A North Wind Comparison

It is already a well known fact that we need south winds for migration.  North winds stir very little migration, as evidenced by the evening radar signatures.  The diurnal flight is just the same, north winds mean little movement.  In general, it’s been assumed that the morning flight on a north wind is only a small fraction, if any, of the flight seen on a south wind.  Most folks don’t even both to show up to see, knowing it will be a pretty boring morning.

Wind Map (from http://hint.fm/wind/) showing north wind rotation on April 17. The south winds are coming, as seen to the west of here.

Enter our spring migration counter.  By having the funding and time, we’re able to collect the valuable data that shows what migration is on these slow days.  With a very light north wind, we did indeed attempt a count this morning.  Tuesday, April 17 brought a chilly 45 degree start, but light winds.  The flight involved only 390 birds, comprised of 40 species.  This is the lowest one day total of the entire season.  North winds are statistically averaging a total flight of about 5-10% of what you see on south winds.  Despite the low numbers, this data will go into the season totals and will add to the valuable data we are collecting this year.

The full list is below.  One single highlight did stand out… more Merlins!  3 more were logged this morning, bringing the season Green Tower total to 23 birds!  Most folks are lucky to see one in a year!

Canada Goose 2
Double-crested Cormorant 35
Great Blue Heron 24
Great Egret 2
Turkey Vulture 2
Sharp-shinned Hawk 1
Merlin 3
Caspian Tern 7
Mourning Dove 5
Red-bellied Woodpecker 1
Yellow-bellied Sapsucker 5
Downy Woodpecker 1
Eastern Phoebe 1
Blue Jay 8
American Crow 16
Tree Swallow 5
Barn Swallow 1
Black-capped Chickadee 1
Tufted Titmouse 1
House Wren 3
Blue-gray Gnatcatcher 2
Ruby-crowned Kinglet 1
Eastern Bluebird 3
American Robin 16
Brown Thrasher 4
European Starling 9
Pine Warbler 1
Yellow-rumped Warbler 1
Eastern Towhee 2
Chipping Sparrow 2
Field Sparrow 2
Song Sparrow 2
Swamp Sparrow 9
White-throated Sparrow 8
Northern Cardinal 2
Red-winged Blackbird 157
Common Grackle 23
Purple Finch 1
House Finch 2
American Goldfinch 26

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