Native Delaware: Seasonal Symphony of Frog Calls Returns

April 19, 2013 under CANR News

On April nights, Holly Niederriter can be found driving slowly down the back roads of New Castle County. Although she appears to be meandering, her excursions are quite purposeful.  A wildlife biologist with the Delaware Department of Natural Resources and Environmental Control, Niederriter is listening for frog calls.

She is one of dozens of Delawareans who drive around after dark searching for frogs as part of the Delaware Amphibian Monitoring Program. The first survey period kicked off in late February, the second starts in a few days, and the final survey occurs in June. Participants are volunteers from the community; most don’t have Niederriter’s wildlife savvy. But they all receive training, and before their debut, take an online quiz to ensure they can distinguish the calls of Delaware’s 16 species of frogs.

American toad by Jim White“Frog calls are an important way to determine where different species occur and how populations are doing over time,” says Niederriter.  “Because most amphibians need both aquatic and upland habitats, they can serve as important indicators of water quality and other aspects of environmental health.”

A colder-than-average early spring made for a slow start to the frog-calling season.  Early April is often the peak of spring peeper season, when the sleigh-bell-like chorus of these tiny frogs reaches maximum volume in vernal pools and marshes. But the beginning of this month was so chilly that the peepers didn’t want to peep.

“Male peepers call to attract a mate but if the weather isn’t warm enough they hunker down and wait it out,” says Jim White, associate director for land and biodiversity management at the Delaware Nature Society and an adjunct herpetology instructor at the University of Delaware. “I didn’t hear a single peeper during the first few days and nights of April.”

Now that temperatures are more seasonal, the spring peepers are out in full force. Recently, they’ve been joined by the pickerel frog, with its snore-like call, and the American toad, which boasts a musical trill. In the Coastal Plain region (Kent and Sussex, plus a sliver of New Castle County), you also can enjoy the throaty croak of the Southern leopard frog.

You need a sharp ear to recognize the call of the American toad, notes Jake Bowman, a UD professor of entomology and wildlife ecology.

“American toads are frequently heard all over our area but rarely do people realize what they are hearing,” he says. “Unlike the commonly recognized sleigh bell call of the spring peeper, the American toad has a high pitched trill. Here on the UD campus, you can find them in most of the wetlands on our farm.”

A father of two sons, Lee, 10 and Ethan, 5, Bowman likes the fact that frogs are “kid-friendly.”

“Probably the nicest thing about toads is that it’s often the only amphibian kids have a chance to handle. My boys love the chance to chase and capture American toads and learn more about them,” he says. “After the boys have checked out the toads, we release them back where we found them.”

Like the Bowman boys, James White, Jr. grew up playing with frogs with his father, Jim White. Now a UD freshman, White is majoring in wildlife conservation and hopes to become a national park ranger.

“For as long as I can remember, I went looking and listening for frogs every rainy, spring night,” says White. “We had a marsh only a few yards from our house so it was never difficult to hear them.”

“I will go herping with my father but because of college it probably won’t be until school is out,” he says. “My favorite frog of spring is the pickerel frog. I always found them pretty frogs and very jumpy, making them a challenge to catch.”

If you want to catch frogs with your kids (or at least see and hear them), Bowman has a few suggestions. Look for terrestrial species on the ground in woodlands and other land habitats. Semi-aquatic species can be seen on the shoreline or surface of freshwater habitats. To find breeding frogs, head to vernal pools and marshes. Warm, rainy nights make for the very best frog-watching. Pack a bright flashlight and plenty of patience.

A spring peeper, for example, is only about an inch long and its brown, gray and green colors don’t stand out, especially at night. “You can practically be on top of them and still not see them,” notes Bowman.

But it’s worth the wait to see a peeper, especially a male one. Males have large vocal sacs under their chins that they pump full of air until they look like balloons about to burst, When they peep, the air is discharged and the shiny sac deflates.

How to Help

To learn more about volunteering with the Delaware Amphibian Monitoring Program, contact Vickie Henderson at 735-8651 or vickie.henderson@state.de.us

Article by Margo McDonough

Photo by Jim White

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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

This article can also be viewed on UDaily.

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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

This article can also be viewed on UDaily.

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