"Warbler watching is first-rate recreation for anyone who enjoys wild birds, or nature," said Doug Gross, Pennsylvania Game Commission ornithologist. "Although they can be challenging to find for beginners, once you get the hang of it, you may spend endless hours locating and identifying which warblers comprise the latest wave occupying the Commonwealth. If you get lucky, you may see five or ten different warblers at one location.

"Finding a hotspot, however, shouldn't immediately dominate your efforts afield. First, try to locate warblers by checking the habitats they prefer and by becoming familiar with warbler singing. The yellow warbler's call is a good one to start with. Several other warblers sound similar to it and keying on similar singing will surely get you closer to the action."

Warbler singing - although somewhat lacking in virtuosity compared to other spring singers - announces a male's availability and its claim to territory. The birds call incessantly in spring, particularly during early morning hours, for mates. Listening for that singing - and then slowly closing in on it - is one of the quickest and easiest ways to become familiar with warblers.

A great website to peruse for warbler songs - as well as the sounds thousands more animals make - is provided by the MacCauley Library at Cornell Lab of Ornithology at www.birds.cornell.edu/MacaulayLibrary. If you'd prefer to take something afield with you, consider purchasing the birdsong audio "identiflyer," available through the Pennsylvania Game Commission's "The Outdoor Shop" on the agency's website at www.pgc.state.pa.us. The cost of the identiflyer with batteries and two audio cards is $35.50. A four-card collection of warbler songs - detailing 40 species - is available for $33.75.

After you become proficient with one species and its habitat preferences, learn another's call and partialities. The Annotated list of the Birds of Pennsylvania, by Franklin C. and Barbara M. Haas, can be a useful guide to help choose which warbler species a birdwatcher has the greatest likelihood of encountering afield. Now in its second edition, the book provides bar graphs that show the probability of observing each species by month within seven regions of the state and throughout the year. The book, which sells for $7.61, including postage and handling, from the Pennsylvania Game Commission's online "Outdoors Shop," details when species are at their greatest abundance throughout the state and lists their habitat preferences.

Some of the more common wood warblers are the yellow warbler, yellow-rumped warbler and yellow-breasted chat. Yellow warblers like open areas with some trees and shrubs near water; yellow-rumped warblers, woodlands edges and brushy areas; and yellow-breasted chats, shrubby stream hollows, overgrown pastures and power-line right-of-ways.

If you're looking to see some of the more striking stars of this neotropical homecoming, consider looking for the black-and-white warbler, which prefers woodlands and edges; black-throated green warblers, northern hardwood forests with hemlock and white pine; the northern parula, riparian woodlands, particularly of the Allegheny Mountains in Fayette, Somerset and Westmoreland counties; and Blackburian warbler, large woodlands with conifers and riverside sycamores. Other beauties on the migratory highway that pit-stop through Pennsylvania include the Cape May warbler, bay-breasted warbler, Wilson's warbler and orange-crowned warbler.

If seeing some of the flashier warblers doesn't satisfy your newfound fancy, consider the thrill provided by getting a glimpse of the federally-endangered Kirtland's warbler, which has been found only four times instate, or the state-endangered Blackpoll warbler, which was first confirmed to be breeding in the Commonwealth in 1994, and has been recorded nesting in Wyoming County every year since then. These are the proverbial needles in the haystack of warbler watching.

"Warbler watching can be as carefree or complicated as you prefer to make it," emphasized Gross. "After you become familiar with warblers and some of their songs, you'll head into the woods or out fishing with a more refined awareness of your surroundings and a craving for warbler action.

"To heighten your experience afield, it's always important to have a good pair of binoculars, a songbird field guide, and journal to take notes of where you find warblers. Binoculars are almost a necessity, because some warblers are fond of the upper reaches of the forest canopy. But it also is always better to get closer to the action!"

Since many wood warblers breed and nest in Pennsylvania, birders can enjoy many of these colorful songbirds in summer. Some species are found primarily in conifers, especially the hemlock stands. These include the magnolia warbler, Blackburnian Warbler, and black-throated blue warbler. Warblers often seek out forest structure when choosing nesting habitat. The Worm-eating warbler, hooded warbler, Kentucky warbler, and Canada warbler all are often found where there is a healthy shrub community in the forest.

In addition, old fields and young forests spotted with conifers are a great place to find prairie warblers. They also are found in young Christmas tree plantations and pine barrens. Their song is very diagnostic and easy to imitate; a series of whistles up the scale. The increasingly rare golden-winged warbler prefers regenerating clearcuts, barrens, and rights-of-way where there are lots of shrubs, young aspens, and goldenrods.

Warblers have been dazzling Americans for centuries. Although it's unlikely that William Penn could identify them, he likely had occasion to observe them on his many journeys. John James Audubon, however, recognized warblers for what they were, and wrote extensively about them. Audubon's discovery of a Blackpoll warbler nest truly captivated him.

"I felt as if the enormous expense of our voyage had been refunded," Audubon wrote. "'There,' said I, 'we are the first white men who have seen such a nest.' I peeped into it, saw it contained four eggs, and observed its little owner looking upon us with anxiety and astonishment."

A subspecies of the yellow-rumped warbler, found at least a dozen times in Pennsylvania, was named after Audubon. The yellow-rumped warbler found most commonly in Pennsylvania - as well as throughout the United States - is a subspecies known as the "myrtle warbler."

Warblers, being some 50 species strong, represent the second largest family of North American birds. Finches - including cardinals, buntings and grosbeaks - top the list with more than 80 species. Most warblers nest in trees and shrubs. In Pennsylvania, the prothonotary warbler is the only warbler that nests in tree cavities, a distinction shared by the bluebird in the thrush family.

Prothonotary warblers will live in bluebird nest boxes attached to trees in forested areas near water. Plans for this type of nesting box can be found on the Game Commission's website by clicking on "Wildlife" and then selecting "Bluebirds," and finally selecting "Bluebird Nest Box Plan."

Warbler watching is a fantastic way to spend a May afternoon afield and a good reason to head outdoors, even if it is only into the woods behind your house. Right now, Pennsylvania's forests and thickets, particularly those adjacent to lakes and stream-bottoms, are teaming with warblers. So get outside already! You won't regret it.

For more information on warblers in Pennsylvania, please consult The Birds of Pennsylvania, written by Gerald M. McWilliams and Daniel W. Brauning, published by Cornell University Press.

Created in 1895 as an independent state agency, the Game Commission is responsible for conserving and managing all wild birds and mammals in the Commonwealth, establishing hunting seasons and bag limits, enforcing hunting and trapping laws, and managing habitat on the 1.4 million acres of State Game Lands it has purchased over the years with hunting and furtaking license dollars to safeguard wildlife habitat. The agency also conducts numerous wildlife conservation programs for schools, civic organizations and sportsmen's clubs.

The Game Commission does not receive any general state taxpayer dollars for its annual operating budget. The agency is funded by license sales revenues; the state's share of the federal Pittman-Robertson program, which is an excise tax collected through the sale of sporting arms and ammunition; and monies from the sale of oil, gas, coal, timber and minerals derived from State Game Lands.

By Joe Kosack, Wildlife Conservation Education Specialist Pennsylvania Game Commission