Good news from the field: So far, SVT's volunteer bird box monitors have recorded 67 bluebird fledglings in 2020--and we're awaiting more reports!
We installed our first bird boxes over 20 years ago to encourage bluebirds, which were declining in population, to nest and lay eggs. Even though bluebirds have rebounded, we continue to expand the program both to help the birds and to collect data for researchers.
This year, we had 58 bird boxes spread across 11 properties. Each box was regularly visited by an assigned volunteer who looked for nests, eggs, hatchlings, and fledglings. The monitors recorded their observations on the Nestwatch cellphone app, which was created by the Cornell Lab of Ornithology to track trends in bird reproduction around the country.
Of course, other species make use of the boxes as well, so our volunteers also track data on tree swallows and house wrens. Like any animal, birds are susceptible to predators, and our monitors frequently find a cracked egg, a dead bird, or an abandoned nest.
And now, the reports and photos:
At Walkup & Robinson Memorial Reservation in Westborough, Jan Vanselow made 39 visits between January and August:
- I had a total of 13 bluebirds fledge, 19 tree swallows, and 37 house wrens just this season! The house wrens were really prominent this year. Compared to last season, we were better in all 3 species, although there were equal numbers of tree swallows fledged last year (19).
In Framingham, Jane Joiner and Lynn Joiner made 32 visits to boxes at Henry’s Hill and Stearns Farm:
- We monitored 5 boxes at Henry’s Hill, which in total fledged 9 tree swallows, 5 bluebirds, and 3 house wrens.
- And we monitored 4 boxes at Stearns Farm, which in total fledged 5 tree swallows and 9 bluebirds.
- One of the bluebird nests was taken over by tree swallows and after the 5 tree swallows all fledged, when we cleaned out the box we saw one unhatched blue bird egg.
At Cedar Hill in Northborough, Laura Lane visited the boxes 38 times from March through August:
- I monitored 12 boxes at 2 different areas. I had 6 tree swallow nests with 27 fledglings. There were 7 house wren nests that fledged 38 young.
- I had 4 bluebird nests but only one was successful. It fledged 5.
- Of the 3 unsuccessful bluebird attempts, one pair was driven off by the tree swallows before any eggs were laid, and the swallows built their nest on top of the bluebird nest. Two other bluebird nests had eggs, but the eggs were removed by a predator.
- There was another bluebird pair in the adjacent Crane Swamp property which successfully fledged 2 clutches. They probably nested in a natural cavity, as I haven’t seen any nest boxes nearby.
In Framingham, Pam Keeney visited three fields 27 times between March and August:
- I monitored 6 boxes at 3 separate fields. I had 4 bluebird nests with 10 fledglings and 4 tree swallow nests with 6 fledglings.
- I had one bluebird nest disappear, eggs and all. There were many invasive attempts also.
- Across from these fields in my yard, I had a box with a wren nest so large that I couldn't get a good view into it and adults scolding me every time I tried. I like to think it was a successful attempt!
For Upper Mill Brook in Wayland, Carole Hohl reported:
- I had only 2 boxes at Upper Mill Brook.
- We had 2 successful nesting and 9 bluebirds fledged from one of the boxes.
The other was repeatedly used by a house sparrow. I must have removed 9 different nesting attempts.
At Greenways Reservation in Wayland, Eve Donahue and Shelley Trucksis share the monitoring duties. Shelley sent this report:
- There are 9 boxes, and 7 of 9 produced.
- One box had three broods of bluebirds but the middle brood disappeared at the egg stage.
- 3 boxes nested bluebirds for a total of 23 eggs and at least 16 fledglings
- 4 boxes nested tree swallows for a total of 21 eggs and at least 14 fledglings.
- I loved monitoring!