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Up until 20 years ago, you would have been hard pressed to find bluebirds. But – good news! The bluebird is returning and thriving and is a remarkable conservation success story. It happened because thousands of concerned citizens got together to make a difference. Want to join the team? – Read on.

First of all, we need to take a trip back through bluebird history to fully understand why a conservation movement was needed to save them. Just prior to 1900, the bluebird was the most abundant bird in North America. It was a bird favoring open lands with scattered trees whether it be grasslands or land regenerating from forest fire. It was a cavity nesting bird primarily eating insects such as grasshoppers, crickets and beetles in the summer and berries in the winter months.

Pioneers started to drastically change the landscape of North America by logging and clearing land for agriculture. Down came all the trees that provided homes and nesting sites for all the cavity nesters. Forest fires that were once a natural component of the ecosystems of North America were suppressed.. Bluebirds faced a dilemma of losing cavity sites to agriculture and few new cavities becoming available through the natural process of forest fire. But this was just the beginning of the disaster.

European “alien invasive birds” were introduced to North America namely the European Starling and the House Sparrow. These birds started to directly compete for whatever nesting sites were left and since they were more aggressive than the bluebird, they usually won the competition. Then DDT was introduced to the agricultural scene. Now the bluebird faced increasing survival pressure. Lack of food from the use of DDT killing insects and lack of suitable nesting sites caused bluebird populations to plummet. By the mid 1900’s the bluebird had been placed onto the endangered species list.

That is when concerned citizens and scientists banded together to save the bluebirds. Creations of bluebird trails sprouted up all over North America. Plantings were encouraged for both winter and summer food. By the 1970’s bluebird numbers started to increase and today they are no longer endangered. However, the true habitat and home of the bluebird has been changed by man to the point that we will always have to be concerned for them.

So what can we do here in Ontario to help the bluebird? Here’s some ideas to consider trying.

  1. Erecting bluebird nesting boxes.
  2. Plant with purpose – here’s a listing of shrubs and trees that are beneficial to bluebirds.
    • Eastern Red Cedar
    • Cherry – Black, Pin and Choke
    • Dogwood – any of them
    • Common Hackberry
    • American Mountain Ash
    • Red Mulberry
    • Sassafras
    • Serviceberry
    • American Blackberry
    • American Blueberry
    • Highbush Cranberry
    • American Elder
    • Nannyberry
    • Sumac
    • Black Huckleberry
    • Common Winterberry
    • Wild Grape
    • Virginia Creeper
  3. No spraying!

So the key point to attracting and having bluebirds stay is the nesting box. Here are many things to consider.

A – Nesting box design

The aim is to make the box as appealing to the bluebirds and at the same time to exclude competitors. One critical feature of the box is entrance hole diameter. This should not exceed 1.5 in. since this excludes European Starlings which are too large for this size opening. Contrary to belief – no ventilation holes. Bluebirds are more likely to suffer from cold than heat. Do not forget that brood #1 is already laid, hatched and fledged by the end of May before any serious summer heat occurs. Keep the wood as rough as possible. Put striations in the wood both outside and inside near the entrance hole for both parent and young bluebirds to grip and climb. There are many internet web sites with nesting box plans – I happen to like the Ontario Eastern bluebird society plans.

B – Placement of nesting boxes

Location, Location, Location! Unmanaged poorly located boxes hurt the bluebird population. Even the best nest box will not attract bluebirds if it is in the wrong location. Some ideal spots are: cut meadows, mowed lawns, grazed fields, cemeteries, golf courses and public parks. Bluebirds need scattered young trees or shrubs or fence posts as hunting perches. Bluebirds hunt insects by scanning the ground from a perch and then dropping down on the ground. So the summarize – look for low or sparse vegetation.

C – Box competition

Along with enticing the bluebird with the ideal nesting box and habitat, comes headaches. Other birds, competitors, also find this set up attractive. In case you were skimming through the article – think location, location, location. Box placement will deter some competitors. House wrens prefer wooded sites so be sure to have all boxes away from wooded areas (up to 100 ft.). Another competitor is the lovely tree swallow – don’t go hard on this bird since they have experienced a 90% population reduction and could do with your help. An ideal answer is twinning the boxes. Set 2 nesting boxes 10 – 15 ft. apart where one box can host bluebirds and the other can host tree swallows. Since tree swallows are more aggressive and territorial than bluebirds, the bluebirds will actually receive protection against predation by other birds by having a tree swallow as a neighbor. Curiously, tree swallows are not usually aggressive towards bluebirds and these 2 species of birds cohabit usually in peace. Pairs of boxes can be placed about 100 yards apart.

D – Predation

Even the best located boxes cannot be totally fool proof with regards to predation. A box is pretty easy for a raccoon to get into so a predator protection system is required. Firstly, make climbing impossible by mounting boxes onto T rails or round pipe, not a tree or fence post. Secondly, either grease the mounting pole or attach a predator guard like a baffle.

E – Monitoring your bluebirds

This is hugely important and the one action that can keep your bluebirds safe. There is no way of totally excluding the house sparrow by box design or placement. You need to be vigilant about evicting house sparrows and their nests from your bluebird boxes. Usually, a quick check, weekly, is enough to determine things are progressing nicely. Records are useful since you should not open the boxes when the chicks are near fledging.

Bluebirds are worth the effort so get out there and put up some bluebird boxes.

The bluebird carries the sky on his back. ‘

Henry David Thoreau

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