How birds get from there to here

Robins have already returned to southern New England from their wintering grounds to the south, and soon many millions of other birds — warblers, orioles, swallows, vireos, flycatchers and others — will follow suit. Scott McWilliams, a professor in the Department of Natural Resources Science at the University of Rhode Island, has been curious about bird migration since his childhood in Ohio. He chose to work at URI in part because of its proximity to Block Island, where bird migration

URI Professor Scott McWilliams (Photo by Michael Salerno)

research has been conducted for many years. For more than two decades, McWilliams has studied the physiological changes that birds undergo as they prepare for migration, especially the changes to their digestive system.

How did you get interested in birds?

When I was growing up, I was always fascinated with seasonal changes, and the birds leaving for the winter and coming back in spring were something that really caught my attention. We were surrounded by Amish families, and they had German-Dutch names for all the birds, so I got to learn two or three different names for every species. They knew a heck of a lot about the natural history of the birds, too. Birds were a good talking point with them, and also one of those fascinating things about the harbingers of spring and fall.

What’s the most interesting thing about birds?

The answer depends on who you’re talking to. What I do know is that people are fascinated by birds. Birds are in our backyards and around us, there’s tremendous variety in terms of colors and behaviors, and many of the species have adapted to be around people so they make it impossible for us to ignore them. For me as a scientist, I really like the idea of studying dinosaurs that live with us today. Essentially, they are the remnants of the dinosaur era that have made it successfully despite the dinosaur’s decline. They occur on every continent on the globe, so they are a tremendous example of adaptation and acclimation to various environments.

How do you describe the research you do?

I study birds that migrate and how they interact with their environment and how what we do impacts their life.

What is it about Block Island that’s notable to migrating birds?

The geography of southern New England is such that we have mostly an East-West Coast, with Block Island about 20 kilometers off that coast. Block Island has always been a place where tens of thousands of migrating songbirds end up each fall as they travel south. It allows you to study how the birds’ migration directly interacts with the quality of the environment and the weather patterns that occur. And if you look at the population dynamics of most any songbird, most mortality occurs in the first year during fall migration, so decisions that birds make during that time have much larger consequences for the population of those particular species.

Why do birds migrate in the first place?

Birds that migrate live in seasonal environments, so they’re primarily migrating to get to places during especially cold periods of the annual cycle when it’s too cold and they can make a better living elsewhere. All the birds that migrate have evolved to migrate in part to respond to the seasonality of the environment.

But not all birds migrate. Why not?

Some have decided to weather the storm, so to speak. Many of those species that are resident here do so because they can tolerate really cold temperatures; they’ve evolved an ability to deal with the cold. It’s a minority of species. The vast majority of species do some sort of migration to avoid seasonal declines in temperature or food resources.

How do they know when it’s time to migrate?

I love to think about these kinds of things. Almost all species use the environmental cue of photoperiod [daylight length] as a way to tell them when migration should occur. We can put birds in captivity and isolate them from the environment and just change the light schedule, and we can put them into a migration state — they start jumping around at night, they start fattening up, they start eating lots more. Photoperiod is the environmental cue that underlies the migration tendencies of birds. It tells you when spring happens, when fall happens. But almost all birds also use other cues, like weather patterns. Photoperiod defines the window of opportunity of when you’re going to migrate, but then you use weather and other environmental cues to decide exactly the day and time when you’re going to move.

How do they know what direction to go and when they’ve arrived at their destination?

It’s in their genes. The birds actually migrate for a certain number of days, and that certain number of days is what we call endogenously encoded. The genes they’ve inherited tell them that migration is roughly 40 to 50 days or it’s 20 to 30 days or whatever. There’s a migratory restlessness period that you can define in captivity – they’ll be restless for a certain number of days and then they’ll just shut it off. That tells them the duration. The direction is also coded for most songbirds in their genes. But there are other migration strategies as well. Cranes and geese, for example, learn where to go by following their parents.

What does it take for birds to prepare for migration? Like physiological changes?

Migration takes guts.

What do you mean by that?

Birds have a part of their brain that detects light levels and tells their brain what the photoperiod is. When that happens, there are brain hormonal responses that basically tell the bird it’s time to eat more, and they will increase how much they eat by two, three, four times on a daily basis, and so they start to fatten. Most birds use the amount of fat as their own internal indicator as to whether they are ready to migrate. Then, if it’s warm and the winds are favorable, they’ll take off and burn some of that fuel. Then they’ll end up at a stopover site somewhere and do it again.

