The ideal nest box

NEST BOX LOCATION

Unlike purple martins, which are known for their sociability, tree swallows do not nest in groups. They prefer small boxes set well apart from one another. Although a number of enthusiasts have managed to attract more than one pair within a small area (15 to 20 feet, exceptionally 10), we recommend spacing the nest boxes about a hundred feet apart (30 metres). The year after they are put up, and if the boxes have been occupied, one or two more boxes could be added every fifty feet (15 metres).

In principle, the orientation of a nest box does not matter. Pairs have been seen to ignore the points of the compass altogether and adopt the boxes offered to them. This is especially true in rural areas.

In town, however, you have to take the buildings in the yard into account. The front of a nest box, for example, should not face a wall of any kind. The bird needs a runway for landing and taking off. The position of the trees in the yard matters as well. The nest box must be clear of tall trees. And if the yard is swept by every wind of the season (coming from the west), the box would be better facing east.

At all times, avoid a southern exposure so as to protect the brood from the intense midday sun.

It is wise to watch the behaviour of your swallows and note, among other things, the direction they take when they fly off. There is a good chance that this is the best orientation for the nest box.

If the swallows snub the spot you have chosen, do not wait until the end of the season to move your nest box. Do it now, and try to find the best site and the preferred orientation.

You may say that swallows have already nested in the present spot; yes, but will a new pair have the same taste, especially if a better choice is available to them? Changing the location, several times if need be, means increasing your chances of success.

THE IDEAL NEST BOX FOR TREE SWALLOWS

Let us introduce our latest find, our nest box with windows.

Three small openings cut into one or two sides of a nest box make for a heartwarming sight. The hungry young poke their heads out and scan the horizon, chirping away. The parents will come back often to feed those hungry beaks, and we can watch them at leisure.

But if you feel like building your own nest box, here are a few basic rules that will encourage swallows to nest at your place:

THE FLOOR

It should measure 4 1/2 x 5 in. (11 x 13 cm). You can build a smaller nest box, but the tree swallow will readily choose the neighbour's box if its dimensions let her nest comfortably. The box could be roomier without going to extremes. The birds need only a very small space to raise four or five nestlings that will grow up healthy, without crushing one another.

It is worth remembering that the nestlings like to exercise their wings before setting out on their own. They will be better prepared if the box allows for this exercise.

THE HEIGHT OF THE NEST BOX ENTRANCE

When building a nest box, you must absolutely avoid cutting the entrance at floor level or only a few inches above it. It would not take predators long to feed on the brood itself.

The height of the entrance can vary by a few centimetres. The idea is to allow the swallows to protect themselves from any predators. At the same time, you have to make sure they will be able to get out easily. Very often, tree swallows (the female especially) die at the bottom of the nest because they are unable to reach the exit.

In general, the entrance should be cut between 4 and 6 inches (10 to 15 cm) from the floor. If the entrance happens to be higher, then it would be wise to fasten a small screen inside, or to score the front (on the inside) with a few saw cuts.

THE COLOURS OF THE NEST BOX

What matters is the entrance to the nest box. From high in the air, the tree swallow must be able to recognize the cavity. A dark front would not make the cavity stand out. For this reason, white is a must, or a pale colour. The colour of the other walls of the nest box is of no importance. It is a matter of taste.

THE SHAPES OF THE NEST BOX

You can let your imagination run free; the swallow will not tell the difference. The front, however, must be perpendicular to the base. That is the natural position of the tree swallow when she clings to a nest box. If she is hard pressed, she may well adopt a box with a slanted front anyway. But there is always the risk that she will go and settle elsewhere.

THE NEST BOX ENTRANCE

Look no further: the entrance of a nest box for tree swallows is 1 1/2 inches (3.8 cm). Do not try to reduce the diameter to keep house sparrows out. In any case, house sparrows slip in wherever tree swallows try to build their nest. What is more, the tree swallow could well end up trapped by an entrance smaller than 1 1/2 inches. In that case, the female is often unable to leave her box, particularly during the period when she is forming her eggs.

If the tree swallow has a choice, she will above all adopt a nest box that is easy to get into. Careful: she may well prefer the neighbour's box if it meets all her requirements.