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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Butterfly season only average, according to UD entomologist and others

July 17, 2012 under CANR News, Cooperative Extension

Brian Kunkel’s weekend strolls at Middle Run Natural Area make him see red – not because he’s angry but because the red admiral butterfly has been abundant at this 850-acre park east of Newark. A large, red-banded butterfly, the red admiral has been seen in large numbers throughout Delaware this summer.

“The red admiral is experiencing an irruption – a rapid and irregular increase in population numbers,” says Kunkel, an entomologist with UD Cooperative Extension. “It’s not just here in Delaware; this irruption also has been reported in New Jersey, the Poconos, western New York and other Northeastern locales. The last time a red admiral irruption was seen locally was 2001.”

The red admiral is the bright spot for Delaware butterfly watchers this summer. All in all, it’s shaping up to be just a so-so season for butterflies.

“Butterfly numbers were good at the end of May and into June but then things really backed down,” says Sheila Vincent, a group program coordinator for the Delaware Nature Society who maintains Ashland Nature Center’s Butterfly House.

“Mid-July to mid-August is typically the peak of butterfly activity in Delaware but we’ve seen fewer individuals flying,” says Vincent, “Right now, I don’t think we’re going see a repeat of 2011 and 2010, both of which were very good years for butterflies.”

Butterfly populations are influenced by a complex interplay of temperature, moisture and food supply. Different species are impacted by different factors. For example, a species that overwinters in the adult form – such as the mourning cloak — will have better survival rates in milder winters, says Kunkel. If the butterfly’s host plant flourishes during a rainy spring, odds are that butterfly will do well that season, too.

“With so many factors influencing population density, I can’t begin to speculate on why overall butterfly numbers appear lower this year,” says Kunkel.

Delaware has about 120 species of resident breeding butterflies. Considering that most states have about 100 species, Delaware is a pretty good spot for butterfly watching.

“Delaware is home to both the Piedmont Plateau, in the north, and the Coastal Plain, in the middle and southern parts of the state. This makes for a greater diversity of butterflies,” says Vincent. “For example, we don’t get cloudless sulphur butterflies in the Piedmont but on occasion you see a straggler cloudless sulphur fly up from the Coastal Plain.”

If you want to attract butterflies to your yard, Kunkel has two important tips. “First, get lots of plants that caterpillars like,” he says. “Gardeners tend to focus on nectar plants that provide adult butterflies with energy but you also need plenty of food sources for caterpillars – the next generation of butterflies.”

Most caterpillars eat only one specific plant or from one plant family. Do your research. If you love the great spangled fritillary butterfly, plant violets, the food source for this butterfly’s caterpillar. If it’s Eastern tiger swallowtails that you’re trying to attract, plant tulip poplar, sweetbay magnolia and black cherry trees.

If you’ve always prided yourself on a flawless, neat-as-a-pin garden, you may not like Kunkel’s second piece of advice – “tolerate insect feeding.”

Caterpillars eat the leaves and stems of plants, which mean, of course, little holes on the leaves of your plants. “If you want to enjoy the sight of the pipevine swallowtail butterfly, with its brilliant blue wings, you’ll have to accept that your pipevine plants are going to get chewed up a bit by this butterfly’s caterpillars,” says Kunkel.

At the University of Delaware Botanic Gardens, feeding the caterpillars is seen as just as important as feeding the butterflies. The gardens’ Lepidoptera Trail, which opened in 2009, features a wide range of plants to attract caterpillars.

“The trail is not a butterfly garden, which is designed to attract butterflies to feed on nectar,” says garden director John Frett. “It is an ecosystem to attract Lepidoptera throughout their life cycle. It’s a place for them to lay their eggs, which become larvae or caterpillars before entering the inactive pupal stage and then emerging as butterflies, moths or skippers.”

Besides, caterpillars are cool in their own right. “Take the caterpillar of the spicebush swallowtail butterfly. It looks like something out of a cartoon,” marvels Kunkel.

This caterpillar features oversized fake eyes on its thorax and is a garish neon green color at certain stages of development. The fake eyes and bright color is supposed to make the caterpillar look like a snake and thus scare away birds and other predators.

The Lepidoptera Trail, as well as the rest of the UD Botanic Gardens, is open daily from sunrise to sunset for free self-guided trails. For more info, go to http://ag.udel.edu/udbg or call 302-831-0153.

Article by Margo McDonough

Photo by Brian Kunkel

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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

This article can also be viewed on UDaily

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