Giving songbirds something to sing about

For birds, migration is hard. Really hard. Many migratory species travel thousands of miles through all weather conditions with limited food resources. While many mysteries still remain around bird migration, scientists are learning more and more about the whys and hows of this incredible phenomenon. And it has a group of scientists in the Northeast asking: can we make migration a little easier for some songbirds by enhancing their favored habitats?

In 2015, a collaborative project began between the U.S. Fish and Wildlife Service, the University of Massachusetts, and the U.S. Forest Service’s Northern Research Station. By collecting data on bird health and by tracking movements of migrating songbirds in the Connecticut River Valley, the team hopes to determine the best habitat types for certain migratory birds that stop over in the area.

To gather this information, the team has been capturing woodland birds during spring and fall migrations using mist nets. Once captured, birds are banded and several measurements are taken including wing and beak size. Blood is drawn from some target species and brought back to a lab for analysis. The research team is getting a picture of the birds’ overall health by determining body composition (fat, lean mass, and water content), and instantaneous refueling rates which help determine if birds are gaining or losing mass during a stopover.

Biologist measuring a songbird included in the study

Banding

least flycatcher

Bird ready for release

Preparing the nanotag

Nanotag placed on the hermit thrush

Additionally, select birds are fitted with NanoTag transmitters which allow biologists to track the birds’ movements. NanoTags are tiny tags that emit a signal that can be tracked with telemetry equipment. Biologists can identify individual birds and their locations for months using the devices that are attached to the birds with a tiny elastic harness. Among the species targeted in this study are Swainson’s thrushes, northern waterthrushes, yellow-rumped warblers, Lincoln’s sparrows, and white-throated sparrows. Data collection for this project wrapped up this spring; and over the past four years, biologists were able to band nearly 3,000 birds and fit over 200 target birds with NanoTag transmitters.

This study has been taking place within the Silvio O. Conte National Wildlife Refuge. The Refuge encompasses an impressive 36,000 acres of the Connecticut River watershed in the states of New Hampshire, Vermont, Massachusetts, and Connecticut. The team has focused its capture and banding efforts on old-field sites within the Conte Refuge for this study, including the Fort River Trail area in Hadley, MA and the Orchard Hill section of the University of Massachusetts in Amherst, MA. Each site is less than 1/3 of a mile from the Connecticut River.

U.S. Fish and Wildlife Service wildlife biologist, Troy Wilson, says, “We are interested in how physiological condition affects performance during the life stage of migration. Condition metrics – fat, lean mass, water – are used as indicators of the heath of birds, as well as a means to determine the quality of the habitats they occupy as they refuel from one location to the next.” The end goal is to determine how the Connecticut River Valley and the Silvio O. Conte National Fish and Wildlife Refuge can be a better host for migrating birds. The team hopes to be able to make recommendations for habitat management, specifically where forested areas should be converted to early successional habitat through forest management, and where old fields and shrublands might be managed for specific plant species and habitat structure that provide the highest benefits to birds during migration.

Jennifer Lynch Murphy is a wildlife biologist with C&S Engineers, specializing bird-aircraft collisions. She lives in Sunderland, MA with her husband, Kevin, and dog, Levi.

 

 

 

 

 

 

 

A Sweet Solution to a Sticky Problem

When you’re a biologist at a site named for a legendary environmentalist, you feel a responsibility to do your job with the planet in mind.

Just ask Dr. Susan Adamowicz, Land Management Research and Demonstration Area biologist for the Northeast Region of the Fish and Wildlife Service. Stationed at Rachel Carson National Wildlife Refuge in Maine, she is tasked with finding innovative ways to manage wildlife habitat and takes inspiration from the renowned author.

Service biologist Dr. Susan Adamowicz examines Spartina patens, a native salt marsh cordgrass, at Parker River National Wildlife Refuge. (Credit: Steve Droter)

Rachel Carson conducts marine biological research in 1952. (Credit: USFWS)

In 1962’s Silent Spring, Carson, who also worked for the Service, sounded the alarm about pesticides that imperiled wildlife and people alike. She knew that many of the synthetic chemicals used to control unwanted plants and insects were dangerous to more than their targets.

For a healthy environment, Adamowicz seeks other solutions … and hopes she has found one with the help of a University of New Hampshire researcher.

