By Ethan Hatchett
On a damp powerline right of way in southeast Georgia, biologists search for a tiny brown bird in a tangle of dried, brown grass. It’s like looking for a needle in a haystack.
Volunteers work to find Henslow’s sparrows in a survey (Todd Schneider/DNR)
It doesn’t help that these birds like to stay close to the ground, preferring to run and always hesitant to fly, making them even more difficult to spot. Often biologists only glimpse them when they poke their distinctive green heads above a clump of grass or utter their curt, sharp alarm call.
It’s understandable why Henslow’s sparrows are nicknamed “mice with wings.”
Henslow’s sparrows breed in the northern part of the eastern U.S., but they winter in pine savannas and similar grasslands in southern states, including Georgia.
DNR biologist Todd Schneider with a Henslow’s sparrow (Rick Lavender/DNR)
What exactly they do in their southern wintering grounds is not well understood. Biologists are only now beginning to identify key aspects of the life history of Henslow’s sparrows, such as their preferred microhabitat and food sources.
Yet like many grassland birds, this species is becoming increasingly rare because of habitat destruction and degradation. The pine savanna that Henslow’s sparrows relied on in past winters is disappearing; lost to development, conversion to cropland and pine plantations, and fire suppression. The birds now survive in scattered fragments of habitat and unusual areas with similar grassland characteristics, such as powerline rights of way.
That status and these factors are key to Henslow’s being considered a high priority species for conservation in Georgia’s State Wildlife Action Plan.
This comprehensive conservation strategy, which is undergoing a periodic revision, lists 640 native animal and plant species as priorities for conserving statewide. The 150 conservation actions recommended in the plan focus restoration and protection efforts where they’re most needed and most effective.
Thankfully, DNR and others are working to help the Henslow’s sparrow. Key wintering sites are being restored through efforts such as prescribed fire.
A banding study conducted by DNR and Georgia Southern University from 2011 through 2021 has provided helpful information about these elusive birds. Using three survey sites, data was collected on annual return rate as well as physical measurements like wing length and weight. From 2019 to 2021, Georgia Southern also studied the Henslow’s sparrow habitat, surveying for the specific features that help the bird thrive. Individual birds were also tracked using radio telemetry to assess the size and area of the wintering grounds. In addition to these surveys, biologists from the university have been studying the contents of the bird’s diet.
The plight of Henslow’s sparrows is a reminder of the importance of habitat preservation. This tiny bird may spend most of its time north of Georgia, but changes that deplete its southern wintering grounds can put the species in peril.
Ethan Hatchett is a communications assistant in DNR’s Wildlife Conservation Section.