Breeding birds at Fredericksburg and Spotsylvania: what the 2019 survey found

In 2019, despite population declines of more than 50% across the region, field sparrows were the second most common bird observed in the grasslands of Fredericksburg and Spotsylvania National Military Park, where the park uses prescribed fire and herbicide to maintain native warm-season grass meadows. The National Park Service's Mid-Atlantic Network summarized that year's breeding bird monitoring in a brief. Its highlights:

• Four volunteers conducted 66 surveys at 33 sites across the park during the summer of 2019.
• Several species of regional concern were recorded in relatively high numbers, including eastern wood-pewees, wood thrushes and field sparrows.
• Forest bird community index scores suggest high ecological health of the park's forest bird communities.

The park uses prescribed fire and herbicide treatments to maintain native warm-season grass meadows, which provide habitat for many increasingly rare and threatened birds. NPS / John Stoddard.

How the monitoring works

The brief says Mid-Atlantic Network scientists have worked with skilled local volunteers for 10 years to monitor bird populations in national parks across the mid-Atlantic region. The information helps them understand how breeding birds, available habitat and park resource management relate, with the goal of developing the best available science so parks can better understand and protect their resources. In a survey, volunteers record every bird heard or seen over ten minutes. Sites in both forest and grassland were visited several times during the breeding season.

Species 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 species that are declining and facing increasing threats across the mid-Atlantic region, and park managers take a particular interest in them. Nine of those species were observed during the 2019 monitoring.

Grasslands

For years the park has worked to maintain its acreage of native warm-season grasses to benefit birds. Despite population declines of more than 50% across the region, field sparrows, a regional species of conservation concern, were the second most common bird observed in the grasslands. Most birds seen at grassland sites were habitat generalists, though, and more grassland specialists would be present under ideal habitat conditions. Continued and improved management of the meadows should support an increase in grassland-dependent species.

Chart from the National Park Service's brief: the ten most abundant birds at grassland sites in 2019, as the average number observed per site.

Forests and the forest bird index

The most abundant bird at forest sites was the red-eyed vireo, a widespread and common forest bird. Eastern wood-pewees and wood thrushes, both species of regional conservation concern, were also relatively abundant. Wood thrushes depend on larger intact forest, so with urbanization increasing around the park, their relatively high abundance shows how important park forests are to local bird populations.

Chart from the National Park Service's brief: the ten most abundant birds at forested sites in 2019, as the average number observed per site.

Scientists can judge the overall health of a bird community from the abundance of all its species. The park's forest bird community index score (O'Connell et al., 2000) shows a healthy forest bird community, one with "high integrity". Continued management for mature forest habitat will help keep the score high, but because the park is relatively small and its geography fragmented, conserving mature forest on surrounding private land may be important for the long-term persistence of its forest birds.

Chart from the National Park Service's brief: the forest bird community index score, 2009-2019.

Sources

• National Park Service, Mid-Atlantic Network, Breeding bird monitoring at Fredericksburg and Spotsylvania National Military Park: 2019 status and trends; a yellow-breasted chat photograph credited to a Flickr photographer is left out; rewritten in hubnx's own words.