Waterfowl conservation focus of new UD Ducks Unlimited chapter

December 12, 2013 under CANR News

UD adds a Ducks Unlimited chapter to campusThe University of Delaware has added a Ducks Unlimited chapter as a new registered student organization on campus.

Ducks Unlimited (DU) is the world’s leader in wetlands and waterfowl conservation and started in 1937 during the Dust Bowl when, according to its website, North America’s drought-plagued waterfowl populations had plunged to unprecedented lows.

DU has an active presence in the state of Delaware, with more than 6,000 members in now 16 chapters who have conserved over 15,000 acres of the state’s wetlands.

At UD, the chapter will have three goals for its members: fund raising for the national organization, educating the public about waterfowl and wetland conservation, and providing students with conservation experiences.

Chris Williams, associate professor of entomology and wildlife ecology and the club’s adviser, explained that because UD is situated in the center of the Atlantic Flyway — one of four flyways corridors waterfowl use to move between northern breeding and southern wintering landscapes — “we have an amazing resource, starting in New Jersey and continuing through Virginia, where there are a lot of wintering waterfowl.”

As such, UD is “naturally a central hub for potential waterfowl research and education,” Williams said, adding, “It’s exciting that we have the ability to offer this resource in terms of education and research for the East Coast as a whole.”

Williams said that other than a DU chapter at Yale University, there are no other university chapters in the Mid-Atlantic and northeast regions. “When you think about that flyway, and all those ducks piling down starting at Long Island, we have a hole in university representation, so it was perfect that we could add a chapter.”

DU has a youth education outreach component that is broken up into three groups: Greenwing, for grade school; Ducks Varsity, which is geared toward high school students; and Ducks University, of which the UD group is a part.

Williams said he is hopeful that the UD group can give back by educating those in the Greenwing sections during an annual statewide event in April, while also exploring other opportunities as they arise.

Through the program, UD students will be directly involved in conservation efforts, Williams said, adding that they have already taken a trip to Bombay Hook National Wildlife Refuge.

Chase Colmorgen, a senior majoring in natural resource management in UD’s College of Agriculture and Natural Resources (CANR) and president of DU at UD, said the trip to Bombay Hook was very interesting as the students “met with the regional biologist for Delaware Ducks Unlimited, a Bombay Hook biologist, and a UD graduate student conducting waterfowl research. We had a tour explaining Ducks Unlimited’s projects in Delaware and in Bombay Hook, specifically. We hope to do more trips like that, where we can actually get insight on how Ducks Unlimited is getting involved and how we can help to get involved with conserving wetlands.”

Colmorgen, who has been a member of DU since he was 12 and participated in the Greenwing program, also said that while some may look at DU as simply an organization focused on hunting, it is much more than that and he wants to help spread their message of conservation. “Ducks Unlimited was founded by hunters but it’s priority is for conservation, so we want to do a lot of hands on work — maybe adopt a wetland on campus or go out and do work somewhere around the state in one of the main areas for the Delaware Department of Natural Resources and Environmental Control (DNREC). We also want to do a lot of education for the public and for younger people.”

Colmorgen said the University’s DU chapter offers something for everyone. “If you’re interested in the outdoors, and you might not be a CANR student, we want to offer a chance for you to learn more about wetlands. We’re trying to do activities that pretty much cover anything that anyone would be interested in with regards to wildlife and the outdoors. We really just want it to be a group that everyone can have something to relate to.”

Getting DU to UD

Williams pointed out that the DU chapter at UD was formed in large part to efforts made by U.S. Sen. Chris Coons and Bill D’Alonzo, a Delaware resident who is on the national board of directors for Ducks Unlimited and who was named the 2012 Budweiser Conservationist of the Year.

“Both Senator Coons and Bill D’Alonzo have been interested in increasing our younger citizens’ involvement in Ducks Unlimited, so a conversation was opened up in the early part of the summer to extend DU to the University of Delaware, where a waterfowl research program already exists,” said Williams.

He explained that after a meeting with DU officials, D’Alonzo, Dan Sarkissian, director of development for CANR, and Mark Rieger, CANR dean, the decision was made to start a DU chapter at UD.  The chapter became official in October.

For those interested in joining DU, Colmorgen said to contact him or Williams and that DU will be present at the spring activities night — scheduled for Thursday, Feb. 13, at the Perkins Student Center — during which students can learn more about campus organizations.

Article by Adam Thomas

Photos courtesy of Chris Williams

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Two UD professors assess habitat degradation in wake of Hurricane Sandy

December 4, 2013 under CANR News

Greg Shriver conducts research on habitat degradation due to Hurricane SandyUniversity of Delaware researchers Greg Shriver and Chris Williams have been awarded funds from a $162 million U.S. Department of the Interior project that will be invested in 45 restoration and research projects to better protect Atlantic Coast communities from future powerful storms by restoring marshes, wetlands and beaches, rebuilding shorelines, and researching the impacts and modeling mitigation of storm surge impacts.

