REPORT FOR NRMP-1 (MAY 25) + REMINDER FOR NRMP-2 = MAY 29
The first national monitoring night for 2016 collided with a major weather system that kept dumping rain down in most of Manitoba. We were fortunate to have hearty volunteers who toughed out the evening to generate a fascinating dataset!
A warm welcome is extended to Beth who joins the Assiniboine School (St. James, Winnipeg) monitoring team. “I don’t dissolve in the rain” was last heard from Beth. True to form, clad in two layers of rain wear and sporting a waterproof bag/paper, she knocked on David’s door to usher him to the chimney side. It turned out to be an amazing experience – over 156 Chimney Swifts funneled into the roost! As background, there had been close to 4 straight hours of moderate rain and the temperature had sunk to ~14 C when the birds entered between 8:48 – 9:01 PM; sunset was 9:21 PM.
Up in Dauphin, Ken was on stand at his roost site – rain had stopped about 2 hours before the monitoring session began. The final head count = 29 Chimney Swifts.
At a somewhat lower latitude, in Selkirk, Carol and Dorothy had 33 Chimney Swifts roost at the large stack and 0 entered the yellow chimney which is in a direct sight-line from the large stack.
Now here is where the story gets interesting…
Also in Selkirk, Gerald and James, saw 0 swifts while monitoring the infirmary chimney. This site was first discovered in 2014 and had 10 swifts using it; in 2015, 3 swifts were observed.
Tim, in Fort Rouge, saw 0 swifts around the Leisure Centre on the west side of Osborne. This chimney was a possible nest site in 2015 and was used by 2 swifts.
Jim, in Fort Rouge, saw 0 swifts around Beresford on the east side of Osborne St. He noted Chimney Swifts tearing around the area on May 24 and May 26. In 2015, Quinn monitored this site and it was used by 2-4 swifts before a nesting attempt appeared to be abandoned in early June.
Out in La Broquerie, David saw – yes – 0 swifts around the church. In 2015, a breeding pair successfully fledged young at this nest site.
So a pattern seemed to appear with this admittedly small sample size. Large numbers of swifts entered the “big three” roost sites – the three sites which house the largest known groups of Chimney Swifts in Manitoba. At other sites which typically house smaller group sizes of roosting swifts, and at nest sites, no birds were seen at all.
What does this all mean? My working hypothesis is that the energy budgets of non-breeding and breeding Chimney Swifts drive them to behave differently under some conditions. And we had those conditions Wednesday night. If a bird can rely on the thermal advantage of huddling with dozens of other swifts, surviving the night is possible, even if it toughs out feeding in a storm longer (feeding is more difficult when the heavy rains wash the aerial prey out of the air). However, if your breeding partner is the only source of extra warmth, it would be a better “choice” to save precious calories and call it a day earlier. It is likely that breeding adults were in some nest sites well before the start of monitoring. Barn Swallows nesting on the side of our home near St. Adolphe tucked in for the night ~ 8 PM Wednesday night!
The forecast for NRMP-2, Sunday May 29, is improving – Brandon can expect sun; La Broquerie has 30% chance of showers; Portage La Prairie, Dauphin and Winnipeg have 60% of showers…so I hope that everyone can get out without being drenched and enjoy counting Chimney Swifts.
Thanks for all of your monitoring efforts and early returns.
Let’s stay in touch, Barb.