PHOTO PROVIDED Shown clockwise from upper left are blackburnian, CapeMay, yellow and bay-breasted warblers in this composition by Bill Tyler.

Spring is an exciting time for birders. The arrival of migrating ducks and other waterfowl in March sets the stage for the arrival, beginning in mid-to-late April through mid-to-late May and June, of a group of colorful, small, song birds — the warblers — migrate from Central and South America to their breeding grounds in the boreal forest of Canada and also parts of the United States, including Pennsylvania.

At this time, the male warblers, dressed in their finest colorful plumage, can also frequently be heard singing as they are looking for a mate. There are 50 species of warblers. Some of these are found only in regions west of Pennsylvania. Thirty-eight travel through and sometimes remain in Pennsylvania. Because they feed mostly on insects and larvae, you will not see these birds at your backyard feeders.

If you go out into the woods and fields surrounding your homes, however, there is a good chance that you will be able to see a variety of these birds as they pass through or stay to nest.

The large area of relatively undeveloped, Canadian, sub-arctic boreal forest provides a secure breeding location. In the spring, the extended hours of daylight and warming temperatures lead to an explosion of the insect population, providing an abundant food source. Similar conditions can be found, along the way, within the United States, including parts of Pennsylvania, and some warblers choose to remain here to breed.

Thirty-two warbler species breed in Pennsylvania but the distribution and density is variable. The most prevalent are yellow warbler, common yellowthroat, American redstart and ovenbird. “The Second Atlas of Breeding Birds in Pennsylvania” displays the distribution and density for each breeding species on state map diagrams at the regional and county levels.

Your chances of spotting and recognizing warblers will be enhanced if you study and familiarize yourself with them in advance. There are many excellent resources available to learn about these colorful travelers. Your local library is an excellent place to start.

The Dewey Decimal code for birds and birding is 598. Go to that section and check out a field guide to study the photos of warblers and learn more about them.

A good place to start on the internet is YouTube. You will find introductory and more advanced recordings of and about warblers and the audiovisual format provides an additional dimension to the study of the static photographic images and text of field guides. One particularly good YouTube video for an overview of warbler migration is “Gulf Crossing, Story of Spring.”

You can also type in any specific warbler species, for example the yellow warbler, and find selective information and high quality audiovisual recordings of just that species. The Cornell Laboratory of Ornithology, National Audubon Society and American Birding Association are all excellent online study resources. Download the free Audubon App for your phone, as well as the free apps Merlin and eBird provided by Cornell.

Discussion of these very valuable Apps is beyond the scope of this article but you will find that they are intuitive to use and there are also online helpful tutorials. Bobby Brown, from Lycoming Audubon, has also produced a series of short tutorial YouTube videos on specific warbler species with helpful tips on identification (www.lycobirds.com).

Although colorful, warblers are small, about the size of a sparrow, and they move fast as they glean insects and insect larvae from tree limbs and leaves and other vegetation. Many prefer to forage near the tree tops but some may also be seen at eye level or even on the ground. The resources above provide information about preferred habitat and other tips for improving your chances of spotting warblers.

Since the males are not only colorful but also very vocal at this time, learning to recognize their songs can also be very helpful. Many of the available resources have very good sound recordings of the various species. There is also an application for your home computer and phone that is like language learning software but for birdsong. It is called Larkwire and combines images with vocalizations in a study and quiz format.

The free app Merlin can also assist your song recognition, as you travel on your bird walk, by use of artificial intelligence software that is integrated into the app. Merlin will display on your phone the names of the birds it is hearing. It also simultaneously records a sonogram tracing of the bird song. Your job then is to see if you can locate the bird that Merlin has heard.

Once prepared and excited about going out to observe firsthand, take the plunge and apply what you have learned. The best time to begin your search is early morning from sunrise and for the next three to four hours. An additional time is late afternoon and early evening but morning light and activity will often be the best.

You will also need a pair of binoculars as well as practice using them efficiently. Although large numbers of warblers are migrating, they are dispersed over a wide area. Look for movement and color and listen for song. Be prepared and attentive.

Check Facebook for opportunities to go on a walk with groups of experienced birders who will be helpful in finding and observing these birds. Montour Preserve, Dale’s Ridge, Raymond B Winter State Park, Rose Valley Lake and Ricketts Glen are excellent places to start your search. Later, beginning in late July and peaking in September, warblers will be returning south to their winter homes, providing another viewing opportunity.

On their southbound journey, because of the geography and need to cross the Delaware Bay, Cape May, New Jersey provides a concentrated experience analogous to Magee Marsh.

Learn, experience, and enjoy the amazing warblers coming through our state right now.

Bill Tyler is originally from Cape May County, New Jersey. Following residency training in pathology at Geisinger and Board Certification, Tyler joined the Department of Laboratory Medicine as an associate pathologist in 1977 and retired from Geisinger in 2020. Since then he has been more free to follow his interests in birds and bird photography. He joined Seven Mountains Audubon in 2015 and is currently serving as its president. He has lived in Danville since 1973.

BIRD LORE is produced by the Lycoming Audubon Society (serving Lycoming and Clinton Counties) and Seven Mountains Audubon (serving Union, Snyder, Northumberland and Columbia Counties) and Tiadaghton Audobon Society (serving Tioga and Potter Counties). Information about these National Audubon Society chapters can be found at: http://lycomingaudubon.blogspot.com, http://sevenmountainsaudubon.org and https://tiadaghtonaudubon.blogspot.com.