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Enchanting Butterflies

July 18, 2011 under CANR News

Sheila Vincent may be the only person in Delaware who gets paid to catch butterflies. Every summer day, Vincent heads out with a net and collects butterflies, caterpillars and larvae to stock Ashland Nature Center’s Butterfly House.

As group program coordinator for the Delaware Nature Center, Vincent spends the bulk of her time teaching natural history programs and only about 15 minutes with her butterfly net. “I really look forward to butterfly catching. It’s a bit of peace and quiet during hectic workdays,” she says.

Last season was a “spectacular butterfly season,” according to Vincent and this summer looks to be shaping up to be a good one, too.

“Most years, butterflies are abundant in Delaware from June through August,” says Brian Kunkel, an entomologist with University of Delaware Cooperative Extension. “Mid-July to mid-August is typically the peak of activity.”

But bad weather or insufficient food sources can be game changers. Two years ago, the butterfly season was lackluster because of too many cool, rainy days. Other times, host plants may not be well developed.

Delaware is a good place for butterfly watching. There are about 120 species of resident breeding butterflies in the state. Some entomologists make a distinction between butterflies and skippers – in which case, there are 70 species of butterflies and 50 of skippers. Named for their rapid flight pattern, skippers have small, angular wings and bodies that are proportionately larger than true butterflies, says Kunkel. There’s even a skipper known as the Delaware skipper because it was first spotted here.

But speedy skippers aren’t good for teaching purposes. Monarchs are Vincent’s go-to butterfly for nature programs, especially when she’s working with kids. Monarchs are fairly slow, abundant and easily recognizable. Her own personal favorites include the pipevine swallowtail, a relatively rare species that has orange spots and iridescent blue wings. Vincent also appreciates what she calls the “somber beauty” of the mourning cloak butterfly, which is dark brown with yellow borders around the wings and a row of blue spots.

The black swallowtail butterfly, which has distinctive yellow and bright-blue markings, tops Kunkel’s list of favorites. His wife grows herbs on their deck and always plants dill or fennel, which attract black swallowtails and their caterpillars. Kunkel also likes the Eastern-tailed blue. The males are usually light blue and the females a charcoal color but some varieties are pink or purple.

When Kunkel was a boy, he saw scores of Eastern-tailed blues in his yard every summer. That’s because his parents weren’t perturbed by a bit of clover in the their lawn.

“The caterpillars of Eastern-tailed blues feed on clover,” says Kunkel. “If you eradicate every piece of clover in your yard, I guarantee you won’t see any Eastern-tailed blues.”

Kunkel says he’s a “lawn guy,” who loves a carpet of green, but he’s happy to let clover or wild strawberries coexist with turf. He also can handle a little leaf damage on ornamental plants for the sake of the butterflies.

“Don’t get overly excited about caterpillars on your plants,” he says. “Yes, they’ll munch on some leaves but if you want butterflies, you’ve got to have host plants for the larvae, too.”

Vincent has incorporated plenty of host plants for caterpillars, as well as food plants for butterflies, into her New Castle yard. Her perennials include butterfly weed, milkweed, phlox, asters and goldenrod.  She also plants parsley and fennel in the ornamental beds to attract black swallowtails.

If your yard isn’t lepidoptera friendly just yet, there are other places to spot butterflies. To see the largest number, as well as the most species, choose a sunny, open location – like a meadow or field – that features plant diversity. Vincent recommends the meadow at Ashland Nature Center, Middle Run Natural Area, and White Clay and Brandywine Creek state parks.

Kunkel suggests the UD Botanic Gardens, which opened its Lepidoptera Trail in 2009. This self-guided interpretative trail showcases trees, shrubs, wildflowers and native grasses that provide food for butterflies and moths during both the caterpillar and adult stages. Right now, the Trail is abundant with butterflies.

Special events

• Open House in the Native Plant Teaching and Demonstration Garden will be held Monday night, July 18. Join Kunkel for a plant, pest and beneficial insect walk. Get your questions answered about butterflies, caterpillars and other insects. New Castle County Cooperative Extension Office, Newark. 6-8 p.m. For more information, call 831-COOP or email cjmurphy@udel.edu.

• A Mid-Summer Night’s Stroll through the Gardens will be held Wednesday, July 20. Watch butterflies feast on natives on the Lepidoptera Trail and enjoy all the mid-summer blooms in the UD Botanic Gardens. Live steel drum music and light refreshments. 4-6:30 p.m. Reserve a spot by contacting Donna Kelsch, 831-2531 or botanicgardens@udel.edu.

