Harvey Surge and Few Wetlands Puts Migrating Birds in Tough Spot

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By Nushin Huq

Hurricane Harvey not only destroyed towns and flooded homes but also laid waste to precious bird sanctuaries that dot the Texas coast during birds’ fall migration.

Conservationists worry that the hurricane, which battered the coast and dropped over 50 inches of rain will also negatively affect the long-term survival of bird species that rely on those areas.

The Texas coast is often associated with refineries, chemical plants, and fishing, but the state’s islands are also an important habitat for birds, some of them endangered.

A number of tiny islands, called rookeries, along the coast suffered erosion and destruction of areas where birds nest. Fixing this will take time and resources, but these islands are important to the survival of bird species including the Aplomado Falcon, Attwater’s Prairie Chicken, and the Whooping Crane.

While birds have evolved with hurricanes, storms like Harvey—which are slow moving and destructive over a relatively small and focused coastal and inland area—could increase stress and mortality, especially for already struggling populations of birds and limited habitat, conservationists told Bloomberg BNA.

Island Sanctuaries

Hundreds of islands off the Texas coast that provide critical habitats for birds year round, and offer the first line of defense for coastal communities, were damaged in the storm’s surge, Iliana Pena, director of bird conservation for Audubon Texas, told Bloomberg BNA.

Birds that migrate to these areas such as Rockport, Texas—where Harvey made landfall—may have less food needed for migration and shelter than in previous years. But, the magnitude of the effect on migratory birds will depend on how quickly their habitat is restored.

“It is difficult to know the impacts of a single storm because many factors determine the survival of birds in the dynamic coastal area,” Pena, who’s organization’s local chapters manage many of the islands off the Texas coast, said. “Assessments are being conducted right now to better understand impacts and possible future impacts.”

Because Harvey hit during the peak of migration for many songbirds and shorebirds, according to Pena, migratory patterns are likely to be affected from the damage to their nesting and feeding sites.

For colonial waterbirds, ground-nesting species like Terns, Black Skimmer, and Oystercatchers may have lost valuable habitat from erosion and the loss of small but important islands.

Additionally, shrub-nesting species like Reddish Egret, Little Blue Heron, and White Ibis may have lost nesting habitat both to seawater inundation and erosion.

Migratory Stopover, Traffic

In terms of stopover and migration traffic, the central Texas coast experiences migration like no other part of the U.S., Andrew Farnsworth, a migratory bird scholar at Cornell University, told Bloomberg BNA.

“We see this on radar, and many birders have experienced this,” Farnsworth said. “In part, the region’s geography and the distribution of where birds breed and winter, ultimately, are defining features of why this region is so well traveled. But this area also has a significant amount of habitat for stopover in some places, whether for landbirds, shorebirds, or waterbirds.”

Storms like Harvey can drastically change the landscape by shifting the distribution of water and land. Strong winds have downed trees and some coastal areas no longer exist. Stopover habitats could be destroyed or, in time, might even be created.

“Birds may take advantage of these changes for good or bad,” Farnsworth said.

From a water fowl perspective, bird professionals expect to see short-term impacts to the habitats they would use, Dale James, director of conservation science and planning for Ducks Unlimited, told Bloomberg BNA.

“This is primarily from storm surges pushing salt water, changing the salinity of some of the wetlands,” James said. “We may see some immediate impacts from that.”

The wetlands are pretty resilient, James said. More rain may even help to flush out the salt water from coastal wetlands. The main issue in the short term is the salinity levels from the storm surge into the coastal wetlands. Some local species, like the mottled duck, may experience habitat loss in the short term because of salt water coming inland, James said.

“It’s a natural cycle, in terms of clearing out these marshes, making them more productive,” James said. “It’s just the fact that we’ve lost wetlands and they’re not able to be as resilient as they have historically.”

Impacts from Harvey, while still present, would have been reduced with a larger base of wetland acreage, James said. Other areas impacted by the storm’s surge could include public lands managed for water fowl.

“If they’ve had damage to their infrastructure and are not able to manage the wetlands properly, then there could be some impacts to water fowl habitat and especially to access for birders and hunters to those areas,” James said.

Long-Term Impacts

It’s too early to tell if destruction due to Harvey will have any long-term impacts to bird populations that depend on the Texas coast for food and shelter, conservationists told Bloomberg BNA.

In terms of noticeable impacts—other than the changes in the landscape and perhaps chemistry of certain areas—Farnsworth doesn’t expect patterns of movement to vary tremendously this winter.

“When spring migration comes, and the changes in the landscapes have played out over several months, some more apparent changes in usage patterns may emerge,” Farnsworth said. “And some of these may ultimately translate to changes in the ways birds move through this landscape.”

Depending on the guild of birds and their habitat types, the damage can be long term if actions aren’t taken to restore the shorelines and replant vegetation, Pena said. On rookery islands, shrub-nesting habitat is already limited in some areas, so re-vegetation projects will be helpful but can take time.

“I am concerned about loss of nesting islands, which are vital to the long-term survival of bird species and are quite costly to replace,” Pena said. “The island habitat is already greatly reduced, especially in areas like Matagorda Bay and San Antonio Bay just northwest of Rockport.”

To contact the reporter on this story: Nushin Huq in Houston at nHuq@bna.com

To contact the editor responsible for this story: Rachael Daigle at rdaigle@bna.com

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