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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UD grad student, local botanic gardens work to protect threatened plant species

March 29, 2012 under CANR News

Last spring, Raakel Toppila trekked through Atlanta’s Stone Mountain Park and other wooded areas in Georgia and Alabama, collecting leaf samples from the Georgia oak, a scrappy little tree that grows on granite and sandstone outcroppings.

A student in the University of Delaware’s Longwood Graduate Program, Toppila’s intent was to discover how each leaf — and the particular oak population that it came from — differed in its DNA make-up. Armed with this information, Toppila says that botanic gardens and other natural areas will be able to better protect and revitalize the Georgia oak, which is listed as threatened by the U.S. Fish and Wildlife Service.

The Ontario native is interested in the role that botanic gardens can play in cultivating tree species that are at risk of extinction. “Thousands of plant species world-wide are currently threatened with extinction,” says Toppila. “Just as zoos have been at the forefront of animal conservation, gardens can start to play a similar role.”

Locally, she notes that several botanic gardens, including Mt. Cuba, are ahead of the curve and already have done considerable work focused on the conservation of native species. Since its inception as the private garden of Lammot and Pamela du Pont Copeland in the 1930s, Mt. Cuba Center has maintained well-documented, wild collected plants.

Since the early 1980s, plants from the Piedmont region, which stretches from northern Delaware to central Alabama, have been a special focus, says Phil Oyerly, the center’s greenhouse manager.

Most of Delaware — from south of Kirkwood Highway to the beaches — lies in the Atlantic coastal plain region. Plants from this region also have received conservation help from Mt. Cuba.

One notable example is seabeach amaranth, an annual plant that grows on beach dunes from New York to South Carolina. This plant had not been seen in Delaware for 125 years until one day in 2000 when state botanist Bill McAvoy found a single tenacious seabeach amaranth plant at Delaware Seashore State Park. He promptly collected its seeds and brought them to Oyerly, who propagated them in Mt. Cuba’s greenhouses.

Year after year, Oyerly has continued to propagate seabeach amaranth seeds, which McAvoy distributes on Delaware’s beach dunes each April. Today, seabeach amaranth grows at Cape Henlopen and Delaware Seashore state parks.

“Numbers fluctuate annually, but we find at least a few plants every year,” notes McAvoy.

Toppila would love to see her research into the Georgia oak be the impetus for a conservation partnership similar to the seabeach amaranth project.

“Botanic gardens could serve as a safeguard against the complete loss of the Georgia oak species,” says Toppila. “They could work on its propagation and cultivation and augment existing populations in the wild.”

Every plant species has its own particular conservation challenges and in the case of the Georgia oak (and oaks, in general) one issue is its tendency to hybridize.

With the legwork portion of her research over, Toppila is now busy analyzing the allelic variations and understanding the genetic diversity of the wild populations of Georgia oak that she surveyed last summer.

“By looking at DNA from different wild populations, botanic gardens can determine how to best represent the full diversity of the species,” she says.

Currently, the greatest threat to the Georgia oak isn’t its tendency to hybridize but human impact. At woodlands such as Atlanta’s Stone Mountain, which receive lots of visitors, Toppila saw numerous Georgia oak seedlings that had been trampled.

Likewise, people are one of the greatest threats to the seabeach amaranth plant, says McAvoy.  When he first began re-seeding the dunes, he used to see tire tracks on the tiny plant, which is particularly vulnerable because it grows on the foredune, the dune closest to the waves — and closest to the vehicles that are allowed on certain state beaches. However, state park staffers now fence off areas where seabeach amaranth grows.

Article by Margo McDonough

Photos by Danielle Quigley

This article can also be viewed on UDaily

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