Henry Miller
This year, bluebird numbers were the lowest they have been since the Fort Frances Sportsmen’s Club began the project in 1991.
Only 36 pairs successfully fledged their young. In 2006, there were 69 pairs and 55 pairs in 2007.
Several factors contributed to the decline. For instance, many perished in the snowstorm in April and during the cold weather that followed.
There also were reports from U.S. sources which stated the bluebirds were affected by West Nile virus.
Nesting also occurred much later than normal this year. Although a few nested in May, the majority were just laying their eggs during the first two weeks of July.
Meanwhile, wren numbers increased dramatically. These small, aggressive birds took over many of the bluebird birdhouses.
Their occupying the boxes is not the problem because there are plenty of empty houses.
Wrens do not tolerate competition in their territory. They peck holes in bluebird eggs and fill the boxes up with twigs.
Along many of the side roads, suitable habitat for bluebirds (i.e., open fields on both sides of the road) is disappearing. Brush is growing because many municipalities no longer cut it.
As such, bluebirds have to go elsewhere to nest.
All the volunteers who monitored the birdhouses this summer agreed many nests with intact eggs were abandoned. The adults did not return to incubate them.
As well, many nestlings were left to die. Why the adults did not return is a mystery.
Of course, some predation of eggs and nestlings did occur as evidenced by broken shells and remains of feathers of chicks. Only nine nests were affected.
Whatever affected the bluebirds did not harm tree swallows. Some 146 pairs successfully fledged their young this year.
