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Vaux's Swift Migration

Swift Information

Vaux’s Swifts have been roosting in the Rio Lindo Adventist Academy chimney since 1989, the first year the school’s boiler wasn’t producing steam year-round. The chimney is still used in the winter when the boiler generates heat for the school campus, but that is after the fall migration. The first small groups of migrating birds usually appear in mid-August. The numbers increase and generally peak between September 10 and 20. In an average year, the count peaks between 5,000 and 10,000 birds for a few evenings. The highest numbers that have been observed were in 2015 when a couple evenings the estimate was between 35.000 and 40,000 birds. We believe this was because of the Middletown fire which may have narrowed the migration path. The lowest was in 2005 when the highest count was only 300. This was a West Nile year.

The incredible sight of thousands of birds flying in a tornado-like pattern against the dusk sky is simply incredible. Bird and nature enthusiasts travel from all over to see this unforgettable phenomenon. Most years, the birds arrive in small numbers by the first of September and leave by the end of September. Check back with this website as numbers are posted on a regular basis.


We are glad to welcome visitors to our campus to see the swifts. We only ask that you remember this is a boarding high school campus with students present 24 hours a day, seven days a week, which means no smoking or alcohol is allowed on the campus. Please keep dogs on a leash, even friendly ones. Also, please stay in the area of the chimney and do not roam the campus. Keep in mind that we do not know exactly when they will arrive for the evening or when they will begin to enter the chimney. Generally the best time to arrive on the campus is 30 minutes before sundown. We have observed that the time they begin to enter the chimney is sensitive to the air temperature (the colder it is the earlier they enter the chimney), sundown, and the number of birds here entering the chimney (the higher the number the earlier they begin to enter). Please leave the campus within 15 min. after the birds are finished going in the chimney.

Swift Count

Thank you to our new bird counter, Star, for getting these numbers up.

Swifts are counted by timing from the moment the swifts enter until they finish and multiplying the number of minutes by 360, which is determined by a video calculation that was performed by the Audubon Society in the early 1990s. The number is only an estimation and not precise.

2020 Swift Numbers

Date Estimated Number of swifts
August 31 5,500
September 1 10,440
September 2 8,600
September 3 6,200
September 4 6,300
September 5 6,500
September 6 1,800
September 7 No count (Temperature 113)
September 8 9,000
September 9 3,700
September 10 No count
September 11 6,480
Sept. 12  
Sept. 13


Sept. 14 5,400
Sept. 15 6,500
Sept. 16 5,940
Sept. 17 No count
Sept. 18 6,480
Sept. 19 No count