What do you mean when you say that migration takes guts?

If you or I were going to run a marathon, the last thing we’d want to do is begin by getting really fat. Our digestive system won’t allow that, we’ll get too full, and that’s true of birds, too. Birds have evolved this incredible flexibility in their digestive system. When the hormones come from their brain in response to the photoperiod that tells them to start eating more, their digestive system responds by increasing in size by three or four times over the course of a couple days. Then they’re able to consume lots more and convert it to fuel. When they migrate, they may fly for several days and not eat at all. They basically reduce the size and the function of those digestive organs during that time, and then once they land, they have to build it back up. They’ve evolved this tremendous flexibility in their digestive system to accommodate this alternating feeding and fasting period.

What else is interesting about bird physiology?

A lot, especially the physiology of those that stay here for the winter. They have some incredible adaptations, like how ducks can stand on ice and still keep their feet warm, or how tiny songbirds can stay warm on very cold winter nights. They’re pretty amazing creatures.

This article first appeared in the Newport Mercury on March 20, 2018.

Longer days trigger nature's activities

            Around this time each year – oftentimes even earlier – most of us are pining for budding trees, migrating birds, and even the appearance of flying insects. Those environmental cues are a sure sign that the cold of winter has retreated for another year and shorts-and-sandals season will soon be upon us. Even though we had a record warm February this year, it didn’t appease our desire for even warmer weather.

            Part of the reason for this feeling has little to do with the actual temperature and more to do with the short length of winter days. Those short days can lead to what many of us call the

Cartoon by David Chatowsky

winter blahs, and as days grow longer we are reinvigorated and start to feel happier.

            In ecological terms, the length of daylight in a given day is called the photoperiod, and it is an important trigger for all sorts of natural history events. We sometimes assume that the awakening of wildlife in spring is linked to warming temperatures, and for some species it is. But for many others, it’s the increasing photoperiod that launches these activities.

            Birds are the perfect example. They use an ancient part of their brain called the pineal gland to detect light and dark through their thin skulls. When the daylight length is just right, it triggers them to prepare for migration by doubling their food intake and becoming active at night, which is when most songbirds migrate. In laboratory experiments at the University of Rhode Island, researchers have artificially manipulated the photoperiod to which birds are exposed, which cues the physiological changes required for migration even if it’s the wrong time of year.
               Using daylight length as a trigger for migration isn’t always a good thing, however. Those bird species that do so are having the most trouble adapting to the changing climate. During years when spring comes late, those species arrive when it’s still too cold to raise a family; during years when spring comes early, they’ve missed out on the early-flying insects they need to fuel reproduction. The birds that combine day length with temperature in determining when to migrate seem to be responding better to climate change.

                According to Hope Leeson, a botanist at the Rhode Island Natural History Survey, many plants are also triggered by daylight length to launch the next stages in their life cycle. Norway maples in Rhode Island, for instance, are one of the earliest trees to sprout leaves each spring, even though in their native Norway the trees don’t leaf out until later in the season. That’s because the leaves are triggered to emerge by a certain photoperiod, which occurs in Rhode Island several weeks earlier than in northern Europe.

                The bloom time and growth of many flowers in the aster family are also regulated by day length. Their growth is delayed – when compared to many other local flowers – until the days are sufficiently long, and they don’t flower until the day length gets shorter again in the fall, regardless of the temperature.

                The longer days of spring also trigger reproduction in many species, from green frogs to mink, and other aspects of some animals’ life cycles, like growth rates and molting of fur, can also be affected. Many humans are influenced by it, too. As I told my wife the other day, I’ll take out the trash as soon as the sun comes up a little earlier.

This article first appeared in the Newport Daily News on March 17, 2018.

Volunteers needed for 'funny-looking' bird study

            One of the region’s most unusual birds is the subject of a research project by University of Rhode Island doctoral student Erin Harrington, and she’s seeking at least 80 volunteers to become citizen scientists to contribute to her work. All it takes is a commitment of 38 minutes at dusk on four dates between April 20 and May 10, plus attendance at a two-hour training session.