Shriver and Williams will begin multiple projects to assess habitat degradation and restoration efforts with a focus on tidal marsh birds such as Nelson’s and saltmarsh sparrows, the American black duck and the Atlantic brant.

Shriver, associate professor and assistant chair of the Department of Entomology and Wildlife Ecology (ENWC), and Williams, associate professor of entomology and wildlife ecology, were awarded funding in large part because of work that occurred before Hurricane Sandy and the amount of pre-storm data that they collected.

“We were both well positioned,” said Shriver. “The challenge with determining the effects of disturbances is having the pre-disturbance data; Chris and I both have that so we can go back to the same place after the disturbance and assess the effects.”

SHARP continued

Shriver’s work will build off of the pre-Sandy work that he is conducting as part of the Saltmarsh Habitat and Avian Research Project (SHARP) research. SHARP aims to provide the information necessary for all states in the bird conservation region stretching from coastal New England through the Mid-Atlantic to protect regionally important habitats for tidal marsh birds.

Of particular interest is the saltmarsh sparrow, which is listed as “vulnerable” by the International Union for Conservation of Nature and has a limited breeding range from Virginia to Maine.

“The SHARP surveys are conducted at over 1,700 locations from Virginia to Maine where we are sample breeding tidal marsh bird populations and vegetation communities so we have a nice extensive survey that goes all the way through the hurricane impact zone, from the most intense area all the way to Virginia and Maine,” said Shriver.

Another goal of the project is to provide a regionally consistent platform for tidal marsh bird monitoring in the face of anticipated sea-level rise and upland/watershed development to produce population estimates for all bird species found in the high tidal marsh — including a global population estimate for saltmarsh sparrow — and identify regional population centers.

Shriver said the research team has two years of pre-hurricane data from 2011-12, and explained that this project will last until 2016 with a big part aimed at assessing the effects of Hurricane Sandy restoration projects. “A lot of them will be happening on places we already surveyed, and we will survey new sites that are identified as tidal marshes that are going to be restored. We will complete pre- and post-restoration sampling so that, as we get into 2015-16, the focus will be on the ‘before and after’ restoration sites.”

Black duck, Atlantic brant

Atlantic brant flockWilliams’ research focuses on the American black duck, which has been a bird of priority concern in the Atlantic flyway and the Mid-Atlantic, as well as the Atlantic brant, which is a small goose.

Explaining that he has been working with Southern Illinois University and the state governments of Connecticut, New York, New Jersey, Delaware and Virginia, Williams said that his research has many facets. “We monitor the populations of these two species, how they’re using the habitat, how productive the habitat is in the way of feeding,” he said. “All of this work has been going toward the greater goal of assessing the potential on the landscape at a very large macro scale over a long period of time for the populations of black duck and Atlantic brant.”

Williams said his research is looking at the initial impact of habitat loss and the secondary effects, such as loss of food supplies and the impact that might have on population. “For the black duck, we can come in a year later and we can measure how much habitat there is, and whether the food has responded or not, and we can do that at all of these sites that we previously measured,” said Williams.

The research is a little bit more complicated for the brant. Williams explained that the brant mainly eat sea lettuce, algae and eelgrass, and it is likely those food supplies were severely impacted by the hurricane.

“Part of what we’re trying to do is better map and predict where those foods are on the landscape,” said Williams. “If the models we have created work well using remote sensing and geographic information systems (GIS), we can apply them to a series of aerial photographs that were taken pre- and post-Sandy. The goal is a really nice pre- and post-storm scenario to evaluate the effect that a destructive storm can have on the brant food supply.”

Williams said the researchers are both just happy that they can be of service to those communities impacted by the hurricane in any way possible. “From an academic standpoint, we’re lucky that we can help,” said Williams. “While we can only minimally help with the human component, we have a well developed program at UD to provide assessment of the ecological and wildlife community and provide recommendations for future landscape planning.”

Article by Adam Thomas

Photos by Danielle Quigley and courtesy of Chris Williams

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Owl breeding season has begun in Delaware

January 29, 2013 under CANR News

Heard any owls lately? Maybe you’ve seen one of these elusive raptors perched on its nest.

If so, please tell Jean Woods.

Woods is the curator of birds for the Delaware Museum of Natural History, one of the organizations supporting the Delaware Breeding Bird Atlas. The atlas is a five-year, state-led project to determine the area bird population and assess any changes since the last atlas, which was held 20-plus years ago.

Data gathering for the atlas was supposed to end in 2012 but there was a bit of a problem, says Woods, who sits on the project’s technical committee. Well, make that a big problem, at least when it comes to owls.

a winter owl in Delaware“We discovered that we didn’t have enough data on the nocturnal birds, especially owls,” she says. “We extended the atlas into 2013 to try to get some additional information.”

Woods is eager to hear from birders or, anyone, frankly, who has heard or seen an owl recently. It can be hard to distinguish the sounds – or sight – of many of the state’s shore and marsh birds. But it’s pretty easy to identify the calls of Delaware’s owls. Their hoots are distinct, and there are only a handful of species in the state.