Article by Margo McDonough

Photo by Danielle Quigley

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Nature’s Fireworks

July 11, 2011 under CANR News

 Annelid worms do it. Certain species of centipedes and millipedes do it. Even a tropical land snail can do it.

But here in Delaware, fireflies and glow worms are the only terrestrial creatures that light up the night with their own built-in flashlights.

Bioluminescence results from a chemical reaction in which chemical energy is converted to light energy, according to Doug Tallamy, chair of the University of Delaware’s Department of Entomology and Wildlife Ecology in the College of Agriculture and Natural Resources.

Fireflies (Lampyridae) aren’t actually flies and glow worms (Phengodidae) aren’t really worms. Both are considered to be beetles and are closely related species.

The fireflies’ glow adds beauty to a summer night but there are several pragmatic reasons for bioluminescence, too. Fireflies and glow worms light up to attract the opposite sex. Adult fireflies, both male and female, flash coded messages to attract prospective mates. Males fly about while they flash, females usually flash while hanging out in bushes. It’s all about “speed dating” not lengthy courtships — there’s no time to waste since adulthood only lasts for about two weeks.

There’s another reason why fireflies light up, at least in the case of juvenile larvae. Almost a decade ago, UD scientists led by Tallamy discovered that baby fireflies light up to keep predators at bay.

Previous studies had shown that mice and other would-be predators shun adult fireflies because of a compound in fireflies’ body that produced a bitter taste. The UD study demonstrated that baby fireflies flash to advertise that they also exhibit this bitter taste.

“A flashing neon sign may lure hungry humans to an all-night diner but the bioluminescence of firefly larvae sends a very different message to would-be predators,” says Tallamy.

Summer season

This summer is shaping up to be a good but not spectacular season for fireflies.

“Lightning bug populations at my house have been strong but not record-breaking,” says Tallamy. “In general, populations fluctuate from habitat availability more than from weather. However, if we get a bad drought during the summer and fall that does impact the population of lightening bugs the following summer.”

Fresh strawberries for a few short weeks around Memorial Day. Carnival rides at the State Fair for 10 days in July. Like other summertime pleasures, firefly season is short-lived.  “Nature’s fireworks” begin a few weeks before July 4th and are at their peak now. By the end of July they’re gone, save for a few stragglers.

Where to find different species

Several species of fireflies can call themselves native Delawareans. The beach region of Sussex is home to the coastal firefly, which prefers sandy, even salty, soil and generally stays close to the ground. Inland Sussex and Kent counties are home to yet another species. But the greatest diversity in firefly species is found north of the Chesapeake and Delaware Canal, says Tallamy.

“Fireflies are especially abundant in the Piedmont region, in the northernmost part of Delaware,” he says. “Most firefly species favor ‘old field habitat.’ In New Castle County, that type of habitat is most commonly found around the White Clay and Red Clay creeks and along the Brandywine River.”

At first glance, one species of firefly may not look much different from another. But pay close attention to fireflies as they begin to light up. “If you look closely, you’ll start to notice some distinct variations in their flash pattern,” says Tallamy.

There are three characteristics that differentiate firefly species:

  • Where the fireflies are located. Some species like to be close to the ground; others prefer shrubs and low trees.
  • The flight track, or style of flying, varies from species to species. Some fly in a “J” pattern then swoop down low, others take looping flights.
  • The pattern of the bug’s flashing. Think of the flashes like Morse Code — do they resemble a dash-dash-dash pattern or dash-dot-dash?

If your kids like to catch fireflies and put them in a jar, go for it, says Tallamy, as long as you punch some holes in the lid and release the fireflies after a few hours. Fireflies are beneficial insects; in their larval form they feed on garden and crop pests.

Article by Margo McDonough

The article can also be viewed online on UDaily.

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Happy National Pollinator Week

June 21, 2011 under CANR News

Debbie Delaney looked like she was feeling the heat on a recent 95-degree day at the University of Delaware apiary, despite the shade of black walnut and tulip poplar trees. It was hard to tell how the 22 hives of honeybees – some two million bees in all – were handling the steamy weather.

But Delaney, an assistant professor of entomology and wildlife ecology in the College of Agricultural and Natural Resources, had no worries. “Bees are much better at thermoregulation than humans are,” says Delaney. “Honeybees maintain strict temperature control. The colony always stays between 89 and 92 degrees, ideal for a honeybee, and the humidity never varies more than 5 percent. Worker bees flap their wings to cool the air and some periodically leave the hive to reduce the effects of body heat.”

Delaney has been researching bees for years but continues to be amazed at their abilities, including staying comfortable in the heat while we wilt. She’d like to see bees get a bit more respect — if not the all-out enthusiasm she displays.

