Barn Swallow Recovery Strategy Executive Summary
This document provides a summary of the recovery strategy for the Barn Swallow, which advises the ministry on ways to ensure healthy numbers of the species return to Ontario.
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Executive Summary – Recovery Strategy for the Barn Swallow (Hirundo rustica) in Ontario
Prepared by Audrey Heagy, Debbie Badzinski, David Bradley, Myles Falconer, Jon McCracken, Ron Reid and Kristyn Richardson
The Barn Swallow (Hirundo rustica) is a medium-sized migratory songbird found in open country habitats. The most abundant and widespread swallow in the world, this familiar species breeds in temperate regions across North America, Europe and Asia, and overwinters in Central and South America, southern Africa, and southern and southeast Asia. Throughout its range, it is found in close association with human populations. Six subspecies of Barn Swallow are recognized but only one subspecies, H.r. erythrogaster, breeds in North America. Due to population declines across the northern portion of its North American breeding range, the Barn Swallow is listed as threatened under Ontario’s Endangered Species Act, 2007 (ESA) and has been designated as threatened in Canada by COSEWIC. The Barn Swallow is one of many diverse species of common aerial-foraging insectivorous birds that are of conservation concern in Ontario, Canada and the northeastern United States due to long-term population declines for a combination of reasons that are not well understood.
This species breeds throughout Ontario but over 90 percent of the provincial population (ca. 350,000 individuals) is concentrated in southern Ontario, south of the Canadian Shield. Its distribution in northern Ontario is localized, being closely associated with roads and human settlements and largely absent in more remote areas. Since 1970 the Ontario Barn Swallow population has declined at an average annual rate of 2.56 percent, amounting to a cumulative loss of 66 percent. The rate of decline over the most recent 10-year period is similar to that since 1970.
Barn Swallow habitat needs include foraging habitat, nest sites and nests and nocturnal roost sites. Across Ontario Barn Swallows forage over a wide range of open country habitats including farmland, lakeshore and riparian habitats, road right-of-ways, clearings in wooded areas, parkland, urban and rural residential areas, wetlands and tundra. Barn Swallow nests in Ontario are commonly situated inside or outside of buildings, under bridges and wharves and in road culverts. A small portion of the population nests on cliff faces. Outside of the breeding season swallows congregate nightly in communal roosts. Roost sites in Ontario are often associated with marshes or shrub thickets in or near water.
Numerous factors have been proposed as possible explanations for the recent declines in Barn Swallows and other aerial insectivores. The information needed to critically evaluate known and potential threats to Barn Swallows in Ontario is generally lacking. Many knowledge gaps must be addressed in order to understand the most significant threats to this species' survival. It is likely that multiple direct and indirect threats at various stages (and locations) in its life cycle along with population fluctuations due to natural processes, are having an additive or synergistic impact on Barn Swallow populations.
Known and potential direct and indirect threats affecting reproduction and survival include: (1) loss of nest site habitat, (2) loss or degradation of foraging habitat, (3) environmental contaminants, pesticides and pollution, (4) reduced productivity due to predation, parasitism and persecution, (5) habitat loss, disturbance and human persecution at roost sites, and (6) climate change and severe weather.
Lack of understanding of the causes of the population decline hampers recovery planning. Key knowledge gaps that must be addressed to focus recovery efforts include: (1) vital rates and population source/sink dynamics, (2) diet and food supply, (3) habitat use, requirements and trends in Ontario, (4) wintering and migration habitat and ecology, (5) best management practices, and (6) climate change effects.
The recovery goal is to maintain a stable, self-sustaining population of Barn Swallow in Ontario by 2034 (within 20 years) and to slow the rate of decline over the next 10 years. The recovery objectives identified in this strategy are to:
- fill key knowledge gaps to increase understanding of the nature and significance of threats to Ontario Barn Swallow populations and the biological and socio-economic factors that may impede or assist recovery efforts;
- maintain or improve nesting productivity through the development of appropriate practices and policies for managing Barn Swallow nests, nest sites and associated foraging habitat in Ontario;
- promote stewardship, education and increased public awareness of the Barn Swallow in Ontario;
- identify and protect important roost sites used by Barn Swallows in Ontario; and
- inventory, monitor and report on the state of Barn Swallow breeding populations and habitats in Ontario and elsewhere to track the progress of recovery activities.
Approaches to recovery focus on research to address key knowledge gaps and also a range of short-term activities designed to maintain, and where possible enhance the reproductive output of the breeding population.
It is recommended that until key knowledge gaps are addressed, habitat for Barn Swallow in Ontario be defined narrowly as follows:
- nests (including unused nests) on natural or human-created nest sites during the current breeding season (between May 1 and August 31) plus the area within 1.5 m of the nest and the openings the birds use to access nests in enclosed situations;
- all used nests at any nest site that has been occupied by Barn Swallows within the previous three breeding seasons; and
- significant roost sites that are used regularly by at least 5,000 birds (approximately 1% of Ontario’s breeding population, adjusted for young-of-the-year) during the post-breeding season (July 1 through October 31).