Final Chimney Swift Count - Tuttle - 2007
E-mail from Dick Tuttle:
Hello Everyone,
The last migrating Chimney Swifts used Delaware, Ohio for a roosting site on October 10 as two birds dropped into the chimney above One West Winter Street. The most swifts using this chimney occurred on October 4 when 186 birds roosted there.
I started counting roosting swifts on August 10 for the 2007 migration season. I completed 41 counts from three chimneys and the season ended on October 11 when no swifts showed up.
Two popular chimneys were ignored after heavy rains. Swifts quit roosting at the National Guard Armory sometime after September 23, and the United Methodist Church in Galena was snubbed prior to September 9. I hypothesize that ammonia gases percolate from guano deposits after rainwater pools in chimneys. Hopefully, someday, this question will be investigated.
More or Less Swifts in 2007?
Occasionally, people ask me about long term population trends among migrating swifts. I offer the following calculations that contain unknown variables, but the stats are offered, nonetheless.
For each of last five seasons at the National Guard Armory chimney, I averaged the five largest counts for each year since I began taking serious counts in 2003. For example, the five largest counts for 2003 are 1650, 1420, 1100, 1060 and 925. The average for the largest five counts is 1231 swifts, the highest average among five years of counting. For comparison purposes, I called 2003's average one and divided all other averages by 1231 to find relative values.
Below, I list values from five years of counting. Each row shows the year, the range of five highest counts for that year, the average for the five highest counts, and the comparative size of each year's average relative to year 2003.
Heavy rains can wash swift nests from the walls of chimneys, but 2007 was extremely dry during the swift's nesting season. Was 2007 a good year for nesting Chimney Swifts? I think so.
Swift on, Dick Tuttle
Hello Everyone,
The last migrating Chimney Swifts used Delaware, Ohio for a roosting site on October 10 as two birds dropped into the chimney above One West Winter Street. The most swifts using this chimney occurred on October 4 when 186 birds roosted there.
I started counting roosting swifts on August 10 for the 2007 migration season. I completed 41 counts from three chimneys and the season ended on October 11 when no swifts showed up.
Two popular chimneys were ignored after heavy rains. Swifts quit roosting at the National Guard Armory sometime after September 23, and the United Methodist Church in Galena was snubbed prior to September 9. I hypothesize that ammonia gases percolate from guano deposits after rainwater pools in chimneys. Hopefully, someday, this question will be investigated.
More or Less Swifts in 2007?
Occasionally, people ask me about long term population trends among migrating swifts. I offer the following calculations that contain unknown variables, but the stats are offered, nonetheless.
For each of last five seasons at the National Guard Armory chimney, I averaged the five largest counts for each year since I began taking serious counts in 2003. For example, the five largest counts for 2003 are 1650, 1420, 1100, 1060 and 925. The average for the largest five counts is 1231 swifts, the highest average among five years of counting. For comparison purposes, I called 2003's average one and divided all other averages by 1231 to find relative values.
Below, I list values from five years of counting. Each row shows the year, the range of five highest counts for that year, the average for the five highest counts, and the comparative size of each year's average relative to year 2003.
- 2003, (1650 - 925) Average = 1231, 1.00
- 2004, (1020 - 537) Average = 851, 0.69
- 2005, (680 - 536) Average = 591, 0.48
- 2006, (430 - 346) Average = 396, 0.32
- 2007, (769 - 661) Average = 716, 0.58
Heavy rains can wash swift nests from the walls of chimneys, but 2007 was extremely dry during the swift's nesting season. Was 2007 a good year for nesting Chimney Swifts? I think so.
Swift on, Dick Tuttle
