Most appropriate nest sites are found in dead or dying trees where it easier for woodpeckers to excavate a hole. If these are in the middle of a woods, they may stand for many years and be used by many different species. But if they are along a fencerow, on the edge of a woods, or in someone's yard they are not likely to last for more than one or two nesting seasons. Many people view dead trees, especially one with holes, as ugly or even dangerous. They don't think about the value of such trees to wildlife.
A trend that has been happening for many years, but that seems to be accelerating here in Mid-Michigan, is the removal of fencerows between fields. Farmers do this to maximize agricultural production, but unfortunately it removes valuable habitat for many species, including cavity-nesting birds.
So things might look bleak for cavity nesting birds, but there is one easy step that can be done to help them: build and install artificial nest boxes. Do it right now before nesting season begins. The birds will find the boxes and use them.
There are many available plans that can be built from a single board with simple hand tools. This plan is one that we have available in our office for people to take. I have found this same plan available on numerous websites, and do not know the original source of the plan.
|Simple one board nest box plan.|
This box will attract not only Eastern Bluebirds, but also Tree Swallows, Black-capped Chickadees, House Wrens, Red-breasted Nuthatches, White-breasted Nuthatches, and possibly Downy Woodpeckers. The 1 1/2 inch entrance hole is too small to admit European Starlings, but another non-native species the House Sparrow is able to enter. If you find House Sparrows using a nest box, remove the nest - you may have to do this repeatedly before the sparrows move one.
I build a modified version of this box, extending the roof to 9 inches and adding a predator guard made from a 3' x 3' piece of 1x scrap wood (this is attached before the entrance hole is drilled - I then drill through the double thickness of 1x. I also cut off the corners of the bottom piece instead of drilling drainage holes and drop the sides down slightly for ventilation instead of drilling ventilation holes.
Last spring, I helped the then-3rd and 4th grade students install 13 nest boxes at Winn Elementary. Within a few days, bird began to discover and claim the new nest boxes. Students monitored the boxes from a respectful distance and kept track of those that they saw birds using before the end of the school year. I visited the school several times over the summer and saw birds using several boxes.
Last week, I went out to Winn Elementary to help the current 3rd and 4th grade students do annual maintenance on their nest boxes. Before cleaning out the boxes, students recorded data on the types of materials in the boxes and how full the boxes were. Out of 13 boxes on site, all 13 had been used last year. Many of the boxes had remains of nests from more than one species. at least one box was being used this winter as home for a mouse, when students opened the box, the mouse scurried away.
Here are photos of the boxes and their contents:
|Full of coarse grasses, filled to the top - a House Sparrow Nest|
|Lots of feathers - a Tree Swallow nest|
The box above was one that appeared to be layered, fine grasses and feathers on the bottom - probably a Tree Swallow, topped by small twigs - House Wren.
|Fine grasses with a few feathers - I know this one was used by Tree Swallows, I saw them nesting in it.|
This one (above) was probably used by more than one species. The grass on the bottom probably indicates that a Tree Swallow or Eastern Bluebird began a nest here, but may not have completed it. Later Black-capped Chickadees constructed a nest of moss - the Chickadees may have removed much of the prior nest before building theirs.
|Lots of small twigs - House Wren|
|The students removed this nest before I saw it - possibly Eastern Bluebird, not sure.|
|Another Black-capped Chickadee nest|
|This House Wren nest was removed before I could photograph it.|
|Another removed nest, lots of fine grasses - probably Eastern Bluebird|
This nest box held a surprise. A non-viable egg had pushed aside by the Eastern Bluebird that nested here. The girls that found this nest very carefully removed it, placed the egg inside and showed all the other students at the school. I plan to put this nest in a broken nest box to be used as a display.
|Grass and feathers - Tree Swallow|
|This nest box had a mouse wintering in it. I think it held a House Sparrow nest before the mouse moved in.|