July has arrived with sizzling heat, storms, and a record number of forest fires across the prairies. Over the last week, Manitoba has experienced blankets of smoke from Saskatchewan blazes. The unexpected bonus of the dense smoke may have been easier foraging for the swifts – even in afternoons with high temperature (>28 C), strong winds, and high humidity, insects seemed to be held to low levels in the air column. Frequent daytime sightings of roof top level feeding by swifts, swallows, and martins were seen in St. Adolphe while the smoke was present.
Backing up to May, I need to offer my apologies to Millie and Margaret in Brandon. Their NRMP-2 and NRMP-3 reports were buried, in what seemed to be an impenetrable chasm of my computer, and were not reported in previous monitoring updates. The now excavated data are: 2 swifts roosted on May 24, which was the first occupancy for 2015; and 4 swifts roosted on May 28, which was the season maximum – 8 swifts also were seen in the air at the end of the evening and their roosting destination was unknown. For the subsequent NRMP-4 and the Manitoba Blitz nights, a pair of swifts were busy nest building and they were the only birds in the chimney for the night. I hope the nesting activity in Brandon is still ongoing. On Saturday, July 4, torrential rains were widespread in the province and these events can wash nests off the interior face of chimneys.
Fortunately, all the established nests in St. Adolphe made it through the 70 mm deluge. Here is the season summary for St. Adolphe to date ~ of FIVE available nest sites, FOUR are occupied in 2015 – no chsw are using the SE Club Amical chimney. Interestingly, no late June immigrants have arrived in town this year. THREE stages of nesting were evident over TWO days this week. On July 6, the NE Club Amical and Main St. pairs were feeding brooded young (up to 6-7 days of age). On July 7, the Church pair was feeding non-brooded young (older than 6-7 days of age) and at Brodeur Bros., incubation continues. The ONE unifying theme for the breeding activity is VARIATION.
For any given season, there is no absolute synchrony to nesting. Even for a close knit community such as St. Adolphe, on a given date you can expect breeding pairs of swifts, at different sites, to be at different stages of nesting. This variation reflects the time of spring arrival, the start of nest building, and clutch size (usually 2-7 eggs are laid; incubation starts with the second last egg laid). Between-years, you will see differences in site occupancy, nesting success rates, clutch sizes, and the number of fledglings per nest site. Weather and insect availability are important factors in nesting outcomes.
Monitoring data can determine the stages of nesting as each stage is characterized by a different frequency and sequence of entries/exits. Backtrack to previous BlogSpot updates (postings on June 5, 8, and 24) for the explanations of nesting stages plus how to calculate the duration in (or partner change-up) and between visit intervals. If you have monitoring data for your nest site(s) that you would like help interpreting, please be in touch – help is only an email away.
Frank and Jacquie continue to monitor the Providence College chimneys in Otterburne. The swifts there are not faring as well as the birds in St. Adolphe. To recap, all three Providence chimneys were occupied on June 8. There were: 2 roosting entries to the chimney south of the bell tower; 2 roosting entries to the large chimney; plus entry/exit cycles which indicated nest building and 3 roosting entries to the skinny chimney. On the evening of July 5 (the night after the massive storm), no swifts roosted at the chimney south of the bell tower and at the large chimney. Only 2 entries by roosting swifts were made at the skinny chimney; further monitoring will indicate if the nesting attempt has failed.
Back to good news of opportunistic observations. Paul and Valorie’s June 30 posting on Manitobabirds indicated 2 westbound swifts were over the old post office in Morden. Our database has 325 Stephen St. listed as Site 1400, but no official monitoring has been done. We would welcome further reports about Morden swifts!
Your July sightings and monitoring data will help us track chimney swift activity in the province throughout the summer…
All the best for your birding experiences, Barb.
