Scrub Barrens Are Great for Birds

Pennsylvania has a few different types of barrens.  Along the Mason-Dixon line, serpentine shales inhibit plant growth and create a unique soil chemistry that results in a series of pine-oak barrens.  These go by many local names like the Chrome Barrens, the Nottingham Barrens, and the Serpentine Barrens.  Collectively, they are called the State Line Barrens in Chester and Lancaster counties. In the State College area of Centre County, the Scotia Barrens are known for their pitch pine - scrub oak thickets that support good populations of American Woodcock, Whip-poor-will, and Golden-winged Warbler.  The Poconos Till Barrens are unique for their mixture of scrub oak-pitch pine with boreal plant communities.  The Poconos barrens have the highest concentration of rare plants in the state.  They are a bit unusual that they might be considered moist or wet barrens.  Underneath the multiple layers of trees, heaths, and grasses, there is usually a dense mat of mosses and ground herbs and sedges.  So, you find many ground-nesting forest birds in these barrens (Ovenbird, Hermit Thrush) as well as Common Yellowthroat and Prairie Warbler.  Much of the Scotia barrens is included in State Game Lands 176 (SGL 176).  Part of the Long Pond barrens are included in SGL 38.   Prescribed burns and other vegetative work have been employed to return some of these barrens to their former condition.  

            The most poorly studied barrens are the many ridgetop barrens that perch on top Pennsylvania’s mountains.  The scrub oak, pines, and stunted aspens and birches may support large populations of thicket and early succession birds, but we don’t have the inventories of these areas to know for sure.  Some of these are parts of state game lands or state forests and beg for adoption for IBA monitoring or eBird hotspots.   These include Wyoming Mountain barrens found in SGL 91, Arbutus Mountain barrens including part of SGL 191, and Broad Mountain barrens that are found in part of SGL 141. One of the most extensive scrub barrens in Pennsylvania are the Moosic Mountain barrens of Lackawanna County near Carbondale.  A large section of these barrens are in included in SGL 300.   Another section is being managed as part of the Dick and Nancy Eales Preserve at Moosic Mountain.   Although not as well-known, there scrub barrens scattered around south-central and southwestern Pennsylvania. There are some Golden-winged Warblers in the Wills Mountain barrens in SGL 48 in southern Bedford County.  

The Pennsylvania Game Commission is working collaboratively with The Nature Conservancy and other partners to manage barrens for the betterment of wildlife habitat and to share our growing knowledge and appreciation with the public. An article was just published in Pennsylvania Game News August 2010 edition that explains a project to restore scrub barrens.  It is entitled “Wills Mountain Scrub Oak Barrens Restoration” by Justin Vreeland, Robert Criswell, Robert Einodshofer, and Jonathan Zuck.

            The Poconos Long Pond, Scotia Barrens, and the Stateline Barrens were all selected as Important Bird Areas for their important ecological communities.  If we knew more about other barrens, they might also be selected as IBAs or get other conservation recognition.  Perhaps, ignorance and misunderstandings are even more detrimental to this important ecosystem than development.  We don’t protect what we do not know about. 

            Our barrens have lots of birds, especially in the summer, but also in migration.  For those of you who yearn to hear “drink-your-tea!!!” all day long, go to Long Pond.  In the Poconos, I had a hard time avoiding Eastern Towhee, Gray Catbird, and Common Yellowthroat.  They are omnipresent there.    Prairie, Black-and-white, Pine, and Nashville warblers are common birds in high elevation scrub barrens.  Not found much along roads in the Poconos, Prairie Warblers are locally abundant in off-road scrub barrens of Long Pond.   In conifer groves, northern specialties like Yellow-rumped (Myrtle) Warbler, Magnolia Warbler, Blue-headed Vireo, Red-breasted Nuthatch, Blackburnian Warbler, and Purple Finch add to the blend.  In fact, Yellow-rumps are among the most common Poconos barrens birds.  Many birders would be surprised to find that typical forest birds like Black-capped Chickadee, Hermit Thrush, and Ovenbird are common denizens of barrens.  In wetter areas, there are dense rhododendron thickets that support populations of Canada Warbler, Northern Waterthrush, and White-throated Sparrow there as well, sometimes within earshot of the drier barrens.  Alder Flycatchers call from shrubby areas near streams and ponds.  The healthy moth population supports a local population of Whip-poor-will, a species many believe to have declined in the state.  They also are great places to have an encounter of the ursine kind --- black bears are common ---- or to see a wild turkey.   Both find good cover and forage with all of the acorns produced by the scrub oaks. 

