Becoming Penguins?

     Alcids are a family of seabirds that live and breed in the northern latitudes of the northern hemisphere.  They range in body length of 17 inches to eight inches, depending on the species, and look and act much like penguins, most of which live in the southern hemisphere.  Alcids are largely black on top and white below, as penguins are dark above and white underneath.  Alcids are plump and stand nearly upright when at rest on seaside cliffs.  Their legs are near the rear of their bodies, as are penguins', to give them steering while they swim under water.  Alcids and penguins both "fly" under water with their wings, but alcids can also fly through the air with rapid whirs of wing beats.  Another trait that penguins and alcids share is their spending winter in the open ocean to catch prey animals, the former species in the southern hemisphere and the other in the northern.
     Because they live in similar niches, though in opposing hemispheres, the unrelated alcids and penguins look and behave much alike.  Their environments shaped them, literally, to be what they are.  Alcids and penguins are specialized in the same ways to make their livings, though alcids can still fly through the air, which allows them access high on islands and cliffs to raise babies in relative safely.  Penguins nest on low shores and ice, and developed layers of fat as insulation against the intense cold of Antarctica, therefore they lost the power of flight. 
     There are six kinds of alcids, razorbills, thick-billed murres, thin-billed murres, Atlantic puffins, dovekies and black guillemots, nesting along the Atlantic sea coast of North America, most species in large, crowded colonies on rocky islands and cliff edges along the ocean where native predators are limited.  Today, however, cats, rats, dogs and other introduced animals create havoc among certain colonies of alcids, reducing their populations. 
     Each female alcid of every type, but black guillemots, lays one egg each breeding season: Each guillemot female lays two per season.   The eggs of razorbills, thin-billed murres and thick-billed murres are strongly tapered to keep those eggs from rolling off narrow cliff ledges.  Imagine the number of eggs of these species that fell off cliffs until a genetic quirk caused tapering of egg shapes so they would roll in tight circles and not off rock walls.  Because more chicks from tapered eggs survived to adulthood, all these birds now lay tapered eggs.  that genetic quirk helped the reproductive success of those bird species. 
      Puffins hatch young in underground burrows for the safety of the offspring.  They dig many of those nursery tunnels themselves.
     All species of alcids feed on small fish, crustaceans and molluscs.  They get their food by diving into the ocean from the air and swimming with their wings to snare their prey.  When their beaks are full of victims, they lift from the water and whir back to their breeding colonies to feed their young.           Each alcid species nests in habitats that separates it from its relatives, thus reducing competition for nesting space and food to an extent, though there is overlapping.  Razorbills breed in cavities in boulders in the coastal waters of Greenland, Iceland and in North America south to Maine.  They winter on the Atlantic Ocean south to Long Island. 
     Thick-billed murres breed on cliffs from the Arctic Ocean south to Hudson Bay and the Gulf of St.Lawrence, where they are preyed on by peregrine falcons and gyrfalcons.  This species winters on the ocean.
     Thin-billed murres nest on rocky islands and cliffs in high latitudes around the northern hemisphere.  Winters on the ocean south to the latitude of Maine.
     Atlantic puffins nest exclusively from Greenland south to Maine in North America.  It winters from Massachusets as far north as there is open water on the ocean.
     Dovekies are the smallest alcid species.  This bird breeds north of the Arctic Circle.  It winters in great flocks on the ocean below the pack ice of the polar regions, usually south to the Virginia coastline, or beyond during some winters.  Sometimes they can be spotted on the Atlantic from land on the Lower 48.  
     Black guillemots don't nest in large colonies.  They breed in cracks in cliffs from the Arctic Ocean south to James Bay and Maine.  They winter along leads in the pack ice of the Arctic Ocean and Atlantic and Pacific Oceans.   
     Alcids are a family of birds in northern latitudes that are becoming penguin-like.  It is amazing the number of traits those two unrelated families of birds share, simply by living in similar environments.  Genetic codes and habitats work together to shape the life in each environment to be ever more efficient in getting a living in each habitat. 

