Bluebird Diary 2020

Please do not check inside boxes without FOBM permission. Too much disruption may cause birds to abandon their nests. Thanks!

Two lovely photos by Jean-Claude of Bluebirds checking out our nest boxes this year.

The one on the left is a male Mountain Bluebird and the one on the right is a Western Bluebird. 

April 21     Again Western Bluebirds have been spotted by 2 nest boxes. Both pairs of Western Bluebirds were seen with straw in their mouths going into the boxes to add a bit more to their architectural masterpieces. Small bits of straw were also seen in boxes 6, 7 and 8. Could these possibly be the beginnings of new nests? 

April 24

Box 1    Western Bluebirds were hanging around, eyeing the box.

Box 2    Another pair of Western Bluebirds were eyeing this box.

Box 3    No evidence of nesting.

Box 4    No evidence of nesting or Bluebirds or Swallows at this site.

Box 5    No obvious sightings of birds but a nest here is clearly underway.

Box 6    A pair of Mountain Bluebirds were hanging around this box. 

Boxes 7 - 12 had no evidence of nesting activity or Bluebirds or Swallows in vicinity.

May 6

Box 1     5 Western Bluebird eggs

Box 2     Western Bluebird nest almost completed

Box 3 - 5   Nothing in boxes

Box 6      6 Mountain Bluebird eggs

Box 7 - 12  nothing in boxes

May 15

Box 1      Western Bluebird sitting on nest (still 5 eggs, I presume)

Box  2     Western Blubird nest with 5 eggs

Box  3 - 5    Empty

Box 6      Mountain Bluebird box with 6 eggs (female flew off the nest when we opened the box. But all seems well as we saw both male & female near box later.)

Boxes 7 - 12   Empty

May 23

Box 1      5 Western Bluebirds all hatched

Box 2       5 Western Bluebird eggs

Box 3      Violet Green Swallows seen in vicinity

Box 6       6 Mountain Bluebirds all hatched

Box 4, 5, 7 - 12 empty

6 Mountain Bluebird eggs in box 6

Joan peaks into a nest.

May 30

Box 1     5 Western Bluebirds young in nest. 

Box 2     5 very young Western Bluebirds in nest. They can be checked once more.

Box 6     5 or 6 young Mountain Bluebirds on nest. See photo below. 

Boxes 3-5 empty. We didn't check the last 6 boxes as nothing likely. 

Box S2   Western Bluebirds were building a nest. 

June 15

Box 1     The Western Bluebirds that were so recently thriving are now all dead. At least 3 birds seemed to have been abandoned. Could this be related to the cold, wet weather we are having? 

Box 2     The nest had 6 dead Western Bluebirds in it. There was an adult flying nearby, but sadly the young are no more. First time this has happened since we started.

Box 3     Had the beginnings of a nest in it. 

Box 6     The Mountain Bluebird box was empty and it seems as if the young have all fledged. Some good news at least.

RDCO box (eastern one) had Violet Green Swallows swooping around, but I couldn't see into the bottom of the box. 

RDCO box (more westerly) had 6 Tree Swallow eggs in it.

S02 box on the knoll had Western Bluebirds flying around it, but I wasn't able to look inside. 

S01 box had an adult Western Bluebird (or is it a Mountain?) sitting on nest. Eggs are visible under it. 

Box #2

Box S01

June 22

Box 1     empty

Box 2     cleaned out and it appears all 6 birds were in it and dead

Box 3     3 Bluebird eggs in it with a Western Bluebird in the vicinity

Box 4     1 Violet Green Swallow egg in it

Box 5     Tree Swallow on nest 

Box 6     Cleaned out box that had the Mountain Bluebirds in it. Their were a few sticks                     ontop of the nest which looked like wren activity

Box 7     cleaned out beginning of wasp nest

Box 8     Cleaned out a false house wren nest 

Box 9- 12   empty

S01         5 Western Bluebird eggs and adults nearby

S02         6 Western Bluebird eggs in nest

RDCO western box  6 Tree Swallow eggs in it

RDCO eastern box    Violet Green Swallows hanging around, but box is inaccessible

July 4

Box 1 & 2   empty

Box 3     5 Western Bluebird eggs in nest

Box 4     There were 4 Tree Swallow eggs in nest.