She’ll have an opportunity to spread the word about bees this week, which marks National Pollinator Week. The event recognizes not only bees but all pollinators – birds, butterflies, bats and beetles. One in every three bites of food humans consume has been made possible by one of these pollinators.

Pollinator Partnership, a nonprofit organization that sponsors the week, calls bees the primary pollinator of most plants. Delaney agrees, with a slight qualification.

“Bees are definitely the most important pollinator in our state in terms of the numbers and the importance of the crops they pollinate,” she says. “But bats also are important in a different way. Bat-pollinated flowers generally open at night and have distinct floral tube sizes and shapes that can accommodate bats.  So bats are very important pollinators for a certain subset of plants.”

Even while giving bats their due, Delaney rattles off the Delaware crops that bees do pollinate: apples, asparagus, blueberries, broccoli, cabbage, carrots, cantaloupe, cucumber, eggplant, honeydew melon, nectarines, peaches, pears, peppers, pumpkins, okra, onion, squash, strawberries, tomatoes and watermelon. She’s quite sure she has missed a few. After all, bees pollinate more than 90 crops in North America.

Non-native honeybees are responsible for some of this pollination. But Delaware’s native bees deserve credit, too.

There are at least 200 native bees in the state, according to the state Department of Agriculture, which recently completed a five-year study of native bees. “Recent research has shown that native bees can play a major role in pollinating agricultural crops,” notes Delaney. “Native bees often will visit flowers in wet or cold weather when honeybees don’t want to come out of their hives. And farmers who use managed honeybees will see increased yields when native bees interact with the crops.”

Wild honeybees – descendants of honeybees introduced by European colonists – also play a role in agricultural pollination. Research on these feral bees may even help combat colony collapse disorder, a poorly understood syndrome that can wipe out entire hives of managed honeybees.

The Feral Bee Project, sponsored by North Carolina State University, asks beekeepers and “citizen scientists” to log the location of wild honeybee hives at the Save the Hives website.

“Colony collapse disorder in domestic honeybees continues to be a major concern,” says Delaney. “We still don’t know the cause or causes of this syndrome. But the Feral Bee Project may give us a better understanding of the role that natural resistance plays in fighting disease or environmental stress, as well as a better understanding of genetic components that contribute to ‘survivor stock.’”

Learn more

To find out more about pollinators and National Pollinator Week, go to the Pollinator Partnership website.

The Brandywine Zoo will be hosting “Pollinator Power” on June 25, a family friendly event from 10 a.m. to 4 p.m.

Article by Margo McDonough

Photos by Danielle Quigley

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

 

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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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Stink bugs shouldn’t pose problem until late summer

April 1, 2011 under CANR News, Cooperative Extension

Last fall, Stephanie Sturmfels battled stink bugs at her Pike Creek home and yard. “Stink bugs were on my deck, they were on my front porch, some were even in my house,” recalls the mother of two small children. “My four-year-old daughter, Madison, would go around and collect stink bugs in pieces of tissue.”

Now that spring has arrived, Sturmfels is worried that stink bugs may return in full force. So far, she has seen a few stink bugs but nothing like the invasion last September and October.

Brian Kunkel, a UD Cooperative Extension entomologist, has some good news for Sturmfels and anyone who despises the brown marmorated stink bug. “The adult stink bugs that were driving people crazy last fall will be giving birth this June and dying off soon afterwards. From now until then, they will be too busy feeding on plants in the landscape to spend much time around houses.”

“Their offspring — the nymphs — will spend most of the warm-weather months outside as they mature. They don’t feed in houses so you shouldn’t expect to see many on decks and patios or inside houses this summer,” adds Kunkel.

Best yet, nymph stink bugs can’t fly — they have wingbuds but not mature wings — so they can’t land in your hair, on your shoulders, or in a bowl of potato salad, the way those annoying adults were doing last autumn.

So rest easy and host a Memorial Day or Fourth of July cook-out, says Kunkel. You shouldn’t worry about scads of brown marmorated stink bugs crashing the party. However, when Labor Day rolls around, your guest list could unexpectedly rise.

“By late August, the nymphs have become adults and are able to fly,” says Kunkel. “What’s more, they start to congregate in houses, decks, garages and other warm spots during this time period. There is a lot that researchers don’t yet understand about the stink bug’s behavior but we do know that cooler temperatures at night motivate them to seek shelter.”

Twenty-six states now have populations of the non-native brown marmorated stink bug. If you have friends in other regions who shrug off stink bugs as a minor annoyance, you may have already guessed that Delaware has more of the critters than most places.

