Posts Tagged ‘frogs’

Throwback: Stuffed

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Monday, December 10th, 2012

Common Gartersnake eating a Green Frog

Having just returned from a Thanksgiving vacation in Massachusetts, I had hoped to write about something uniquely New Englandy. To me the greater Boston area is all about clams, lobsters, shorebirds and cranberry bogs. Granted it’s a narrow, stereotypical view but if I could expand my limited expectations then my trip would be a success.

Unfortunately I only spotted a few dumpster gulls and a couple of Deer Ticks (Ixodes scapularis). I probably should have gotten out more. But you know how Thanksgiving is. It’s all about the thanking and the eating and despite picking up a cold on the plane ride up (thanks open air sneezer in seat 24A!) I still managed to eat more than any normal person should at any given meal. It’s a funny thing, I don’t need to eat so much. I just want to and this makes me wonder how much joy a snake gets when it consumes a feast much larger than it appears it should.

A few years ago I was leading a summer camp in Vermont. A couple of kids heard a strange noise in the woods, called me over and we discovered a Common Gartersnake (Thamnophis sirtalis) eating a Green Frog (Lithobates clamitans). Several kids were horrified but for the most part there was great interest in the likelihood that this slender snake could eat this wide-bodied and seemingly unflappable frog. The snake meticulously maneuvered its ever widening mouth to position the frog into an easy transition down its throat.

Once in the intestine, the gartersnake has the ability to elevate its metabolic rate, increase enzyme activity and blood flow to the digestive system and increase the mass of the intestine, liver and kidney to aid in removing and storing nutrients from its prey. It can just as quickly reverse all of these functions and revert to normal conditions. Ultimately the quick digestive process prevents a snake from slithering about with a large meal in its belly.

No such luck for me on Thanksgiving. My digestive system is used to a pattern of thrice-a-day feedings and I had clearly overwhelmed my system. Happy Belated Thanksgiving.

Tree Frog in the Bathroom

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Tuesday, November 27th, 2012
Cope's Gray Treefrog and Common Gray Treefrog

Cope’s Gray Treefrog and Common Gray Treefrog © David Liebman

Tree Frog in the Bathroom by Julie Craves

The first amphibian we found at our new property was a gray treefrog. We have a wooded wetland, but we found the frog on the floor of an interior, windowless bathroom on our second walk-through prior to buying the house. Presumably it gained entry through the exhaust fan. I suppose this would have been a turn-off to some prospective buyers, who might wonder what else could make its way into the crapper from outdoors, but it charmed us. My husband scooped up the little hopper and placed it outside where it belonged.

We’ve since seen and heard many of this frog’s kin and neighbors. In the eastern U.S., Hyla versicolor and Hyla chrysoscelis are the two sister species of gray treefrog, Eastern and Cope’s. The former has a slower call than the latter, which is the best way to tell these two apart, unless you have your heart set on counting chromosomes.

Cope's Gray Treefrog and Common Gray Treefrog

Cope’s Gray Treefrog and Common Gray Treefrog © Bill Beatty

My ear has not yet heard enough of both species to be able to distinguish the pace of the bird-like trills. Some studies have suggested that Cope’s Gray Treefrogs can tolerate (or prefer) lower humidity, more often call from trees, and consequently eat more arboreal insects, while Eastern Gray Treefrogs like it more humid, tend to call closer to the ground, and eat more terrestrial insects. Even at the end of a dry, hot summer, treefrogs were pretty ubiquitous high and low around the property. Perhaps we have both species, although confirmation will prove difficult.

But no matter. These are my favorite frogs, so beautiful in mottled, slightly warty patterns of green, gray, and brown. They are especially hard to spot when perched on tree bark, but stick out like a sore thumb when adhered by sticky toe pads to porch lights, window screens, sliding glass doors…or bathroom floors.

American Bullfrog – The Lopsided Leaper

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Wednesday, August 1st, 2012

American Bullfrog – The Lopsided Leaper by Lisa Densmore

Location: Chateaugay Lake, Adirondack Park, NY

I was sitting in the living from of my house on Lower Chateaugay Lake, enjoying my second cup of coffee when my 15-year-old son screamed from the beach, “Mom, get out here! You gotta see this frog. It’s huge! Bring your camera!”

I thought he was being a wise-guy. Expecting to see one of the Spring Peepers that occasionally hop along our modest strip of sand, I picked up a camera, briefly debated whether to put a macro lens on it, then walked down the grass to the beach. However, Parker was not being facetious. An American Bullfrog squatted by his feet, pretending to be a rock with long toes. It was an exceptionally dark one and male, which I could tell from its yellow chin and the fact that its tympanun (ear drum) was larger than its eye. It was about 5 inches long, large by frog standards but average for a bullfrog which can get at big as 8 inches long. (The females typically grow larger than the males.)

American Bullfrog

American Bullfrog © Lisa Densmore

Bullfrogs are the largest frog in North America and one of six frog species in New York’s Adirondack Park, which also includes the Northern Green Frog, Pickerel Frog, Northern Leopard Frog, Wood Frog and Mink Frog. They reside near permanent, slow moving bodies of water and wetlands and are voracious hunters, willing to eat anything that will fit in their sizeable mouths. Given the plethora of mosquitos and black flies that hatch each evening by our house, this fellow is well-fed, though I wish he would invite a few friends over. That’s not likely, as bullfrogs are extremely territorial. They protect their turf by calling, chasing, wrestling and jumping.

