Historical High Counts
Since Vaux's Happening began in 2008, volunteers have documented an extraordinary amount of activity along the Pacific Flyway. A few numbers stand out.
| Record | Site | Count | Date |
|---|---|---|---|
| Largest single-night roost ever documented (non-migratory) | Morelos Old Refinery, Oacalco, MEX | 263,025 | September 27, 2025 |
| Largest 1-night spring migration count | Frank Wagner Elementary, Monroe, WA, USA | 21,938 | May 6, 2022 |
| Largest 1-night fall migration count | McNear Brickyard, San Francisco, CA, USA | 107,650 | September 2, 2025 |
| Biggest network-wide single day | All sites combined | Coming soon! | TBD |
The Records
In 2020, Vaux's Happening tracked down a massive roost at an old hacienda in Oacalco, Mexico. In 2025, it set the record as the largest single-site count the project has ever recorded. For decades before that, the best-known Pacific Northwest roost was the chimney at Chapman Elementary School in Portland, hosting tens of thousands of birds a night at its peak. And it all started at the Frank Wagner Elementary chimney in Monroe, Washington, where volunteer Judy Alles counted over 21,000 swifts in a single evening back in 2008, a number that helped launched Vaux's Happening.
Single-night high counts
The most number of swifts recorded in each roost in a single night.
| Roost | State / Province | # of Swifts |
|---|---|---|
| Frank Wagner Elementary | WA | 21,938 |
| Rainier Riverside School | OR | 21,131 |
| Eugene UO Agate Hall | OR | 15,590 |
| Hedrick Middle School | OR | 11,030 |
| Portland Chapman | OR | 10,000 |
| LA Chester Williams (demolished) | CA | 10,000 |
| San Diego Church Lofts | CA | 10,000 |
| JBLM #2068 | WA | 8,890 |
| Selleck Old School House | WA | 8,320 |
| Old Northern State Hospital | WA | 8,191 |
| Albany Fire Station (demolished) | OR | 5,774 |
| Roseburg UVAA/Clay Place | OR | 5,280 |
| Bend Boys and Girls Club | OR | 2,750 |
| SF McNear Brick | CA | 1,065 |
| Healdsburg Rio Lindo | CA | 500 |
Spring Migration
| Roost | State / Province | # of Swifts |
|---|---|---|
| SF North Bay McNear Brick | CA | 107,650 |
| Healdsburg Rio Lindo | CA | 41,040 |
| Frank Wagner Elementary | WA | 26,552 |
| Rainier Riverside School | OR | 25,620 |
| Portland Chapman | OR | 21,000 |
| Old Northern State Hospital | WA | 20,965 |
| JBLM #2068 | WA | 19,260 |
| Selleck Old Schoolhouse | WA | 17,591 |
| Oregon City Old High School | OR | 12,220 |
| Eugene UO Agate Hall | OR | 12,000 |
| Roseburg Courthouse | OR | 8,195 |
| Portland Abernethy | OR | 7,130 |
| Monroe District Offices | WA | 6,153 |
| Sumas Old Customs | WA | 3,650 |
Fall Migration
Related resources