This is a great time to listen for owls. The end of January marks the start of the breeding season so there’s lots of hooting out there. Owls call for a variety of reasons, including defending territory, communicating with their young, or, as is the case now, to advertise their availability as a mate.

“I can tell that the great horned owls are getting ready to nest,” says Jim White, associate director of land and biodiversity management for the Delaware Nature Society. “I’ve been hearing great horneds when I take the dog out for a walk.”

Delaware has four species of owls that are year-round residents – the great horned, barred, barn and Eastern screech, according to Chris Williams, a University of Delaware associate professor of wildlife ecology in the College of Agriculture and Natural Resources. The great horned owls are the first nesters; they’ll soon be followed by the barred owl and barn, and finally, the Eastern screech owls.

Three more species of owls – short-eared, long-eared and Northern saw-whet – are regular winter migrants to Delaware. A fourth species, the snowy owl, appears sometimes in what is known as an irruption, says Williams.

2013 isn’t shaping up to be an irruption year for snowy owls. But, on the plus side, there are a good number of Northern saw-whets here this winter, says Woods.

Four Delaware owls are considered to be “species of special concern” – the barn, barred, short-eared and long-eared, according to Wayne Lehman, a regional wildlife manager with the Division of Fish and Wildlife. Lehman bands juvenile barn owls every year, from May to July. Banding is easiest then because the fledglings are still on the nest and unable to fly.

The state has been banding barn owls since 1996. It also has established nesting boxes for owls in state wildlife areas.

“Banding provides valuable information on an owl’s life span, home range, nest site fidelity and migratory patterns,” says Lehman.

If you want to go on an owl prowl, set out after dark, especially on windless nights, says White. However, a few species aren’t strictly nocturnal. The Eastern screech – a short, pudgy owl with a large head and almost no neck – often exhibits a burst of activity just before dawn and at dusk.

To increase the chance of success, head to Port Mahon Road in Little Creek Wildlife Area, east of Dover. This is known as the No. 1 spot in the state to see owls — the short-eared owl likes to hang out here. And you won’t need to wait until dark – the short-eared starts hunting in late afternoon, when the sun is setting. This species is a migrant, so get to Port Mahon Road soon. By March, the short-eared will be returning to Newfoundland and other northern locales to begin breeding season.

How to help

If you see or hear an owl in Delaware let Jean Woods know so she can add this data to Delaware’s Breeding Bird Atlas. Contact her at 658-9111, ext. 314 or via email at jwoods@delmnh.org.

Not sure which species you’re hearing? Check out owl calls on All About Birds.

Learn more

On Feb. 10 there will be a program on “Owls and Other Winter Raptors.”

Look for great horned, Eastern screech, barn, barred, short-eared, and other owls on a day-long program with Jim White. The program has a good track record – owls have been spotted every year. To register, call 239-2334.

Article by Margo McDonough

Photo courtesy of Jim White, Delaware Nature Society

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Stewart studies birds to understand trade-offs between reproduction, immunity

November 20, 2012 under CANR News

Does parenting take a toll on the immune system?

If you’ve ever been the parent of a newborn who demanded to be fed every three to four hours, your gut instinct tells you the answer is an absolute, unequivocal yes.

University of Delaware post-doctoral researcher Ian Stewart is conducting research to answer this question a bit more scientifically. His subjects – tree swallows – make human parents look like slouches. Both the mother and father tree swallow feed their hatchlings every five minutes, 12 hours a day.  (It should be noted, though, that their parenting gig is much shorter than ours — after 17 or 18 days the young leave the nest.)

Stewart is studying these small, migratory birds to better understand the trade-offs they make between reproduction and immunity. His research could potentially help scientists who study human biology better understand our own immune system and its stressors.

Stewart is part of a young but growing interdisciplinary field called ecoimmunology, which combines aspects of immunology with ecology, biology, physiology and evolution. He chose to focus his research on tree swallows and bluebirds because both are fairly tolerant of human interaction. “Some birds don’t like being observed but tree swallows and bluebirds don’t get stressed from being watched or handled,” notes Stewart.

There’s another very important benefit to working with these birds — since they nest in boxes, not up in the trees, they’re a heck of lot easier to catch.

Throughout the breeding season, Stewart catches the parent birds, injects them with a harmless antigen and releases them. Then, he re-catches the same birds a few days later to take blood samples and assess each bird’s immune response to the antigens.

“Some of the tree swallows work harder at parenting,” notes Stewart. “It may be because the bird has four hatchlings to feed instead of just three. Other times, the bird is simply more energetic at taking care of its hatchlings, regardless of brood size.”

“We’re monitoring the reproductive effort of the adults – mostly the rate at which they feed their nestlings – so that we can test whether the adults that are working harder produce weaker immune responses,” he says.

Stewart is conducting his research at Coverdale Farm Preserve, a 352-acre tract in Greenville owned by the Delaware Nature Society. The preserve already had 50 bird boxes in place last spring, when Stewart began his field work, and he installed another 50 boxes.

Now that it’s autumn, Stewart spends most of his time in the lab, crunching the data and performing immune assays on the samples he collected.  But earlier this season, he was at the preserve by 7 a.m. every day and after a full day of catching and observing birds, would head to the lab each evening to centrifuge the blood samples for storage.

“Prof. Mike Moore is overseeing my research and I had a grad student, Andrew Hydrusko, assist me, but I worked alone a lot,” he says. “So I enjoyed it when school groups passed by the bird boxes and there was time for them to learn a bit about my bird research. They loved to help catch the birds.”

“Ian’s work is quite interesting,” says Chris Williams, a UD associate professor of wildlife ecology. “One might think that having more offspring would improve your chances of passing off your genes to the next generation. However, if the parent’s health is compromised to make such an effort, natural selection may have something else to say about it. The evolutionary trade-offs between maternal health and maximum number of young ultimately produces optimal clutch sizes.”

So what’s the verdict — do parents shortchange themselves if they devote more resources to their offspring?

Stewart is still analyzing this year’s data and has another year of field research to go. But the preliminary answer, for tree swallows, appears to be yes. As for humans, he will defer to sleep-starved parents of newborns and let them have the final word.

Article by Margo McDonough

Photo by Danielle Quigley

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Now’s the time to watch migrating raptors, says UD’s Williams

September 27, 2012 under CANR News

If seeing a kettle of birds is on your bucket list, head to Hawk Watch at Ashland Nature Center or Cape Henlopen State Park ASAP. If this natural phenomenon isn’t on your bucket list, perhaps it should be.

“Kettle” is the word that birders use to describe a group of birds wheeling and circling tightly in the air on a thermal updraft, says Chris Williams, a University of Delaware associate professor of entomology and wildlife ecology. Nature photographer M. Timothy O’Keefe speculated that the term comes from the fact that these furiously flying flocks look like “something boiling in a cauldron.”

Your jaw is bound to drop the first time you see hundreds of birds swerving and soaring inside a thermal bubble as it rises aloft. (It’s still pretty jaw-dropping the sixth or sixteenth time you see it.)

Now’s the prime time to catch a kettle. That’s because broad-winged hawks are currently passing over Delaware on their fall migration to the neo-tropics. Although all raptors utilize thermals to make their flights more efficient, certain species, such as broad-winged hawks, are known to be frequent users of these air currents.

Large kettles of broad-winged hawks started showing up in Delaware in mid-September – more than 2,000 broad-wingeds were spotted at Ashland on Sept. 11 alone – and will continue through the end of the month.

“When it comes to the fall migration, my favorite species is actually the golden eagle,” says Jim White, associate director of land and biodiversity management for the Delaware Nature Society, which owns Ashland Nature Center. “The golden eagle is the ‘holy grail’ of fall bird-watching,” adds White. “But, in terms of pure spectacle, nothing beats the broad-winged hawk migration and the sight of hundreds and hundreds of hawks overhead.”

Long before the leaves turn or the autumnal equinox even occurs, the fall bird migration gets underway. “In August and September, songbirds migrate, beginning with hummingbirds and kingbirds and followed by warblers,” says Williams. “Slowly a parade of migrants work their way south, some leaving our area while others are coming in. Expect to see the shorebirds leave first followed by teal passing through and finally wintering waterfowl setting up shop.”

Now through October is peak season for the raptors – birds of prey, including hawks, eagles, falcons, ospreys and owls. However, every raptor flying overhead isn’t necessarily a migrant.

“Some raptors migrate south; others in the same species choose to overwinter here in Delaware,” notes White.  “For example, there is a pair of resident bald eagles that nests at Hoopes Reservoir. If you’re up on Hawk Watch Hill and see two bald eagles just monkeying around, flying low over Ashland’s Treetop Woods, then it’s probably these residents and not migrants. We train the Hawk Watch coordinator to exclude resident raptors from the counting records.”

The Hawk Watch sites are each staffed by a coordinator who is there to educate visitors as well as to count birds. Both programs are funded by the Delmarva Ornithological Society with additional support from other nature organizations.

Williams finds value in citizen-scientist initiatives such as Delaware’s Hawk Watch program. “These programs offer useful data for ornithologists,” he says. “Bird populations are dynamic and constantly in flux. No single researcher or team of researchers working alone could document the distribution and movements of so many fall migrants the way Hawk Watch efforts throughout the nation do.”

Of course, you don’t need to be part of a formal citizen-scientist program to track fall migrants. Just ask Ethan Harrod, a 5-year-old North Wilmington resident who counts birds with the help of his trusty field guide for young birders.

“Ethan sighted a red-tailed hawk on the Wilmington waterfront and he saw a sharp-shinned hawk fly over our backyard,” reports his father, John Harrod, who is manager of the DuPont Environmental Education Center in Wilmington. “He loves to try to id a bird and then check his field guide to see if he was right.”

