Tag Archives: Migratory birds

Tree Swallows, Mercury Contamination, and Middle River

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A Tree Swallow on our farm in Swoope. (Photo: R. Whitescarver)

Today we share a story from Bobby Whitescarver, of Whitescarver Natural Resources Management, about recent work to study and mitigate the effects of a mercury leak on tree swallows in Virginia. The research helped secure a settlement from DuPont, the synthetic fiber production plant responsible for the leak. Read the original post here 


There are many harbingers of Spring in Swoope; the yellow blooms of daffodils and forsythia, the sounds of spring peepers, and pastures changing from brown to green are only a few. My favorite harbinger of Spring is the arrival of Tree Swallows, Tachycineta bicolor. I start looking for them in late February. This year they arrived in Swoope on March 18.

Our Tree Swallows migrated almost 2,000 miles North from Florida and Cuba. They come here to breed and raise their young, returning South in the fall.

We maintain forty-eight nest boxes for them and other cavity nesters such as Eastern Bluebirds and Carolina Chickadees. There must be a hundred Tree Swallows along Trimbles Mill Road and the Middle River. There are often two or three birds around each nest box.

Anytime we drive a truck or tractor into a pasture it disturbs insects. The Tree Swallows come to get them. They are joined by Barn Swallows, Cliff Swallows and Northern Rough-wing Swallows in the feeding frenzy. It’s an amazing show of flight with colorful dives and swoops.

The College of William and Mary Research Team
We have always had a few nest boxes but in 2005 Dan Cristol, Chancellor Professor of Biology from the College of William Mary asked us if we would participate in a research project to study the biomagnification of mercury up the food chain. He and his students put up hundreds of nest boxes along the Middle, South, and North Rivers in Augusta County. On our farm, they added thirty nest boxes to the ones we already had.

Dr. Dan Cristol, Ornithology Professor at the College of William and Mary. He is holding a Tree Swallow captured along Middle River in Swoope, VA. (Photo: R. Whitescarver)

Mercury Contamination of South River
Waynesboro, Virginia, was the site of a Dupont synthetic fiber production plant that discharged mercury into the South River from 1930 to 1950. The Middle and North Rivers were used as reference sites in the research because they didn’t have legacy mercury discharges in the River.

Tree Swallows Were the Main Species of Study
Tree Swallows were their main species of study because during the breeding season they eat only flying insects. Insects such as mayflies, dragonflies, caddisflies, and stoneflies spend their immature life in streams and rivers. The ones in the South River spent their aquatic life in the sediments contaminated with mercury. When these aquatic insects hatch from the water becoming flying insects, many are eaten by Tree Swallows. Subsequently, they feed their babies these insects and they, in turn, ingest the mercury.

Their groundbreaking research was published in Science magazine in the April 2008 edition. The article, “The Movement of Aquatic Mercury Through Terrestrial Food Webs,” states,

“Mercury is a persistent contaminant that biomagnifies up the food web, causing mortality, reproductive failure, and other health effects in predatory wildlife and humans.”

Their studies proved that mercury, in fact, does biomagnify up the food chain; twenty times higher than in the reference birds on our river.

Their six years of field research was, to their knowledge, “the first study to suggest disruption of multiple endocrine functions by mercury in wild animals,” one research paper attests. Cristol and his students published over fifty papers on their findings of mercury in wildlife.

Dr. Cristol taking scientific measurements on a Tree Swallow. (Photo: R. Whitescarver)

Mercury Greatly Reduced Tree Swallow’s Ability to Withstand Heat
“The mercury-exposed swallows suffer a reduced hormonal response to stress, altered thyroid hormone levels, suppressed immune system, twenty percent fewer offspring annually, and most interestingly, a greatly reduced ability to withstand heat waves. Normally hot weather is great for them because of the increased number of insects flying around, but on the contaminated sites, that is when the babies tended to die…so there is trouble ahead when mercury and global climate change run into each other,” Cristol wrote.

The William and Mary field research ended in 2010 but we still maintain the nest boxes and added even more. It is a joy to see their metallic blue/green upper bodies and white breasts flying around the pastures in pursuit of insects.

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Largest Natural Resource Damage Settlement in Virginia History
Their research was used as part of the South River/South Fork Shenandoah River Natural Resources Damage Assessment Plan which led to a settlement from Dupont of $48 million to various environmental organizations to improve our landscape and waters. This is the largest natural resource damage settlement in Virginia history and the eighth largest in US history.

The College of William and Mary was a member of the South River Science Team that used research to understand, educate and reduce the effects of mercury in the South River.

We are very proud to have been a small part of this massive research project that resulted in some form of environmental justice for the decades of mercury contamination of a major river.

Read the original post here 

Wetland Wonder

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Click image for full story (Photo: Kayt Jonsson, USFWS)

By Megan Lang

For many a growing season, Matt and Marilyn Spong thought of the wetland on their farm as a problem spot. Year after year, crops they planted there would either fail completely or produce a smaller yield then the rest of the farm.

