Breeding birds of Virginia

Virginia supports a diverse community of breeding birds that has been the focus of investigation for more than 400 years. The avifauna reflects the latitudinal position of the state and the fact that the border extends from the Atlantic Ocean to the Appalachian Mountains. A total of 224 species have been recorded breeding in Virginia, 214 of which are extant. Twenty species have colonized the state since 1900 including 14 since 1950. Of all extant species, 102 (48%) are considered common at least somewhere in the state and 64 (30%) are rare to very rare. Diversity varies by physiographic region with 179 (83%), 168 (78%) and 141 (66%) in the Coastal Plain, Mountains and Piedmont, respectively. Two significant landscape features make significant contributions to the state-wide diversity including tidal waters along the coast and isolated spruce-fir forests of the Appalachians that represent Pleistocene-era relicts. In all, nearly 25% of the state-wide avifauna is either wholly or nearly confined to tidal water and 10% is confined to “sky island” refugia. Since 1978, 25 species of birds throughout Virginia have been identified as requiring immediate conservation action. A retrospective assessment shows that 5 of these species including osprey (Pandion haliaetus), bald eagle (Haliaeetus leucocephalus), peregrine falcon (Falco peregrinus), brown pelican (Pelecanus occidentalis) and piping plover (Charadrius melodus) have recovered to or beyond historic numbers. Three species including Bewick’s wren (Thryomanes bewickii), Bachman’s sparrow (Peucaea aestivalis) and upland sandpiper (Bartramia longicauda) have been lost from the state and the black rail (Laterallus jamaicensis), loggerhead shrike (Lanius ludovicianus) and Henslow’s sparrow (Ammodramus henslowii ) are in imminent danger of extirpation. Several species including the peregrine falcon, piping plover, Wilson’s plover (Charadrius wilsonia) and red-cockaded woodpecker (Picoides borealis) are the focus of intensive monitoring and management programs. The underlying causes of imperilment remain unclear for several species of concern, limiting our ability to development effective conservation strategies. 1 Corresponding author: bdwatts@wm.edu Virginia Journal of Science, Vol. 66, No. 3, 2015 http://digitalcommons.odu.edu/vjs/vol66/iss3 224 VIRGINIA JOURNAL OF SCIENCE INTRODUCTION The ornithological record in Virginia stretches back more than four centuries. From the time of settlement at Jamestown in 1607, residents of Virginia and visitors to the state reported on the birds they encountered or were told about by Native Americans. William Strachey who lived in the settlement from 1610 to 1612 remarked at length on the birds he observed (Strachey 1849). Contemporaries including Captain John Smith, Raphe Hamor, and Edward Topsell describe many species including the waterfowl on the Chesapeake Bay, cardinals, mockingbirds and ruby-throated hummingbirds (Smith 1612, Hamor 1615, Christy 1933). Later in the century significant accounts by George Percy and John Clayton, Vicar of Crofton, would describe immense flocks of passenger pigeons and Carolina parakeets (Clayton 1685). These were followed by contributions by Thomas Glover and William Byrd (Glover 1676, Byrd 1841). Early accounts were primarily anecdotal descriptions or lists of birds within localities. As time passed, early local accounts began to coalesce and were compiled into growing lists that began to provide a more complete assessment of the avifauna within the state. One of these early treatises, Mark Catesby’s work (Catesby 1771), though centered to the south, had its beginning on Westover Plantation and generally includes the species described to that time. Thomas Jefferson would later give a list of 125 bird species for the “Virginias” (Jefferson 1787). These early treatments lead up to two significant works that gave a more complete assessment of the breeding birds including William Cabell Rives’ “A catalogue of the birds of the Virginias” and Harold Bailey’s “The Birds of Virginia” (Rives 1890, Bailey 1913). Throughout the early 1900s a community of bird enthusiasts including academics and citizen volunteers would form, eventually leading to the establishment of the Virginia Society of Ornithology in 1929 (Johnston 2003). One of the stated missions of the organization was “to gather and assemble data on the birds of Virginia.” Through annual forays designed to document breeding birds in specific locations that moved throughout the state an increasingly complete accounting of the breeding bird community would emerge over time. The long period of “ornithological exploration” in Virginia would eventually come to a close with Murray’s production of “A check-list of the birds of Virginia” (1952). This benchmark work was a comprehensive compilation of birds observed in the state that provided a blueprint followed by subsequent updates (Larner 1979, Kain 1987, Rottenborn and Brinkley 