Nest Box Monitoring
2026 Monitoring Season
A season of 60 boxes, six sites, and a lot of good work
Here's how the season came together — the big picture first, then a closer look at each site.
97
Nesting attempts recorded
467
Eggs laid
370
Live young (nestlings) hatched
325
Chicks fledged
Every box, at a glance
Each square is one of the 60 boxes. Color shows how its season went — note some boxes hosted more than one nesting attempt.
Fledged at least one chick — 52 boxes
Attempted, no fledge — 6 boxes
Not used this season — 2 boxes
Tree swallows vs. western bluebirds
Tree swallows were the dominant tenant this year, with western bluebirds nesting at every site except Adobe Creek Bridge.
Tree swallow
82 nesting attempts · all 6 sites
Eggs laid406
Live young (nestlings)326
Chicks fledged284
Nest success rate80.5%
Western bluebird
15 nesting attempts · 5 of 6 sites
Eggs laid61
Live young (nestlings)44
Chicks fledged41
Nest success rate66.7%
Site by site
Nest success rate is the share of nesting attempts that fledged at least one chick.
| Site | Boxes | Attempts | Eggs | Nestlings | Fledged | Success rate |
|---|---|---|---|---|---|---|
| Point Blue Fenceline | 13 | 22 | 105 | 90 | 82 | 81.8% |
| Eucalyptus Grove at Ellis Creek | 5 | 9 | 42 | 32 | 32 | 88.9% |
| Adobe Creek Bridge | 6 | 11 | 60 | 46 | 32 | 81.8% |
| Ellis Creek Oxidation Area | 11 | 23 | 110 | 96 | 89 | 82.6% |
| Ellis Creek Driveway | 5 | 7 | 36 | 24 | 24 | 71.4% |
| Tolay | 20 | 25 | 114 | 82 | 66 | 68.0% |
21 nest boxes had one failed attempt. One box (Point Blue Fenceline 11) had two failed attempts. Tolay 7 and 16 were not used this season.
Species by site
Tree swallows nested at all 6 sites; western bluebirds nested everywhere except Adobe Creek Bridge.
| Site | Species | Attempts | Eggs | Nestlings | Fledged | Success rate |
|---|---|---|---|---|---|---|
| Adobe Creek Bridge | Tree swallow | 11 | 60 | 46 | 32 | 81.8% |
| Eucalyptus Grove at Ellis Creek | Tree swallow | 8 | 38 | 28 | 28 | 87.5% |
| Eucalyptus Grove at Ellis Creek | Western bluebird | 1 | 4 | 4 | 4 | 100% |
| Ellis Creek Driveway | Tree swallow | 3 | 17 | 9 | 9 | 66.7% |
| Ellis Creek Driveway | Western bluebird | 4 | 19 | 15 | 15 | 75.0% |
| Ellis Creek Oxidation Area | Tree swallow | 20 | 98 | 87 | 80 | 85.0% |
| Ellis Creek Oxidation Area | Western bluebird | 3 | 12 | 9 | 9 | 66.7% |
| Point Blue Fenceline | Tree swallow | 20 | 98 | 90 | 82 | 90.0% |
| Point Blue Fenceline | Western bluebird | 2 | 7 | 0 | 0 | 0% |
| Tolay | Tree swallow | 20 | 95 | 66 | 53 | 65.0% |
| Tolay | Western bluebird | 5 | 19 | 16 | 13 | 80.0% |
Point Blue Fenceline's two western bluebird attempts did not produce any fledglings this season — both nests failed.
Every other site with bluebirds fledged at least one chick from each attempt group.