Atlantic Mole Crabs

     Except for gulls and little groups of sanderlings, which are a kind of sandpiper, the Atlantic Ocean beaches seem devoid of life.  But there is a species of crab, a kind of crustacean, adapted to living in the forever shifting surf zone where the ocean water constantly slides up sandy beaches and retreats again to the ocean from New York to Mexico-Atlantic mole crabs.  These are the little critters we feel wiggling in the sand with our feet.  These animals don't bite or sting us, but most people don't like the idea of something moving against them unseen and unidentified.  But mole crabs are another example of an animal adapting to a special niche.  Everything about their bodily structure allows them to live in the breaking waves and intertidal part of a sandy, ocean beach.
     If we dug them up, we would notice mole crabs are about an inch and a half long, compactly built, and the color of the sand, which camouflages them.  Their shells, known as exoskeletons, are smooth and tapered at both ends for stream-lining in the sand and water.  Their eight limbs, which are tucked compactly against their bodies, are adapted to swimming, and burrowing into the sand for shelter.    
     Mole crabs get food when wavelets slide up the beaches.  Each crab comes out of the sand, swims backward frantically to another spot and quickly digs tail first and backwards into the sand for protection, leaving two pairs of antennae protruding above the sand.  The first pair of antennae take oxygen from the water.  And the feather-like second pair waves in the water to filter plankton and detritus from it as it  moves back to the ocean.  Those antennae transport that food to the crab's mouth.  All the mole crabs gather food in that way, time after time, most of each day, every day through their life span of two to three years.    
     Mole crabs have natural predators on them, which makes them part of several food chains.  A variety of fish eat some of the swimming mole crabs.  Gulls pull them out of the sand to consume them.  Larger shorebirds, including willets and oyster-catchers also take mole crabs from the sand and ingest them as well. 
     But sanderlings are the kind of sandpiper I like to watch feeding from the beaches as the waves roll in and out.  When a wave comes up a beach, the sanderling group runs ahead of it, their little, black legs twinkling rapidly with the speed of their running.  But the instant the water rolls back down the beach, the sanderlings follow it and snatch invertebrates, including younger mole crabs, from the wet sand before those animals can dig into it.  Except for periods of rest, sanderlings continually feed in that way, all day, every day they are on ocean beaches to get food.
     Female mole crabs carry many, orange eggs under their bodies, but release the young into the water.  Those youngsters travel with the ocean currents, often for long distances, and feed on plankton in the ocean.  After floating in the ocean for about four months, each larva settles on an ocean beach where it matures in the sand under the surf.
     If you're on an ocean beach and feel something wiggling against your feet, don't be alarmed.  It's probably a harmless Atlantic mole crab.  They are interesting to see, and to know of their life history in a niche that is hard to imagine living in.  But they are perfectly adapted in bodily structures and habits for that particular niche.        

Big-Eyed Butterflies

     Every summer, I commonly see a couple of species of skipper butterflies here in Lancaster County, Pennsylvania.  I see brownish silver-spotted skippers among a variety of blossoms in flower gardens, particularly on butterfly bushes and bee balms.  And I notice yellowish least skippers, sometimes in abundance, flitting low among grasses and weeds along rural roadsides.
     Skippers, as a branch of butterflies, are different than other kinds of butterflies.  There are about 3,500 kinds of skippers worldwide, mostly in the tropics, and they all have several characteristics in common, revealing their common ancestry.  Some people think skippers are a cross between butterflies and moths, but skippers are strictly butterflies, with a different set of traits.  All skipper species have stout abdomens, are furry all over and have small wings for their body size.  When these butterflies are at rest, their wings are swept back like jet planes and the fore wings are held up at a 45 degree angle while the rear ones are held flat.  With those wings, skippers have a quick, darting flight from flower to flower, giving this branch of butterflies its common name.  All skippers sip nectar from the blooms they visit. 
     But their large, dark eyes are not only a distinctive trait of this family of butterflies, but their most beautiful and appealing features.  That and their fast flight are their two most unique characteristics.  Skippers have huge eyes for the sizes of their bodies, reminding me of the attractive, dark eyes of a white-tailed deer, flying squirrel or white-footed mouse.
     There are two major branches of skippers.  Species in the one division are basically brown, like silver-spotted skippers in the eastern United States.  Silver-spotted skippers have a two-inch wing span and are brown with pale-orange markings and a large, white blotch on each front wing.  Their larvae are yellowish-green with brown heads and two orange spots on the head.  Those orange spots are fake eyes that serve to intimidate birds and other would-be predators.  Those larvae eat leguminous plants, including soybean leaves.       
     Species of skippers in the other, larger, branch are small and mostly yellowish with brown markings.  The different types of skippers in this division are difficult to identify.  Least skippers, that live in the northeastern United States, have a one inch wing span and live in abundance among grasses and weeds along country roads and in moist meadows in my region.  The caterpillars of least skippers are green, with brownish heads.  They eat grasses and sedges on damp ground.
     Skippers are unique and interesting kinds of butterflies.  They add to the beauty and intrigue of Earth.  Look for them in flower gardens and along farmland roads.         