The elder Harrod also has been seeing lots of migrating raptors in recent days. “I went kayaking on the Christina recently and spotted a northern harrier, a bald eagle and an osprey,” reports Harrod.

Make time to get out to a Hawk Watch site soon. The best time to visit is on a sunny, clear day when there is a breeze from the north or northwest, says White. If you’re lucky, you’ll see a kettle or two of broad-wingeds flying overhead.

Hawk Watch sites

Ashland Hawk Watch is located at Ashland Nature Center in Hockessin. Cape Henlopen Hawk Watch is at Cape Henlopen State Park in Lewes. For more information about either hawk watch contact Anthony Gonzon at 735-8673 or go to this website.

Article by Margo McDonough

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Birds aren’t flocking to backyard feeders this winter

February 13, 2012 under CANR News

What’s in short supply this winter? If you said snow you guessed the first (and obvious) answer. But you may not have noticed what else has been scarce — birds at backyard feeders.

“Our customers are talking about the fact that fewer birds are coming to feeders this winter,” says Charles Shattuck who, with his wife, Kathy, owns Wild Birds Unlimited in Hockessin. “I’ve heard reports of fewer birds at feeders across the East Coast.”

Although no one can say exactly why birds are staying away, Shattuck has a hunch that lack of snow and mild temperatures are at least part of the reason.

When Shattuck takes a walk through his 14-acre property, he sees plenty of birds in bushes and brambles. But not so many at the feeders, seed logs and suet feeders near his deck and kitchen windows. “Think about this past Wednesday, when it was 60 degrees,” says Shattuck. “The birds can still find bugs to eat when it’s that warm. They don’t need to come to my suet feeders.”

“It’s been a very light winter in terms of bird activity at feeders,” concurs Derek Stoner, an avid birder and naturalist at the Delaware Nature Society. “The big flocks of songbirds — sparrows, juncos, cardinals, titmice, chickadees — are around, but they are dispersed widely. Since we’ve not had extended periods of cold or snow cover, the birds have been fine and doing well with what nature provides.”

When northern Delaware did have a light dusting of snow Jan. 21, the birds decided to pay Shattuck a visit. “Even a small amount of snow drastically changed the activity level at my feeders,” he says.

Several northern species, like red-breasted nuthatches and pine siskins, haven’t arrived in Delaware at all – probably because weather conditions and food supply have been adequate in their breeding grounds in the boreal forests, says Chris Williams, a University of Delaware associate professor of wildlife ecology.

“Pine siskins sometimes appear in Delaware in great numbers; this kind of irregular migration is known as an irruption,” says Williams. “We had such an irruption in 2009.”

The fact that some northern species are staying away and resident birds are staying in the woods and fields doesn’t bode well for the Great Backyard Bird Count. A joint project by Cornell Lab of Ornithology and other partners, the count has become one of the largest citizen-scientist efforts in the nation. This year’s count starts Feb. 17 and concludes Feb. 20 and provides a real-time snapshot of where birds are across the U.S. and Canada.

Last February, 11.4 million birds were counted. This year’s numbers could be lower unless more participants venture out of their backyards. Any bird sighting can be reported to the Great Backyard Bird Count, not just those in the backyard.

“Last year, I saw a common merganser in the Red Clay Creek and vultures in the supermarket parking lot and included both on my checklist,” says Shattuck, who has participated in the count for eight years. His store, along with Wild Birds Unlimited’s other franchise stores, co-sponsor the count.“You can count birds at a park, go on a guided hike or simply make note of birds in a parking lot – any bird seen during the four days of the count qualifies,” he says.

Williams says he believes that the count offers useful data for ornithologists.  Bird populations are dynamic and constantly in flux. No researcher or team of researchers working alone could document the distribution and movements of so many species the way the Great Backyard Bird Count does, he says.

Solny Adalsteinsson is a graduate student in Williams’ research group and a self-avowed “bird nerd.” Growing up in Wilmington and later Kennett Square, Pa., she enjoyed the blue jays, northern cardinals and white-breasted nuthatches in her backyard in wintertime. As an undergraduate at Penn State, she liked to hike in the mountains and look for common ravens, which aren’t found in Delaware.

When she worked in Kauai, Hawaii, in 2009 and 2010, the seasonal shift in birds was subtler. “Many seabirds spend their lives out on the ocean and return to land only to breed so the return of the Laysan Albatross is a sign of ‘winter,’” notes Adalsteinsson. “In November, the albatross pairs return to their nest sites on Kauai and begin their courtship dances, sometimes right in residents’ backyards.”

You’re not going to spot albatrosses in Delaware but there are plenty of other interesting birds you might see if you join the Great Backyard Bird Count.

A screech owl, yellow-bellied sap sucker and brown creeper were on Shattuck’s tally sheet last year. Other birds spotted in Delaware during the 2011 count include a peregrine falcon, orange-crowned warbler and Baltimore oriole.  More frequently spotted birds were common grackles, red-winged blackbirds, dark-eyed juncos and white-throated sparrows.