“This region is the epicenter of the stinkbug outbreak,” says Kunkel. Brown marmorated stink bug were first found in this country in Allentown, Pa. They arrived in 1998, as stowaways in packing crates from Asia, where they’re native. Here in the U.S., they have few natural predators. Some spiders, including arboreal spiders, feed on the brown marmorated stink bug.

“Don’t get rid of spiders in your yard and garden,” notes Kunkel. “Spiders are beneficial. In addition to stink bugs, they eat a wide variety of other pests.”

Keep in mind, though, that not all of Delaware’s stink bugs are bad guys; a native stink bug known as the spined soldier bug eats aphids and other pests. Delaware is home to three other native stink bugs: green, brown and dusty.

The brown marmorated stink bug has been more of a nuisance than a pest in the home landscape, thus far, but Delaware’s agricultural industry is monitoring the insect closely. This stink bug feeds on many plants, including lima beans and sweet corn, but is a particular threat to fruit-bearing trees.

“There are some orchards in other states that may go bankrupt this year because they had so much fruit damage from the brown marmorated stink bug last year,” says Kunkel.

He and other UD experts are launching several research projects aimed at protecting Delaware’s growers. One project will focus on when the stink bugs arrive in fields or at greenhouses, their life cycle, and the natural enemies (native parasitoids, predators) attacking this pest. Another project will evaluate the effectiveness of insecticides against the brown marmorated stink bug.

According to Kunkel, current insecticides provide little help in keeping this pest out of the house. Exclusion is the best approach. “Seal up every opening — caulk around windows, repair screens, install screens over your attic vents and replace any rotten wood on your house,” says Kunkel.

And take comfort in the fact that you won’t have stink bugs landing in your hair until later in the summer.

Article by Margo McDonough

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Study to quantify turbine impact on birds and bats

March 7, 2011 under CANR News

A study will quantify the impact of the wind turbine at UD's Hugh R. Sharp Campus in Lewes on birds and bats.

The University of Delaware’s 2-megawatt wind turbine is the site of new research that will help answer a common question about the alternative energy producers: How do they affect birds and bats?

The two-year project, which will assess the mortality risk of birds and bats around the turbine, is led by UD Department of Entomology and Wildlife Ecology researchers Jeffrey Buler and Gregory Shriver. It is funded by First State Marine Wind, a partnership between UD-owned Blue Hen Wind and turbine manufacturer Gamesa. The Delaware Department of Natural Resources and Environmental Control (DNREC) also committed funds to support the effort.

A complementary project at the wind turbine that focuses solely on bats is being conducted by an expert at Delaware State University and is funded by the Maryland Department of Natural Resources.

While a University-commissioned pre-construction study found that the turbine’s impacts on birds are likely to be minimal, that study also recommended that UD undertake post-construction monitoring. One motivating factor is the machine’s location at UD’s Hugh R. Sharp Campus in Lewes, which sits along an important international flyway stopover for migrating birds. UD and Gamesa thus placed a priority on this research once the turbine was up and running (it began producing power in summer 2010).

The research also fulfills UD obligations under the federal National Environmental Policy Act. UD has been working closely with U.S. Fish and Wildlife Service, DNREC and other stakeholders on the scope of the study.

“The results of the study will be useful for other coastal communities considering wind turbines and ought to provide some useful lessons for offshore wind energy projects,” said Jeremy Firestone, associate professor of marine policy. Firestone is a wind energy expert and faculty member in UD’s College of Earth, Ocean, and Environment (CEOE) and CEOE’s Center for Carbon-free Power Integration (CCPI).

The UD project began March 1, with spring and fall sampling periods focusing on birds and bats migrating through the area and summer and winter periods on resident bird and bat flight activity.

During each of the four seasons, the researchers will use a variety of techniques to collect data. Acoustic monitoring, visual surveys, radar, and thermal imaging will provide information on bird and bat traffic and flight patterns. Spring and fall carcass searches around the turbine will help determine the fatality rate.

Local and regional weather data, which will help researchers understand bird and bat movement, will be provided by a nearby meteorological tower and the National Weather Service.

“We want to monitor how much bird and bat activity there is in the vicinity of the turbine so we have a context for how much risk there may be for them to collide with the turbine,” said Buler, who specializes in using radar to track bird migration.

The scientists also want to know which birds and bats are moving through the area. Although the main focus is on migrating land birds and bats, other types of birds also occur near the turbine throughout the year. These include raptors, waterfowl, marsh birds, and shorebirds.

The team expects to have a final report of data and analysis completed by December 2013. They will present findings at technical meetings and publish them in scientific journals. The researchers also will share their bat data with Delaware State’s Kevina Vulinec, an expert on the winged mammals whose research looks to determine the type of bats around the turbine and their behavior.