             The subject of Harrington’s study is the American woodcock, which she calls “a funny-looking bird with short stubby legs and a variety of silly nicknames that makes arguably the silliest sounding mating call known to mankind.”

She’s not kidding.

            “They’re an ideal bird for citizen scientists to work with because they’re unique and goofy looking, but their goofiness is endearing in a way that makes them distinctive and easy to identify,” she said.

            Sometimes called the timberdoodle, woodcocks are chunky, brownish birds with large eyes, short tails, and long beaks that they probe into the ground in search of earthworms to eat.

They are found throughout the eastern United States, but their populations have been declining throughout their range. Little is known about their habits and habitat preferences in Rhode Island.

            “We want to figure out where woodcocks are showing up in Rhode Island and where they aren’t,” Harrington said. “Where they’re showing up and where they aren’t are equally important because that tells us a little about what kind of habitat they prefer. And in areas where they are showing up, we’re also interested in how many are there. Areas of high numbers likely indicate a preferred habitat area.”

            According to Harrington, woodcocks are considered an umbrella species for forest management. They require young forest habitat to thrive. If forestry officials manage habitat for woodcock, then many other species with similar habitat needs, including the rare New England cottontail, will also benefit.

            Participants in the research project will listen for the mating call of the male woodcock, which Harrington described as a nasal peent, which is very distinctive. They also perform what she calls a sky dance, an elaborate aerial display that includes a twittering sound made by their wing feathers. However, they only perform these rituals for a short period at dusk.

            “The males start peenting on the ground, move around in a circle and peent in different directions, then fly up into the air and essentially dance in the air before flying back down to the same spot they came from,” she explained. “Hopefully, their sky dance will be appealing enough in some way for a female to think, ‘yes, that bird is worth mating with.’”

Using a protocol developed by woodcock researchers elsewhere, participating volunteers will drive a designated route, stopping every 0.4 kilometers to listen for the birds for two minutes before proceeding to the next stop. Depending on the weather conditions, volunteers must start the route exactly 15 or 20 minutes after sunset and be finished within 38 minutes before it gets too dark and the birds stop displaying.

“After we have a few years of data, we hope to have better information about where they are, where they aren’t, and where they are in high numbers, and apply that information to forest management,” said Harrington. “Data from this study will be combined with data from other studies that tracked woodcock movement patterns and measured habitat characteristics so we can predict where the birds should turn up.”

No experience or knowledge is necessary to participate in the project as a citizen scientist.

“You don’t have to know anything at all about woodcocks,” she said. “We’re interested in people who feel comfortable driving at night, think the birds are cool, and are excited about participating in the project. That’s all.”

Training sessions will be held on Tuesday, April 3, or Friday, April 6 from 6 to 8 p.m. in Weaver Auditorium in the Coastal Institute building on the URI Kingston campus. For more information about the project, or to register as a volunteer, email Harrington at e_harrington@my.uri.edu or visit https://www.facebook.com/ProjectTimberdoodle.

This article first appeared on EcoRI.org on March 15, 2018.

And the dams come tumbling down

            South County is rightfully proud of its rich industrial history, but the legacy of that history includes a long list of rivers and streams with old, unsafe dams that contribute to localized flooding and prevent native fish from reaching their spawning grounds. As a result, a movement is underway to remove many of the dams to restore the waterways to their natural paths.

            “All those dams were built to power mills during the Industrial Revolution, but the mills aren’t in operation any more and the dams no longer serve an industrial function,” said Scott

Bradford Dam prior to removal (Ayla Fox)

Comings, associate director of the Rhode Island office of The Nature Conservancy, which is a partner in several dam removal projects. “Dam removal is beneficial for flood abatement, it reduces the risk of dam failure, and reconnecting the river is important for target fish species like river herring and shad.”

            The Pawcatuck River has been the main focus of dam removal efforts in the region for several years. The White Rock dam – the first obstruction that fish encounter as they try to make their way upriver – was removed in 2015. The Potter Hill dam, a few miles further upstream, was left in place, but improvements were made to its fish ladder in 2016 after sediment build-up around the ladder created what Comings called a reverse eddy, which spun the fish around and directed them away from the ladder.