Subtle Beauties of Hackberry Trees

     There is nothing special about the appearance of hackberry trees.  And they seldom are planted as ornamental on lawns.  But this plain kind of tree has its beauties, in the animals that depend on it for food and shelter. 
     Hackberries range from New England south to Georgia and Texas, but nowhere are they common, living mostly as scattered individuals.  They do, however, prefer moist, rich soil, which my home area, Lancaster County, Pennsylvania, has.  This type of tree is present in Lancaster County, mostly on floodplains along creeks and streams, and in hedgerows between fields.
     The caterpillars of two kinds of butterflies eat the leaves of hackberries.  They include the larvae of hackberry butterflies and the young of common snout butterflies.  Hackberry butterfly larvae are gregarious, feeding together in groups.  They are striped lengthwise with green, brown and white to blend into their surroundings in the trees.  And they have two spiney horns on the rear of their heads to discourage predation from birds and other critters.  Hackberry larvae overwinter in the ground when partly grown and emerge next spring to continue growing, pupate and emerge as adult butterflies ready to consume flower nectar and the juice of rotting fruit, and reproduce.
     Hackberry butterflies are mostly tawny-brown with white spots and black spots on their wings.  Their wing span is a little over two inches.
     The caterpillars of common snout butterflies also consume the foliage of hackberries.  They are green with yellow stripes for camouflage among the tree leaves.  Adult snouts are mostly brown, which camouflages them, and have a two inch wing span.  They are called that peculiar name because each one has two long, labial palps that look like a nose on the front of the head.
     Hackberry trees produce berry-like fruit wrapped in dark skin.  Though small and not attractive, those fruits are ingested by mice, eastern chipmunks and gray squirrels.  Those rodents eat the pulp and the seeds, killing the embryo inside each berry.
     But a variety of birds, including wintering American robins, eastern bluebirds, cedar waxwings, starlings, yellow-rumped warblers and other species, ingest the fruits, digest their pulp, but pass many of the seeds intact across the countryside as they flit from place to place.  Birds don't have teeth to chew the seeds.  Some of those seeds land in good soil and grow into young hackberry trees.  By spreading the intact seeds in their droppings, those birds ensure a future food supply for themselves and other critters.               
     Hackberry trees may not be particularly attractive in themselves, but they sustain the beauties of the creatures that consume their foliage and fruits.  And the birds, in turn, plant future crops of the trees that will eventually produce food for caterpillars, rodents and birds.   

Green Darners

     Green darners are a common species of large dragonflies that live throughout most of North America, and Mexico, Central America and the Caribbean.  We here in the Middle Atlantic States see this kind of three-inch-long dragonfly with a three-inch wing span careening speedily over most every body of still water in the area from mid-April to early in autumn.  During summer, all dragonflies, including this type, catch and feed on a variety of flying insects, including mosquitoes, flies and moths.
     Dragonflies, including darners, are agile, opportunistic predators, well equipped for catching flying insects.  They have two large eyes that encompass most of their heads and give them excellent vision to spot prey.  They have four large, maneuverable wings to track down insects in flight, but are held straight out from the thorax, like a plane's wings, when at rest..  Wings on darners are clear.  And the six legs of all dragonflies, also extending from the thorax, are used to catch prey.
     The heads and thoraxes of male green darners are green, while their long abdomens are pale-blue. The heads and thoraxes of female and young darners are green, but they have green or brown abdomens.  The bodies of all darners are darning needle-like, hence their name.  And all darners have a black spot on the tops of their foreheads, in front of the eyes, which is bordered by thin, blue and yellow lines.  That black dot looks like the pupil of an eye, edged by lids that never close.  Its purpose probably is to intimidate birds and other would-be predators from eating green darners.
     Each male darner patrols a stretch of still water where he chases away other males and pursues females to mate with them.  Female darners spawn eggs in aquatic vegetation under shallow water.  Their mates use pincers at the end of their rears to clasp the females between their heads and thoraxes while they spawn.  The purpose is to keep other males from disturbing the egg laying.  The resulting nymphs are brown, which blends them into their surroundings on the bottom of impoundments.
     Dragonfly nymphs are aggressive carnivores, shooting out their lower jaws that have hooks to snare and eat aquatic insect larvae, tadpoles and small fish.  Most darner larvae overwinter as such and emerge from water the next spring as young adults ready to fly, catch insects and reproduce.           In September, many green darners migrate south to the southern United States, Mexico, Central America and the islands of the Caribbean to escape the northern winter.  Thousands of them may go south in great swarms, feeding on flying insects along the way and competing with migrating swifts and swallows doing the same thing.  It is felt by many scientists that those darners breed in their wintering grounds when they arrive, their larvae overwinter there, but come north during the next spring to spawn in northern waters.
     Watch for the interesting dragonflies, including green darners, this summer and fall.  They are all interesting and entertaining speeding over water and fields after insect prey and spawning in pairs in shallow water near the shoreline.   

