June’s trip to the ranch revealed Tree Swallows taking over many Bluebird houses. They are lovely little birds, and will nest next to Bluebirds and vice-versa; so I came up with a new design of birdhouse to place 25-50ft from the existing wooden houses. Some parameters: I want it to sleeve over the wooden fence poles of the barbed wire fence offering no incentive for cows to rub on them; easy to check for nesting birds via removable lid, with escape for mother out from entrance hole; easy to anchor to post and remove from post and clean out; insulates from heat & cold; waterproof and ventilated; can handle the harsh extremes of Montana highlands- all-weather / UV / extreme wind.
The far right is the first try; all black ABS in two sections connected by a snap-in drain insert (glued to the bottom/footing and pinned with a bolt to top/birdhouse, the lid is an insert bolted in place with a an inner screw-in lid as overkill for cleanout, the whole thing is spray-painted white and cost $17 per unit. Incredibly tough, but too pricey.
Next was an attempt to blend white pvc and fiberglass fitted inserts (ABS don’t fit and there are no similar PVC parts) – so no way to glue and join top to bottom. Plus, the inserts never quite snug-in or are too big. Too many issues and pricey; abandoned to the bin.
Finally I came up with a mix of irrigation tubing (multi-layered freeze-proof), black ABS tubing and black ABS drain insert, capped with a simple white pvc cap.
4″dia x 10″ sections of insulated pvc irrigation tubing (10′ length @ $10.35)
4″dia x 4″ sections of ABS black (2′ length @ $10 x 3ct = $30)
4″dia ABS black Snap-In Drain Insert ($3.08)
4″dia Cap pvc ($2.48ea)
Total $102 per 12 houses, or $9.50 per house. Cost per unit just tops redwood/cedar, but these should easily outlast the wooden houses with no issues of warping & splitting, cleaning/viewing access, livestock damage; we’ll see what the Bluebirds think.
Notes: 1. With reciprocating saw or bandsaw, cut irrigation tubing to 10″ sections / Cut black ABS tubing to 4″ sections (clean & level on sanding belt). 2. Put white cap on 10″ Irrigation tubing and measure down 1″, using 1.5″ hole saw, cut out entrance hole (angle upward slightly to deter water runoff), remove cap. 3. Put Cut-Off wheel on drill; scribe 3 lines below entrance as toe-holds, then move to inside wall and scribe midway at entrance down to bottom for fledging chick’s toe holds. 4. Place white cap as roof, drill hole for bolt undersize and bolt will self-tap, then drill 12 holes around back edge of cap & through pipe for ventilation (upward angle to deter water & small dia to deter insects). 5. Sanding Drum on drill bevels out base of irrigation tubing for seating ABS Snap-In Drain Insert (plus smooth entrance hole)- press insert into place with squeeze clamps or tap with dead blow hammer. 6. Brush out and wipe down interior. 7. ABS glue to bottom of Drain-Insert & 4″ section of black ABS, join and press for 30 seconds, set aside for curing. 8. Drill two holes near bottom of ABS tubing, run galvanized wire through ea. hole to drop well below rim of tubing, and use pliers to clip outside section leaving enough to twist into a loop/anchor. The wire runs down inside tubing and will wrap around woodscrews drilled into the fencepost, holding the house in place. 9. Drill holes into black ABS near joint as ventilation from the bottom (visible on far R prototype).