I asked Parker to give this one a nudge, hoping to get a shot of him leaping into the air. He leapt all right, about four feet with each powerful spring, but he never learned how to land. He exploded into the air, arms and legs spread as if reaching for the sky, then landed on his nose, then on his back, then on his side… I missed the shot because I was laughing so hard after each crash landing.

I Only Have Eyes for You

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Friday, August 19th, 2011

When it comes to Frogs in the Midwest, one of the most often heard and easiest to find is the Green Frog (Rana clamitans melanota). Like most frogs, from dusk to dawn lots of calling can be heard and if stumbled upon, this common frog will sometimes stay put for nice looks. They have what I view as one of the more classic looks for a frog. One of the distinguishing marks on a Green Frog is the tympanum (round spot behind the eye) which is actually larger than the eye in males.

A more striking stance this common frog can display is the top of its head with eyes popping just above the water. When seen from above, the look is pretty standard but when looking at the level of the frog it completely changes the view and adds quite a striking appearance to this large aquatic frog (good beginning tip to nature photography is to get on the level of the subject you are photographing). Typically found in and around lakes, rivers, and ponds they are often seen at water’s edge waiting for prey items to come their way while also trying to avoid predation by predators like dabbling ducks, herons, and some raptors. They feed mostly on aquatic and terrestrial invertebrates such as beetles, spiders, flies, grasshoppers, and caterpillars but they are opportunistic. Being able to adapt opportunistically is probably why this frog has done well even through areas of habitation by humans.

Many homes that have water features in gardens will typically be visited by a Green Frog from time to time. However, watch out for Great-blue Herons as they may stumble across the feature and see it as a buffet!

Interestingly enough, during colder months and throughout most of the winter Green Frogs hibernate underground in moist soils or underwater. During these cold times, all we can do is dream of warm summer evenings in July and August where the droning Green Frog serenades us to sleep each night with its banjo twang.

An Eastern Interlude

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Thursday, July 22nd, 2010

Most of my birding is done near my home. The word “near” is of course used in its relative sense as my travels sometimes take me hundreds of miles from the place my heart resides. But those regions that lie to the east of the Rocky Mountains are mostly avian terra incognita, patiently waiting for me to correct my priorities and wander, a stranger in a strange land.

Good fortune brought me to Lake Erie for a few days last week. Opportunities to enjoy the area’s wildlife were not as abundant as I might have liked, and yet the area was rich with birds, many familiar but not all. A northern cardinal, as red as the rising sun, called from a tree near my window each morning. Eastern wood-pewees, eastern towhees, and field sparrows sang at first unfamiliar songs. Red-shouldered hawks and turkey vultures rode the winds. A bald eagle flew purposefully west one evening, a still struggling fish clenched tightly in its yellow talons.

A great egret determinedly worked the banks of a large pond along a quiet road. Elegant, graceful, beautiful, it was the epitome of concentration as it moved through the water carefully, quietly, utterly ignoring the Canada geese that carried on around it. Every now and then it froze, peering intently at something only it could see, and then it resumed its prowl. Suddenly it lunged, nearly disappearing in haunch-deep water. After a brief commotion the bird emerged, struggling. It vigorously beat the water with its wings several times before it managed to return to a shallower, safer place. A tiny bit of piscean fin protruded beyond the edge of its bill.

The shadows are long. The sun sits low in the west. I check my watch and realize I have spent well over an hour watching the egret hunt. Frogs croak, hidden in the grasses along the pond’s edge. Swallows wheel and dart above the water, through the warm, moist air of a perfect evening. Reluctantly, I start the car. The geese honk and fret but the egret is focused, thinking only of dinner. I find myself wondering if the cardinal will call for me again, as another day begins.

Not Too Cold For a Frog

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Monday, February 15th, 2010

Right now the Wood Frogs behind my house are frozen rock hard. During the fall and early winter when ice begins to form inside the body of a Wood Frog, glucose levels increase in its blood by as much as 200-fold in just eight hours. This “antifreeze” effect preserves tissues and organs through the long winter.

Ice penetrates throughout the abdominal cavity encasing all the internal organs. Large flat ice crystals run between the layers of skin and muscle, and frozen lenses make their eyes white. Their blood stops flowing and as much as 65% of the frog’s total body water is converted to ice. Breathing, heart beat, and muscle movements all stop and the frozen frog is in a virtual state of suspended animation until spring thaw.

When spring rains and melting snow begin to seep into the ground, Wood Frogs are aroused from their frozen state and undertake their annual migration to breeding pools. Remarkably adapted to the cold, it is not unusual to find individuals scampering across old snow or swimming in water amidst ice.

Wood Frogs are explosive breeders, and most mating in a given pool takes place over just a few days. The loud duck-like calls of males are often a key to finding these pools. Females often deposit their gelatinous egg masses communally. The center of an egg mass may be up to 5°F warmer than the surrounding water, speeding development. Eggs often become covered by symbiotic algae (Oophilia ambystomatis) that enhance the oxygen supply to developing embryos in exchange for nutrients and carbon dioxide.

By mid- to late-summer nearly all juvenile frogs have left the pool as it dries up. Over 70% of these will succumb to predation before reaching adulthood. The rest will be frozen in time until spring comes again.