Bringing Back Bobolinks
New England Farming, Biodiversity, and Soil Health
What can agricultural land contribute to protecting biodiversity? Much of modern farming, in order to succeed in a highly competitive marketplace, features intensive land use that is simplified to maximize production. There is not much habitat for wild species in a field of corn.
But what about more complex agricultural landscapes, such as those described by Conrad Vispo in the last issue of From the Ground Up? These were once home to beloved grassland birds and other open land species associated with diversified smaller-scale farming—a landscape that itself is in long decline.
We could view such species as interlopers that migrated here during a few centuries following the removal of native forests, say they don’t really belong, and be content to watch them fade away. Conversely, we could make extraordinary efforts to manage small pieces of the reforested landscape for these open land species. Or, we could ask ourselves whether the landscape that supports them—diversified farming that can produce a healthy part of our food supply, and that many of us find attractive—has broader cultural and ecological value that might inspire us to protect it as a whole.
An integrated approach to conservation of grassland species could weave together efforts to increase New England’s regional self-reliance in food (New England Food Vision; New England Feeding New England) and to improve soil health—storing carbon and keeping farmland resilient in the face of increasingly extreme weather events.
Bobolinks
Bobolink perched in a hayfield. Photo © Kent P. McFarland
Bobolinks and other grassland birds greatly expanded in the eighteenth and nineteenth centuries, when European settlers converted a large part of New England to an agrarian landscape of small farms. These birds, which had formerly been found mostly in the tallgrass prairies and savannas of the upper Midwest, were well-suited to the new landscape of pastures and hayfields that opened up in the Northeast, and so expanded their range and numbers.
However, the rise of twentieth century industrial agriculture across the nation brought decline to New England farming and reversion of farmland to forest, alongside suburban development. Many species thrive in forests and even suburbs, but not most grassland birds—their habitat shrank dramatically. The region’s largest remaining farming enterprise, dairying, shifted away from pasture to confined feeding of corn silage and hay. Cornfields were never a home for bobolinks; but increasingly, neither were hayfields. With horse-driven and then tractor-powered mowers, tedders, rakes, and balers, hay could be cut two or more times a year. Earlier and more frequent hay cuttings improved the quality of the hay but degraded the habitat. Sadly, many hayfields now function as ecological sinks, attracting grassland birds to nest and then destroying nestlings before they can fly. As the scale and intensity of farming continues to increase, grassland birds are steadily declining, both here and in the Midwest.
In response, several state Audubon societies in New England have initiated programs to pay farmers to cut some of their hay later, so that the bobolinks have time to fledge their broods. But cutting later means less hay, and lower-quality hay. It is often difficult for hard-pressed dairy farmers to find a place for rough fodder in their feeding programs. Farmers themselves are an endangered species, always on the financial brink. Paying them to make sacrifices is a nice thought. Finding solutions that contribute to some useful farm production would be even better. We need to think more expansively about farming and biodiversity.
As the local dairy industry is driven steadily downhill by larger producers elsewhere, New England continues to generate neglected hayfields that are no longer worth anyone’s time to cut. Meanwhile, the climate crisis brings new urgency to the task of managing land in ways that maximizes its capacity to sequester carbon, store stormwater and nutrients, and support life. We need an approach that supports farmers in managing part of their hay and pasture to be part of a robust new version of expanded New England farming that also provides biodiversity benefits and ecosystem services.
The Ag Allies program in Maine exemplifies this approach, combining on-farm technical support, bird monitoring, incentives, and workshops to spread the word. So does the Virginia Grassland Bird Initiative. In Massachusetts, Mass Audubon and American Farmland Trust are working to launch a similar program, collaborating to collect field data and farmer observations to find methods to improve forage quality and soil health, while also providing habitat to grassland birds.
The Challenge and the Opportunity
In New England, grassland birds begin nesting around the middle of May and fledge their young in mid-July, with some variation north to south across the region, and by species. They nest in grassy fields of eight acres or more, with a regular shape and without woody plants. Grassland birds do not nest near field edges where risk of predation is highest. They often select hayfields and pastures for nesting habitat, where their nests are then frequently destroyed by livestock or mowing.