But rather than abandoning the area altogether, the Spongs got creative: with the help of the Service, Matt and Marilyn transformed their wet spot back into a natural wetland, creating new habitat for dozens of species.

For decades, wetlands in the U.S. have been in decline. A study in the 1980s found that the country had lost an area of wetlands twice the size of New Jersey from 1950 to 1970, restricting habitat for species like migratory birds that rely on wetlands to make their yearly migration. It’s only in recent years that conservation groups like the Service and its partners have been able to reverse that decline, and it’s only worked with the help of private landowners like the Spongs.

And the results, they say, have been worth much more than the crops that would never quite thrive.

“We see a whole lot more shorebirds and water turtles now, and we also see bald eagles that we rarely saw before the wetland was restored,” Matt said.

Click here to read the full story


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Two Canada geese coming in for a landing over the restored wetland (Photo: Kayt Jonsson, USFWS)

The Spongs’ story is featured in the U.S. Fish and Wildlife Service’s Nature’s Good Neighbors series, which highlights people across the U.S. who depend on the land as much as the land depends on them. These modern-day stewards of the land are working with nature to make a home for people and wildlife.

Welcome Back — Where Have You Been?

This time of year, piping plovers are returning to beaches up and down the East Coast, preparing to lay eggs and raise chicks in their summer homes. But where have these shorebirds been all winter? Biologists have wondered this for years, and they’re gradually gathering answers.

Piping plovers nest on beaches throughout the northeastern U.S. and Atlantic Canada. Credit: Kaiti Titherington/USFWS

Piping plovers are found only in North America, with a total of about 8,000 birds. There are three breeding populations, each listed as either threatened or endangered by the U.S. Fish and Wildlife Service.

Known range of piping plovers, 2004. Credit: USFWS

Many of the birds that nest in the northern U.S. and Canada spend winters along the Atlantic and Gulf coasts of the southern U.S. and in Mexico and the Caribbean. They spread out across a large area that has not been as well surveyed as their breeding grounds, so new wintering areas are still being found. Scientists discovered in 2011 that about 1,000 birds, or roughly one-third of the Atlantic Coast population, winters in the Bahamas.

That still leaves a lot unaccounted for in the colder months. Surely there are other spots in the Caribbean where piping plovers spend half their lives.

Typical piping plover habitat. Credit: Craig Watson/USFWS

In 2016, a team of scientists from the Service, the U.S. Geological Survey, and the Turks and Caicos Department of Environment and Coastal Resources counted wintering piping plovers on Turks and Caicos during the International Plover Census. It was the first organized shorebird survey done on the chain of 40 islands southeast of the Bahamas. They were pleased to find 96 plovers.

Location of the Turks and Caicos Islands. Credit: Google Earth

The same group, bolstered by staff from Environment and Climate Change Canada, Turks & Caicos National Trust, the Royal Society for the Protection of Birds (United Kingdom) and SWA Environmental, fanned out to cover more areas this winter and found 174 piping plovers, an increase of 78 over last year.

Biologists search for plovers from a distance. Credit: Craig Watson/USFWS

Although the numbers may not sound impressive, they are significant. They show that the Turks and Caicos Islands are a major wintering area for piping plovers. Eighty-eight of the birds were found in one place, which could qualify the site for listing as an Important Bird Area by BirdLife International.

According to Caleb Spiegel, a biologist with the Service and member of the survey team, “It goes to show that multiple years of surveys are critical to understanding populations, since there may be variation in how sites are used each year.”

A flock of shorebirds surveyed in the Turks and Caicos. Credit: Craig Watson/USFWS

Ten of the piping plovers that were spotted in Turks and Caicos this year sported leg bands that identified them as mature birds that were banded as chicks in Massachusetts, Rhode Island, New York, New Jersey, and Atlantic Canada. Proof positive that birds we in the Northeast consider “ours” spend half the year in Turks and Caicos.

International efforts, like the Atlantic Flyway Shorebird Initiative, connect science, like that gathered through this survey, with conservation. The Service hopes to work with partners to spread the word about the sites in Turks and Caicos where piping plovers were found and encourage their protection.

“We can use the example of the Bahamas,” noted Spiegel. “With extensive efforts by the Bahamian Government, the National Audubon Society, the Service, and others, those sites were named Important Bird Areas, and one was later protected as a National Park.”

Two piping plovers in pale winter plumage. During breeding season, they have dark neck rings and brow bands. Credit: Craig Watson/USFWS

In addition to piping plovers, biologists discovered about 400 red knots, another threatened shorebird, in 2017. Historically, there have been few sightings of this bird in Turks and Caicos, and none were seen in the 2016 survey. The birds were found on a sand bar that was not surveyed the previous year.

As migratory birds, piping plovers and red knots need both a home and a home-away-from-home. The discovery of new wintering sites in the Turks and Caicos Islands is big news for these little birds and the people who support them.

Click here to learn more about the 2017 Piping Plover Survey in Turks and Caicos.

To learn more about piping plovers, visit the following links: The Search Is on for Piping Plovers blog and our Piping Plover webpage!