Background: The Eastern Meadowlark is a harbinger of spring in southern Ontario, arriving on frosty grasslands before many other migratory songbirds. The species is facing steep population declines (83% in Canada and 80% in Ontario from 1970 to 2023) and is listed as threatened in both jurisdictions. Various factors on breeding grounds, during migration, and on wintering grounds contribute to population declines. Our focus is on nest success and conservation on breeding grounds. Eastern Meadowlarks nest exclusively in grasslands and rely on hayfields and pastures for nesting habitat in southern Ontario because few other grasslands exist in the region. Although agricultural grasslands provide crucial nesting habitat, these working landscapes simultaneously present a risk of nest destruction from hay harvest and livestock grazing. Nests, which are built directly on the ground, are frequently crushed, trampled, or exposed to predators when vegetation is removed. Most conservation guidance recommends delaying haying and grazing until 15 July to provide enough time for nesting grassland birds to raise young, but these guidelines are largely based on Bobolink nesting timelines. Unlike Bobolinks, Eastern Meadowlark females attempt to raise 2 broods in a season and thus, often continue nesting until mid-August. In 2025, we focused our research on Eastern Meadowlarks nesting in rotationally-grazed cattle pastures to improve our understanding of the conditions under which females can raise 2 broods of young. We also continued to collect data on other grassland birds at risk.

Project work: We surveyed 914 acres of hayfield, pasture, and fallow grassland on 7 farms in Grey and Huron counties in late spring. Transect surveys provide information about the distribution, abundance, and habitat associations of Eastern Meadowlarks, Bobolinks, and Grasshopper Sparrows and help us locate study sites for field research.

We conducted intensive field research on 7 farms (3 of which were also surveyed). Two of our research sites, the Grey Dufferin Community Pasture and St. Brigid’s Creamery, were larger operations, each managing ~500-700 acres of grassland. Each farm presents different research opportunities depending on species distribution, abundance, and farm management, as well as different challenges related to stewardship. We monitored 34 Eastern Meadowlark territories across 5 farms (692 acres of habitat) to determine the number of females, the timing of nesting, if females nested successfully, if they raised multiple broods, and the impact of farm management and various kinds of stewardship. Overall, we monitored 81 Eastern Meadowlark nesting attempts. We also collected data on vegetation height, density, and litter depth after fields were grazed on 2 farms to learn more about the relationship between grazing and Eastern Meadowlark nest success. Additionally, we monitored 15 Bobolink and 11 Grasshopper Sparrow nests in 33 and 6 nesting territories, respectively, and collected vegetation data at Grasshopper Sparrow nests to continue increasing our knowledge about the nesting habitat used by this species.

Conservation implications: We communicated with landowners and managers throughout the nesting season to provide information about nesting birds and stewardship recommendations, and to learn from farmers about the factors involved in management decisions. Stewardship actions were implemented on all 11 participating farms. Stewardship included delayed hay harvest, delayed grazing, light grazing, extended rest periods between grazing, livestock exclusion fencing, and leaving fields fallow. Currently, we are preparing individual reports for each participating farm detailing the information we collected about the birds through surveys and monitoring, the impacts of farming and stewardship, and custom recommendations for future stewardship to benefit nesting grassland birds. We plan to continue collecting data on Eastern Meadowlarks nesting in rotationally-grazed pastures to enable us to understand the conditions needed by the birds and recommend stewardship actions that provide suitable conditions for raising 2 broods. The date cattle enter a pasture and rest period between grazing occasions are important factors we are examining.

Project date: 2025

Funding: Support for this project was provided by the Government of Ontario through the Species at Risk Stewardship Program; Environment and Climate Change Canada; The McLean Foundation; Hodgson Family Foundation; K.M. Hunter Charitable Foundation; Gordon & Patricia Gray Animal Welfare Foundation; Henry and Chloe Korenblum Fund, Jewish Foundation of Greater Toronto; The Max and Larry Enkin Foundation; Emerald Foundation; ECO Canada’s Science Horizons program; the Government of Canada’s Canada Summer Jobs program; and our generous donors.

This project was undertaken with the financial support of the Government of Canada.
Ce projet a été réalisé avec l’appui financier du gouvernement du Canada.

This project has received funding support from the Government of Ontario. Such support does not indicate endorsement by the Government of Ontario of the contents of this material.