            The next dam on the Pawcatuck, the Bradford dam, was removed last year in a six-month project that involved construction of a temporary bypass channel to divert water around the dam, demolition of the dam, and the repositioning of hundreds of boulders into the river to create a series of step-like weirs and pools to enable fish to swim upstream. It also allows canoes and kayaks to navigate the waterway safely without portaging and reduces the risk of upstream flooding.

            “Connectivity is the golden word in this project,” Comings said. “By reconnecting the river, everything that depends on the river will benefit – not just the fish, but freshwater mussels, mammals, reptiles, birds and amphibians, too.”

            The next dam to be removed in South County is in North Kingstown adjacent to the Shady Lea Mill on the Mattatuxet River. The former textile mill is now being used as artist studios. Following the 2010 floods, the state inspected the dam and deemed it a high hazard, which increased the liability on the dam’s owner and required preparation of an emergency action plan. The owner ultimately decided to have the dam removed, and she is working with Save the Bay to complete the project this year.

            “We’re always looking for good habitat restoration sites,” said Rachel Calabro, Save the Bay’s Riverkeeper and the coordinator of the Shady Lea project. “There’s a large fish run just downstream at the Gilbert Stuart Museum, and this will open up another half mile of the river for herring, eels and trout.”

Work began last October, when a section in the middle of the dam was removed to lower the water level behind the dam so the sediments could dry out. It also allowed archaeologists to examine and photograph the historic dam, which was found to have been originally constructed of fieldstone in the 1800s and later capped with cement.

This spring and summer, contractors will remove the sediments, which have already been tested and found to be free of contaminants, and then the spillway will be dismantled.

“We can already see that the stones are really loose, so I know when we go in to remove it, the dam will come down in a day,” said Calabro. “Some of those stones will be placed in the channel below the dam to create pools and make riffles in the stream for the fish to navigate. That’s the finesse part of a habitat restoration project like this.”

Once the dam is removed, Calabro said that native plants will sprout to revegetate the site.

“We’ll let the river naturally find its channel, and we’ll end up with a nice stream running through a vegetated wetland,” Calabro said.

Save the Bay will use this project as a showcase of dam removal techniques to encourage other private dam owners to undertake similar efforts to remove their liabilities and restore habitat.

“We’re not just interested in getting fish from point A to point B,” Calabro said. “We want native species to be able to migrate and also have better water quality, better dissolved oxygen, and the other things that happen when you remove a dam. We’re always looking for opportunities to improve stream health, which also improves resilience by removing vulnerable infrastructure.”

            Not every dam in the region can or should be removed, however. Some deserve to be protected for their historic attributes, for aesthetic reasons, or because there are alternatives to removal.

            “Every site is different,” said Andres Aveledo, a conservation engineer for The Nature Conservancy and the Rhode Island Department of Environmental Management. “The best conservation alternative is through removal of the dam, but we sometimes select alternative approaches because stakeholders want the impoundment to remain.”

            The dam on the Saugatucket River near Main Street in Wakefield, for instance, is on the state’s list of historic places, and the town of South Kingstown did not want to lose its attractive waterfall. Yet the site’s fish ladder, which was built in the 1960s, was not working. So in 2016 the fish ladder was re-engineered to ensure more herring make it over the dam and into Indian Lake.

            A similar effort is planned this year at the 12-foot dam at the Palisades Mill Complex in Peace Dale, enabling fish to swim even further up the Saugatucket.

            And in Charlestown, fish now have better access to Factory Pond from Green Hill Pond and the Charlestown Breachway, thanks to an aluminum device called a steep pass that was installed in 2017 to help fish surmount the modest private dam on Factory Brook.

            “That little run can now support about 20,000 river herring,” said Aveledo. “That’s a lot of bang for our buck.”

           

This article first appeared in the spring 2018 issue of South County Life magazine.

Serving up seeds

            Small mammals like squirrels, chipmunks, mice and voles play a surprisingly significant role in determining the tree composition of most forests. That role is based largely on their choice of which seeds to eat. By consuming the seeds of some species – thereby denying them a chance to grow – and hiding other seeds, which helps them germinate, the animals determine which tree species thrive or decline. At the same time, the availability of different seeds influences the population cycles of some mammals.

            Those are among the findings of a series of research studies conducted by a University of Maine biologist who combined data from a 33-year population study of rodents with experiments in the Holt Research Forest, Penobscot Experimental Forest and Acadia National Park.