A “Consummate Invasive Species”

Phragmites australis, or common reed, is an aggressive, nonnative marsh grass that pushes out native wetland plants. You’ve probably noticed its tall (up to 18 feet!), feathery, golden stalks in your neighborhood or along the freeway.

Phragmites is plentiful in the high salt marsh of the Great Marsh, the largest continuous stretch of salt marsh in New England. Three thousand acres of the 20,000-acre marsh in eastern Massachusetts lie within Parker River National Wildlife Refuge.

Parker River National Wildlife Refuge, in eastern Massachusetts, protects 3,000 acres of the Great Marsh, the largest continuous stretch of salt marsh in New England. (Credit: Matt Poole, USFWS)

A boardwalk passes through a stand of Phragmites australis at Parker River National Wildlife Refuge. (Credit: Steve Droter)

Phragmites changes the structure of the salt marsh, filling natural channels and tidal pools where waterbirds, fish, and invertebrates find food and safety. Many wildlife species find its dense patches impassable, and in the fall, when the stalks die back, stands of the plant turn to tinderboxes primed for wildfire, putting nearby homes and businesses at risk.

Biologists have long searched for effective ways to control Phragmites. It’s a determined adversary, however. Like those birthday candles that re-ignite, just when it seems defeated, it springs back to life.

According to Adamowicz, “Phragmites is the consummate invasive species. If you cut it or burn it, it comes back. If you can flood it for six months, that might kill it, but flooding is not always feasible.”

Phragmites grows along a marsh at Sachuest Point National Wildlife Refuge in Rhode Island. (Credit: Tom Sturm, USFWS)

While restoring natural tidal flow to coastal marshes is the preferred way to fight Phragmites,  replacing culverts, filling ditches, and improving drainage can take a long time. Treating it directly is necessary to keep it in check in the meantime.

Sadly, there’s been no good way to do that. Herbicides work in certain locations but pose a risk to native vegetation and groundwater — certainly not a solution Rachel Carson would embrace.

So Adamowicz teamed up with Dr. David Burdick, research associate professor and interim director of the Jackson Estuarine Laboratory at the University of New Hampshire, to explore innovative ways to control Phragmites. One of the methods they tested was sweet and simple.

Turning the Tables

Burdick had a hunch that sugar, the same kind you put in your coffee, might be Phragmites’ Kryptonite.

Dr. David Burdick takes notes at Parker River National Wildlife Refuge. (Credit: Gregg Moore, UNH)

Each summer, rising air temperatures and increased plant growth stimulate bacteria in salt marsh soils to convert organic matter and oxygen into carbon dioxide, water, and energy — a process called aerobic (“with air”) respiration. The activity quickly uses up soil oxygen, forcing other groups of bacteria to make energy using anaerobic (“without air”) respiration.

One by-product of anaerobic respiration is hydrogen sulfide gas, a potent toxin for plants as well as people. At typical levels, the gas is not deadly to most native plants, but it can be toxic to Phragmites.

Burdick thought increasing bacterial respiration, and therefore hydrogen sulfide levels, could kill the invasive.

“Because Phragmites is a master at getting oxygen to its roots for its own respiration, we could use this strength to kill it,” he mused. “By elevating soil hydrogen sulfide levels, we might stimulate the plant to oxidize the gas into a strong acid that it may not be able to tolerate.”

While he couldn’t control air temperatures, he could increase fuel for the bacteria — using glucose in the form of table sugar.

Pour Some Sugar on It

Burdick and his team first tested their idea in the greenhouse. They soaked Phragmites plants with bay water for three hours every two weeks to mimic the flooding that high-marsh plants get during the extra-high “spring” tides that come with the full and new moons each month.

Some plants (the control) received only the bay water; others got water with table sugar; still others water with extra salt; and the remaining, water with sugar and salt.

In the greenhouse study, plants receiving sugar or sugar-plus-salt (right, top and bottom) showed clear signs of distress within weeks of treatment. (Credit: Gregg Moore, UNH)

Both the sugar and sugar-and-salt treatments showed signs of stress within weeks and eventually died. Only the plants that received plain bay water or bay water with added salt lived.

The sugar-treated plants had very high soil acidity, possibly caused by sulfuric acid, the product of hydrogen sulfide oxidation. This supported Burdick’s theory.

Next, Burdick and Adamowicz headed to Parker River Refuge to set up a field study in the northern part of the Great Marsh. The research was supported by federal funds for Hurricane Sandy recovery and resilience projects.

Following the greenhouse trial, Burdick and his team tested the treatments in the Great Marsh at Parker River National Wildlife Refuge. (Credit: Gregg Moore, UNH)

They isolated individual Phragmites plants and applied the same treatments as in the greenhouse. Sugar and salt were put on the plants every two weeks, after the spring tides flooded the marsh.

The plants that got sugar had far greater mortality than the other treatments, even with uncontrollable environmental factors, such as rain — a clear sign that sugar is not sweet to Phragmites.

Refining the Technique

Adamowicz is pleased with the study results so far and eager to set up more field trials. She’s exploring ways to treat Phragmites with sugar and salt more efficiently and broadly, perhaps using a backpack sprayer to apply corn syrup at more-frequent intervals than every two weeks.

“This is another tool in our toolbox, and it’s nontoxic to wildlife, which is very desirable,” she said. “The more complicated response to Phragmites is ecosystem restoration, but in the meantime, we need a fast-acting tool to help native plants come back and buy time.”

If Rachel Carson were alive today, she would certainly approve of this environmentally sound method — and just might be thinking, “Sweet!”

Bog turtles – a One Health Ambassador

A healthy bog turtle from a New York population. Credit: Sandy Doran, USFWS

The One Health Initiative promotes the idea that human, animal, and environmental health are all linked, so by changing one aspect of the triad you inevitably affect the rest.

This initiative encourages collaboration across a variety of scientific disciplines to create synergist approaches to large scale health issues. Recent mortality events in populations of the country’s smallest turtle have provided an opportunity for the U.S. Fish and Wildlife Service to do just this—to bring together partners across a variety of disciplines to explore an issue that could be affecting more than the bog turtle.

Bog turtles, the smallest turtle in North America, are federally listed as a threatened species under the Endangered Species Act. Although these turtles are small they are mighty!

They have a lifespan of 30+ years and remain almost exclusively in the same wetlands where they hatched. They have become threatened primarily as a result of degradation, fragmentation and/or destruction of habitat, due to human activities.

In 2011, bog turtle populations in New York and Massachusetts had unexplained mortality events and individuals were showing clinical changes in their skin that included discoloration and ulceration.

Biologist Sandy Doran holds a health bog turtle. Now you can really appreciate their small size! Credit: Sandy Doran, USFWS

This puzzled many biologists and prompted a response to figure out what was causing the mortality.  The U.S. Fish and Wildlife Service (USFWS) decided to fund a project involving Wildlife Conservation Society (WCS) veterinarians, pathologists and technicians, and state biologists to conduct health assessments on bog turtles at 4 sites in these two states.

Previous research on other turtle species suggested that infectious diseases, such as Mycoplasma (an upper respiratory tract disease), could be an important contributor to mortality.

WCS was unable to determine the actual cause of death, but the research did confirm the presence of Mycoplasma. Tests for ranavirus and herpesvirus came back negative.

Unfortunately, additional research efforts have had mixed results.

• Additional assessments in Dutchess County, New York, were negative for ranavirus as well as Mycoplasma, but were positive for herpesvirus.
• Data from New Jersey suggests that there is a high prevalence of herpesvirus in bog turtle populations in that state.
• Recent results from a 2017 study in Oswego County, New York, indicated that all the sampled bog turtles were healthy.

Ultimately the disease prevalence is highly variable and additional testing is required to understand the disease distribution within a variety of bog turtle populations. The 2017 study, funded by USFWS, allowed WCS and the State University of New York College at Oswego (SUNY Oswego) to assess turtles at a site that is far removed from other parts of the bog turtle range where positive disease detections have been made; it was of particular interest to better understand if bog turtles at this site carried the same diseases.

While there were some old injuries observed, and very occasional unexplained minor discoloration of skin, the sampled turtles were in very good condition.

Continuing to study this species is important because by better understanding these unexplained mortality events we can support a more robust wetland habitat system and ideally eventually recover this species (hooray!).

There are a lot of unknowns in this project like how climate change may play a role in bog turtle populations and whether a changing climate will trigger more disease impacts.  The continuation of research efforts will allow more knowledge to be gained to help protect this species long term.

This collaborative effort remains on-going to protect this tiny turtle and to better understand the impacts to habitat and disease. The more we can encourage and work together toward common conservation goals the better we can promote and protect the biodiversity of our world, one tiny turtle at a time.