Flowers in Moist Meadows

     Four kinds of abundant, native, flowering plants bloom in many moist, sunny meadows in Lancaster County, Pennsylvania, as elsewhere in eastern North America, during the latter part of summer.  They are all noticeable to even casual observers of nature because they are tall with showy blossoms at the tops of their flower stems.  And bees, butterflies and other kinds of insects visiting them to sip nectar, pollinating them in the process, add to the beauties of these plants.  The four are swamp milkweeds, blue vervains, ironweeds and Joe-pye weeds in that arbitrary order of blooming.
     Swamp milkweeds, like all their family, have flowers that appear waxy and sculptured.  Those blooms, in upright clusters, are also pink and sweet smelling.  Standing up to three feet tall, swamp milkweeds bloom from June to August.  Female monarch butterflies lay eggs on their leaves because milkweed is the only vegetation monarch larvae will consume before pupating to become adult butterflies.
     Blue vervain plants are about five feet high and slender.  They have groups of tiny, blue-violet blossoms that bloom a few at a time from July through September on each flower stem.  Four or five flower stems together are shaped like a candleabra.    
     Ironweeds are up to five feet tall and called that because they have hard stems.  This species has several deep, purple-pink blooms per plant during late July into October.
     Joe-pye weeds are the tallest, most stately of this grouping of wild plants in damp, sunny pastures.  Each plant can stand up to seven feet high, or more, and has a few large clusters of small, dusty-pink flowers on top of each flower stem from late July into September.  The larger butterflies, including the various kinds of local swallowtails, and monarchs, like to sip nectar from this species' blossoms.
     When in farmland late in summer, check out the sunny meadows for these kinds of flowering plants.  Their blooms and the insects that visit them add much beauty and interest to those pastures.       

Post-Breeding Egrets and Herons

     Today, July 25, 2015, I went to Middle Creek Wildlife Management Area to experience whatever wildlife was noticable.  Among other bird species, I saw a few each of great egrets and great blue herons fishing from various impoundments during the hour and a half I was there.  And, more importantly, they reminded me that many post-breeding great egrets and great blue herons are in the Middle Atlantic States from late July into September, and later at times, to hunt fish, frogs, tadpoles and other aquatic prey.  Some great blues over-winter here as well, as long as there is open water to fish from. 
     Great egrets raise young in scattered colonies along the Atlantic Coast from Delaware south, the Gulf Coast and inland up the Mississippi River watershed in the United States.  They winter along the Gulf Coast, in Mexico, Central America, South America, and the islands of the Caribbean Sea.  Great blue herons have breeding colonies throughout much of the United States and winter in much of the United States, Mexico and Central America.
     When finished rearing offspring, great egrets and great blue herons scatter across the country to find good fishing areas.  Then we see many of both species here in the Mid-Atlantic States.  We see scores of them along the Susquehanna River, especially on the Conejohela Flats offshore from Washington Boro, scores along the Delaware River, many at Middle Creek Area's lake and many others at creeks and impoundments throughout this area.             
     Because they are large, the stately great egrets and great blue herons are often readily seen by even casual observers of nature.  With their long legs to wade in shallow water to catch prey and their lengthy necks and beaks, the white egrets stand almost four feet tall and the light-gray great blues are over four feet.  And they appear huge when in flight.  To me, great blues fly and soar majestically and the flight of the smaller, slimmer egrets is elegant.
      The magnificent egrets and herons stalk aquatic prey by wading slowly and carefully through shallow water on their long legs and watching the water intently for unwary or handicapped fish that are easy to catch.  Egrets and herons also have lengthy toes that work like snowshoes so they don't sink and get stuck in mud under the water.
     When a victim is spotted, each of these long-necked birds swings out its lengthy beak to catch it, often with success.  Where the fishing is good, these members of the heron family will stay for days, even weeks.  And both these species are territorial, chasing others of their own kinds away from fishing territories with swift, direct flight and raucous calls, all of which mean business. 
     Interestingly, these big members of the heron family also catch meadow voles where they can.  Voles are a larger kind of mice that live in pastures, fields and roadsides in agricultural areas.  Some of the great egrets and great blue herons leave meadow streams and stalk mice among the grass.  When they snare voles, the egrets and herons quickly kill those furry victims so they can't escape, then dunk them several times in a nearby body of water to slick their fur so they can swallow them whole and head-first more easily.
     There was a time, over a hundred years ago, when great egrets were intensely hunted and killed for their elegant breeding plumes that grow from their backs.  As one might guess, they were killed during the breeding season, which wiped out many adults and young birds every year.  In the early 1900's, the National Audubon Society was born to protect great egrets and other kinds of birds and other wildlife as well.  Today great egrets are fairly common again because of that protection. 
     Watch for great egrets and great blue herons fishing around waterways and impoundments during late July, August and September each year.  They are beautiful, stately birds that are intriguing to watch stalking aquatic prey or mice.