Documenting and caring for the mountain bluebird boxes that ring Henry's Lake, Idaho — box by box, season by season, since the 1980s.
For more than four decades, a quiet conservation effort has unfolded along the shores of Henry's Lake in eastern Idaho. In the 1980s, Alma Errol Nielson built and placed a series of nest boxes around the lake to give mountain bluebirds — along with tree swallows and other cavity-nesting birds — safe places to raise their young. Each spring he returned to clean, repair, and monitor the boxes, recording what he found inside.
Errol maintained the boxes himself for many years. After his death, his nephew, Russel Nielson, took up the work, continuing the annual rounds of cleaning, repairing, and replacing boxes around the lake. What began as one man's project has become a multi-generational labor of care.
The boxes follow the lake in two loops. The North Section begins at Box 1 on the lake shore and continues clockwise along Red Rock Road. The South Section begins at Box 108 and runs counter-clockwise around the lake. Together they form a living map of the shoreline and the birds that return to it each year.
This site gathers the project's history, photographs of the boxes as they change over the seasons, and the survey data that volunteers have recorded every year since 1991.
Volunteers walk both routes each spring and record what they find in every box. Both the North and South routes were surveyed in June 2026, with the previous year's notes kept for comparison on each box's page.
Tallied across all 78 boxes on both routes during the June 2026 survey, with the 2025 count shown beneath each figure for comparison.
Select any box to see its location, 2026 and 2025 survey notes, and photographs. Every box was photographed during the June 2026 survey.
North Section · 40 boxes
The project is based around the shores of Henry's Lake near Island Park, in Fremont County, eastern Idaho, at about 6,500 feet elevation.
A volunteer effort that builds, maintains, and monitors mountain bluebird nest boxes around Henry's Lake. The boxes were first placed in the 1980s by Alma Errol Nielson and are maintained today by his nephew, Russel Nielson.
Volunteers have recorded what they find in each box every spring since 1991 — more than three decades of mountain bluebird and tree swallow nesting records.
The project monitors 78 nest boxes on two routes, North and South, that follow the shoreline around the lake.
Mostly mountain bluebirds and tree swallows, which compete for the same cavities. The records track both species box by box.
The Mountain Bluebird Festival is held each summer at Henry's Lake, Idaho. Upcoming dates are posted on the Festival page; the most recent was the second annual festival on June 12, 2026, at 5310 Henrys Lake Rd, Island Park, Idaho.
Across North America mountain bluebirds have declined an estimated 26–34% between 2007 and 2021, but populations in Idaho and the Northern Rockies have stayed relatively stable — where nest-box projects like this one help provide nesting habitat.