Patient Update: Violet-Green Swallows Rescued from a Vent

Two young Violet-green Swallows perch side by side in their enclosure at Calgary Wildlife. At this stage, they are strengthening their wings and practicing the social behaviours they’ll rely on in the wild, where they often gather in loose colonies.

In mid-July, Calgary Wildlife received a group of Violet-green Swallows from south Calgary. They had been discovered trapped inside a bathroom fan vent after their parents stopped returning. Too young to escape on their own, the nestlings would not have survived without help.

The reason they ended up in such a precarious situation lies in their biology: Violet-green Swallows are cavity nesters, instinctively drawn to enclosed spaces for raising their young. In natural settings, they raise their young in old woodpecker holes or tree crevices. But with forest loss and competition from other species, suitable cavities are harder to find. As a result, birds often turn to human-made structures, and vents can look like a ready-made shelter. Unfortunately, they are anything but safe.

Nesting inside household vents creates risks that extend to both people and wildlife. For homeowners, a blocked vent can reduce airflow, trap lint, and, in the case of dryer vents, increase the risk of fire. Moisture trapped behind the obstruction can lead to mould or mildew spreading through the home, while droppings left behind may carry disease. Even when the vent continues to function, the buildup of nesting material can cause long-term damage to the system and compromise indoor air quality.

For the birds themselves, the dangers are far greater. Nestlings that cannot yet fly may tumble deeper into the ductwork and become lost. Adults and juveniles alike may be injured or killed by powerful drafts or sudden bursts of hot air. In many cases, entire broods perish out of sight, never discovered until long after. Although bathroom vents are the most common sites for nesting attempts, dryer vents can also lure in cavity-seeking birds, and when they do, the results are often catastrophic. What looks like a sheltered hollow from the outside is, in reality, a trap.

A household vent fitted with a protective grid. Installing covers like this is the simplest way to prevent cavity-nesting birds from becoming trapped in unsafe spaces.

The best way to stop fan entrapment is prevention. Vent covers are simple, inexpensive devices that allow air to flow while blocking wildlife from entering. Before installing, always make sure the vent is empty; if birds are already inside, contact trained professionals to remove them safely. These guards are available at most hardware stores and can be fitted on bathroom, dryer, and kitchen exhaust vents. A quick spring check to ensure your covers are intact goes a long way toward keeping both homes and birds safe.

If you’d like to help cavity-nesting birds in a positive way, consider putting up a birdhouse. Violet-green Swallows and other species readily accept nest boxes, which provide secure nesting sites without the dangers of vents. With just a few small steps, such as covering vents, checking them regularly, and offering safe alternatives, you can prevent tragedies before they happen.

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A Violet-green Swallow peers out from a wooden nest box. As cavity nesters, these swallows naturally seek out tree hollows or rock crevices, but will also use birdhouses when natural sites are scarce.

Once admitted to Calgary Wildlife, the brood of swallows was moved to our Nursery. Because they were still so young, staff and volunteers hand-fed them with tweezers many times each day. Over three weeks, they grew stronger and began to test their wings. When they showed steady flight and self-feeding, they were moved to an outdoor enclosure to practice their agility. On August 25, just over a month after their rescue, the group was released back into the wild.

A juvenile Violet-green Swallow resting in its enclosure at Calgary Wildlife. At this stage, it has muted, brownish plumage, but in time and especially in sunlight, the shimmering green and violet tones characteristic of adults will show.

By making small changes around our homes, we can protect both ourselves and our wild neighbours. These swallows were lucky, but prevention ensures that others never face the same danger.

For assistance with injured wildlife, please contact the Calgary Wildlife Rehabilitation Society at 403-214-1312.

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