To register for the Great Backyard Bird Count, or for more info, go to this website. While you’re there, print out a regional bird checklist to help identify what you see. There also are many good bird identification apps to figure out what you’re looking at, says Shattuck.

Learn more:

Breakfast and the Great Backyard Bird Count, Feb. 17, 8 a.m.-11 a.m. Help count birds and enjoy breakfast, too, at this program at Ashland Nature Center. To register, call 239-2334.

Article by Margo McDonough

Photo by Derek Stoner

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Colossal flocks of blackbirds are a common wintertime phenomenon in Delaware

December 8, 2011 under CANR News

If your holiday shopping takes you to Christiana Mall, time your drive for a half hour before sunset. That’s when you’re most likely to see a massive flock of black birds winging its way to Churchmans Marsh.

This flock of several million birds forms a solid black carpet in the sky; if it was earlier in the day, when the sun is higher, the flock would blot it from view.  The mixed flock consists of true blackbirds (red-winged, specifically) but also common grackles, brown-headed cowbirds and starlings.

“It’s an amazing spectacle,” says Derek Stoner, past president of the Delmarva Ornithological Society. “The sky is filled with birds returning to roost in the marsh after a day of feeding. You get the very best views of this super flock around the intersection of Route 7 and Churchmans Road — as long as you time it right.”

A flock of blackbirds so colossal that they block the sun sounds like something straight out of Hitchcock’s thriller, The Birds, but it’s a common wintertime phenomenon in Delaware.

“The unique combination of Delaware’s marshes and the surrounding agricultural lands are what make the state an attractive winter residence for millions of blackbirds,” says Chris Williams, a University of Delaware associate professor of wildlife ecology. “You’ll also see this winter flock phenomenon in New Jersey, coastal Virginia and North Carolina, and other coastal regions in the South.”

The Churchmans flock is one of about a dozen winter flocks in Delaware, according to Williams. Each morning the flock splits up and disperses in search of food, including such things as corn stubble or seedy grass. Depending on food availability, the Churchmans flock may travel to Chester County, Pa., or as far as Lancaster before returning to its nightly roost in the marsh.

Blackbirds only form super flocks in winter, says Williams. By March, the flocks will disperse to set up nests and begin breeding. Some of the birds in the super flocks are year-long Delaware residents; others migrate here from Canada and other northern latitudes.

As to why a bird would decide to hang out with millions of other birds each winter, scientists have several theories, says Williams. One possible reason is that a flock provides better protection from predators. Each bird in a massive-size flock doesn’t have to be quite as vigilant as it would be if it was flying solo.

A large flock also creates the conditions for “predator confusion.” For the same reason that fish swim in schools, birds fly in flocks. It can be difficult for a predator to pick out individual prey in large groups. “All the birds massed together create sensory overload for the predator,” notes Williams.

In addition, the dilution effect occurs when there is a large flock. Simply put, this means that the mathematical odds that a bird will get eaten are smaller when the flock is larger.

A large flock also promotes greater feeding efficiency because the birds share information about food sources. “Blackbirds are known to be great communicators,” says Williams.

Although Williams is awed by the Churchmans flock as it wings its way over his Newark neighborhood, heading out for food, he dreads the inevitable February day when 20 or 30 birds will drop down from the flock and take up residency in his backyard.

“I keep feeders up all winter long and enjoy seeing a variety of birds at the feeders,” says Williams. “But all of sudden, in February, a small group of blackbirds will break off from the large flock overhead, descend on my feeders and eat all the seed in minutes.”

“Even if I take the feeders down, the birds stick around,” adds Williams. “Blackbirds in the backyard are a sure sign it’s mid-winter.”

Article by Margo McDonough

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Ducks in the dark

June 14, 2011 under CANR News

Orrin Jones is doing field work using night-vision riflescopes to study the behavior of the American black duck.

Chris Williams and his University of Delaware research team employ standard tools of the trade for waterfowl research – core drills for core sampling, binoculars for waterfowl viewing and lots of coffee for long stints in duck blinds. But Williams may be the first wildlife biologist to use apparatus more commonly seen on the battlefield – night-vision riflescopes.

Williams, associate professor of wildlife ecology in the College of Agriculture and Natural Resources, is studying the behavior of the American black duck to determine if there are adequate food resources on the Mid-Atlantic coast to support this dabbling duck, which has been identified as a “species of concern” by the U.S. Fish and Wildlife Service.

Although there’s lots of data on the daytime behaviors of the black duck, up until now no one had a good idea what it was up to at night.

“We were aware that the American black duck isn’t exclusively diurnal because of anecdotal knowledge about its nighttime calls,” says Williams. “But we didn’t know the extent of its nocturnal activities because we didn’t have the tools to study this.”