New England contains about 2 million acres of agricultural and open land—only about 5% of the landscape. More than half of this farmland is grass. If a substantial portion of those 1.3 million acres could be managed in ways that are compatible with grassland bird habitat, and that also provide agricultural output, it would be a boon for both the region’s food systems and its biodiversity. Here we will outline three pathways by which this could happen:
Early Hay Cutting Followed by a Rest Period;
Rotational Grazing; and
Late Hay Cutting.
These pathways are not mutually exclusive, and they could be combined in different ways on different farms.
1. Early Hay Cutting Followed by a Rest Period
Haying in the early stages of the breeding season results in near total nest failure, not only because nests are crushed, but also because mothers are frightened off their nests and the removal of the grass cover exposes eggs and nestlings to predators.
The most common strategy for preserving nesting habitat is to delay haying until after nestlings have fledged (discussed below), but making that first cut extra early can also work where maintaining the highest quality forage is essential—such as on the commercial dairy farms that comprise about half the hay land in New England. For lactating dairy cows, low-quality late-cut hay is not an option. But research has shown that if farmers can cut some of their hay as early in May as possible, and then wait a little more than two months for their second cut, bobolinks have a window to raise a brood. This strategy can yield similar reproductive success to late-hayed fields.
However, there is a soil health cost to this strategy: Early in the season the soil is likely to be wetter, so early haying carries the risk of intensifying soil compaction. Compaction, in turn, can suppress forage quality by preventing plants from rooting deeply, and by reducing the soil’s capacity to hold water and support beneficial soil organisms. Stressed plants produce less biomass and go to seed earlier, which shortens the time that the plant has to grow more nutritious leaves. So early haying is appropriate only for high, dry, sandy fields.
Fields that are too small, too narrow, or too irregularly shaped to attract grassland birds won’t provide habitat regardless of hay timing. But even if most fields won’t work, technical and financial support programs to assist farmers in identifying those fields that are suitable for early haying could add up to a lot of bobolinks. Of the approaches outlined here, early haying is the most compatible with conventional dairying and the production of high-quality forage, and it has been successfully implemented on several farms in Vermont.
2. Rotational Grazing
Management-intensive rotational grazing (MIRG) utilizes high animal concentration in small paddocks with frequent movement from one paddock to the next. As compared to continuous grazing, where the livestock stay in one large pasture for a long time, MIRG increases forage utilization, plant diversity, carrying capacity, soil organic matter levels, and overall soil health. However, those higher animal concentrations can conflict with grassland bird habitat goals: under MIRG the risk of nest trampling is increased significantly, which is a major cause for nest failure in pastures. However, there are at least two ways to adapt MIRG to accommodate grassland birds: perimeter grazing and nest avoidance technologies.
A beef cow with her calf, born on pasture. Photo © Brian Donahue
Perimeter grazing of large fields presents an opportunity to utilize field edges while still protecting grassland birds. As described above, nesting birds don’t use the outside edges anyway, and are not scared off their nests by grazing animals that don’t come too close. The field center can be left for late haying (or grazing) until nesting is finished. In Massachusetts, Codman Farm has been experimenting with this approach for several years. By creating small paddocks using temporary fencing and rotating cattle in a circular pattern, they are able to balance their goals of improving pasture conditions and protecting interior grassland nesting bird habitat. After the birds have fledged, the middle of the field is opened for grazing.
When livestock graze where birds are nesting, drones equipped with thermal cameras can identify nest locations so that “virtual fencing” can keep the stock away from the nests. Virtual fencing uses GPS technology and collars with auditory signals and mild electric shocks, much like electric dog fencing. In addition to protecting nests, such virtual fencing could reduce the labor of management-intensive rotational grazing, making it viable for more farms.
An expansion of management-intensive pasture-based farming in New England that replaces some confinement dairy and beef farming would be beneficial for the health of soil and waterways, building organic matter and holding nutrients on the land. With careful design of farm systems, this could go hand in hand with supporting more grassland birds.
3. Late Hay Cutting and Grazing
Waiting until about July 15—when most of the young birds have fledged—to cut hay (or to begin grazing) has the greatest promise for reviving populations of grassland birds. It would return part of the agrarian landscape to its condition prior to the twentieth century, when most haying did not take place until July, and bobolinks were ubiquitous.
The downside of cutting late is the poorer quality of the hay, which has passed its optimal leafy nutritional stage and become coarse. There are three ways to address this problem: improving soil quality (and hence forage quality), establishing warm-season forage species, and matching the late-cut hay to the nutritional needs of the livestock. Without these measures, cutting late can lead to declining hay quality and soil fertility that ends in abandonment.
