Barn Swallow

(Hirundo Rustica)

Status: Threatened (SARA 2017, Ontario 2011)

Table of Contents:

Species Identification
Diet
Habitat and Range
Biology and Behaviour
Similar Species
Threats/Reasons for Being Endangered
Conservation and Recovery Strategies, Quick Facts
How You Can Help

Species Identification:

The Barn Swallow is a mid-sized songbird (about 18 cm long) with beautiful orange and blue colouring. It is recognizable by its forked “swallow tail” shape. Its upper feathers are dark blue, and under feathers are light brown with a copper-coloured throat and forehead. Males and females look similar, but males have longer tail feathers.

Diet:

Barn Swallows catch insects above fields and other open spaces while flying at low heights (less than 10 meters). They eat mostly flies, and may feed alone or in groups. Barn Swallows will often follow other animals through tall grass to catch the insects that are disrupted by them.

Range Map Source: https://www.allaboutbirds.org/guide/barn_swallow

Habitat and Range:

The Barn Swallow is the most widespread swallow species in the world. They are found in every continent except Antarctica. In North America, Barn Swallows breed throughout Southern Canada, all across the United States, and into northern Mexico. Most Canadian populations overwinter in South America.

Before European colonization, this species nested in cliffs by finding holes and crevices to build their nests in, but today such locations are rarely used. Now Barn Swallows tend to take advantage of our structures and build their nests on ledges or walls of barns, garages, and bridges. They require nearby wet areas to gather mud for their nests, and foraging takes place in open areas like fields, wetlands, and shorelines.

During migration, Barn Swallows congregate in wetlands or over lakes to feed. Wintering habitat includes pastures, savannahs, fields, or other areas of low-lying vegetation.

Biology and Behaviour:

Barn Swallows return to Ontario in mid-May and start constructing their nests, often using sites from previous years. They usually nest in colonies, but occasionally nest alone. The female lays 1 to 7 eggs and both parents look after hatchlings for about three weeks. After fledging, the young are fed by parents for another week. It is common for Barn Swallows to lay another group of eggs later on in the season in southern parts of their breeding range, and they are more likely to do so if a previous year’s nest is reused. They may also use nests of other species such as the American Robin and Eastern Phoebe. Earlier clutches tend to be larger with higher success rates. Fall migration begins early September, and extends to the first week of November.

Predators include several raptors, corvids, European Starlings, House Wrens, feral cats, squirrels, and mice. Barn Swallows are a short-lived species, typically reaching just four years of age.

Similar Species:

The Barn Swallow can be differentiated from most swallows by its deeply forked tail that is in the classic “swallow shape”. Cliff Swallows have a square tail and brown-yellow coloured forehead and at the base of their tail. The Purple Martin’s tail fork is more shallow, and their bodies are uniform grey in colour. Tree Swallows have a notched tail and white underbelly.

Threats/ Reasons for being at Risk:

Barn Swallows are a very widespread species, but populations dropped drastically in the 1980s, along with many other bird species. While they are still common in Canada- with almost 5 million individuals- their numbers have declined by 76% in the past 40 years. Since most studies on Barn Swallows have taken place in Europe, there are many knowledge gaps for Ontario populations. More research is needed to better understand the threats here in Canada. Common threats include:

1. Loss of nesting habitat: There has been a shift to modern agricultural practices that involve large industrial farming activities. This has reduced the number of old-style wooden barns that Barn Swallows use for nesting, and there has been an increase in nestling mortalities with modern steel barns since they produce much more heat than wooden barns.

2. Declining insect populations: This is due to increased chemical use and insecticides, as well as loss of wetland habitat. There has been an industry shift away from dairy and cattle pastures towards cereal crops, and cattle farms have been known to attract flies, which are a staple diet for Barn Swallows. There have also been mass declines in insect species in general that have impacted Barn Swallows, along with all other flying insectivore species.

3. Climate change: There has been a shift in weather conditions that can cause Barn Swallows to nest earlier in the spring than usual. This can cause egg mortalities if an early, warm spring is followed by a cold snap. These weather conditions also impact insect species if they emerge too early, which can impact Barn Swallows and their reproductive success for that year.

4. Diseases and parasites: Ectoparasites like mites, fleas, lice, and blowflies lowers reproductive success and slows growth rates for nestlings. Since Barn Swallows will often re-use the same nesting site for their second nest that year, and for the years to follow, if that nest is infested with large numbers of parasites they will continue to have a negative impact on reproductive success.

5. Competition with invasive species: Barn Swallows and House Sparrows often compete for the same nesting sites. Since House Sparrows are both non-native and invasive in Canada, they are able to outcompete with Barn Swallows for preferred nesting sites. While House Sparrow populations have also been on the decline recently, there is still enough competition with the Barn Swallow for the House Sparrow to have a cumulative impact on their populations as well.

6. Human persecution: while there are not very many studies on human persecution of Barn Swallows, most nests occur in or on human infrastructure, and are often destroyed if the Barn Swallows are considered a nuisance either due to their activity or their droppings. Nests have also been known to be taken down from bridges and other municipal structures during routine cleaning and maintenance.

Conservation and recovery strategies:

The provincial goal is to stabilize Barn Swallow populations by 2034. To accomplish this, more research is needed to better assess their threats. Bird Studies Canada has been evaluating their preferred nesting sites and experimenting with different artificial nest structures to support their breeding. Broader policies should focus on limiting loss of wetlands, and restrict pesticide use.

Quick Facts:

These birds have benefited from human settlement for a long time. There is evidence of Barn Swallows building nests on First Nations longhouses pre-colonization.
The Barn Swallow is the most abundant swallow species in the world, but most studies have focused on European populations.
Barn Swallows have a mutual relationship with ospreys. When they share a nest site the swallows receive protection, and ospreys benefit from early warning of predators.

How can you help?

Barn Swallows are important for pest control, since they eat hundreds of insects every day. They can be beneficial for farms with livestock since their primary food source is flies.

The best thing property owners can do is to be a good host for breeding Barn Swallows. Leave doors of barns or old buildings open, or encourage them to nest in a specific location by building a nest platform (see this guide).
Droppings around nests are normal, and are unlikely to carry any diseases. Property owners can put newspapers under nests a couple weeks after hatching which can make cleaning easier.
Landowners can also ensure there is a nearby mud source to help Barn Swallows with nest construction.
Everyone can help protect insect populations by putting up insect feeders, reducing pesticide use, and supporting organic or sustainable farming practices.

Additional Resources:

The Government of Ontario has a document on “Creating Nesting Habitat for Barn Swallows”, that provides guidelines for building artificial nest structures.
Cornell Lab of Ornithology page.
Bird Studies Canada fact sheet: How to be a good Barn Swallow host.
Nature Canada’s Species at risk e-book.
COSEWIC Assessment and Status Report, 2011.

Sources:

COSEWIC. 2011. COSEWIC assessment and status report on the Barn Swallow Hirundo rustica in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. ix + 37 pp. https://wildlife-species.canada.ca/species-risk-registry/virtual_sara/files/cosewic/sr_barn_swallow_0911_eng.pdf

Heagy, A., D. Badzinski, D. Bradley, M. Falconer, J. McCracken, R.A. Reid and K. Richardson. 2014. Recovery Strategy for the Barn Swallow (Hirundo rustica) in Ontario. Ontario Recovery Strategy Series. Prepared for the Ontario Ministry of Natural Resources and Forestry, Peterborough, Ontario. vii + 64 pp.