Smith: Nighthawk migration inspires wonder and awe

WAUWATOSA – The mercury hit the low 90s Tuesday and extreme heat advisories were issued in southeastern Wisconsin.

Sweltery summer weather to be sure.

But Tuesday evening one of the leading indicators of autumn had my full attention.

Flying just overhead with its distinctive swift, sashaying motion and white wing patches was a common nighthawk .

I saw it at 6:30 p.m. in the Menomonee River Parkway, a section of the Milwaukee County Parks system in Wauwatosa.

The bird traveled down the green corridor in the state's most heavily developed region like Hall of Fame hockey player Wayne Gretzky skating through a hapless defense.

Banking right, then left, the nighthawk navigated the airspace with an effortless grace.

The oppressive heat melted away and suddenly all I could think about was fall.

You likely have your favorite birds of the fall migration. Perhaps a shorebird such as a plover or sandpiper – some of which begin moving south as early as July – or one of the many warblers or other songbirds.

Since I was old enough to look skyward, nighthawks have been my favorite sign of the fall migration.

In my youth we would often seen flocks of many hundreds traveling through Racine County on late summer evenings.

Along with back to school sales and Green Bay Packers exhibition games, the nighthawks carried the unmistakable message of seasonal change.

The birds inspire awe in every way. They are able to feed on insects (their primary food source) as they fly, usually in low light conditions, according to the Cornell Lab of Ornithology.

"The common nighthawk hunts on the wing at dawn and dusk, opening its tiny beak to reveal a cavernous mouth well suited for snapping up flying insects," Cornell writes in its profile of the species. "Though they forage in low light, they seem to locate prey by sight, possibly with the help of a structure in their eyes that reflects light back to the retina to improve their night vision."

To aid in their feeding on the wing, nighthawks have modified feathers around the base of their beak to help funnel insects into their mouth.

The birds commonly prey on flying ants, midges and moths.

Migrating nighthawks observed in Wisconsin and Minnesota this week

The nighthawks we see are in the midst of a several thousand mile long migration. Most will travel to Central or South America for the winter, some as far as Argentina.

I get a lift each year when I see them again. After the first nighthawk passed, I saw two, then 10, then about 75 in the next 30 minutes.

I wasn't the only one to see them in recent days.

The Hawk Ridge Bird Observatory in Duluth, Minnesota, tallied about 12,000 nighthawks between 6 a.m. and 4 p.m. Monday. Then in the evening it got even better.

"Shortly after 5 p.m., the floodgates opened and did not stop until sunset," Hawk Ridge reported on its website. "A steady flow of birds began overhead that grew and grew, and suddenly hundreds of nighthawk were passing every second. There were easily thousands of birds in view at any given moment!"

Steve Kolbe, a birder also on the Lake Superior shore, reported 35,000 nighthawks on Monday.

On Tuesday evening in southeastern Wisconsin, Spence Stehno reported seeing hundreds of nighthawks at Mitchell Park in Brookfield. Stehno is a member of the Benjamin F. Goss Bird Club in Waukesha.

Bill Volkert, retired Department of Natural Resources naturalist, said his best day was Saturday when he saw 23 nighthawks in about 10 minutes at his home in Dundee.

Nighthawk population in decline since 1960s

Volkert lamented that fewer nighthawks nest in southern Wisconsin than in the past. It's part of a distressing, large-scale problem for the species and other birds.

The U.S. population of nighthawks has declined by about 2% per year between 1966 and 2014, amounting to a cumulative decline of 61%, according to the North American Breeding Bird Survey.

Canadian populations experienced declines of more than 4%, and recent data suggest the species’ numbers may have dropped more than half in Canada since the mid-1960s.

The 2014 State of the Birds Report lists the nighthawk as a "common bird in steep decline." A leading hypothesis for the change in nighthawks is a decline in the insect population.

Such data should lead all of us who value birds and other wildlife to take action.

And if you need more, step outside in late August, look skyward and take courage from the birds flying overhead.

Just think of it: the young-of-the-year nighthawks have never migrated in their lives. They are on a dine-while-they-fly trip to a destination thousands of miles away they know nothing about.

And the adults are survivors of at least one arduous round trip.

"These unprecedented numbers are breathtaking and grounding," Hawk Ridge officials wrote after the nighthawk observations earlier this week. "We are lucky to live in a world where these migratory spectacles occur right overhead, in our own backyards."

The fall migration is on. Get out and take inspiration from the winged messengers of the season.

Bird populations course

William Mueller, director emeritus of the Lake Michigan Bird Observatory, will lead a course this fall in Saukville titled " Understanding Bird Populations and How They Change ."

Over the last 50 years, approximately 3 billion birds have been lost from the U.S. and Canada, across every ecosystem, and including some of the most abundant and familiar bird species, according to a 2019 study published in Science. This course will examine how scientists determine the abundance and distribution of different bird species, for both bird populations in Wisconsin and at the national and international level. State and federal monitoring programs will also be discussed. The course will also consider how bird populations have changed, what species are currently “at-risk” and why, and how monitoring programs can be used in management and conservation. It will also review the many organizations that work on studying bird populations.

The course will be held at the UWM Saukville Field Station from 6 to 7:30 p.m. on Sept. 12, 19 and 26 and Oct. 3 and 10. It's cost is $90. A continuing education credit is available.

Visit uwm.edu/field-station/ or contact sceinfo@uwm.edu to register.

This article originally appeared on Milwaukee Journal Sentinel: Smith: Nighthawk migration inspires wonder and awe