             The Poconos barrens are suffering from development pressure and fire suppression.  The Game Commission is working with the Nature Conservancy to improve the barrens habitat in Game Lands Much of the old barrens are growing into secondary deciduous forest and losing early succession habitat birds like Golden-winged Warbler which is now uncommon around Long Pond.  Perhaps some controlled burns on these properties will help.  

            The grassy openings and game roads of the barrens inadvertently provide feeding lanes for Northern Harriers.  This Candidate-At Risk species nests in shrubby wetlands and cruises the barrens, pipelines, fire lanes, lakeshores, hayfields, and bogs of the Poconos.  It is much more common than we formerly appreciated (as documented in the Atlas).  The mosaic of scrub, grass, and wetland suits the harrier and many other species very well. 

            Barrens are or were the home to other “Pennsylvania Species of Special Concern.” The Greater Prairie-chicken’s eastern race called the “Heath Hen” was once found in our state’s barrens.  This large game bird was commonly found in the scrub along the Maryland border in Lancaster and York counties as well as the Poconos.  Over-hunting and habitat destruction led to its extirpation from the state.  The Northern Bobwhite perhaps is Pennsylvania’s most unappreciated and neglected native game bird.  It is at risk for extirpation as a nesting species in Pennsylvania.  Our understanding of its population and productivity is clouded by the many introduction attempts by hunters and dog trainers.  The State Line Barrens of Chester and Lancaster counties are one the few places where reproduction has been documented lately for this thicket and grassland bird. 

            Ornithologists are wondering out loud whether the now extirpated (and nearly extinct) Appalachian race of the Bewick’s Wren lived extensively on ridgetop barrens.  The scrubby vegetation and rimrock may have provided excellent habitat for this wren that has retreated from the state and our memories.  The loss of hilltop marginal farmland and competition with the surging population of House Wren are other possible explanations for its decline. 

            The high densities of shrub and early successional forest birds in barrens habitat are important for the continued maintenance of these bird populations.  The Partners in Flight strategy for bird conservation is to “keep common birds common.”  Many thicket species have declined steadily in Pennsylvania (look at the Atlas BBS graphs for evidence).  Some thicket species like Yellow-breasted Chat and Brown Thrasher may be “area-sensitive” and not productive or tenacious in areas below a critical size.  Nest predators like cats, chipmunks, raccoons, opossums, field mice, crows, jays, grackles, and skunks, are common in the fragmented, linear roadside and wood-edges that attract many shrub birds.  These areas become ecological traps for the birds they attract.  Barrens may serve as “source areas” from which opportunistic thicket birds spread into marginal or new habitats.  So, barrens can be important bird habitats even where they support birds we coin as “roadside” or brush birds. 

             Barrens are very rich in biodiversity.  They are great place for lepidopterans ---- the globally rare sallow moth and the barrens buckmoth as two moth examples while the persius duskywing and the frosted elfin  are two butterfly examples. Anyone who has walked the fire lanes in barrens also knows that Wild Turkeys, black bears, white-tailed deer, cottontail rabbits, Ruffed Grouse, and other species are abundant there.   The mast crop is very valuable food for many species of wildlife including those just mentioned, jays and many rodents including squirrels. 

             Birders are invited to adopt barrens as eBird hotspots, either near their home or a daytrip out in the country.  Pennsylvania IBAs that include barrens are:

#34 – The Barrens at Scotia (including SGL 176)

#59 – The State Line Barrens

# 64 – Long Pond Preserve

Please check out the Audubon website to learn more about these spots, the Nature Conservancy website to learn more about scrub barrens, and the PGC website for more information about and maps of about the game lands where scrub barrens can be found.