When building a birdhouse for swifts, one of the most important considerations is the size of the entrance hole. This will determine what species can enter and nest in the box. For swifts specifically, the recommended entrance hole diameter is 1-1.5 inches.
Why is the hole size important?
The size of the entrance hole is crucial because it needs to be large enough for the target species to fit through, but small enough to exclude predators and non-target bird species. If the hole is too large, larger birds may take over the nest box or predators like raccoons may be able to reach in and grab nestlings or eggs.
If the hole is too small, the target species may not be able to fit inside to build a nest. In addition to body size, some birds have minimum hole sizes needed to allow their wing span to fit through the opening.
What is the ideal swift hole size?
For swifts, a hole diameter of 1-1.5 inches is recommended. Here are the reasons this size range is ideal:
- It allows easy entry for swifts while excluding larger species like starlings.
- A 1-1.5 inch hole is large enough for swift’s wing span to pass through.
- It is too small for potential predators like raccoons, cats, or snakes.
- This size range is commonly used and accepted among swift enthusiasts and ornithologists.
1 inch holes
A 1 inch hole is on the smaller end of the range but can work well. Some advantages include:
- Optimal for excluding non-target species like House Sparrows.
- May be preferred in areas with intense competition for nest sites.
Potential disadvantages:
- Some swifts may have difficulty entering, especially if the hole is rough or uneven.
- Requires precision drilling to achieve exactly 1 inch.
1.5 inch holes
A 1.5 inch hole is on the larger end but can also be appropriate. Some pros of this size:
- Allows easy entry for swifts.
- Extra clearance reduces potential for jamming at the hole.
- Easier to drill precisely to 1.5 inches.
Potential cons:
- Increased risk of non-target species like House Sparrows, starlings, or woodpeckers.
- Higher likelihood of predators reaching in.
How to drill the hole precisely
To drill an accurately sized entrance hole for swifts, here are some tips:
- Use a drill bit in the desired diameter – 1 inch or 1.5 inches.
- Clamp a block of scrap wood behind the drill site to reduce blowout.
- Drill slowly and carefully until you break through the inner wall.
- Use a file or sandpaper to smooth out the inside edges so there are no obstructions.
- Test the hole size with a diameter gauge or the birdhouse plans dimensions.
The hole only needs to be 1 to 1 1⁄4 inches deep, any deeper risks penetrating the outer wall. An uneven or rough inner surface can impede the birds, so take time to ensure a clean opening.
Where to locate the hole?
In addition to size, hole placement also matters. Some recommendations on swift hole positioning:
- The bottom of the hole should be 5-7 inches above the birdhouse floor.
- Centering the hole on the front panel is typical.
- It can be positioned closer to one side to provide attachment support.
- Orient the entrance away from prevailing winds and rain.
Locate the hole high enough so the nest remains dry, but low enough for easy entry and exit. Placing on the front allows swift’s straight approach into the box.
How high should the swift house be?
Proper placement of the swift birdhouse is also key. Some tips on height:
- Install at least 12-15 feet above ground.
- Higher is better – 30 feet or more is ideal.
- Near the top of the structure, under the eaves is a prime spot.
- North and east sides get more shade and protection.
Swifts like to swoop down into their box, so a high placement is best. This also reduces threats from predators. Ensure the structure is strong enough to securely hold the nest box.
What design and materials to use?
Here are some swift birdhouse recommendations:
- Medium to large size – at least 6x6x12 inches interior.
- Made from untreated wood like cedar, cypress, exterior ply.
- Wood thickness of at least 3/4 inch.
- Ventilation holes near the roof.
- No perches necessary.
- Dark color helps mimic chimney interiors.
- Apply waterproof sealant if desired.
Adequate interior space and proper materials will help create an appealing nesting spot for swifts. Other optional enhancements are rough-textured interior walls, a concave floor, and extended landing ledge.
Conclusion
An entrance hole diameter of 1 to 1.5 inches is ideal for attracting nesting swifts. Careful hole placement near the front and high off the ground will maximize usage. Combine this with suitable dimensions, materials, and installation height, and you can provide an enticing nesting site for these aerial acrobats.