Bird Nests in Ottawa Eavestroughs: Damage and Prevention

Birds nesting in eavestroughs is a surprisingly common problem in Ottawa, and yes, it causes real damage that goes beyond simple inconvenience. Ottawa is home to aggressive cavity-nesting species like European starlings, house sparrows, and pigeons that frequently build nests in open eavestrough runs, behind downspout elbows, and in gaps between the gutter and fascia board. These nests create blockages that are just as damaging as leaf clogs, and they come with additional complications that debris alone does not.

Damage From Bird Nests and How to Prevent It

A bird nest packed into an eavestrough or downspout opening creates a dam that blocks water flow during rain. In Ottawa's heavy spring thunderstorms and summer downpours, even a single nest can cause an entire gutter run to overflow, sending water cascading down your siding, pooling against your foundation, and saturating the fascia board behind the gutter. Nesting material, which typically includes twigs, grass, mud, and feathers, absorbs and holds moisture against the aluminum or steel, accelerating corrosion at the contact point. Bird droppings are acidic and eat through eavestrough paint coatings over time, leading to bare metal exposure and rust on steel systems.

The timing is particularly problematic in Ottawa. Birds begin nesting in late March through May, which is exactly when spring melt and rain put the heaviest demand on your gutter system. A nest that blocks a downspout during the spring thaw can cause ice backup, fascia rot, and even water infiltration into your attic if ice dams form behind the blockage during a late-season cold snap.

The most effective prevention is installing gutter guards or mesh covers that physically block birds from entering the eavestrough channel. Micro-mesh guards at $18 to $30 per linear foot in Ottawa provide the best protection because the openings are too small for nesting material to pass through. Perforated aluminum covers at $10 to $18 per linear foot also work well for bird prevention.

For downspout openings, install downspout screens or strainers that allow water through while preventing birds from entering the pipe. These cost $5 to $15 each and take minutes to install. Check them during your spring and fall cleaning to ensure they remain clear.

If you already have active nests, be aware that most bird species in Ontario are protected under the federal Migratory Birds Convention Act, which makes it illegal to disturb active nests with eggs or chicks. You can legally remove empty or abandoned nests outside of nesting season, which is generally August through March in Ottawa. Starlings, house sparrows, and pigeons are not protected under the Act and their nests can be removed at any time.

Prevention is always better than removal. Adding gutter guards during your next eavestrough cleaning or replacement eliminates the problem permanently. Browse eavestrough and gutter guard installers through the Ottawa Construction Network directory at justynrookcontracting.com.