You may have seen nest boxes as you walk the trails on Ann & Sandy Cross Conservation Area and wondered why they are there?  Who are they for?  Primarily… Mountain Bluebird but we also find Tree Swallows, House Wrens and Chickadees raising families in nest boxes.

There are three species of Bluebirds in North America, Eastern, Western and in Alberta, our stunningly blue, Mountain Bluebird.  Bluebirds are ‘secondary’ cavity nesters. 

Because bluebirds are unable to chisel out a hole in a tree, they nest in pre-built cavities they find… be it an old woodpecker nest, a suitable crack in a rock face or even a nest box.  Thus, they are known as a secondary cavity nester.

Did you know that there are 85 species of cavity nesters in North America?  Ducks like the Common Golden Eye, Bufflehead or Mergansers and even predators of our bluebirds like some owls and small falcons (Merlin) are cavity nesters.

Nest boxes were likely first attached to fence posts and trees around the ASCCA in the 1980’s.  Since then, bird nerds have tracked which species has adopted the nest box, counted eggs and young, cleaned  out the nest box at the end of the season, then anxiously waited to see who’s there next year.

In the spring of 2020 we built 100 new nest boxes and hung them though out ASCCA.  Some were new and others were replacements for older deteriorating nest boxes.  Thanks to Chevron families and other volunteers many of the 100 new boxes were painted and now being occupied.   

Today we have a small group of volunteers who have adopted strings of nest boxes and are monitoring to record:

·        Nest?                           Yes or No

·        Species?                      Mountain Bluebird or Tree Swallow (most common) or House Wren

·        Egg Count?                 How many?

·        Egg Laid Date?           Estimate, Female Mountain Bluebird usually lays 1 egg / day

·        Hatch Date?               Estimate or Actual, we sometimes see babies hatching!

·        Fledge Date?             Estimate or Actual, date young left nest

·        Clean out Date?        Date nest box was cleared of nesting material – ready for next year. 

Want to help with the nest box monitoring or building project?

Learn about how you can become a volunteer.

Jim Critchley (monitor) – Sep 2020 – hanging box painted by a Chevron Family

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