Part III: The Morning After

This is the third and final article in a three-part series about my observations of Chimney Swifts. The site is the 1919 Building at 144 West Bridge Street in old Dublin.

My official counting of the chimney swifts at the 1919 Building in old Dublin began September 10, 2003 (3700 birds). By Friday, Sept. 12, there were 4300 birds roosting in the chimney. Not having a clue about how they came out of the chimney, the next morning I arrived at 8:30 am. I saw very little activity until 10:25-10:40 when approximately 1000 birds exited the chimney. I planned to return the next morning before sunrise.

I knew that at least 4000 birds had roosted in the chimney on Saturday night. Sunday morning I arrived at the site at 6:50 am. It was nearly light but the sun had not yet risen. (Sunrise was at 7:12 am.) Between 7:00-7:07 am 1200 birds “popped” out of the chimney. The chimney reminds me of a popcorn popper and the birds coming out seem like kernels of popcorn popping up and out. All birds exiting the chimney headed in a N/NE direction (toward the Scioto River). At this point the data collection became difficult. At 7:11 and for the next 30 minutes, approximately 2/3 of those birds returned to the chimney. Were they “going back to bed” because there were not enough insects to feed that number of birds? The temperature was 63 degrees. I wondered if the swifts entering the chimney were new migrants arriving, but then I learned that swifts migrate during the day. That meant that swifts would be leaving, not arriving. A few hundred birds remained out of the chimney and always circled the chimney. Dick Tuttle of Delaware sent me some information about emerging swifts from a book entitled The Birds of North America. It states that:

Foot candles of light is a determinant as to when they roost and when they emerge. Swifts enter the chimney from 0-2 fc, and morning departures of 70% occurred at 0-7 fc. In Illinois, they left between 11.1 minutes with a standard deviation of 2.8 minutes before sunrise.

In other words, swifts typically come out of the chimney 11 minutes before sunrise (give or take three minutes). I have found that to be true, but that only 1/4 to 1/3 of the roost exits at that time. My guess is that the swifts leave the chimney in stages as the light of the sun penetrates further down this extremely tall chimney. That would explain why I had seen 1000 swifts exit the chimney between 10:25-10:40 the previous morning.

To continue with the Sunday observation, by 8:20am there was not a bird to be heard or seen. I knew that 3500 swifts were probably still inside the chimney. By 10:00 am it was 75 degrees and sunny with plenty of food source available for the swifts. Between 11:40-11:50 I counted 500 birds leaving the chimney and then I had to leave the site. I figured that 3000 swifts remained in the chimney and it was already noon! It was frustrating to have observed for five hours and still not to have seen all of the birds leave.

This summer during the week of August 15 I would like to observe the emerging swifts for one entire day. I would begin one hour before sunrise and continue 30 minutes beyond the time the last bird entered the chimney at night. I mention staying later because on Oct. 4, Darlene Sillick came to count the swifts with me. The last bird entered the chimney at 7:33 pm and 2800 birds were inside. Darlene and I continued to visit, but since Darlene was still facing the chimney, at 7:38 she noticed more birds silently entering the chimney! Between 7:38-7:46 an additional 200 birds entered the chimney! It seemed odd that these birds arrived when it was very dark and that they did so in total silence. Regarding the daylong observation in August, I hope to enlist the help of Bill Likens and Asa Wright, custodians at adjacent Sells Middle School. Both men have been observing the swifts for many years. If any Audubon members are interested in daytime observation and data collection, please contact Darlene Sillick and she will get word to me.

One other interesting morning observation occurred on Sept. 26. More than 2000 birds were roosting in the chimney. From 7:07-7:08, 80 birds came out but then a curious crow perched on the lip of the chimney and peered down inside. The crow moved on, but as of 7:50, when I had to leave, no more swifts had emerged.

Other Roosting Sites

Mark Skinner mentioned this site – the Masonic lodge one half block north of the intersection of Fifth and High. On August 29 I observed unusual swift behavior at this site. This was before I began to count swifts, but I estimate that 1200-1500 birds entered the chimney between 8:30-8:35 pm. At 8:30, the tight black “smoke ring” of birds suddenly tilted up to a nearly vertical ring so that all birds plummeted straight into the chimney. It was one of the most spectacular shows I have ever seen. I think there may be a tree near the chimney and that it would cause the swifts to tilt their “ring” up on end.

Rob Lowry of Powell mentions an older, unoccupied white house at 55 Olentangy St. in Powell. The house is east of the main intersection in Powell. Dick Tuttle observes swifts at the old armory in Delaware and reports his data to the Colunbus Audubon site at the end of the season.  Rob Thorn of Gahanna has found large roosts at the old fire station in Gahanna, at the Masonic lodge in Westerville, at Yearling High School in Whitehall, and at Watterson High School in Clintonville. I have also observed a large roost across the road at Indian Springs Elementary near Henderson and High. Rob reports that big roosts in past years have included Grandview High School, Montrose Elementary in Bexley, and Hamilton High School south of Columbus. If you know of other roost sites, please pass on that information to Darlene Sillick.