            “Small mammals can reach extremely high densities; in some years up to 100 individuals per acre,” said Alessio Mortelliti, assistant professor of wildlife conservation. “They can actually eat every single seed of the species they like, which means they can have a massive impact on forest regeneration.”

            By pointing trail cameras at plates left in the forest with different tree seeds, Mortelliti found strong preferences among different animal species. None of the animals liked the seeds of balsam fir, for instance, which Mortelliti said is one reason why there are so many balsam firs in Maine forests. Paper birch seeds were also avoided by most of the animals. Mice had a preference for red oaks, which voles ignored, and all of the animals liked white pine, spruce and maple seeds.

            In another study, the researcher found that different seeds affect the vole population differently, and the effects were largely dependent on the animal’s population density. White pine seeds were found to be especially important when vole populations were low by helping them survive and reproduce in greater numbers. The animals only ate paper birch seeds when the vole population was high and few white pine seeds were available.

            Mortelliti hopes to use his research findings to help forest managers minimize the impact of small mammals on the most commercially valuable tree species.

            “With a little more research, we should be able to figure out how to optimize timber production by understanding how small mammals are affecting the regeneration of the forest,” he said. “We hope to be able to give timber companies prescriptions for the best way to manage the forest so they can maximize the regeneration of the trees they want.”

            He said this will become especially important as the climate changes and new tree species expand their ranges northward.

            “Tree species composition is going to change, and small mammals will play a key role in affecting the expansion,” Mortelliti said. “They’re the gatekeepers. They’re going to decide which plants will regenerate. The results of our studies will tell us what tree species will be blocked by the animals and which will be favored, and that will inform the management actions that can be taken to deal with this process.”

           

This article first appeared in the winter 2018 edition of Northern Woodlands magazine.

Go easy on the salt

            The use of salt on snowy roadways is effective at melting snow and ice and making driving safer. But when that salty snowmelt runs off into nearby lakes and ponds, it can make the waters toxic to aquatic ecosystems. While that has long been believed to be true, there was little data from a broad geographic region to back it up. Until now.

            A study by a Dartmouth College graduate student and 14 collaborators from throughout North America found that 44 percent of the 371 lakes analyzed had “undergone long-term salinization” as a result of salt run-off from roads, driveways and parking lots.

            Flora Krivak-Tetley said that 26 of the lakes had salt concentrations over 100 milligrams per liter, more than five times that of rain water. “Salt at high levels like that starts to be directly toxic to large lake organisms like fish and amphibians,” she said. “For the most part, our lakes here in New England are below that level and aquatic life can handle it.”

            But 14 of the lakes in the study are predicted to increase to levels above the Environmental Protection Agency criterion that places aquatic life at risk.

            “Our big question, though, is what happens at lower salt concentrations, those between 20 and 100 milligrams per liter and slowly rising over time,” Krivak-Tetley said. “Phytoplankton and zooplankton communities might not be directly killed, but it may cause shifts in community composition.”

            She said that smaller organisms can lose their ability to compete against others for resources in high salt environments. And because many of the less common native species tend to be intolerant of salty conditions, she believes that increasing salt concentrations could lead to a loss of biodiversity.

            In a research paper published in the Proceedings of the National Academy ofthe Sciences, Krivak-Tetley and her colleagues found that the primary drivers of increased salt in lakes was a high density of roads and parking lots around the water bodies.

            “Impervious surfaces around lakes puts them at risk,” she said. “Even as little as one percent impervious surface correlated to rising salinity. That may seem like a small number, but a small amount of development around a lake and the use of salt in that area is having an impact on most lakes.”

            The good news, she said, is that most of the lakes studied in the Northeast, especially those in the Adirondack region and in Vermont and New Hampshire, are not in highly developed areas, especially compared to those in the urbanized Midwest.

            “It’s nice to see that we have a lot of lake systems that are really healthy in our area, and even some of those that are increasing in salt concentration are still pretty low,” Krivak-Tetley said. “So if we make a point of good management and limit development around our lakes, or if homeowners around the lakes don’t over-salt their driveways, then that can make a difference and help keep our ecosystems in good shape.”

This article first appeared in the winter 2018 edition of Northern Woodlands magazine.

