Wednesday, September 27, 2017

New technology revealing details of bat migration

            The Pettersson D500X ultrasound recorder looks a bit like an old-fashioned transistor radio with square buttons, a modest display screen, and a built-in microphone. Yet despite its unimaginative appearance, the device can detect the echolocation sounds made by bats and, with the help of software that identifies the bat species involved, is helping scientists reveal new information about the movements and migration behavior of local bat populations.
            Biologists at the Rhode Island Department of Environmental Management and the University of Rhode Island have deployed the bat detectors throughout the state this year in a variety of ways. DEM wildlife biologist Charles Brown, for instance, mounts one on the roof of his truck as he periodically drives five routes around the state to look for trends in bat numbers and to compare his findings with those driving similar routes in other states. He also places the
Silver-haired bat (The Nature Conservancy)
devices in various state wildlife management areas to scout for locations to trap bats for more detailed studies.
            The most revealing use of the detectors, however, has been as a way of monitoring bat migration through the state.
            “Not a lot is known about bat migration, so we’re just trying to figure it out for various reasons,” said Brown. “There’s a great interest in wind turbine development – turbines kill hundreds of thousands of bats every year – so we want to know when they migrate and where.”
            Brown selected several locations along the Rhode Island coast to place the detectors for long-term monitoring of bat movements. Every week since early August, he has downloaded the data from the detectors to learn what he can about the seasonal movement of bats.
            “Much like birds, they migrate at the same times and during the same general weather patterns,” Brown said. “They head south until they hit the coast and then they follow the coastline. There are certain locations where you’d expect them to pile up and be concentrated, like Point Judith, Sakonnet Point, Beavertail, Brenton Point.”
            While he admits he didn’t know what to expect with the data he was collecting, he was somewhat surprised to learn that bat migration appears to begin much earlier than he anticipated.
            “We’re seeing pulses of activity beginning in August, and I’m not sure that’s well known,” Brown said. “But they’re opportunistic animals, so when they get the right weather conditions, they probably just figure that this is a good time to go.”
            Bat migration is believed to continue through October and early November.
            The only difficulty with the bat detectors is that it’s impossible to know how many bats are being detected.
            “It might detect a thousand calls in one night, but we don’t know if it’s a thousand bats flying by or one bat that flew by a thousand times,” he said. “There’s no way to differentiate it.”
            Most of the bats Brown has detected are red, hoary and silver-haired bats – collectively called tree bats – all of which migrate south each fall. He also occasionally detects small numbers of little brown bats that migrate north to hibernate in caves and mines in New Hampshire and Vermont. Little browns have declined dramatically in the last decade due to the effects of white-nose syndrome, a fungal disease that has killed millions of hibernating bats throughout the Northeast. Big brown bats, many of which spend the winter hibernating in Rhode Island, are also detected.
            URI Professor Peter August has conducted similar monitoring of bat migration at Napatree Point in Westerly using the same kind of detector, and his results mirror Brown’s.
“While in mid-summer I’d have a couple hundred bats passing by in a week, starting in August I’ve been getting a couple thousand in a week. The activity has really peaked.”
            He plans to continue to monitor for bat activity at Napatree until he detects no bats at all.
            “Nothing brings great clouds of bats to Napatree in the summer, which is what I expected,” said August, who earned his doctorate studying bats in South America. “It’s not an active summertime habitat, but it changes this time of year. We have lots of bats moving around now. Our migratory bats are headed south, and our hibernating bats are moving around the area looking for places to hibernate.
            By combining data from the detectors with anecdotal information from other sources – like surfers who report large movements of bats at sunrise and wind turbine owners who report dead bats at the base of the structures – Brown and August are piecing together the story of bat migration in Rhode Island.
            “With all this information, we’re finally getting a better sense of what’s going on here,” Brown said. “The information we’re getting will give us a better sense of how big a problem wind towers will be for our bats. As more and more wind turbines pop up on the landscape, it’s probably going to be a problem. It’s already a problem. And then we’ll have to question whether the mortality is sustainable.” 