Addressing soil health involves improving the capacity of the hayfield’s plant-soil community to cycle nutrients, store water, and support a healthy soil biological community capable of maximizing the productivity and nutrient density of the forage crop. This means increasing New England’s often acidic soil pH to promote legume persistence, and reducing synthetic nitrogen fertilizers in favor of organic amendments. Common grass forage species are most productive at or above a pH of 5.8, but a higher pH of 6.5 is needed for legumes to flourish. Legumes provide nitrogen for the grass, boosting yields and reducing reliance on synthetic nitrogen fertilizers. Periodic liming is effective but is expensive and laborious for farmers themselves to apply, whereas bulk lime trucks can cause soil compaction. If pH management is neglected, nitrogen-providing legumes disappear. Managers sometimes respond with synthetic nitrogen fertilizers that further acidify the soil, continuing the downward spiral and loss of soil health.
Farmers can reverse this cycle by investing in organic (meaning carbon-based, not “certified organic”) inputs such as wood ash, biochar, manure, and compost. Compost and manure increase soil organic matter, which helps to buffer pH while supplying nutrients, reducing the need for synthetic fertilizer. Wood ash has a mild liming effect, as do some biochar products; and wood ash also supplies potassium, which encourages clover. All of these amendments can help increase the health of forage crops, allowing them to produce more biomass, resist stressors such as drought, and regrow more quickly after haying—improving late grazing or even allowing a second cut of hay. Grazing after the hay is cut also enlists the stock to continually reseed clover throughout the field in their manure.
A technical support provider and farmer survey a grassland in southeast Massachusetts. Photo © Caro Roszell
To further improve summer grazing, some farmers are adding native warm-season grasses such as switchgrass (Panicum virgatum), big bluestem (Andropogon gerardii), and Indian grass (Sorghastrum nutans) to their forage mix. Native warm-season grasses start growing later than the European cool-season grasses that typically dominate hay and pasture. They tolerate drought better and hold their nutritional quality later into the season. Cool-season grasses decline in production in July, go nearly dormant in August, and resume growth in fall; meanwhile, warm-season grasses produce vigorously through the warmest months. This makes warm-season grasses a good fit with late haying.
Late-cut hay may not be the best quality, but with proper management it can incorporate enough legumes to raise its protein to an adequate level. It is good enough for one class of livestock in particular: beef cows that are not in their last months of pregnancy or first months of lactating after calving. Therefore, cows who calve on pasture in late spring or summer can be fed late-cut hay in the early part of winter, when their nutritional needs are not so high. The better hay can be fed to the young stock to maintain a steady rate of growth, and to the mothers when they need it most. Late-cut hay is also suitable for horses, which consume a sizable portion of New England’s hay crop. However, consumer education may be necessary to support a regional market for late hay among horse owners. In Maine, Ag Allies has invested in educating horse owners about the nutritional suitability of late hay for non-working horses.
Improving soil health by building organic matter and lessening compaction has the added benefit of storing more carbon and increasing resilience in the face of climate change. Taking fewer cuts of hay reduces equipment traffic and allows forage species to increase rooting depth, which can build deeper, more porous soils that sequester carbon at greater depths, further increasing the drought resilience of the plant community. Herein lies a significant potential synergy between the goals of protecting and enhancing grassland nesting bird habitat and healthy soils. Healthy soils themselves provide biodiversity: They support more kinds and numbers of living things. Some of these are insects that emerge from the soil as they pass into later stages of their life cycles and become part of the diet of grassland nesting birds.
The pastures and hay meadows at Mesa Farm in Rutland, Massachusetts, support sheep, horses, and grassland birds. Photo © Caro Roszell
A Triple Win
A rebirth of New England grass farming, after more than a century of decline, could yield multiple benefits: new opportunities for farmers and an increasing regional food supply; improved soil health, carbon storage, and resilience; and real biological conservation value from our farmland. Much of this hay and pasture, of necessity, will not be overly hospitable for the nesting of grassland birds. But a significant portion of it could be, by weaving the three pathways we have outlined into working farm systems.