2007). Incredibly, virtually all of the breeding species that have been added to the avifauna since Murray’s initial checklist have been the result of range expansions into the state rather than new discoveries of long-existing species. The early writings about Virginia birds were more than lists of occurrences. Descriptions of forces effecting populations such as market hunting and habitat loss demonstrate a conservation ethic that extends back in time. This ethic would build throughout the twentieth century and eventually become consolidated with the passage of Virginia’s Endangered Species Act (§29.1-563 §29.1-570) in 1972 and the federal Endangered Species Act (16 U.S.C. 1531-1543; 87 Stat. 884) in 1973. These two laws laid the foundation for the establishment of an organized effort to protect the nongame bird species of Virginia. In order to facilitate this mission, an avian taxonomic committee was formed and charged with identifying bird populations that were most in need of conservation efforts and funding. The committee would report on its assessment to a symposium held in Blacksburg during the spring of 1978 focused on Virginia Journal of Science, Vol. 66, No. 3, 2015 http://digitalcommons.odu.edu/vjs/vol66/iss3 BREEDING BIRDS OF VIRGINIA 225 endangered and threatened plants and animals of Virginia (Linzey 1979). This event would be followed by subsequent assessments in 1989 (Terwilliger 1991) and 2005 (VDGIF 2005). Both the avifauna of Virginia and the conditions experienced by threatened populations are ever changing. The objectives of this paper are 1) to present an updated list of the bird species known to breed in Virginia and 2) to provide an update and retrospective on the status of species that have been identified as requiring the highest level of conservation attention (i.e. recommended for threatened or endangered status or placed in Tier I) during the 1978, 1989 and 2005 benchmark treatments. METHODS This treatment includes all bird species (extant or extinct) with recognized breeding records within the state of Virginia as of June 2014. Presentation follows the scientific and English nomenclature, and the order, of the seventh edition of the American Ornithologists’ Union check-list of North American Birds (American Ornithologists’ Union 1998) through the 55 supplement (Chesser et al. 2014). In order to provide information on broad distribution within the state, status is provided by physiographic region. To simplify for this presentation, regions include the 1) Coastal Plain, 2) Piedmont and 3) Mountains and Valleys. The Coastal Plain is bounded by the Atlantic Ocean to the east and the fall line to the west. The fall line is an erosional scarp where the metamorphic rocks of the Piedmont meet the sedimentary rocks of the Coastal Plain. Between these two boundaries the land slopes gently toward the fall line where it generally reaches an elevation of less than 80 m. The Piedmont is bounded to the east by the fall line and to the west by the escarpment of the Blue Ridge. In the northern parts of the state the Piedmont is only 75 km wide but broadens to the south reaching nearly 300 km wide at the state line. The land slopes up to the west reaching 300 m in elevation at the escarpment. The Mountains and Valleys Region is bounded by the east slope of the Blue Ridge and the state line. For ease of presentation this region has been forged from three provinces including the Blue Ridge Province, the Ridge and Valley Province and the Appalachian Plateaus Province. The region supports many areas above 1,000 m including Mount Rogers (1,746 m) and Whitetop (1,682 m), the two highest peaks in the state. Within each physiographic region, the status of breeding populations was assessed in broad categories including common, uncommon, and rare. For species with known population estimates these categories follow the values: common – greater than 10,000 pairs, uncommon – greater than 1,000 but less than 10,000 pairs, rare – greater than 100 but less than 1,000 pairs and very rare – less than 100 pairs. For species with no population estimates these categories follow the following conditions: common – species with a relatively common habitat that is found easily, uncommon – species that requires a limited habitat and may be difficult to find, rare – species that is restricted to a limited habitat or is so scarce that it cannot be expected with any certainty, very rare – species that is restricted to only a few localities or has a small number of documented occurrences in the state. Although these categories are broad and have not been subjected to rigorous evaluation, they provide a description of relative abundance. Sources of data The treatment of breeding status and distribution presented here relied heavily on the work of the Virginia Society of Ornithology. Over the past 70 years, the society has Virginia Journal of Science, Vol. 66, No. 3, 2015 http://digitalcommons.odu.edu/vjs/vol66/iss3 226 VIRGINIA JOURNAL OF SCIE