Make boxes to stop birds from nesting in your homes

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By Sylvia Brockner

Today has been a cold, damp, miserable day. After a week of unusually warm April weather, it was a blow to have a big low pressure area move in that brought together cold arctic air from the north and warm, wet Gulf Coast air from the south right over Colorado.

This is typical of April in Colorado. If anything can be called typical of our spring weather, it is the pendulum swing, back and forth, from cold to hot without warning.

I had gone to Home Depot to look for soil additives and to see what plants they had in, but it kept getting wetter and colder, and I soon decided that it was no day to work outdoors, and I would sooner be home sitting in front of the fireplace. The weathermen are predicting cold rain turning to snow tomorrow, so it will be a cold soggy weekend.

A phone call yesterday started me thinking that it is the time of year when I should write once again about the birds that make holes in our houses. Despite the snow and cold weather, birds are making pair bonds and are looking for nest sites.

The birds that cause problems by making holes in our houses are mostly cavity nesters, either some of the woodpeckers or nuthatches. The reason for this is that these birds have for hundreds of years chiseled nesting cavities in dead trees. Since our new forestry practices require us to remove dead or dying trees, there are none in which they can build and they therefore try to make holes in our houses, which are wood and sound hollow when they drum on them.

Of the three species of nuthatches that occur here, the smallest one, the pygmy nuthatch, is the one most likely to make holes in a house. They are tiny birds and the holes are small and usually several in one area. This is because they are social flock birds that like to have friends nearby. In the past there would frequently be five or six pairs nesting in the same old dead ponderosa pine tree. To them your house is just a natural effective substitute.

The hairy woodpecker is probably the second most troublesome nest builder. This black-and-white woodpecker is bigger than the very similarly colored downy woodpecker and has a much longer and stronger beak. They nest singly and in the past used dead aspen or pine stubs for their nest sites. They are very persistent and will keep working on one hole until they can pull out enough insulation to make a cavity about 12 inches deep.

If they are making a series of small holes, it is because they hear something that they believe to be an insect. They have done this for years in one place in my house, which is near where the electric line comes into the house. Apparently the electric lines cause a hum or vibration that they think sounds like an insect. Every year we have had to fill in holes and repaint that area. It is a losing battle, but I know of no permanent cure.

Northern flickers are the third bird that is notorious for making holes in buildings. They are big woodpeckers that make big two-inch holes in the outer wall. If discovered early enough, they will often use a flicker nest box, which has been placed directly over the hole they have started. By covering the hole, they would have to start all over and are just lazy enough to use the box provided.

However, it is against the law to kill, molest or destroy the eggs of all of our native birds. If they have completed their cavity or nest and have already laid eggs, there is nothing you can do but endure them and enjoy watching them raise their family.

Another cavity nester is the European starling. They are big, bold and pugnacious, and will often chase native birds from their cavities and then take over the site. Because they are not native American birds, they are not protected by national law and in most states their nests can be removed to give our native birds a second chance.

Other cavity nesters are tree and violet-green swallows, house finches, wrens and bluebirds. They can help protect your trees from damage by insects and can be attracted to your yard by putting up nest boxes of various sizes. Below is a chart that gives the required dimensions for nest boxes for many birds. Birds are not usually very fussy about the material used to make a nest box, but the other requirements are important.

They do not have to be a work of art. I have even seen nest boxes made out of milk cartons. If they are about the right size, they will work fine. Since the boxes must be cleaned out very year to protect the new tenants from bird lice, etc., a milk carton nest box might be a good thing since it could be thrown away and a new one made to replace it.

All of these birds pay for your kindness by helping to keep your trees free of insect pests.