On Wednesday, sale August 12th, I couldn’t see or hear any Chimney Swifts above downtown Shelburne during about 15 minutes of noon-time observation near the church where I had previously seen them diving into a roosting chimney during the daytime. On Thursday and again today, August 14th, I couldn’t see or hear any Chimney Swifts above downtown Orangeville after 30 minutes of observation around the two chimneys (Broadway, and Mill Street) I’d previously seen them using during daylight hours.
It seems quite possible that they have they left already on their migration. That’s within the standard timeframe of mid-August onwards.
We first saw them on June 2nd, and our interpretation was that they had only recently arrived. On July 29th, I and others twice observed birds diving into and leaving the Broadway chimney, spending less than a minute inside the chimney each time. That’s typical behaviour for feeding pre-fledglings. If so, then from recent fledgling to migrating bird takes place in about 2 weeks. Impressive!
The last Chimney Swifts I have seen this year were 4 flying above downtown Orangeville on August 4th.
We do not know the breeding success of the three roosts being used in our area. It would take considerable attentive field work to determine that!
I’m amazed that about 10+ weeks is all the time they spend on their breeding grounds. Their breeding success is now so constrained simply by a lack of suitable chimneys in which to nest. That’s why it’s so important to identify and protect suitable chimney, as well as to better census Chimney Swift populations.
Citizen science is worthwhile!