The early cut hay pathway aligns with the need to continue to produce top-quality hay for dairy cows and young growing stock. It can be used on a subset of the most productive hay land that is cut two or more times per year. As such it could cover a relatively small but still significant area of land—probably in the range of 100,000 acres.
The rotational grazing pathway aligns with the much larger need to move New England dairy farming back into more resilient grass-based systems, and to greatly expand regional pastured beef and lamb production (replacing feedlot production from other regions). Such intensively grazed land will not be a perfect home for grassland birds—a percentage of the nestlings will inevitably be trampled. But some will be successfully reared, and that percentage can be improved by the use of nest avoidance technology. And some of the grazing can take place at the nest-free perimeter of larger fields, leaving the interior for late-cut hay. The center section can then add to late summer and fall pasture, after the hay has been cut.
The most tantalizing potential for grassland birds lies with that late-cut hay. If it can be made well enough to feed beef cows and horses—as research shows it can—this could unlock hundreds of thousands of acres of under-utilized open land across New England. Such land could be ideal for supporting cow-calf operations, supplying feeders to be finished on better grass. It could help supply the extra acreage needed to support the increase in regional food production called for in A New England Food Vision and in New England Feeding New England. It could be part of a region-wide effort by all six New England states to improve soil health, store carbon in soils, protect water quality, and support biodiversity. In particular, it could provide ample habitat for our declining grassland birds.
State Audubon programs, regional land trusts, soil and water conservation districts, academic institutions, and independent research and education organizations can show the way by supporting on-farm research and programs that help enable farmers to implement and explore these methods. We need grassland bird programs that are framed not as an alternative to active farming, or as a sacrifice made by farmers for which we compensate them. To succeed broadly, these programs must be part of working farm systems with recognized co-benefits for people and for birds.
Read More:
Brown, L.J. and J.J. Nocera. 2017. Conservation of breeding grassland birds requires local management strategies when hay maturation and nutritional quality differ among regions. Agriculture, Ecosystems & Environment, 237: 242–249.
Perlut, N.G., A.M. Strong, T.M. Donovan, and N.J. Buckley. 2006. Grassland songbirds in a dynamic management landscape: Behavioral responses and management strategies. Ecological Applications, 16(6): 2235–2247.
Perlut, N.G. 2014. Grassland birds and dairy farms in the northeastern United States. Wildlife Society Bulletin, 38(3): 574–579.
Renfrew, R.B., K.A. Peters, J.R. Herkert, K.R. VanBeek, and T. Will. 2019. A Full Life Cycle Conservation Plan for Bobolink (Dolichonyx oryzivorus). U.S. Fish & Wildlife Service.
Strong, A. 2015. How much is a bobolink worth? Bird Observer, 43(1).
Suomi-Lecker, L. n.d. Grassland Habitat Conservation [Fact Sheet]. Somerset County Soil & Water Conservation District.
White, C. and J.A. Williamson. 2018. Soil pH Affects Forage Production. Penn State Extension.
Sawyer, S., et al. 2023. New England Feeding New England. New England Food Systems Planners Partnership.
Donahue, B., et al. 2014. A New England Food Vision. Food Solutions New England, University of New Hampshire.
Caro Roszell farmed full time for 10 years while concurrently working for Northeast Organic Farming Association, Massachusetts Chapter, prior to stepping into her role with American Farmland Trust. She designs and implements programs that combine financial assistance, technical knowledge transfer, and peer learning models to help farmers protect and build soil health. Her efforts to expand support systems for farmers are guided by the understanding that farmers are the leaders of the soil health movement, the experts in their fields, and the frontline workers of climate change. She is the author of Farmers Share Experiences and Challenges Adopting Healthy Soils Practices (2021) and was a contributing author on the Massachusetts Healthy Soils Action Plan.
Brian Donahue is Professor Emeritus of American Environmental Studies at Brandeis University and a farm and forest policy consultant. He co-founded and for 12 years directed Land’s Sake, a nonprofit community farm in Weston, Massachusetts, and now co-owns and manages a farm in western Massachusetts. He sits on the boards of The Massachusetts Woodland Institute, The Friends of Spannocchia, and The Land Institute. Donahue is author of Reclaiming the Commons: Community Farms and Forests in a New England Town (1999) and The Great Meadow: Farmers and the Land in Colonial Concord (2004). He is co-author of Wildlands and Woodlands, Farmlands and Communities (2007) and A New England Food Vision (2014).