Where are the bluebirds? Our expectations were that it would be another great year because of last year’s phenomenal success with an abundance of bluebirds nesting in our many bluebird houses. Usually by mid-May many are already nesting but sadly we saw only two nesting pairs thus far this year. Bluebirds, as well as tree swallows have thrived in hot, dry conditions before, so where have all our bluebirds gone?
Wondering what had happened, we contacted Bill Read, the president of the Ontario Eastern Bluebird Society (OEBS). He suggested that many had probably perished in the ice storms that ravaged the southern states this past winter. Other species, such as the tree swallows were not affected as they spend the winters in Mexico instead.
In May of this year, volunteers began monitoring the established bluebird trails in our area. They counted 109 pairs of tree swallows, 4 chickadees, 7 wrens, 1 northern flying squirrel, but found only 2 bluebirds that were nesting in the boxes. Bluebirds interesting enough do not nest near one another, but will tolerate tree swallows even if their nest is built on the very same post. They are known to be quite a shy bird and whenever a predator or even a volunteer checking the bluebird houses approaches, they usually always fly away before they can be seen. If they have not detected the danger coming before hand and can no longer fly away undetected, they then try to hide by crouching down at the back of their nest.
Bluebirds construct their nests mostly of grasses in which the female then lays 4-6 eggs that are blue in colour, although sometimes they can be white instead. They are known for keeping their nests very clean by removing all fecal matter and egg shells, carrying it out and dropping it far away from their nest. The bluebird sits on her eggs for 14-16 days before the young bluebirds finally hatch after which both adults are then involved with feeding the nestlings until they fledge (leave the nest) usually occurring about two weeks later.
In direct contrast to the bluebirds, the tree swallows prefer to nest close together so that they can chase intruders away with help from birds in the adjacent nests. By driving at the enemy one at a time, these birds actually scare most predators away. Tree swallows are also much better at hiding in their nesting boxes should the need arise because their nests are composed of many large feathers, not just grass which they then easily can hide behind. Tree swallows lay a slightly greater number of eggs than the bluebirds, usually five but sometimes even 6 or 7. The incubation period for their eggs is slightly longer lasting 14-17 days and the nestlings then leave their nests in 15-17 days. Although swallows are plentiful this year, they sometimes take a year or two to find new boxes which is probably why our volunteers did not see many of them nesting.
The nesting boxes must be cleaned out yearly in the fall. As the nest is pulled out it can become very dusty, so always be sure to stand upwind so you don’t breathe in the dust. Birds, like most wildlife can carry diseases. Hornets or wasps sometimes occupy these nesting boxes as well. These insects can become quite upset when one opens the box and breaks their nest, so watch out!
Although those who constructed bird houses may be a little disappointed this year because of the low bluebird population, looking after birdhouses is still a great activity! Not only does it get a person outside in our great outdoors, it also makes for a great conversation piece. Happy trails everyone!