Advertisements
Posted by: atowhee | September 12, 2018

SWIFTS GO TO CHURCH, AGAIN

The annual fall migration of Vaux’s Swifts is on.  Once again each evening a flock gathers above the Cooperative Ministries Church at Second and Evans Streets in downtown McMinnville.  Then at sunset or a little after, they seem to be drawn down into the chimney where they hng for the night…hang, not perch…before they emerge the next morning for more bugging.

Tonight I estimate 250, plus a nearby crow who trumpeted his feelings about nightfall.  The began to enter the chimney about 732PM, and were inside by 740PM.

The sequence of flight and roost entry:

Click on any image for full screen view.
There seems to a system at work, either through swiftly communication or else visual analysis by the birds.  Only pulses of 20-30 birds enter at one time, then the rest still in the air swirl around, sometimes as much as 200 yards from the chimney before they once again form a tight tornado and some more of the swifts tumble down into the opening.  In this case the opening can’t be more than 18 inches by two feet, not a lot of room for birds with 7 inch wingspan that must flutter in the air until they can find the right crevice for their sharp toes to find purchase where each one can hang for the night.  If too many entered at once there would be crowding, crashing and bashing, perhaps wing damage.  Somehow they understand that and ration themselves…each pulse is separated from the next pulse by at least twenty seconds. Time for the new arrivals to get hung up before more enter.  Roost entry began about 732PM, all were hung up for the night by 740PM

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

Categories

%d bloggers like this: