Monday, November 9, 2015

Adaptable Birds in a Winter Meadow

     Today as I drove within a few yards of Mill Creek in farmland about a mile south of New Holland, Pennsylvania, a great blue heron floated down to the creek right beside me.  Because great blues stand almost five feet tall with over five foot wing spans, that close-up heron startled me as it landed in the creek to catch minnows and other fish.  I stopped along Mill Creek several yards downstream from the heron for an hour and a half to experience what wildlife was abroad and visible.
     I watched Mill Creek and its narrow strip of riparian trees in a cow pasture from inside my car so as to not put neighboring birds to flight.  And, as it turned out, I saw several kinds of birds in spite of the minimal cover in that short-grass meadow and all the human activities and structures near the creek and its bordering meadow.  Some of the adaptable birds were there because of the creek, while other species were present because of the trees and a few thickets of bushes and vines.
     I saw two majestic great blue herons stalking minnows in different sections of the creek.  Herons establish hunting territories, driving away others of their kind if those others infringe on their "properties".  But these herons were at peace.  They probably already settled border disputes.
     A few mallard ducks and a handsome belted kingfisher were also along that stretch of Mill Creek while I was there.  The mallards mostly rested in inches-deep water while the kingfisher perched on a limb hanging over the water to watch for small fish.  But after a few minutes the kingfisher moved on.  When prey is spotted, kingfishers drop into the water beak-first to catch the fish in their bills.
     A winter wren and a song sparrow stalked invertebrates on the few small gravel bars on the edges of the creek.  Both were brown and hard to see, until they moved.  The wren was comical to see because of its tiny size, short tail sticking straight up and quick movements.
     The winter wren lived farther north in summer, but was along Mill Creek for the winter.  The song sparrow was a permanent resident along this waterway.  Both species will stay along the water and in the thickets bordering it through the coming winter.
     A permanent resident Carolina wren and a few each of wintering dark-eyed juncos and white-throated sparrows stayed in the sheltering thickets as I watched them.  All these birds were well camouflaged and, again, hard to see, until they moved.  The juncos and sparrows lived farther north in summer, but are here for the winter.  The wren will consume invertebrates it will find in the soil under logs, dead leaves and other natural litter on the ground.  The juncos and sparrows, however, will ingest weed and grass seeds they will find in the meadow and along the waterway.
     But it was the clumps of ash-leafed maple and black walnut trees that harbored the most birds while I was there.  A half-dozen mourning doves and a stately red-tailed hawk perched on the tops of some of the trees, the doves simply to rest, but the hawk to watch for vulnerable gray squirrels and mice.
     And I saw a few Carolina chickadees, a couple of white-breasted nuthatches, a red-bellied woodpecker, a downy woodpecker and a yellow-bellied sapsucker, which is a type of woodpecker from farther north, among the tall trees.  All those birds were actively looking for invertebrates, each species in its own way, among the trees.  The chicks gathered insects and their eggs from twigs and buds, while the nuthatches looked for the same food in crevices in the bark.  Sometimes the nuthatches were up-side-down on tree trunks in their search for food.  And the woodpeckers, being woodpeckers, chipped their invertebrate food out of dead wood among the living trees.
     I was impressed with how many bird species I saw late in the morning in November in a pasture of minimal shelter in cropland with all its activities.  Obviously, these are adaptable species able to make do in less than ideal habitats, which increases each species' chance of survival as a species.  One of the keys to success is being adaptable.                       

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