“We are pleased by the collaboration with Delaware State University,” Firestone said. “These research projects are a prime example of how the UD wind turbine can serve as a platform for important research that will benefit society.”

Article by Elizabeth Boyle
Photo by Kathy F. Atkinson

This article can also be viewed 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

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

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Tallamy awarded gold Eddie Award for article

February 8, 2011 under CANR News

Doug Tallamy, chairperson of the Department of Entomology and Wildlife Ecology in the College of Agriculture and Natural Resources at the University of Delaware, has received the gold Eddie Award from Folio magazine for his article “A Call for Backyard Biodiversity,” first published in American Forests.

The Eddie Award is part of the Eddie and Ozzie Awards Gala in New York City, which has celebrated editorial and design excellence in the magazine industry for over 20 years.

The article deals with the dangers of the diminishing biodiversity in the American urban and suburban landscape and the need for suburban lawns to be populated with natural native plant species instead of unnatural plant species imported from across the globe.

It also focuses on the importance of functional landscaping, using plants that, in addition to their beauty, help support ecosystem development, instead of aesthetical landscaping, using plants which may look nice but serve little ecosystem function.

Tallamy was honored in the category for association/non-profit publication with circulation less than six times a year.

Article by Adam Thomas

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How insects survive the long, cold winter

February 3, 2011 under CANR News

Baby, it’s cold outside. Time to put another log on the fire, wrap up in a thick sweater, or make a steaming mug of tea. These human adaptations to cold weather are quick, easy and get the job done. Even more effective, of course, is the central heating that is ubiquitous in our homes, offices and schools.

It takes a lot more effort for other mammals, birds and insects to make the necessary adaptations to survive harsh weather. Next week, we’ll look at animal and bird strategies; today we’ll see how insects make it through the winter.

In many species, insects adapt to the cold by dying off; it’s the larval stage of the species that goes through winter. Insects that do over-winter as adults usually enter a hibernation-like state called diapause.

“Insects don’t technically hibernate in winter but many go into diapause, a dormant state that allows them to withstand cold temperatures,” says Brian Kunkel, a UD Cooperative Extension entomologist.

The mourning cloak butterfly exists in a type of diapause called freeze susceptible. It avoids freezing in much the way that car owners do — by adding anti-freeze. This butterfly replaces the water in its body with antifreeze compounds — called cryoprotectants — which supercool its bodily fluids and tissues.

The other form of diapause, called freeze tolerant, is used infrequently by North American insects but is a common strategy of Southern Hemisphere insects. In this type of diapause, the insect freezes its bodily fluids.

Not all insects go into diapause in winter. A few, like the stonefly and mayfly, can be seen out and about in their adult form. The best time to look for stoneflies is after a snowfall — these small dark critters are much easier to spot in the snow.

The social insects take a middle-of-the-road approach to winter. They don’t enter diapause, like many butterflies, but they’re not bounding about, full of pep, like stoneflies. Social insects that live through winter in Delaware include honeybees, termites and a number of different ants.

Many of the social insects, including ants, consolidate their living quarters during the winter, says Deborah Delaney, an assistant professor in the Department of Entomology and Wildlife Ecology in UD’s College of Agriculture and Natural Resources. In late fall they move deeper into their nests and close up the exit with soil, leaves and other organic materials.

Honeybees slow down in winter and stick close to the hive. The focus is on eating and huddling close to each other on cold days, notes Delaney.

When the hive temperature drops below 64 degrees, honeybees cluster together into a carefully organized, compact ball. The interior bees generate warmth by vibrating their wing muscles. The outer bees are motionless, acting as an insulation layer. The colder the temperature outside, the tighter the cluster. A single bee can increase heat production 25-fold.

The honeybees take turns enjoying the warmth in the middle of the huddle and then move to the outside. Not surprisingly, the queen bee reigns supreme in the middle and never takes a turn on the outskirts of the huddle.

Despite huddling and other strategies, winter takes a toll on honeybees, says Delaney. Hives that may have had a peak of 60,000 bees in the summer may diminish to 20,000 bees by mid-winter. Some hives are totally lost, due to insufficient food or other factors.

Worker honeybees toiled long hours in the fall, collecting nectar to feed and maintain the colony until spring. If their work wasn’t adequate, there is nothing they — or Delaney — can do about it now, in the depths of winter.

Nonetheless, Delaney checks on the hives at UD’s Apiary about two to three times a week this time of year. “I hold my ear to each hive and if I hear buzzing inside, I know everything is good,” she says.

“The hives are kind of like my fourth child,” admits Delaney, who is the mother of three small children.

Article by Margo McDonough

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

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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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