Photo: Northern Harrier, Gary Zeng/Audubon Photography Awards
Is that an Owl Flying Low Across the Grasslands?
Jessica Bigger
While living in Humboldt County, CA, I would see Northern Harriers (Circus hudsonius) flying low with their “V” shaped wing formation hunting in the Arcata Bottom on a regular basis. Harriers were a common sight there. The Arcata Bottom, with its open grasslands as far as the eye can see, is prime habitat for the Northern Harrier, and other hawks and falcons. They were easy to identify by their obvious white rump and black-tipped wings.
So, seeing a Northern Harrier flying over the Reston Library during fall migration was quite a surprise, especially since there isn’t any spacious grasslands or wetlands nearby. But there is no doubt in my mind that what flew over the library, was a harrier. So, this harrier was likely just passing through.
Northern Harriers spend their breeding season throughout the Canadian provinces and winter throughout most of the United States, Mexico, and a small portion of Central America. Harriers spend their winters foraging in habitats like deserts, coastal sand dunes, farmlands, grass lands, floodplains, marshes, and estuaries.
Northern Harrier Female, Timothy Shore/Audubon Photography Awards
Hawks and raptors have keen eyesight to zero in on their prey, but the harrier relies more on its hearing than its sight when hunting. Their disc-shaped face – similar to an owl – enables them to use their hearing to locate prey. Harriers usually eat small birds and mammals, but they will occasionally hunt larger prey, like waterfowl and rabbits. Since larger animals are impossible to grab, harriers will attempt to drown them.
Northern Harriers have been found flying around the September 11, 2001 Memorial of Flight 93, in Stoystown, PA, which has been transformed into an ecological hotspot for many birds, as the area surrounding the crash site has transitioned into grassland. “There are now family members who say the most important part of the site to me is that all this nature came back, and it’s very healing to see that,” said John Reynolds during an interview with WESA-FM.
As far as conservation goes, Northern Harriers are currently of low concern, but there are states where this bird has been listed as endangered like in northern New Hampshire. Currently Chris Martin, a biologist with the New Hampshire Audubon Society, has been conducting monitoring surveys of Northern Harriers during the breeding season since 2019. Last year in 2020 Martin and his team identified ten breeding pairs that successfully raised nine fledglings. After reaching out to Martin for this year’s monitoring results, he informed me that unfortunately they had fewer successful breeding pairs than last year. They only counted six breeding pairs and 3 fledglings. When I asked Martin in an email what might be the cause for the decline he said, “I suspect several factors involved, including wet weather late (in the season) and reduced early-season survey effort.”
Northern Harrier Male, Gary Zeng/Audubon Photography Awards
Climate Change will continue to have a negative effect on the population. As the planet’s temperature increases, the Northern Harrier’s range will continue to push further north into Northern Canada, with estimated range loss of 39% in northern midwestern range, western habitats of the United States, and portions of Canada. Climate Change threatens the Northern Harrier population as it does all bird species. Wildfires will reduce habitat and heat waves will harm nestlings during breeding season, according to the National Audubon Society.
Sources:
https://www.allaboutbirds.org/guide/Northern_Harrier/overview