Petersburg National Battlefield's Birds: What Two Summers of Surveys Found

Petersburg National Battlefield has worked for years to increase its native warm-season grasses to benefit birds, yet some grassland birds remain very rare: in two summers of surveys the eastern meadowlark, a species of regional conservation concern, was recorded once. The forest bird community, by contrast, scores as moderately healthy.

How the birds were counted

Scientists of the National Park Service's Mid-Atlantic Network work with park staff and skilled local volunteers to monitor bird populations in national parks across the mid-Atlantic region. The information is used to improve understanding of the relationships between breeding birds, available habitats and park resource management. In the summers of 2017 and 2018, park seasonal staff conducted a total of 107 surveys at 36 monitoring sites, in both forest and grassland habitat, visiting each site multiple times during the breeding season. During a survey, staff documented every bird heard or seen over a ten-minute period.

Birds of regional concern

The Partners in Flight Program is a network of organizations involved in bird conservation in the Western Hemisphere. It has identified a number of bird species that are declining and facing increasing threats across the mid-Atlantic region, and nine of them were observed during the 2017–2018 monitoring. Several were documented in relatively high numbers, including eastern wood-pewees, wood thrushes and yellow-billed cuckoos.

Grassland

The park is working to convert more of its open landscapes into warm-season grass meadows to support bird species diversity. NPS / Tim Blumenschine.

Eastern bluebirds, tufted titmice and American robins were the three most common birds in the park's grasslands in 2017–2018, and all three are relatively abundant and widespread across the region. Continued and improved management of warm-season grass meadows should support an increase in grassland-dependent species that are currently very rare at the park, like grasshopper sparrows, which were not observed during the 2017–2018 monitoring.

Ten most abundant birds at grassland sites in 2017–2018 (average number observed per site). Chart from the Park Service's brief.

Forest

The three most abundant birds at forest sites were the tufted titmouse, the red-eyed vireo and the Acadian flycatcher. The eastern wood-pewee and the wood thrush, both of regional conservation concern, were also relatively abundant. Wood thrushes depend on mature forest ecosystems, and given the increasing urbanization around the park, the brief says, their high abundance shows how important the park's forests are for local bird populations.

Ten most abundant birds at forest sites in 2017–2018 (average number observed per site). Chart from the Park Service's brief.

Forest bird community index

Scientists can study the abundance of all the bird species in an area to judge the overall health of the bird community. The forest bird community index score for the park (O'Connell et al., 2000) shows a moderately healthy forest bird community, one with "medium integrity". Continued management for mature forest habitat should help maintain or increase that score. Because the park's land holdings are fragmented, conservation of mature forests on surrounding private lands may also be important for the long-term persistence of the battlefield's forest bird communities.

Forest bird community index score, 2017–2018. Chart from the Park Service's brief.

The brief points to the park's 2019 breeding bird monitoring report (Johnson, 2020) for more detail.

Sources

• National Park Service, Mid-Atlantic Network, Breeding bird monitoring at Petersburg National Battlefield: 2019 status and trends; rewritten in hubnx's own words.