On the morning of September 1st, I arrived at Hawk Ridge at 8:30. Counters Alex Lamoreaux and Karl Bardon had been hard at work since dawn. Since I'm focusing on hawks, I come a little later in the day, because the hawk migration tends to start in the mid morning. But I arrived in time to witness the middle and tail end of what turned out to be a historically huge migration of nighthawks and passerines.
The word "passerine" refers to a bird of the order Passeriformes. Birds in this order are often referred to as "perching birds" or "songbirds." They include finches, robins, chickadees, thrushes, crows, jays, sparrows, warblers, vireos, cardinals, swallows, orioles, and mockingbirds.
Like raptors, many species of passerines migrate. Unlike raptors, they're small and wickedly difficult to identify in flight. When you see a soaring hawk as a black speck against the sky, it's hard to tell what kind it is. Now imagine trying to identify a much smaller black speck, only instead of soaring by above your head, it's zipping past your face, taking only seconds to pass out of sight.
Remarkably, Alex and Karl were able to identify by sight most of the passerines that passed close by, and they identified other, farther birds by their size, flight style, or flock formation. Colorful warblers flashed by, Cedar Waxwings whizzed across the ridge in their tight flocks, and once in a while a woodpecker flew overhead with its uneven, undulating flight. I did my best to be useful, pointing out passerines and doing my best to count the easier birds, like Blue Jays and waxwings, which are relatively easy to identify in flight. Then Alex put me to work counting Common Nighthawks.
This is a Common Nighthawk. (Photo by Eric Heisey, one of my friends from the Cornell YBE. You can see more of Eric's awesome photos here!).
Common Nighthawks are not passerines; they're in the order Caprimulgiformes, and they're pretty funky-looking. They're related to owls, not hawks, despite their name, and they are mostly crepuscular (meaning they're active at dawn and dusk). Nighthawks are very distinctive in flight: they have long, narrow wings, and they sort of flutter, flying around in circles and dodging back and forth. They do this because they are aerial insectivores, which means they eat insects in the air. In fact, a Common Nighthawk needs to eat insects in the air. Its beak is practically useless, and its throat muscles are weak. Instead of picking up bugs and swallowing them, it simply flies around with its mouth open and lets the bugs go down its throat, where they are zapped by its digestive juices.
Until I got to Duluth, I had never seen a Common Nighthawk. That changed abruptly yesterday morning. Nighthawks migrate en masse from their breeding grounds across the United States and Canada to their wintering grounds in South America. When I arrived at Hawk Ridge, hundreds of birds were streaming past on all sides of us. Often, they were far enough away that I could barely pick them out with the naked eye. But when I raised my binoculars... WOW.
The birds wheeled through the air, rising on thermals and forming massive flocks in the sky. This behavior is called "kettling" and it's most obvious in the first photo, where you can see the birds in the center of the flock forming a spiral shape. Broad-winged Hawks are another species that forms "kettles" as massive numbers of birds ride thermals up into the sky, so you'll probably be seeing more kettling hawks on this blog when the Broad-wings start moving through, in mid-September.
Here's a closer view of one of the flocks of nighthawks, where you can see their narrow silhouette and flapping flight:
And here you can see the birds' telltale white wing patches and blunted heads:
Everyone was impressed with the numbers of nighthawks and songbirds that we saw yesterday. All together, the counters tallied over 28,000 Common Nighthawks, the third highest count ever recorded in MN, and over 33,000 warblers. These are near-record numbers. You can read Karl Bardon's detailed summary here, and Alex's morning eBird checklist here. I want to emphasize that my own checklist is greatly reduced in species and numbers; I didn't identify nearly the number of species that Alex and Karl saw, nor was I able to count all the birds. But I'm glad to have made some sort of contribution, however small, to recording this incredible flight. And it sure was amazing to watch!
Stay tuned for more updates! I'll try to fit in some non-bird stuff at some point, too, but the hawks are starting to come in full force, so it might be all I can do to keep up.
Jump to a Post
Welcome to Hawk Ridge
A Massive Migration
A Happy Birdthday
Photos from the Week
Visiting the Banding Station
A Watched Kettle Never Streams
Food, Part 1
The Big Picture
Last Weeks at the Ridge
Belize, Part 1
How to Look at Birds, A Guide (or: Belize, Part 2)
All Creatures Great and Small
Kids and Language, Again
More Photos from France
Food, Part 2
Building Nests in California
Please Do Not Pet the Woodpecker
Condors and Creatures in Big Sur
A Day at Hastings
I am a high school graduate taking a gap year before college. I’m interested in birds, biology, and the natural world, as well as history, foreign languages, writing, and reading.