Sunday, July 22, 2018

What Lives On Assateague Island? - Other Critters

Besides the mammals and the huge variety of birds to be seen on Assateague Island, the ground and waters are teeming with other types of life, too.  I'm not even going to try to get into the insect realm deeply - let's just say there are probably thousands of kinds of insects that live in, around, and on the island, as well as the butterflies, who use it as a migratory stopping place - most specifically, the Monarch.  There are ants, beetles, ticks, flies, spiders, wasps, bees, gnats and mosquitoes galore.  Besides the trees, grasses, and shrubbery, there are flowers in multitudes.
  Other inhabitants of the island are less conspicuous than the large mammals and sudden flights of flocking birds.  Seven species of frogs and toads depend on fresh water ponds in the center of Assateague for breeding, and a variety of six snakes, none of them poisonous, are native inhabitants. The black rat snake can be found across the forests, dunes, and marshes preying on rodents, small birds, or toads.  The eastern hognose snake - which is often mistaken for the copperhead - prefers beaches, dunes, and grassy areas; while the northern water snake prefers salt marshes and freshwater or brackish ponds.
  Several factors are thought to account for the discrepancy in the species present on the island (6) and those on the mainland (19).  Geographic isolation and the difficulty posed for most reptiles in crossing the salt waters of the bay are some obvious causes.  It is suspected that humans have also played a role by intentionally introducing some species to the island (as in the Sika deer).  Harsh conditions, as well as limited range size and habitat types, may also restrict the species that can successfully survive on Assateague.
   Several species of reptiles possess morphological adaptations necessary to survive the varying and sometimes harsh conditions of barrier island life.  Many of these animals, for instance, have tough skins that exclude salt and retain moisture.  Still others exhibit behavioral adaptations that limit their exposure to severe temperature or salinity.  The eastern box turtle, one of the island's terrestrial reptiles, has the ability to retreat completely within its shell and will burrow under vegetation to escape extreme weather.
   Assateague also hosts five species of aquatic freshwater turtles and three species of sea turtles, including the Maryland State Reptile, the Northern Diamondback Terrapin.  One of the island's most charismatic species, Diamondbacks are unusual in that they are one of the few species of turtle that prefer estuarine habitats.  They reside in all of the waters surrounding the island, but are most common in the salt marshes that border the bay.  These turtles are a common sight to visitors paddling through these areas during the warmer summer months.  Snapping turtles also abound - a very large fellow was mistaken for an alligator in Eel Creek on Chincoteague a month ago.  One frequently sees turtles sunning on downed tree branches or trunks  that arise from drains, channels and marshes on Assateague - these include the Eastern mud turtle, the Eastern painted turtle, and the red-bellied turtle.  Atlantic loggerhead sea turtles are again laying eggs on Assateague beaches, as are leatherback sea turtles.
   Fowler's toads make a home on Assateague, as do the upland chorus frog, American bullfrog, the gray and green tree frogs, and the Southern leopard frog.  The red-back salamander is also a native inhabitant.   Though not common, lizards can occasionally be seen on Assateague Island.  Northern fence lizards live in forested and shrub thickets on the island.  They feed on small terrestrial invertebrates, ares are usually seen sunning themselves on rocks, tree stumps, and other exposed areas within reach of a close hiding spot.
   Numerous invertebrates, such as fiddler crabs and mud snails play key roles in maintaining the health of the island's salt marshes.  Even the seemingly barren beaches provide habitat for nocturnal ghost crabs.
   Finally, the coastal waters that surround Assategaue Island teem with life.  The sheltered, nutrient rich waters of the estuary formed by the island provide ideal breeding and spawning habitats for many aquatic species.  Many of these water-dwelling creatures are commercially important to the local area - the blue crab, three types of clams,  oysters, mussels and scallops.  Shrimping is done off-shore. And four types of eel can be found in the waters, marshes and ponds of the island.
   Each spring a variety of fish, including spot, Atlantic menhadin, and summer flounder migrate into the area to breed.  Later, the juvenile fish provide an abundant food source for birds, marine mammals, and larger fish.  One hundred and sixteen ray-finned types of fish have been identified in island waters.  (A few days ago a tourist caught an oyster toadfish from a local dock and wanted to know if it was edible.)  One can surf fish at specified areas on Assateague; or bring or rent a boat for your use.  Charter fishing trips are available.  Flounder, croaker, drum, sea bass, and striped bass can be caught in the channels and bays.  Mahi-mahi, cobia, tuna and sharks are found off shore.  There are many types of jellyfish in the area, as well as sharks and rays.  The most common sharks are makos, tigers, hammer-heads, sand, and dusky.
   Occasionally one of three tagged Great White sharks are in the area - Mary Ann is, at last sighting 16 feet long and weighs about 3,500 pounds; the two smaller ones are Yeti and Hilton.  They have transponders and are tracked - social media and/or the news will let you know if they are near.
   If you're interested in the wide variety of life in, around, and on Assateague Island (including lichens), I suggest you visit the 26 pages of the Species Check-List for Assateague Island  at:
https://www.inaturalist.org/check_lists/372430-Species-Check-List-for-Assateague-Island-National-Seashore?page=1

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