Until recently, night-vision technology wouldn’t have been up to the challenge of detecting subtle movements in the dark-colored (and aptly named) black duck, which is just 13 to 19 inches in height. But night-vision technology has improved dramatically since the military began using it extensively during the Iraq war. The latest devices can amplify light up to 50,000 times, producing clear images even on moonless nights.

It’s critical for Williams to know what black ducks do at night, as well as during the day, so he can accurately determine how much energy the birds expend. With this data, Williams and his research team will be able to establish an area’s “carrying capacity,” the number of birds a habitat can support.

“Habitat loss is a threat to the American black duck,” notes Williams. “Nationwide, black ducks have declined by as much as 60 percent. We need to understand the carrying capacity for the black duck so we can make appropriate land management decisions.”

Graduate student Orrin Jones led the field research for the project, which took place in Edwin B. Forsyth National Wildlife Refuge, six miles north of Atlantic City.  American black ducks overwinter on the Jersey shore, as well as refuges and open land on Delaware’s coast, from November through March.

Field work is never a piece of cake but the black duck project could have qualified for that old reality show America’s Toughest Jobs. Jones, graduate student Jeremiah Heise (who is studying the Atlantic brant but helped with the duck research) and four technicians divvied up round-the-clock shifts, five days a week.

Because it was important to study the duck’s behaviors in a variety of habitat, from high marsh to mud flats, some study sites were only reachable by boat. After 15-minute paddles in a canoe or hour-long motor boat rides, Jones would settle in for the 9 p.m. to 3 a.m. shift and painstakingly record each time a duck swam, flew or preened. Weather ran the gamut – the infrequent mild spell, but more often, cold, rain, snow or outright blizzard conditions.

“We only missed one day of observation, during the 2010 Super Bowl blizzard, because the snow was too deep even using our 4×4 work trucks,” he says.

But for Jones field work is a piece of cake compared to what this summer holds – hour after hour inside a climate-controlled laboratory, where Williams’ research team is cataloging how much energy was available in the marsh core samples.

Working in the laboratory as part of the black duck research are Zariel Johnson, Alexandra Joesten, Amanda Dunbar and Marissa Goldstein.

“I enjoy the challenges of rugged field work; it’s one of the reasons I got into avian research,” says Jones. “It’s going to be hard to be stuck inside.”

Hard but necessary. It takes about 64 hours in the lab to analyze data from each quadrant of marsh studied, estimates Williams. All told, that’s 8,000 hours of lab work for Williams’ research team.

“The American black duck was once one of the more abundant waterfowl species in eastern North America,” says Williams. “I hope this research gives us a much better understanding of the black duck’s habitat needs.”

Article by Margo McDonough

Photos by Danielle Quigley

View this article online on UDaily by clicking here.

 

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Wild animals cope with harsh winter weather

February 10, 2011 under CANR News

Humans may whine about the harsh weather but for most of us winter isn’t a matter of life or death. For many wild animals and birds, the stress of winter is life-threatening. Wild animals and birds must contend not only with extreme weather but with a lack of food and other resources, such as adequate shelter.

Winter adaptations vary by species. Some species migrate, some go into dormancy and some develop a thick skin and tough it out. The thick skin is literal — from the bushy cold-weather undercoat of the fox to the thick winter coat of the raccoon.

Many birds adapt to winter by getting the heck out of here. About half of Delaware’s common summer birds are migratory and depart for warmer climes each autumn, according to Chris Williams, a UD assistant professor of wildlife ecology in the College of Agriculture and Natural Resources.

The birds that do stick around Delaware often form flocks in the winter, comprised of members of the same species, or sometimes flocks of different species (known as mixed flocks). Common mixed flocks include small birds, like chickadees and titmice, which join larger birds, such as nuthatches and woodpeckers.

Flocking is a form of cooperative behavior that rarely occurs during spring and summer nesting season. Williams says that flocking can increase wintertime avian survival rates. Flocks have an easier time securing food since birds are foraging together. And when flocks roost together, heat loss is reduced. Flocking also can provide safety in numbers from predators.

Birds utilize a number of other survival strategies in winter, such as fluffing their plumage, which creates an insulating layer by trapping air. They cope with the cold by shivering, just like we do. And many species increase their metabolic rate to produce more body heat. The downside of this adaptation is that they need to eat more food, even though food supplies are limited.

A handful of species lower their metabolism, but only in the evening when food isn’t available. These birds enter a state called torpor, which causes lowered body temperature and decreased oxygen consumption.

Plenty of mammals also slow their metabolic rate in winter. Groundhogs that live in northerly climes are “true hibernators,” meaning they exist in a state of uninterrupted, deep sleep for six to seven months, with body temperatures so low their metabolisms are almost at a standstill.

However, Delaware’s groundhogs are “semi-hibernators,” says Derek Stoner, conservation coordinator at the Delaware Nature Society.

“In February and March, if it warms up to about 50 degrees, Delaware groundhogs will come out of their burrows,” says Stoner. “By St. Patrick’s Day, the males, in particular are very active on warm days. They visit other burrows in hopes of finding a mate.”

