Surveying Breeding Birds

Ever since I began documenting bird species on our central Pennsylvania mountaintop back in 1971, bird numbers and species have been declining, not only here but throughout the world. Most of these estimates by scientists are based on a wide variety of bird counts and studies, especially in North America and Western Europe. But in the last couple decades, due to the ease of submitting bird lists online, birders and scientists worldwide have joined in.

Here in Pennsylvania we’ve conducted two breeding bird atlasing projects (1983-1989) and (2004-2009). In addition, Audubon Pennsylvania launched its Important Bird Areas breeding bird point count in 2003. Since our Bald Eagle Ridge property is part of IBA#32, my son Dave and I participated in the count from 2005 to 2014. Each time we followed the identical protocol, counting birds at the same 15 points 500 feet apart in some of the varied habitats on our property.

That first year we conducted two counts. The one in May yielded 48 species and the second in June 47 species. But by 2014, when the IBA point count project was discontinued, our species number was down to 37.

I had grown increasingly dissatisfied by this approach because I knew that we had far more species breeding on our mountain than the point count indicated. And the route that we had to follow in less than three early morning hours up and down steep slopes, was becoming more difficult as I entered my seventies.

In the meantime, the Pennsylvania Society for Ornithology started its ongoing Breeding Bird Blitz in 2015. This survey encourages teams of birders to cover the commonwealth during four days in mid-June in order to get a quick snapshot of the state’s breeding birds and put their reports on eBird, the online reporting system that birders throughout the world use.

Last June I decided to spend three days of the Breeding Bird Blitz on foot searching for breeding birds on our mountain, following no protocol but my own knowledge of an area I have been living in and studying for almost five decades.

I examined Pennsylvania Audubon’s 13 priority birds list for the state, all of which are threatened in terms of the species’ long-term survival according to rigorous analysis by qualified scientists. I hoped to find at least a few of the songbirds, specifically cerulean warblers, wood thrushes, golden-winged warblers, and black-throated blue warblers, all of which have nested here in the past. There was also a chance that I would find a breeding American woodcock or bald eagle, the latter now nesting regularly at the other end of our Brush Mountain portion of Bald Eagle Mountain.

But I was absolutely certain that I would not find breeding piping plovers, northern goshawks, bobolinks, prothonotary warblers, Canada warblers, common terns, and grasshopper sparrows because we have no habitat for those species.

On day one—June 16—I was out before 6:00 a.m. and counted an easy 11 species singing in our couple acres of overgrown yard—gray catbird, chipping sparrow, eastern towhee, indigo bunting, field sparrow, red-eyed vireo, common yellowthroat, eastern phoebe, song sparrow, eastern wood-pewee, and tufted titmouse.

I added other species as I hiked up the forested Dump, Short Circuit, and First Field trails, through our 43-year-old Norway spruce grove, over to the still-filled vernal ponds, along Sapsucker Ridge Trail to the Far Field and back on the Far Field Road, Laurel Ridge Trail and Guesthouse Trail—a two –mile circuit that brought me home by 7:22 a.m. Altogether, I garnered 27 species, several of which were repeats from my yard count but also it included six scarlet tanagers, nine ovenbirds, four hooded warblers, three black-throated green warblers, and one black-and-white warbler. All of those species were listed as migrating songbirds whose numbers have been cut in half since the 1960s, which sounded about right, because I had passed whole areas on our mountain that were silent in our closed canopy forest.

I especially remembered back in the 1970s the wood thrushes that nested in many of our mountain laurel shrubs, some as close as 10 feet from one another. Yet today our bushes are mostly dead and dying from a leaf fungus and wood thrushes have deserted most of our forest. I still can hear their ethereal songs, but I have to hike much farther to find even one wood thrush.

The following morning I walked part way down our hollow road to record three Acadian flycatchers and two worm-eating warblers, but with all the rain we had been having, our small stream, which is usually low by mid-June, was flowing as strongly as it does in early spring and was so noisy that it was difficult to hear much except the loud birds—more scarlet tanagers, red-eyed vireos, and the Acadian flycatchers.

Finally, I hiked up a flooded Dogwood Knoll and along the soggy Ten Springs Trail to hear an eastern wood-pewee, chorusing tufted titmice, and at last, a wood thrush. Again, I covered about two miles in the early morning.

The last day, which was hot and humid, I was down our hollow road before the sun rose at 5:38, but I only added more numbers to my list even though I walked most of the mile-and-a-half road. Still, the noisy stream continued to defeat me and again I retreated upslope, this time to Greenbrier Trail where I picked up American redstarts, hooded warblers, eastern towhees, a common flicker, eastern wood-pewee, scarlet tanager, and red-bellied woodpecker, several northern cardinals, and a brown-headed cowbird.

By then my socks and boots were thoroughly soaked by the invasive, knee-high, Japanese stiltgrass that clogs the old logging roads and, incidentally, was brought in on logging trucks back in 1991, before we could purchase this part of our property. Already, it was heating up, and by the time I reached Butterfly Loop around our 37-acre First Field, it felt like a blast furnace. Still, I persisted and was rewarded by a gorgeous, singing rose-breasted grosbeak, but not a golden-winged warbler as in years past.

Back at our yard, a cerulean warbler and gray catbird joined the morning chorus. The veranda eastern phoebe was sitting on her second clutch of eggs, the yard nesting blue-gray gnatcatcher called, and a chipping sparrow buzzed louder than usual.

Then it was time to tally up my numbers and species of birds during the three-day period. Even though I had covered the IBA point count area Dave and I had followed as well as other portions of our property, I ended up with 38 species, only one more than we had gotten back in 2014.

The winner in numbers remained the same—the red-eyed vireo—with 33—followed by 17 eastern towhees, 12 hooded warblers, 10 ovenbirds, scarlet tanagers, common yellowthroats and indigo buntings, seven American redstarts and eastern wood-pewees, five wood thrushes, and three cerulean warblers and black-throated green warblers. But alas I found not even one black-throated blue warbler or golden-winged warbler and no surprise birds either. I did, however, find all five of the most common bird species in Pennsylvania, according to the Second Atlas of Breeding Birds in Pennsylvania—American robins, song sparrows, chipping sparrows, red-eyed vireos, and gray catbirds.

But since I had been listening to and counting singing species since late April, I had also recorded the songs of other breeders here, for instance, blue-headed vireos, brown thrashers, Louisiana waterthrushes, whip-poor-wills, wild turkeys, barred owls, yellow-billed cuckoos, black-capped chickadees, white-breasted-nuthatches, common ravens, American crows, house wrens, common grackles, pileated, hairy and downy woodpeckers, as well as the calls and courtship displays of red-tailed hawks, Cooper’s hawks, and turkey vultures, in all at least 57 species.

This exercise led me to conclude that both Breeding Bird Blitzes and in depth, breeding season coverage of as much habitat as possible in Pennsylvania are necessary to assess the numbers, species, and overall health of our breeding birds, a task that continues to be done by both professionals and amateurs who cherish our birds.