2 days ago
Saving grasslands
A drive through Niagara County's rural areas in June offers waves of tall, wispy grasses swaying in the breeze. While there may seem to be open green spaces everywhere, environmentalists say grasslands and the bird species that depend on them are disappearing.
In the study 'The State of the Birds,' the North American Bird Conservation Initiative assessed the status and health of all US bird species. The research showed that grassland birds have suffered the biggest decline of all bird species, said Heidi Kennedy, wildlife biologist for the NY Department of Environmental Conservation's Bureau of Wildlife Region 8 Office, located at Iroquois National Wildlife Refuge. Kennedy works with conservationists to manage refuge grasslands along the borders of Genesee and Orleans counties that are key to preserving vulnerable bird species.
Grassland birds depend on extensive stretches of open space, without shrubs and trees, that are dry enough for nesting on the ground. These birds include the short-eared owl, a ground nester that is on the state endangered species list, and the upland sandpiper, sedge wren, Henslow's sparrow, and northern harrier, which are on the state's threatened species list. Species of special concern include the grasshopper sparrow, vesper sparrow, and horned lark.
Kennedy said Henslow's sparrow, a buff bird with dark streaks, declined 7.39 percent a year from 2000 to 2022, a dangerous trend.
Habitat loss, agricultural practices, and pesticides are the primary factors behind these declines, said Brett Ewald, a Ransomville native who is director of Cape May Bird Observatory in New Jersey.
Developing parcels of grassland can have a surprisingly significant impact on birds by effectively splitting the remaining space into pieces.
'They need a certain size of grassland,' Ewald said. 'More of the time, those big broad grasslands are getting divvied up. It breaks up that continuous habitat that they need. They get disturbed more or young don't survive their nesting.'
For the birds, Ewald said, 'It's a matter of feeling safe and undisturbed. The raptors need that larger expanse. They will feed on different things — rodents and small birds. They can theoretically find food around, but it's how far do you have to go for food and leave young unprotected.'
Decades ago, hay fields were a habitat for these birds, but Ewald said that has changed.
'I really do think that the early haying is having an impact on them,' Ewald said. 'I understand that if the farmers can get an additional haying in, it means more bales. It used to be much later in the season that they did the first cutting.'
Kennedy said grasslands need to be mowed to keep out shrubs and trees and maintain conditions for ground nesters, but timing is important. On Iroquois National Wildlife Refuge and its adjacent state lands, mowing is delayed until the year's hatchlings have matured, typically mid-August.
Ewald said if property owners who are not farming can delay mowing until late June or early July, it will reduce the impact on birds.
As early as the 1970s eastern meadowlarks and bobolinks began to decline because of DDT. Ewald said although that chemical was banned, it was replaced by decades of other pesticides and the addition of Round-Up.
Pesticide use has cut down on the caterpillars, flies, and bees that many grassland species rely on for food, he said. While some vulnerable bird species may eat seeds, Ewald said most species feed insects to their young.
The types of plants in wild fields make a difference in supporting wildlife, said Josh Randall, natural resources educator for Cornell Cooperative Extension of Niagara County. Native plants support more of the insects that grassland birds rely on, such as caterpillar species, which conveniently can't fly. Standing chest high in the little blue stem, Canadian rye grass and switch grass at Lytle Nature Preserve in the Town of Lockport, Randall said some Wisconsin prairie plants had been introduced to the plot decades ago. He said the extension is collaborating with the town, the WNY Land Conservancy, and WNY PRISM, to assess the preserve's grasslands and determine management strategies for non-native species. This includes invasive black locust and autumn olive, which threaten to close in the fields.
Randall said it defeats the purpose of a nature preserve to let it convert to invasives.
'There needs to be an effort to continually manage this,' he said.
Ewald thinks that a variety of non-agricultural lands offer an opportunity to support grassland species.
'If we can take those parkways and median strips, and instead of mowing them every two weeks, put in annual and perennial plants that don't need to be mowed, you're going to get a ton more resources for bird life to live on.'