This article first appeared on on September 27, 2017.

Sunday, September 24, 2017

Wildlife weathering the storm

It may not be the smartest activity, but hurricane season provides a unique opportunity to make exciting wildlife observations. Just as surfers tend to head for the beach during major storms – because that’s when the increasing waves offer an especially fun and challenging ride – those who enjoy watching birds often flock to the coast during and after hurricanes to look for rare species blown into the region on the powerful winds.
I can’t imagine what it’s like for a gull or other coastal bird to get pulled into the vortex of a hurricane near Cuba or Haiti and be unable to get out until they had traveled more than a
thousand miles. But it happens every year. It must be a traumatic experience, not to mention exhausting.
But there are few opportunities more enticing to a birder than to stand at a prominent coastal site and scan the horizon for a mega-rarity during a hurricane. It really gets the juices flowing.
Not that I’ve ever actually done it, however.
I worked for the electric company for 13 of my most obsessive birdwatching years, so when all my friends were headed to Point Judith or Beavertail or Brenton Point to watch for birds, I had to go to work. Which means that I missed out on seeing innumerable tropical birds make landfall along the Rhode Island coastline.
Bridled terns from Florida, brown boobies from the West Indies, brown pelicans from the Carolinas, and magnificent frigatebirds from the Caribbean have all turned up on southern New England beaches during especially powerful storms, and I missed them all. While I was working without sleep for days at a time as the electricity was being restored, my birding friends were making the avian observations of a lifetime.
Of course, coastal birds aren’t the only wildlife affected by hurricanes. Our local resident species can face devastation, too.  Fish, crabs and other marine creatures, for instance, can be thrown onto shore by waves and storm surge and become stranded. Beach plants are often ripped from the dunes by the winds or covered in sand. Animals that raise their young in trees, like squirrels, bats and raccoons, can have their homes uprooted and destroyed. Ground-dwelling creatures like opossums, skunks and chipmunks often drown in floodwaters.
Those that survive may find it difficult to find food because local berries have been torn from their bushes, insects have been smashed or drowned, and seeds have become moldy and unfit for eating. As difficult as it is for humans to weather a severe storm, our native wildlife has it even harder.
As a result, it’s a busy time for local wildlife rehabilitators, who are committed to rescuing injured or abandoned animals. One rehabilitator told me that it’s not uncommon for Rhode Islanders to deliver 100 baby squirrels to raise in the days after a hurricane because their nest trees have been knocked down.
It may take a while before normal wildlife activity resumes after a hurricane. Some species may have moved far inland to avoid the storm; others may seek new habitat if their former territory is damaged; and still others remain hunkered down for days or weeks as they recover from the stress of the storm.
In other words, they behave like most of the rest of us – happy that it’s over and thankful to have survived.

This article first appeared in The Independent on September 21, 2017.