Box 5     Tree Swallow sitting on nest

Box 6     Cleaned out a few Wren sticks

Boxes 7 - 12  no nesting activity, just a couple of wasps building a nest. These were             cleaned out

Box S01    4 Western Bluebird babies in nest. Parents close by.

Box S02    5 Western Bluebird babies in nest. Parents close by.

RDCO box 1   5 Tree Swallow babies

RDCO box 2   Tree Swallows flying in and out of box.

 July 12

Box 1     there was a partial wren's nest, so we removed it

Box 2     empty

Box 3     A Western Bluebird female was on nest and flew when we opened the box. 4        young could be seen in the box. They looked to be no more than a week old.

Box 4     A Tree Swallow was sitting on nest. 

Box 5     There were 4 tiny Tree Swallows in nest with 1 yet to be hatched egg. Adults flying around close to box.

Box 6     empty

Box 7 - 12 not checked

S01         4 young Western Bluebirds in nest. They look to be close to fledging.

S02         There appeared to be at least 4 dead Western Bluebird young on nest. Very sad and no obvious reason why.

RDCO box 1  empty, it appears as if the Tree Swallows had feldged.

RDCO box 2  Tree Swallows were attending to the box, but the box cannot be accessed.

July 19

Box 1 & 2   empty

Box 3    5 Western Bluebird young in box

Box 4    5 Tree Swallow young in box

Box 5    Where did the baby Tree Swallows go? Just 1 unhatched egg in box. Cleaned

Box 6    empty

Box 7-12 empty

S01        Still 4 young Western Bluebirds on nest.

S02        The dead Western Bluebirds and nest were cleaned out. It was suggested that maybe blowflies got to them due to the wet weather we've had this year. 

July 28

Box 3    The box was empty, so it seems the 5 Western Bluebirds have fledged. Yay!

Box 4    The 4 + Tree Swallow young were all alive, but checking the box 5 days later, they were all dead.

Box S01  The box was empty, so it appears the 4 Western Bluebirds had fledged. 

Summary of year

6     Mountain Bluebirds fledged

10   Western Bluebirds fledged

5     Tree Swallows fledged

15   Western Bluebirds died

5      Young Tree Swallows disappeared. Predators?


With 15 boxes monitored, the results are disappointing. Especially, the number of Bluebirds ready to fledge and then all be found dead in their nests.  At least the cattle were out of the park so none of the boxes were knocked off their posts. At first we thought the unusual wet weather this year, might have created a blowfly situation, as one group of dead Western Bluebirds had maggots on them. However, after reading an article in the North American Bluebird Society summer 2020 journal, I wonder if the lack of insects was the cause of the deaths. Most of the deaths happened just before fledging, so perhaps the adults were unable to keep up with the hungry mouths. We saw adults around while the bluebirds were alive. It is possible that the adults died or abandoned the nests for lack of food. 

The article I refer to is "Insect Populations Continue to Plummet -- What Does This Mean for Bluebirds?" by Bernie Daniel, Ph.D.  After sharing the recent drastic fall of populations of insects worldwide, a few possible causes are suspected:

1. intensification of agriculture (in our case the decimation of grassland just to the west of the bluebird trail).

2. the development of newer generations of pesticides which are a little too effective on insects (phenylpyrazoles and neonicotinoids in particular).

3. biological factors such as pathogens introduced by species from other continents.

4. unfavourable conditions brought on by climate change. 

Next year we plan to remove boxes 7 - 12 which have not been productive for a few years and put them and some extra boxes we have along the Gopher Creek fence line. We will do this and clean out the boxes in the fall. Maybe, we'll have to start providing meal worms for the bluebirds!!! How will we do that?