FALL BIRDS ON THE MISSISSIPPI FLYWAY

      By the beginning of August, flocks of still-summering, and migrating, water-loving birds congregate in mixed flocks on the many broad mud flats, and shallow channels between those flats, on Lake Onalaska, a large backwater off the Mississippi River in Wisconsin.  At times, some flats and shallows are covered with at least six to eight kinds of birds at once, an exciting, beautiful sight to see.  And I see the birds of the Mississippi Flyway by gaining access to their live camera on my computer screen.    

     Some of the larger, higher flats are covered with tall, lush vegetation from wild rice to deciduous trees, which offer food and cover to wildlife.  And the hills bordering the Mississippi and Lake Onalaska are covered with deciduous woods, providing a natural background to this watery wildlife sanctuary.  

     Autumn birds on Lake Onalaska's flats and shallows could be divided into three groups- fish-eaters, invertebrate consumers and vegetarians.  Fish-eaters include resident bald eagles, and flocks of summering American white pelicans, migrant double-crested cormorants, post-breeding and north-drifting great blue herons and great egrets, post-breeding ring-billed gulls and Franklin's gulls, and Caspian terns.  

     Each of the above-mentioned fish-catchers snares fish in a unique way, reducing competition with other fish-catchers for their scaley prey.  Soaring bald eagles swoop to the water to catch larger fish in their sharp talons without touching the water.  White pelicans work together as a group floating on the water to scoop fish from shallows with large, pouched bills.  Cormorants dive under water from the surface to catch fish in their beaks.  Herons and egrets wade the shallows on long legs and reach out their lengthy necks and bills to snare their finny victims.  Gulls catch small fish with their beaks from the water's surface, and scavenge dead ones.  And Caspian terns dive bill-first from the air and plunge into the water to seize small fish in their beaks.    

     Occasionally in August and September, I was excited to see flocks of pelicans, cormorants and gulls feeding together on little fish in the shallows.  All species caught fish in the same place at the same time, but each kind did so in its own way.  

     Invertebrate-eating birds on those same flats and shallows include flocks each of post-breeding tree swallows, shorebirds, sand-hill cranes and red-winged blackbirds.  Regularly, thousands of tree swallows swept through the air, back and forth among their fellows, without collision with them, to snap up flying insects in their broad mouths.  

     Those swallows, themselves, were entertaining to watch, but when southbound shorebirds that nested on the Arctic tundra, and their young, peppered the flats and shallows to eat invertebrates, the entertainment was doubled.  It was enjoyable and exciting to see many swallows and camouflaged shorebirds, including least sandpipers, semi-palmated sandpipers, short-billed dowitchers, golden plovers, black-bellied plovers and other types of shorebirds, feeding together on the flats and shallows, and in the air above them, in the case of the swallows. 

     The long-legged and long-necked sandhill cranes wade the shallows and walk the flats to seize and ingest a variety of invertebrates, small fish, grain and other foods.  Some of those majestic cranes raised young on Onalaska's islands, but others migrate in when done rearing offspring farther north.  It's exciting to hear their musical trills wherever those cranes may be.

     Many post-breeding red-winged blackbirds that nested in stands of cattails and tall grasses at Lake Onalaska, now feed on a variety of invertebrates, and kernels of wild rice.  Both male and female re-wings, and their young are handsome among tall vegetation as they get their food.

     Vegetarian birds include Canada geese and mallard ducks, both of which nested on Lake Onalaska, and flocks of migrating blue-winged teal, northern pintails, American wigeons, wood ducks and other types of ducks, and American coots.  The geese mainly consume land-based vegetation while the ducks and coots feed mostly on aquatic plants, including algae, duckweed and wild rice seeds, in the shallows.  Sometimes, the flats and shallows are filled with ducks of various kinds at once, making those niches more exciting to watch.

     Each evening in August and September, the flats and shallows fill with many birds of several kinds, including white pelicans, double-crested cormorants, ring-billed gulls, Canada geese, a variety of ducks, sand hill cranes and great egrets, all of which spend each night on those exposed niches.  At night, by camera, I can see the eyeshine of the birds with their eyes open.  

     All the above-mentioned birds are there because their needs for food and refuge are met in niches they are adapted to.  Many of those birds will remain there until winter pushes them farther south to wait for spring.