TWO GULLS AND A TERN

     Via a live camera and our computer screen, I saw flocks of post-breeding ring-billed gulls, Franklin's gulls and Caspian terns resting together, in early autumn of 2021, on mud flats and in inch-deep water on Lake Onalaska, a large, shallow back-water off the Mississippi River in northern Wisconsin.  These attractive birds are noted for regularly flocking together because they share inland, large-water habitats for nesting and wintering, and scavenge and catch fish and other aquatic creatures.  But each species also has lifestyles of its own, which sets it apart.       

     All these handsome, easily-seen species are graceful, buoyant fliers, quite adaptable and common across much of North America.  They are interesting to watch going about their daily activities, including nesting, getting food and loafing in big gatherings on rivers and larger lakes.

     Ring-billed gulls, so-named for a black ring on each beak, scavenge dead fish and other critters along shores and in fields.  They also catch small, live fish swimming near the water's surface. 

     These familiar gulls often follow plows and drop into furrows to ingest worms and other invertebrates that are turned up.  They mass on landfills by the many thousands to consume edible garbage.  And like most species of gulls, ring-bills also eat the eggs and young of terns and other types of  water-loving birds, and feed those items to their young.   

     Ring-bills nest along lakes and rivers across Canada and Alaska and down to the Great Lakes area.  And they winter from the northeastern United States, down to Cuba and southern Mexico.

     Franklin's gulls are pretty, black-headed gulls when nesting in summer.  They look much like their close relatives, the laughing gulls.  And like laughing gulls, Franklin's gulls lose much of the black feathers on their heads by fall.

     Franklin's gulls nest in colonies around lakes on the American prairies.  There they eat lots of small fish and insects, including egg-bearing grasshoppers.  By using different habitats, related species of life spread themselves out to take advantage of different food and shelter sources, thereby creating the differents pecies.  

     Franklin's gulls winter along sea coasts south of the United States. 

     Caspian terns are the largest terns in North America.  In summer and autumn they have red bills and black caps on their crowns, making them attractive.  These striking terns are the size of ring-billed gulls and often soar on high like them.  This type of tern utters deep, hoarse croaks that give away their presence before they are spotted.    

     But being terns, Caspians plunge, as do their kin, into water to snare live, smaller fish.  All terns are entertaining to watch diving gracefully, beak-first, into water to catch fish.

     Unlike most kinds of terns, Caspian terns also scavenge dead aquatic creatures, and eat the eggs of smaller, water birds.  

     Many pairs of Caspian terns raise young in colonies of their own, as do ring-billed and Franklin's gulls.  And some Caspians rear offspring in gatherings of other kinds of gulls and terns, perhaps because of limited suitable nesting space along lake and river shorelines.  

     Caspian terns are cosmopolitan nesters.  They breed across Eurasia, Africa, Australia and North America.  And they winter where water remains ice-free so they can catch fish.

     After nesting, these kinds of water-loving birds flock together around inland lakes and rivers where they can alternately rest on mud flats and catch fish.  Their flocks are interesting to see in those habitats until they migrate farther south for the winter.