WINTERING LOONS AND GREBES

          Duck-like loons and grebes, though distinct families of birds, have several characteristics in common because they are adapted to the same habitats- ponds, lakes and larger waterways.  Those watery environments forced loons and grebes to have similar physical features so individuals of both families can make efficient use of their shared habitats to catch fish, crayfish, tadpoles, insect larvae and other aquatic creatures, though I think there is some competition between these families of birds for that food.  

     Loons' and grebes' duck-like bodies allow them to float and swim easily.  Loons and grebes both have legs far back on their bodies for more powerful paddling and diving in the water.  But individuals of both families can barely walk on land because of the placement of their legs.  In fact, they hardly ever walk at all.  They have put so much emphasis on swimming and diving that they are practically helpless on land.  Loons have webbed feet for more powerful paddling, and grebes have lobed toes for the same reason.  In flight, individuals of both families have a hunch-backed appearance, with stretched-out heads and legs of all species held lower than their backs.  All loons and grebes have dagger-like beaks they use to seize prey under water.  And both genders of all species of loons and grebes are similar in appearance, allowing both parents of each pair of loons and grebes to care for the young.   

     At times over the years, mostly during milder times of winter, and in spring and fall, I've been thrilled to see common loons, red-throated loons, pied-billed grebes, horned grebes and red-necked grebes floating on larger waterways and impoundments here in southeastern Pennsylvania.  I've never spotted them in big numbers here, and usually notice them on the Susquehanna River, Delaware River, the lower Conestoga River, and larger, human-made impoundments, all bodies of water where they dive under water to catch fish and other aquatic prey. 

     Sometimes during April, while I am watching for north-bound hawks and other kinds of migrating birds, I see individuals and small groups of common loons winging high and north to ponds and lakes, including ponds created by beavers' dams, to rear offspring.  Those migrating loons resemble flying crosses.       

     Loons and grebes, as bird families, hatch young in unique niches; on the very edges of impoundments in the northern parts of the northern hemisphere, and other parts of the globe, depending on the species.  Loons either place their cradles of aquatic plants on soil right at the water's edge or create piles of water vegetation floating among and anchored to emergent reeds in shallow water near shore.  

     Grebes' nurseries are floating masses of plants on submerged beds of vegetation in shallow water, again near the water's edge.  

     But, in spite of the parent loons' and grebes' efforts to protect eggs and youngsters from predation, raccoons, opossums and crows eat some of their eggs.  And snapping turtles, mink, great blue herons and other predators catch and consume some of the youngsters.  

     Loons and grebes are unique, water-living birds.  They inhabit niches no other kinds of birds do.  Those families of birds are similar in forms and lifestyles because they share habitats that mold them into what they are, as do all other habitats.  Every living species on Earth is "shaped" by its home, making it more efficient living in it.       

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