Date: 7/31/20 4:05 pm
From: Gordon Andersson <gpandersson...>
Subject: [mou-net] Chimney Switts in St Paul
Ornithophiles



I live in W. 7th neighborhood of St Paul kiddiecorner from a school with a
tall chimney. Every summer the CHSW's start chittering and flying around in
small and large groups beginning about sunset. On Monday eve I decided to
count them as they dove down the chimney. As you know, the most accurate
count would require a video recording played back in slow motion. The
number dropping into the tower accelerates suddenly and then it is over
except for a few independent spirits.



On Monday eve I counted 92 birds. On Tuesday 142 birds. Last eve Thursday
122 birds. The last count is probably the most accurate with the smallest +
and - ranges. But I think the numbers actually fluctuate each evening
also. There might be a rolling average increase before departure for the
south.



For years Audubon MN conducted a volunteer CHSW count at two times during
the summer, with a retired volunteer coordinator. For 40+ years, St Paul
Audubon Socy had a "warbler weekend" every Mother's Day weekend at Villa
Maria in Old Frontenac on Miss River. Every evening Friday and Saturday
people would count the birds going down the chimney of the 4 story limestone
block residence. It was a scheduled event.



About 15 years ago, on a weekend, I came back from birding somewhere and
decided to sit in my bkyard and count the CHSW's. This was before the AM
organized count. As I remember there were 246 or so birds and I sent the
observation to DNR non-game staff.



My thought with these summer tower roosters has been that they were all
non-breeders. Since they only appear in the evenings, they could not be
feeding young in nests in the chimney. Someone who knows more and has
actually studied CHSW's might offer some facts. I was told once that only
one pair nests in each chimney. Alternatively, perhaps these birds are
already swarming, preparatory to migration to Central America. a long ways
to go and if young have already fledged they can head south.

This is from CLO allaboutbirds.org "Unmated swifts continue roosting
together in the summer, sometimes in large groups. But the species does not
nest colonially: you'll find only one breeding pair nesting in any one
chimney. The pair may tolerate other nonbreeders roosting in their chimney."


This represents a huge number of non-breeders. CLO does not mention age of
sexual maturity. The loss of chimneys has been gradual over time so these
numbers are not due to a sudden surplus of adult birds from one year to the
next.



PS I just read Jim Williams article in the Star Tribune from July 28 on
Chimney Swifts. He notes the decline of all four of N America swift
species, that NAS labels as species of "special concern".



GAndersson

St Paul




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