Tuesday, September 12, 2017

Wildlife refuges are nature's defense against climate change

            The late winter and early spring of 2010 was not a time for enjoying the outdoors in the Ocean State. In what may have been the most significant flooding Rhode Island has experienced in its recorded history, more than 20 inches of rain fell during a 38-day period, culminating in a storm that dropped eight inches on the state from March 29 to April 1. The effects were devastating, especially along the Pawtuxet River in Warwick and West Warwick, which rose to more than 11 feet above flood level. Dams and bridges were washed out, homes were destroyed, and businesses and infrastructure were severely damaged.
            “The malls in Warwick were flooded because all the water in the Pawtuxet River is forced through a narrow channel between the malls where there are no wetlands, and it got over the
bank and covered the parking lots,” recalled Scott Ruhren, Audubon’s senior director of conservation. “It was a mess.”
            Audubon’s refuges weren’t spared. The trails at the Fisherville Brook Wildlife Refuge in Exeter were completely impassable – water was waist deep in places – as the brook overflowed its banks. The house at the Marion Eppley Wildlife Refuge in West Kingston became an island for several days as the surrounding flood plain swelled. And the 11-acre Carr Pond at the Maxwell Mays Wildlife Refuge in Coventry multiplied in size.
            But none of the refuges were irreparably harmed. In fact, they played a crucial role in helping to mitigate even greater damage that could have occurred in nearby areas. It’s a role they will likely play more and more often as the changing climate delivers increasingly severe storms, rising sea levels and damaging storm surge.
            “Conservation lands are resilient,” Ruhren said. “Whether they’re in a river floodplain or a coastal area, natural lands do what they’re supposed to do when the water rises – they absorb the water and release it slowly.”
            According to Ruhren, the most valuable elements of any conserved property during flooding are wetlands, which he describes as “nature’s kidneys. In addition to absorbing and holding large quantities of water,” he said, “they also filter out any contaminants from the water.”
            The difference is clearly visible. Water that surges downstream after a storm often looks like chocolate milk, he said. This is especially true where upstream areas are heavily developed with pavement and other structures that contribute to erosion and roadway run-off.
            But when that water has a chance to filter through wetlands and other natural areas, it’s much cleaner when it reaches the bay.
            “Sure, the trails might get flooded, but that’s just a short-term inconvenience,” Ruhren said. “But the water recedes as it filters down into the ground or continues downstream, and the forests are no worse off because of it. You might have a flooded forest for a short time, but they rebound quickly, and the plants and animals are adapted to it.”
            The danger comes when wetlands are filled, when impermeable surfaces like pavement prevent water from seeping into the soil, and when increasing development is permitted along waterways.
            “It’s like we’re filling a bathtub,” said Audubon’s Executive Director Lawrence Taft. “The more you fill in these places, the less water it can hold. By having areas where you just don’t develop – by backing off development from wetlands, rivers and marshes – then when the waters creep up, there is a place for it to go.”
            Taft and Ruhren agree that floodplains should be protected from extensive development so they can serve to mitigate damage when the waters inevitably rise again. Many local communities are finally getting the message.
            The Rhode Island Coastal Resources Management Council’s interactive mapping system, Storm Tools, is helping public officials visualize flood-prone areas and places that will likely be under water due to sea level rise in the coming decades. Coupled with a growing awareness of the important role conservation lands play in flood mitigation, some communities are now recognizing that the protection of open space should be a key component of their comprehensive planning.
            Taft is working with the state to develop new rules that factor in climate mitigation values when communities seek grants for open space and recreation lands in the future.
            “We really ought to start prioritizing those places that can be safely flooded in our open space decision making,” he said. “Properties would be ranked higher if they’re near a river or in a flood zone because of the climate mitigation services they provide.”
            But flood mitigation isn’t the only environmental benefit that conservation lands provide in this era of climate change. Established ecosystems like forests and salt marshes sequester carbon from the atmosphere while producing oxygen, and they provide critical habitat for birds and other wildlife whose habitat is rapidly changing.
            “The more conservation land you have, the more places there will be for wildlife to shift their ranges to when they need to,” said Ruhren. “And bigger is better, especially when the protected lands are connected.”
            He also emphasized the important role that forests play in keeping streams and rivers cool.
            “A lot of aquatic species are vulnerable to overheating, like native brook trout and freshwater mussels,” Ruhren said. “A good way to kill brook trout is to cut down the trees along the stream. We don’t think of heat as a pollutant or a stressor, but it is.”
            “We often talk about how our forests are the lungs of Rhode Island because they clean the air and produce oxygen and absorb carbon and keep us cool,” added Taft. “Putting aside land for conservation helps us with resiliency and adaptation and mitigation of some of the effects of climate change. Will the forests still change? Yes. Will the species change? Yes. But at least those open areas are here to function for air quality, flood protection, habitat and cooling.”
This article first appeared in the September 2017 issue of Audubon Report, the newsletter of the Audubon Society of Rhode Island.

