by Debbonnaire Kovacs
It all started with some tiny birds: Vaux’s Swifts, only 4” (11 cm) long and weighing less than one ounce (<28 gms), the smallest of the four Swift species found in North America. These little creatures can fly at speeds exceeding 90 miles an hour—a good thing, since they must migrate hundreds of miles each year, from as far north as Alaska to as far south as eastern Panama and northern Venezuela.
Vaux’s Swifts been doing this for millennia, (long before they were named for 19th century scientist, William Sansom Vaux.) But one day in 1989, a small group of swifts made a discovery. In Sonoma County, California, north of San Francisco, right at a convenient stopping point in their southern migration in the fall, there was a tall chimney. The chimney had been there for a long time, but usually, hot steam was issuing out of it. This particular fall, there was no steam. A small flock of swifts circled down into the chimney to roost for the night, clustering together on the walls as bats do. (In fact, when they are flying, they are sometimes mistaken for bats—they have the rapid, erratic flight pattern of bats and other insect eaters.)
The swifts could not know they were about to become a celebrated tradition at Rio Lindo Adventist Academy, Healdsburg, CA. Nor could they know this was the first year the boiler was not being used to heat all the water on campus, because natural gas prices were going down and now water was heated with gas. They just knew they’d found a great hotel.
The biology teacher at Rio Lindo noticed the vortex of birds entering the chimney and called someone he knew in the Audubon Society, who sent someone that identified the migrating birds. In about 1991 or 1992, with the flocks growing larger each year, Audubon Society personnel video-taped them, then slowed the tape so they could count. They counted for five minutes and determined that approximately 360 birds enter the chimney each minute.
Using this number, the academy has kept count ever since, timing the main portion of the “vortex” and multiplying minutes by 360. According to information sent to Adventist Today by Brad Benson, Alumni/Development Director, “ Typically the peak will have 6,000 to 10,000 birds in an evening.
In 2008 there were two evenings with between 18,000 and 20,000 birds entering the chimney. The lowest numbers were in 2005 when the highest count was 300.”
Benson says the chimney is 32 feet tall, though it doesn’t look it, as part of it is underground. He estimates that 30,000 birds could fit in the chimney. “On a night when we had 20,000 birds, I looked down into it, and there were no birds at all in the top eight to ten feet.”
The swifts begin arriving in small groups in mid-August each year, increasing night by night until the peak, between September 10 and 20. They stay in the Rio Lindo area for several weeks, fattening up (? All the way to an ounce, maybe?) for the next leg of their arduous journey south. They come out of the chimney in the morning when the air warms enough that the insects they eat are active. Some think that on colder mornings they may fly to the Sacramento Valley to eat, then return to their chimney hotel in the evening.
Benson believes that Rio Lindo is one of the four or five largest sites on the coastal migratory route where the birds congregate. “There is a group in Washington trying to identify all the sites on the Pacific coast. I have people call me from states as far away as Florida calling me to ask when the dates will be, so they can come and watch.”
A local newspaper, the Santa Rosa Press Democrat, published an article about the academy’s famous swifts, along with several pictures. (You will find the website below.)
The academy has a special biology class event for credit, one evening during the migration, and Audubon has special kids’ nights as well as weekend nights for members. Rio Lindo also allows visitors to come and watch, so long as they “remember this is a boarding high school campus with students present 24 hours a day, seven days a week. Remember that means no smoking or alcohol is allowed on the campus. Also, please stay in the area of the chimney and do not roam the campus.” (From the academy website.) On a typical evening, Benson says, there are 30-60 people watching the swifts, and sometimes as many as 250, especially on peak nights in mid-September, when the numbers reach above 10,000 per night.
Part of the excitement is watching (or worrying) when raptors such as merlins or sharp-shinned hawks attack the flocks. Benson says some people cheer for the hunter catching its supper, while others are upset and try to chase the predators away.
To learn more about the Rio Lindo Vaux’s Swifts, visit one of these sites below:
https://healdsburg.towns.pressdemocrat.com/2012/09/news/healdsburgs-unusual-roadhouse/[9/26/2012 11:07:58 AM]
You can see a video at https://www.californiareport.org/archive/R201110071630/e The clip is 2 minutes, 13 seconds long, so using the 360-birds-per-minute estimate, you will see about 798 birds enter the chimney, though it appears as though many more are circling overhead. Be aware, at the very end of the clip, a predator attacks.