|Female bluebird at McKnight Prairie in 2011|
Eastern bluebirds have made a good recovery in recent decades, thanks to diligent and sustained efforts to help them successfully raise young by providing and monitoring nest boxes. Their numbers had previously diminished dramatically, owing to loss of habitat and nesting locations for these cavity nesters (birds that make their nests in old woodpecker holes and other tree cavities).
|Male bluebird at McKnight Prairie in 2011|
Recently Dave happened to make the acquaintance of Carroll Johnson, who is both a statewide coordinator and one of the Rice County coordinators of the Bluebird Recovery Project of Minnesota (BBRP). Carroll stopped by our house and agreed that our property, which is fortunately situated right next to some park-like private land on the far east side of Northfield, offers quite good bluebird habitat: an open, grassy area with occasional trees. So we've joined the BBRP, and Carroll brought us two PVC bluebird houses mounted on conduit over rebar. We put them up late last week while the ground was soft from the recent rains. Bluebirds are seasonal residents here and often arrive in March, though they may not start nesting immediately, so this is a good time to put up new houses.
|Pair of nest boxes by our house|
We have also asked if we can help monitor a few of the many bluebird houses being maintained in this area by Carroll and his fellow state/county coordinator, Keith Radel. (We're lucky that Rice County is the nerve center of the state bluebird organization!) Carroll and Keith each assigned us a few of their sites, and last Saturday morning Keith took us around to eight sites we'll be taking on near Northfield -- four pairs and four single houses. A set of monitored bluebird nest boxes is referred to as a bluebird trail, so these eight sites plus the ones at our house make up our first bluebird trail.
|Cleaning out nest boxes|
Agreeing to monitor bluebird houses is a serious responsibility. If you want to help the bluebirds raise young, you don't just put up nest boxes and forget about them; if you do, you'll probably end up raising house sparrows.
It's important to choose your location thoughtfully, check the nest boxes weekly, and keep detailed records of any activity at each box, including nesting, eggs and young, as well as absence of birds, use by other species, insect problems, and losses, so that appropriate adjustments can be made to increase the likelihood of future success.
It's also important to deter and if necessary remove house sparrows, a nonnative, unprotected species that aggressively competes for nesting locations and will evict and injure bluebirds if given the chance. House wrens are also very aggressive and will destroy the eggs and young of other species in their territories, which is one reason to locate nest boxes at a distance from wooded areas that are prime wren habitat.
So one key to having a successful bluebird trail is to learn to distinguish bluebird nests, eggs and chicks from those of other species that are also drawn to the same types of houses: tree swallows, chickadees, house sparrows and house wrens. That way you can tell what you've got in your nest boxes. Bluebirds: great! Swallows and chickadees: fine. House sparrows and house wrens: not fine!
|A wren filled this house with twigs last year|
On Saturday we cleaned out signs of wren occupation and one old bluebird nest. Bluebirds don't reuse nests, so it's good to provide a clean nest box each year.
|Taking out an old nest - grasses, twigs and a few feathers|
There are several kinds of nest boxes that allow the contents to be easily checked and cleaned. The boxes on our trail are all the Gilbertson PVC style. They are lightweight and detach from the roof for easy viewing and cleaning.
|House taken over by wrens - filled with twigs|
While we were out and about on Saturday we saw bluebirds near most of our nest boxes, which was a great sign, and we were very pleased to discover one new nest and the beginnings of another.
|New bluebird nest -- a neat cup made mostly of grasses|
We'll be attending the annual Bluebird Expo in Byron, Minn., on April 14, where I'm sure we'll learn much more from knowledgeable speakers and will get to meet other bluebird enthusiasts. I'll be reporting here on the successes as well as the inevitable mishaps or disappointments of our bluebird trail, so stay tuned for that. I'm just learning all of this, so I'll probably make some mistakes. I welcome corrections and other advice from more experienced bluebird fans.