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.
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