Birds at Lincoln Boyhood National Memorial: what the 2007-2019 surveys found

Of the bird species that breed at Lincoln Boyhood National Memorial in southern Indiana, 43% are in decline across the region, but the number of species found at the park has changed little. An NPS page from the Heartland Inventory and Monitoring Network sums up what its breeding-season surveys found from 2007 to 2019.

A Louisiana Waterthrush, which lives in the park's oak-hickory forests. NPS photo.

Why birds are monitored

The page says birds eat pests, disperse seeds, pollinate plants and feed people, and birdwatching is a multi-billion-dollar industry. They are also indicators of environmental change, the proverbial canary in the coal mine. Clearing land for agriculture and urban development threatens bird habitat around the park. Some birds that breed there, including the Chimney Swift, Common Grackle, House Sparrow and Northern Bobwhite, are declining at alarming rates in the region.

Network scientists survey birds during the breeding season, record the structure and makeup of the park's plant communities, and compare park bird trends with the larger region, to learn how birds respond to changes in their habitat and to help the park restore and keep its landscapes.

What the surveys found

Surveys began in 2007. There were none in 2008, 2009, 2010 and 2012. Across nine years of surveys, the team found 82 bird species, and sixty-five of them could breed in the park, about 57% of the species that could reasonably be expected to breed there. The number of species found, and how they were spread across the landscape, changed little over the years, at an average of 23 species a year. Three breeding species are of conservation concern for the Central Hardwoods Bird Conservation Region, and 43 breeding species are woodland associates or obligates, which need woodland to survive.

The Red-headed Woodpecker, a species of conservation concern for the region and a year-round resident of the park. NPS photo.

Habitat and trends

The park sits in what was once a heavily forested part of the interior highlands of the Central Hardwoods Bird Conservation Region, one of 67 regions identified in the North American Bird Conservation Initiative. Much of the region has been converted to agriculture, but the park is still mostly forested, and the steady diversity of birds suggests its habitat has stayed similar.

The Central Hardwoods Bird Conservation Region and the park's location. NPS map.

Only five species were common enough for the team to measure abundance. Overall, common bird populations in the park are doing about as well as those in the wider region. Northern Cardinals increased significantly in the park after 2007. Four species held stable: Blue-gray Gnatcatcher, Eastern Wood-pewee, Indigo Bunting and Tufted Titmouse.

A Blue-gray Gnatcatcher, a common summer resident whose populations are stable in the park and the region. NPS photo.

A bird that never lands

Chimney Swifts roost in an abandoned chimney at the park. The page says they stop their endless flight only to roost, build a nest or incubate eggs, and they feed, drink and gather nest material on the wing. Their numbers are declining in the wider region but have stayed relatively stable at the park.

Sources

• National Park Service, Heartland Inventory and Monitoring Network, "Bird Community Monitoring at Lincoln Boyhood National Memorial, 2019" (https://www.nps.gov/articles/libo_birdmon.htm); the Chimney Swift photo, credited to an unknown photographer, is left out; rewritten in hubnx's own words.