Bird House Sizes and Territories

There has been some call for more information on bird houses and the timing couldn’t be better. There’s still plenty of time to get houses out before the birds begin nesting, even if you decide to make your own.

A couple things to clear up first: I’ve had comments from people that they would love to have a few bird houses, but don’t want the hassle of keeping feeders stocked and cleaned. Well, worry not, the most common bird to take up residence in your house is the Tree Swallow, and he won’t require seed. They only eat flying insects, (and the odd berry on cold days when there is little bug activity, but they find their own). That makes the beauty of having Tree Swallows in your yard two fold, you don’t have to do anything and they eat mosquitoes and feed them to their young all day. If a Black-capped Chickadee moves in they’ll find food in one of your neighbours yards, they’re likely in the area for a while before nesting starts and will have cased the neighbourhood for the best stocked feeders and much of the diet fed to the nestlings will be insect based. The Eastern Bluebird won’t be looking for seed either, but will take a meal worm or two if you want, but you don’t have to.

Which leads me to the second thing to clear up; Blue Jays and Bluebirds are entirely different birds, the jay is large and obnoxious…the bluebird is small and polite. I’ve had numerous comments about the nest box looking “awfully small” and I discovered people were confusing the Blue Jay with the Eastern Bluebird that is most closely related to our robin (they’re both thrushes).

For those people who don’t read this column every week I’ll back up just a bit, (and you can get back dated columns on line or contact me if you can’t find it) we have basically two types of birds that will nest in a cavity, the primary cavity dwellers, these guys drill and excavate their own nests and the secondary cavity dwellers who come along next year and take an old (usually woodpecker) cavity. This arrangement was working fine in the wild for centuries, trees were allowed to get large, old, and start to rot enough for a woodpecker to easily do the drilling. Now trees are usually harvested before they get that old and dead trees often have to be taken down for safety reasons, especially after a woodpecker makes a weak spot right in the middle. Luckily, the nest site problem is somewhat easy to overcome as most of our species will readily take an artificial cavity aka a bird house.

The more bird houses you put out the more likely your are to get a nest. You probably won’t get a bird in every house, but you increase the odds of getting one if you provide options for the house hunting couples.

For those of you who read the bird house column from a couple weeks ago you may already have your rough lumber and it’s drying. For every one else it’s not too late and/or you can use kiln dried planed wood or plywood, just remember to score the inside under the hole so the young birds can climb to the hole. You still have time to build and get them out but the sooner the better, if you have some ready it would be best to put them out now, usually houses placed after April won’t have a nest until next year, but not always.

I keep a copy of this chart by my saws and by the phone, the first so I have a quick reference for building all the bird houses I’m likely to have call for in the area, the latter so I look smart when you call me with questions. If I’m out of breath by the time I give you the answer, it’s because you caught me out in the yard with the cordless phone and I had to run back to the base for the chart.

Species	Hole diameter	Height above floor	Floor dimensions	Total height of box	Height off ground (ft)	Territory size
Black-capped or Boreal Chickadee	1 ⅛-1 ½	6-8	4x4 to 5x5	9-12	5-10	10 acres
Eastern Bluebird	1 ½	6-8	4x4 to 5x5	11-12	4-6	2-5 acres
Tree Swallow	1 ⅛-1 ½	6-8	4x4 to 5x5	9-12	4-10	100 ft radius
White-breasted or Red-breasted Nuthatch	1 ⅛-1 ½	6-8	4x4 to 5x5	9-12	5-10	20-45 acres
House Finch	1 ⅜ - 2	5-8	4x4 to 5x5	9-12	4-10	nest site
House Wren	1-1 ½	6-8	4x4 to 5x5	9-12	4-10	½-¾ acre
Purple Martin	2-2 ½	1	6x6	6	8-20	nest hole
Great-crested Flycatcher	1 ½ - 2 ½	6-8	5x5 to 6x6	9-12	6-20
American Kestrel	3	10-12	8x8 to 9x9	14-16	15-30	250 acres
Saw-whet Owl	2 ½ - 4	10-12	6x6 to 8x8	15-18	5-20
Barred Owl	6-8	14-18	13x13 - 14x14	22-28	5-20	1 sq. mile
Wood Duck	3x4	16-18	10x10 - 12x12	24-25	{all ducks	just nest
Hooded Merganser	3x4	16-18	10x10 - 12x12	24-25	4 over water
Common Merganser	4x5	16-18	10x10 - 12x12	24-25	10 over land}
Downy Woodpecker	1 ¼ -1 ½	8-12	3x3 to 4x4	10-14	6-20	¼ acre
Hairy Woodpecker	1 ¾ - 2 ¾	10-14	5x5 to 6x6	14-16	6-20	¼ acre
Northern Flicker	2-3	10-20	6x6 to 8x8	14-24	10-20	nest site
European Starling	1 ⅝ - 4	6-10	5x5 to 6x6	13-20	not fussy	nest site
House Sparrow	1 3/16 - 2	6-8	4x4 to 5x5	9-12	not fussy	nest site

For step by step directions with pictures go to the articles section of our website and click on BYOB, build your own birdhouse.

This is all the information you’ll need to get started, the sizes of the houses for individual species (in inches), the length of the pole you’ll need and based on the territory size and your property how many boxes you’ll eventually want to place. The territory given is the area the birds will defend against the same species, usually they will tolerate pairs from other species within this distance. This is to guarantee food supply for the nestlings and to prevent another male from sneaking in and trying to spread his genes or a female from making sure her eggs get fertilized. The back yard during breeding season has more fights and infidelity than a soap opera.

The smaller houses would be best placed on a post at least a few feet from the woods this will deter squirrels from taking over. The larger houses especially owl and kestrel can be placed in trees but if you have some stand alone trees it would be better than large groups.

Next week I’ll get more into habitat, nests and even offering nesting material if you see some interest in the house. Then move on to attracting open-cup and ground nesters. Finally talk about a few with very unique nests and what can be done to help and encourage them.