Catching birds for research takes patience, Christopher Goguen said after setting up nets at the Nescopeck State Park.
While waiting for a bird to fly into the nets, Goguen, an assistant professor of biology at Penn State Hazleton, gave an impromptu lecture to visitors watching with him during the park's Fall Festival on Oct. 20.
He said his nets hang between shrubs like fine, black mist that birds barely notice until they fly into the mesh and plop into a pocket.
The Chinese developed mist nets to catch birds for food.
Goguen deploys nets in his study of how birds survive.
His subject is the veery - a spotted, brown thrush slightly smaller than a robin. The veery nests in the shrubs and underbrush at the park.
Goguen wants to study fledglings - young birds that just learned to fly.
For three to five weeks, the young veery remains vulnerable to hawks, owls and other predators.
"They can barely fly when they leave the next. Initially they depend on parents to bring them food," Goguen said.
Nests usually contain four eggs. The mother and father gather food for two of the young birds apiece.
To gauge the survival rates of the fledglings, Goguen wants to affix a transmitter to each young bird that he nets.
The transmitters are about the size of a pinky fingernail from which a fine, wire antenna extends like a tail. They cost about $150 and contain enough battery life to last a month.
After Goguen catches a young veery, he cuts away a patch of feathers and attaches the transmitter to the skin with Superglue.
The transmitters send a signal every 1 to 2 seconds. Goguen tracks the signal using a collapsible antenna, which he holds while turning in a circle. A receiver beeps loudest when the antenna lines up with the bird, Becoming attuned to the signal takes practice.
"It's really sort of an art," Goguen said.
He let a boy, Jarret Groshek, of Berwick, and a girl, Ekta Arora, of Dallas, aim the antenna at a transmitter hidden a few hundred yards away.
"It didn't sound any different," Jarret said after spinning around with the antenna. After a few tries, the children honed in on the signal and found the transmitter hidden in a tree.
Before starting his study of the veery in the Nescopeck State Park, Goguen used the transmitter, receiver and antenna on research in New Mexico. He noted the distances that cowbirds flew from the herds of bison that they accompany along grasslands. Cowbirds contribute to the decline of songbirds in whose nests they lay their eggs. The cowbirds hatch faster so they shoulder out the young songbirds to receive the food brought by adult songbirds.
Goguen's research in New Mexico offered suggestions for how far away herders who want to protect songbirds should keep their cattle, which cowbirds also follow, from the songbirds' nests.
At the Nescopeck State Park, Goguen keeps tabs on the movements of the young Veery. If he notices that a bird stops moving, he can hunt down the transmitter. If the transmitter fell off, he can deactivate it with a magnet and reuse it later. The transmitter also could lead him to the body of a veery or indicate how a young bird died if, for example, he finds a transmitter in a pellet ejected by an owl.
To locate a bird or other animal wearing a transmitter, Goguen uses a method called triangulation.
He turns the antenna, recognizes the direction from which the signal comes and takes a compass reading. Then he hikes or drives to two other sites and repeats the process. Lines on a map representing the three compass bearings intersect at the resting place of the bird or animal.
"You don't bother the animal, but you don't see it either. It's really boring," Goguen said.
He likes seeing the animals better, and during the demonstration Goguen and the group got a good look at a black-capped chickadee that became ensnared in the net.
Freeing the chickadee took more effort than usual, so Goguen and an experienced volunteer who helped him, Cara Menzel, had to cut some of the net's strings.
Menzel who works for an environmental engineering firm became skilled at untangling birds in nets while volunteering with a research project at the Powdermill Nature Reserve in Rector, Westmoreland County.
The study draws on the ability of birds to recognize ultraviolet light and will help develop glass that will protect birds.
Flying into windows is the leading cause of death for birds.
The researchers developed glass with patterns such as spiderwebs etched with ultraviolet light. Birds fly a toward the glass while researchers note which patterns make them veer away. A net protects birds from crashing into the glass.
Menzel said companies are developing bird-safe glass that builders and remodelers soon will have an option of using.
"If it's a comparable price, why not?" Menzel said.
Meanwhile, vertical blinds alert birds to windows. So does spraying the glass with a soapy mist, leaving dust on the windows or stretching a tight net in front of windows so birds will bounce away.
Menzel also suggested placing feeders at least 15 feet from windows to reduce the chance that a bird will fly into the glass.