In the fall, Delaware’s groundhogs gained some 50 percent of their body weight to prepare for their long — if somewhat fitful — snooze. But they also stashed grass in their burrows for the occasional snack when they do awake. Chipmunks also are “semi-hibernators” at Delaware’s latitude.

Deer don’t hibernate in winter although they do move around less to conserve energy. In cold conditions, they gravitate to areas with good thermal cover, such as a patch of evergreen trees that’s protected from the wind and cold and thus a degree or two warmer than surrounding terrain.

In the Poconos and Adirondacks you can see herds of several hundred deer hanging out together in the woods. Here in Delaware, herds are smaller, usually about 40 deer. Stoner says that a herd has congregated on Coverdale Farm, near Way Road, for the past several weeks.

Like flocking behavior in birds, herding is a wintertime phenomenon that increases survival rates. Come spring, the herd breaks up and the deer will go their separate ways.

Unlike us, wild animals and birds don’t need to turn to the Weather Channel to know when a storm is brewing; they sense the shift in barometric pressure, says Stoner. While we make our pre-storm trip for milk, bread and eggs, they, too, make a mad dash for adequate provisions before the snow flies.

Article by Margo McDonough

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Changing seasons provide varied birding opportunities

January 10, 2011 under CANR News, Cooperative Extension

One of the things that Derek Stoner likes most about living in Delaware is that every season brings new things to see and enjoy outdoors. Birding is a great example of nature’s diversity throughout the year.

“Birding in January, when owls are breeding, is a lot different than birding in July, when shorebirds flock to the Delaware Bay during their southward migration,” notes Stoner, the past president of the Delmarva Ornithological Society.

Here are some of the avian highlights that each season brings. How many of these birds will you spot in 2011?

Winter

As the New Year begins, the woods come alive with the calls of owls. Delaware’s most-common woodland owl, the great-horned owl, begins nesting now. Listen for its territorial hooting calls at night. The Eastern screech owl is also active and makes a trilling call. So how do you identify all those trills and hoots? Before heading out, Stoner suggests listening to owl calls at this website.

In February, take part in the Great Backyard Bird Count, a citizen science project throughout the U.S. and Canada. Last year’s count tallied more than 11 million birds of 602 species. Beyond the important scientific data that’s collected, the count generates excitement for birders, notes Chris Williams, UD assistant professor of wildlife ecology. Get involved by visiting this website.

Spring

In late April and the first half of May, birders flock to White Clay Creek State Park, where warblers, tanagers, orioles and other migrants are attracted to the large expanse of healthy woodlands. The best time to see lots of migrants, says Stoner, is after a night with steady winds from the south.

If you want to see red knots in the spring, there’s one place to go — Mispillion Harbor on the Delaware Bay, which attracts up to 90 percent of all the red knots in the world during this time period. Red knots fuels up on horseshoe crabs at the harbor. Check them out from the observation deck of the DuPont Nature Center. For a map and directions, visit the DuPont Nature Center website.

Summer

Summertime to Carrie Murphy means the return of the American goldfinch. This small finch is attracted to native perennials in her garden, including echinacea, black-eyed Susan and hardy ageratum. In its spring plumage, the brilliant yellow-and-black male looks like he belongs in a tropical rain forest instead of a Delaware backyard. Murphy, horticultural agent for New Castle County Cooperative Extension, says the goldfinch also likes annual sunflowers.

In July, look for blue grosbeaks, gorgeous blue birds with silvery bills. Doug Tallamy finds a pair nesting in his dogwood tree every July. “The male sings from May to September every morning for two hours,” says Tallamy, the chair of UD’s Department of Entomology and Applied Ecology.

Want to attract blue grosbeaks to your own yard? “Blue grosbeaks like to include snake skins in their nests, so if you hang a snake skin up on a fence, you’re more likely to get them,” notes Tallamy.

Late summer is prime time for migrating shorebirds all along the Delaware Bay. Visit the impoundments at Fowler Beach and Broadkill Road of Prime Hook National Wildlife Refuge to see black-necked stilts, black-bellied plovers and many varieties of sandpipers.

Fall

“I like watching hawks fly out of trees to kill unsuspecting rodents during the fall,” says Brian Kunkel, an entomologist with UD Cooperative Extension. If the thought of watching hawks feasting on rodents makes you lose your lunch, just keep your eyes skyward. The northern tip of Delaware is the place to see hundreds of migrating broad-winged hawks on their way to South America. Check out the Ashland Hawk Watch page.

In November thousands of ducks, geese and swans funnel into the First State to take advantage of the abundant food and resting places. Places like Thousand Acre Marsh, Woodland Beach Wildlife Area and Silver Lake in Rehoboth offer great viewing.

Wrap up the year by taking part in the Christmas Bird Count, the world’s longest-running biological survey. Seven Christmas Bird Counts take place in Delaware. Learn more at the Delmarva Ornithological Society website.

Article by Margo McDonough

This article can also be viewed online on UDaily by clicking here.

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