Reading Bruch Falls robin roost account I looked up mine. It is a bit long.
That roost site has not been used since with any high numbers.
Winter Roost Site for American Robins
I live on Grey Cloud Island, the very southwest corner of
Washington County, and in early February I observed many robins flying toward a
plantation of spruce and pine trees, located where Pioneer Road met county road
75. A few days later I started counting the robins coming to the area and
counted 900, but the robins just kept coming. On February 15, 2010, I started
counting at 4:30 p.m., about one hour before sunset. It was cloudy with a
fairly stiff breeze out of the northwest. The robins flew in one at a time and
then in groups of up to about 30 birds. By one hour after sunset the stream of
robins had subsided, but by then I had counted 2,300 birds. I know we have had
an increase of American Robins wintering in Minnesota, but I did not ever
expect to see so many at one time.
The number seems exorbitant, but I firmly believe it is a minimum,
as when estimating the size of some groups flying in, I was careful to use my
lower estimate. All of the birds came in from the west, where the Mississippi
River is less than a half-mile away. Also many came from the open water areas
at the bottom of the Aggregate Industries limestone quarry less than one fifth
of a mile west of the conifers.
The plantation was never thinned, so the trees are very dense. The
spruce trees are all less than 20 feet tall and the pines less than 30 feet.
The arriving robins would first perch in surrounding deciduous trees before
descending into the conifers. I found it amazing to observe so many robins
disappearing in only 1.5 acres (0.6 hectares) of densely growing conifers.
Being curious about when the robins left their nightly roost site,
on 22 February, 2010, I set up my vigil. The first robins left one half hour
before sunrise, being cloudy it was quite dark at that time. Ten minutes later
there was a fairly steady stream of birds flying out to the west. One hour and
fifteen minutes after sunrise the last of the observed robins left. On leaving
the birds did not first perch in a surrounding deciduous tree, they just flew
directly away.
Tom Bell
5868 Pioneer Rd. So.
Grey Cloud Island, MN 55071
Tom Bell
Grey Cloud Island
5868 Pioneer Rd. S.
St. Paul Park, MN 55071
651 459-4150
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