Friday, September 8, 2017

Tough year for piping plover chicks at Rhode Island beaches

            Rhode Island’s population of piping plovers – the rare, sand-colored shorebird that breeds primarily on ocean-facing beaches – has grown significantly since it hit an all-time low of fewer than 20 pairs in the early 1980s. But 2017 was a bad year for the birds. The spring rains and a continuing battle with predators caused a decline in the number of chicks the plovers produced.
            According to Jennifer White, the biologist with the U.S. Fish and Wildlife Service who monitors the plover population, the statewide breeding population is about 100 pairs, though
the population fluctuates each year as some birds move back and forth to beaches in Massachusetts and Connecticut, depending on changing beach conditions.
            On South County beaches, where most of the birds’ breed, White counted 73 pairs of piping plovers this summer, mostly at Trustom Pond National Wildlife Refuge in South Kingstown, Quonochontaug Beach in Charlestown, and East Beach in Westerly. Another 23 pairs nested in Little Compton at Goosewing Beach Preserve, Briggs Beach and Fogland Marsh Preserve. In addition, one pair nested at Third Beach in Middletown.
            White said that each nest, on average, produced just .68 chicks, well below the 1.25 needed to maintain a stable population and far below the 1.62 chicks produced last year. The one bright spot was at Ninigret Conservation Area, where seven pairs of plovers produced an average of 2.29 chicks per nest.
            “Productivity this year was very very low, we think because of a lot of predators, both avian and mammalian,” she said, noting that crows, gulls, foxes and coyotes are the primary predators on plover eggs and chicks. “At some sites, we saw canine footprints that went from nest to nest.”
            The chilly, wet spring also caused many nests to fail.
            “We had a lot of nest failures right after the chicks hatched because of the rain,” White said. “The chicks can forage as soon as they hatch, but they can’t thermoregulate, so they still rely on their parents to keep them warm and dry. We had a lot of young chicks under five days old when we had rain all day, and we lost those broods.”
            Staff and volunteers from The Nature Conservancy monitor the piping plovers on Little Compton beaches. Tim Mooney, the Conservancy’s director of communication, said those beaches faced similar declines in chick productivity.
            “I’m struck by how many things really have to go right for the plovers to fledge chicks,” he said. “The habitat conditions have to be right, the tides, storms, predators. It really demonstrates how difficult it can be to bring a species back to healthy self-sustaining numbers.”
            Mooney and White also noted that the abundant human beach-goers can also be a factor in the success or failure of piping plover nests, though the beaches that attract the most human visitors seldom have any plovers attempting to nest.
            “It’s a perennial issue,” Mooney said. “Every day there is potential for user conflict, and we do our best to work with the visitors and the community to manage that threat.”
            The Nature Conservancy and the Fish and Wildlife Service conduct daily patrols of the beaches where the plovers nest, rope off nesting areas, and place mesh “exclosures” around nests to keep predators at bay while allowing the birds free access to and from their nest. They also keep daily records of how many plovers are nesting at each beach, how many eggs are laid, and how many chicks survive to fledge.
            “This was a rough year, but we know our management activities helped the birds,” White said. “But we still have a lot of work to do to make sure people follow beach guidelines and are aware of the birds, keep their dogs leashed, and carry out their food, which attracts predators to the beach.”
                Mooney said that an important part of The Nature Conservancy’s monitoring efforts is pointing out the plovers to beach visitors so they can develop an appreciation for the birds.
            “Once you’ve looked through a scope and seen a chick run across the beach, you can’t help but want to do something to help them,” he said. “That’s the job of our education folks – getting more eyes behind that scope.”
            Piping plovers are categorized as threatened on the federal Endangered Species List. They breed on Atlantic coastal beaches from Newfoundland to North Carolina. (A separate population breeds in the Great Lakes region.) To be removed from the list, they must achieve a chick productivity rate of 1.5 per pair for five consecutive years and maintain a breeding population of 2,000 pairs.
            “We’re committed to plover restoration in Rhode Island, but we’re just one spot in the range of these birds,” Mooney said. “The whole North Atlantic population would have to achieve that level of chick productivity to be delisted, so while individual sites may reach that target here and there, I don’t think we’re close to seeing the whole region reach it.”
This article first appeared on on September 6, 2017.