Beware: Frogs, salamanders on the move

            During last week’s warm spell, Emilie Holland saw and heard something she seldom detects this early in the year – the first movement of frogs and salamanders from their woodland wintering grounds to their springtime breeding pools. She observed wood frogs, spring peepers, spotted salamanders and even a rare marbled salamander near her house not far from the Great Swamp Wildlife Management Area in South Kingstown.

            “We often get pretty early activity here,” said Holland, an environmental scientist for the Rhode Island Department of Transportation and a board member of the Rhode Island Natural

Marbled salamander by Emilie Holland

History Survey. “For whatever reason, the micro-climate is good for them. The problem is that my hotspot is along a road, and the frogs and salamanders are often crossing it,” which puts them at risk.

            During the same warm days last week, other observers reported hearing spring peepers in North Kingstown and Cumberland and seeing a red-backed salamander in Middletown.

            According to amphibian expert Lou Perrotti, director of conservation at Roger Williams Park Zoo, frogs and salamanders don’t typically migrate to their breeding ponds until mid-March in most areas of the state. During the cold winter of 2015, when many ponds were still frozen until April, amphibian migration was delayed by almost a month. But it’s not unusual for rain showers during an especially warm period in late February to trigger an early migration.

            “When that happens, the migration period tends to get extended,” Perrotti said. “A snowstorm or cold snap shuts things down for a while, and then it picks back up again. You don’t have the usual massive explosion of breeding activity all at once. It trickles along instead.”

            What happens to the frogs in the ponds when the cold returns and the ponds freeze over again? Not much. Perrotti said the animals are adapted to survive such conditions for short periods of time. In fact, University of Rhode Island herpetologist Peter Paton said he commonly sees wood frogs and spotted salamanders swimming beneath the ice of local ponds in late winter. And wood frogs are uniquely adapted to freeze solid and thaw out later with no negative consequences.

            The bigger concern – as Holland expressed – is that many frogs and salamanders must cross roads to reach their breeding ponds, and untold thousands of them get run over by vehicles each year in Rhode Island in the process.

            “It’s a huge problem, one of the biggest threats to amphibians and reptiles in the area,” Perrotti said. “I’ve seen nights where there were hundreds of smashed wood frogs at just one site. Toads get hammered, too, because they typically have huge breeding explosions over a period of two or three nights. And gray tree frogs, too, which are pretty clumsy on the ground.”

            Amphibian movement to and from their breeding ponds will likely continue through April – some species, like green frogs, migrate later than others – but it typically happens at night when it is raining. So Perrotti and Holland recommend driving carefully at night along back roads in wetland areas during rain showers.

            “It’s hard to avoid every frog in the road, especially if you catch it on a good night for migration when they’re everywhere,” Perrotti said.

            One strategy that Perrotti said has been employed in western Massachusetts to avoid the problem of amphibian roadkill is the installation of what he calls “salamander tunnels” beneath roadways in areas where large numbers of frogs and salamanders migrate across roads. Barriers along the roadside funnel the animals toward the tunnel, which avoids much of the mortality.

            The idea has been discussed in Rhode Island, but the cost is high and finding funding in municipal budgets is an impediment. Signage encouraging drivers to slow down at certain locations is another strategy that officials in the state have considered, though few have been installed to date.

            Holland notes that homeowners with sump pumps should regularly check the system for amphibians that wander in and cannot escape.

            “I’m constantly fishing salamanders and frogs out of mine,” she said. “People should monitor the sump in their basement and maybe they can keep a local breeding population healthy by not letting the adults die in a pitfall trap that they didn't even know they had.”

            Those interested in learning more about local amphibians and participating in a related citizen science project should consider signing up for Frogwatch, a national program administered locally by Roger Williams Park Zoo. Volunteers attend a training program to learn the breeding calls of the various frog species that reside in Rhode Island, then visit a designated pond in the evening once a week from March through August to document breeding activity.

            The next training session is Saturday, March 3 at 1:30 p.m. and Sunday, March 4 at 1 p.m. Perrotti said that families with children over 10 are encouraged to sign up together.

            “Kids are especially good at it because they’re inspired by the program and they’re good at remembering the calls,” he said.

This article first appeared on EcoRI.org on March 1, 2018.