The Next Tern in the Fall Lineup

Fall migration is starting to really ramp up in the Indiana Dunes area.  We’ve been watching shorebirds for several weeks, but there’s been little else as of yet.  Many birds start moving in August, but often go unnoticed as most visitors are still in summer mode and don’t think of fall until Labor Day has passed.  Long before the last lifeguards have hung up their preservers for the season, birds are dodging bikinis and loose dogs.

To set the stage for the next couple months, shorebirds will continue through August and into September.  By early September, the beautiful warblers, vireos, and tanagers will begin their migration, peaking in mid-September.  The vexing sparrows will follow in October, while many birders will be setting up on the lake at the same time to capture a glimpse of migrating ducks, jaegers, and other waterbirds.  Hopefully winter finches will be appearing, only to peak in great numbers by November.  The birding will continue strong with the chance of rarities through November.  All in all, fall is a great birding season in NW Indiana.

Aside from shorebirds, the observant eye can notice another spectacular lakefront migration right now, the tern migration!  Three major tern species can be seen staging a large migration along the lake’s southern shore.  The first to peak in late August are the easily identifiable and impressive Black Tern flocks.   Flocks of a hundred of these giant dark butterfly birds can be seen skimming above the waves in search of some migration morsel in the water.  Their migration season is quick, so you need to be out on the beach now to get a chance to see them.

Migrating Black Tern in the dunes area.  Photo by John Cassady.
Migrating Black Tern in the dunes area. Photo by John Cassady.

By Labor Day, our other two terns, affectionately called the Sterna terns (due to their shared genus name), begin peaking in their migration.  First the Forster’s Terns, then the Common Terns.  Often unidentifiable far off shore, beach sitting and nearshore birds can be easily identified based on a few characteristics.  Once molted, the Forster’s signature earpatch is useful, whereas the dark wing mark (called the carpal bar) on the Common Terns are just two features to look for in migrating Sterna.  Of course this overly simplifies things, and doesn’t take into account rarer terns, such as the Arctic Tern.

Flock of Common Terns on the Beach.   Photo by Pete Grube.
Flock of Common Terns on the Beach. Photo by Pete Grube.
Molted Forster's Tern migrating along Lake Michigan.  Photo by Pete Grube.
Molted Forster’s Tern migrating along Lake Michigan. Photo by Pete Grube.

With Labor Day just over a week away, expect to see more birds and more birding opportunities in the dunes.  The first great chance will occur the Sunday of Labor Day weekend, September 1, when the state park offers a entire afternoon of bird banding at the park nature center.  It will be a chance for visitors to see both common feeder birds and some newly arrived migrants up close and in the hand.  Come for an hour or stay for the entire banding afternoon.

Also worth mentioning is the Dunes Big Sit.  For those not familiar with Big Sits, they are sedentary birding events, where all birds are counted within a close proximity circle.  No scouring the miles of shoreline in search of birds.  A few Big Sits have been done at the old green tower site in the past, but this year’s should be spectacular, as it will be the public’s first birding opportunity from atop the new Bird Observation Platform.  Join local birders for a full day of birding on Saturday, September 21 from atop the tower.  We’re aiming for 100 species of birds!

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