massive dredging and shell removal projects destroyed some islands and created others and increased boat traffic that in turn increased erosion. The removal of most of the top-level predators on the mainland led to a profound increase in populations of smaller mammalian carnivores such as raccoons and coyotes — animals that can cause complete nesting failure for thousands of birds if they reach a nesting island. The spread of introduced invasive grasses and pests such as the red imported fire ant has also taken a heavy toll on water bird colonies.

Conservationists realize that the key to maintaining healthy populations of wildlife is the protection and management of their habitats throughout their entire life cycle. For most of the year, colonial water birds on the coast depend on the same habitats as fish and shellfish. But just as redfish and flounder need a gulf pass in order to spawn, the birds need islands when it comes time to nest, and a few scattered coastal islands are all they’ve got. Because birds have a lower reproductive potential than fish, recovering dwindling water bird populations becomes even more difficult. That’s why Audubon Texas’ Coastal Stewardship Program focuses most of its efforts on protecting these critical nesting islands.

A network of wardens forms the backbone of Audubon’s coastal conservation efforts. Complementing the efforts of TPWD game wardens, these dedicated citizens have devoted countless thousands of hours to patrolling important nesting islands, cleaning up shorelines, removing predators, planting trees and shrubs, posting signs around islands and installing nest platforms.

“The coastal wardens are the frontline conservationists that make this program so special. This group’s passion for the resource is unparalleled,” says Bob Benson, executive director of Audubon Texas. They’ve worked in every bay system in the state from Sabine Lake to the Lower Laguna Madre. When you see a heron stalking killifish in the marsh, or terns bombing anchovies in the middle of the bay, there is a good chance the bird came from an island nurtured and protected by a warden with Audubon’s Coastal Stewardship Program.

In addition to managing islands and providing wardens, Audubon engages with a wide variety of state and federal agencies and other conservation organizations to help water birds make gains. Many of these entities are members of the Texas Colonial Waterbird Society, which conducts an annual census of all the nesting water bird islands along the coast and gathers to discuss trends and research to better understand the conservation needs of this diverse group of birds. The census has been carried out for more than 35 years, and the data is used to determine where things are going well and to provide an alert system when birds are in trouble so that appropriate action can be taken. While there are some bright spots evident in the census data — such as the recovery of the brown pelican — the picture has not been quite so rosy for most of the other water bird species. Declines in overall numbers and loss of diversity are apparent in several bay systems, especially in the central coast.

Photo by Joe Richards

In the Coastal Bend, Audubon has partnered with the Coastal Bend Bays and Estuaries Program for almost a decade to focus efforts on reversing water bird declines. A team of two biologists and a warden has been implementing a wide-ranging program of on-the-ground island management projects. One of the most conspicuous examples is the nesting platform that was designed by an Audubon warden. To date, more than 30 of these structures have been installed on islands in the Coastal Bend, and all have provided nesting structure for several pairs of great blue herons every year. The platforms supplement other management actions such as the removal of invasive grass and the planting of brush that will one day provide much-needed nesting structure so that the platforms can be removed. An added benefit is that great blue herons begin nesting early in the season and appear to serve as “sentinels” for other species. Attracting the big birds may improve chances for recovery of a whole suite of brush-nesting species. Another innovative project getting under way reuses oyster shells from a local restaurant to provide improved nesting substrate for bare-ground nesting birds like the black skimmer.

While these direct habitat management actions have real and immediate benefit, one of the biggest and growing challenges in water bird conservation is the disturbance of nesting sites by human activity. In spite of everything else that is done to provide ideal habitat for successful nesting, all can be undone by an untimely visit from an unwary visitor, and it doesn’t take a direct, intentional act of destruction to have an effect. A boat or a person or a dog coming too close to a nesting colony can be enough to cause birds to leave their nests. And even a short absence from the nest can result in eggs and chicks dying from heat stress or make them vulnerable to predation by opportunistic gulls or grackles. In the worst-case scenario, birds leave and don’t come back, and since their reproductive cycles are timed to coincide with the peak availability of their prey, that often means they won’t have another chance to raise young that year.

Data from the Texas Colonial Waterbird Census indicates that water bird losses are occurring more frequently in areas that are also seeing major increases in the amount of bay traffic.

“The remaining rookeries represent an important part of the rich avian diversity of our state, yet are very vulnerable to human disturbance,” says Matt Wagner, acting deputy director of the Wildlife Division for TPWD.

It is critical that bay users recognize nesting water bird colonies and respect their need for a comfortable distance. The distance at which a bird is disturbed can vary depending on a number of factors, but the best advice is — if the birds are getting agitated, you’re already too close. The perimeter they require to nest successfully is tiny in comparison to the rest of the bays and shores, so there’s still plenty of room out there for everyone.

Audubon and partners have been paying rent and keeping house for the water birds of Texas for nearly a century, but in the end the birds belong to the coast, and to the present and future generations of Texans lucky enough to behold this spectacular part of our natural heritage. They are indicators of how well we are taking care of our coastal ecosystem. Healthy populations of colonial water birds can exist only if Texas bay users embrace water bird conservation both in ethic and practice, and give the nesting birds a wide berth. Their offspring will thank us for it.

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