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red-tail and cooper's hawks

Hawk Watch at Forest Beach Migratory Preserve

January 11, 2021  |  Topics: Spotlight, Stories

Story and photos by Kate Redmond

Every day on the tower is a good day, but some are especially memorable. On a day in mid-October with 15 to 25 mph winds, Sharp-shinned hawks were whipping past so low that I sometimes felt like ducking. I looked down at the backs of some birds that passed below the platform at brush-top level. Another breezy, freezing cold day in November, 17 Bald Eagles flew past the hawk tower at Forest Beach Migratory Preserve in two hours, the last eagles this season. At about noon that day, five eagles, accompanied by two Red-tailed Hawks, passed the tower high, heading south-southwest. Two hours later, five eagles and two Red-tails passed over a park at the south end of Ozaukee County. Were they the same birds? It’s possible.

Bald eagle
Bald Eagle

Former Western Great Lakes Bird and Bat Observatory (WGLBBO) director Bill Mueller started the hawk watch at Forest Beach, an Ozaukee Washington Land Trust property near Lake Michigan in northern Ozaukee County. Ours is a small, volunteer effort, and the tower, located at the northeast corner of the property, isn’t manned constantly, but we’ve recorded 15 species of raptors since 2009. That first year, 197 birds were logged during just a few days of counting, but 1,690 birds were seen in the fall of 2011.  

The hawk tower at Forest Beach Migratory Preserve
The hawk tower at Forest Beach Migratory Preserve

In the past two years, we’ve tried for more coverage, making the effort to be there on days with west and northwest winds, and cussing inaccurate weather forecasts and the wind’s sudden shifts off the lake. Hawks don’t like to migrate over open water, so when northwest winds bring them to the western edge of Lake Michigan, they veer south to fly along its shoreline. The first thing you learn, though, is that the birds didn’t read the book, and on days that seem ideal, the sky may be empty. 

We saw 1,151 birds in the fall of 2019 and 887 in 2020.

Sharp-shinned hawk
Sharp-shinned Hawk

Our four most numerous species are Sharp-shinned Hawks, Merlins, Turkey Vultures, and Red-tailed Hawks. The first two are early migrants—most pass the tower in September and October—and there can be some big days. On Oct 10, 2011, 292 Sharp-shins and 156 Merlins were tallied.

Common green darner dragonfly
Common Green Darner Dragonfly

The Common Green Darner is a large dragonfly that also migrates along the shoreline in late summer and early fall. There are days when tens of thousands of darners pass the tower; when you scan with binoculars there are darners in the air as far as you can see. 

Sandhill cranes
Sandhill Cranes

Merlin migration is synced with, and fueled by darners. Merlins can grab a darner from the air and eat it in flight. The total for 2011 included 703 Sharpies and 309 Merlins; in 2019 we saw 309 Sharpies and 144 Merlins; but in 2020 we saw 288 Sharpies and only 59 Merlins.

Turkey vulture
Turkey Vulture

Red-tail numbers were close—209 in 2019 and 187 in 2020—but Turkey Vulture numbers were down. Peregrine Falcon numbers doubled in 2020, and our Bald Eagle numbers jumped from 25 in 2019 to 89 this year!

To be counted, birds must move past the tower in a purposeful way. Resident Red-tails and Bald Eagles may approach the tower, then change direction and move north again.  

Tree cricket

The count ended on December 1. Because of November’s warm weather and southerly winds, the birds probably didn’t feel any urgency to move south early this year (fall migration is about food, not cold). Fewer Northern Goshawks and Rough-legged Hawks, those exciting late fall migrants, were seen this year.

Red-tailed hawk
Red-tailed Hawk

In late September of 2019, I happened to turn around and look south of the tower in time to see 150-plus Broad-winged Hawks streaming directly in off of the lake (which I can’t explain). The instant they were over land, they picked up the warm air thermals rising off the prairie, circled, and shot up into the sky, heading southwest, disappearing aloft faster than I could count them. Late in November of 2020, one of this fall’s few Rough-legged Hawks cruised over so high up that the sun was shining on its belly! 

Northern Shrike

Hawks aren’t the only things we see from the tower—Cormorants, Snow Geese, Tundra Swans, Sandhill Cranes, and lots of Blue Jays fly by. Also, Monarch butterflies, early finches, tardy swallows and Common Nighthawks. Northern Shrikes, Snow Buntings, and White-winged Crossbills make appearances, too. This year, Pine Siskins by the bushel.  The voices of tree crickets in the prairie provide the background music for the watch well into October.

Juvenile bald eagle
Juvenile Bald Eagle

What do these two years of more intensive coverage tell us? That we need more data. In Broadsides from the Other Orders, Sue Hubbell says “Each observation, however, has raised more questions than it answers, so the sum of my watching has caused me to grow in ignorance, not in knowledge.”  Here are some of my questions:

  1. If the birds aren’t coming through on the days when they’re “supposed to,” when are they coming through?
  2. Was 2020 “normal” or was 2019? Or both? Or neither?
  3. If we staffed the tower on the northwest corner of Forest Beach, too, what would we add? 
  4. Where do our birds come from? 

When you look at Wisconsin’s borders, the Mississippi Flyway is on the west, Lake Superior is on the north, and Lake Michigan is on the east. There has been some research about where the birds come from that fly past Hawk Ridge outside Duluth, but where do they go afterward? It’s hard to imagine that the birds that pass Hawk Ridge would cut east and follow Superior’s curvy south shore until they get to the west shore of Lake Michigan.

Broad-winged hawk
Broad-winged Hawk

Do the birds we count at Forest Beach mostly originate in northern Wisconsin and Michigan’s Upper Peninsula?  These are exactly the kinds of questions that the Motus Wildlife Tracking System, being promoted by the WGLBBO, is designed to answer.

Related story by Kate Redmond: The Importance of Raptor Watches.

Kate Redmond is a naturalist, WGLBBO board member, Friends of Cedarburg Bog board member, and self-described “Bug Lady.” See her “Bug of the Week” column on the UWM Field Station website.  All images by Kate Redmond. The featured image at the top is of a Red-tailed Hawk being mobbed by a Cooper’s Hawk.

WGLBBO and OWLT are partner organizations to A Wealth of Nature.