An online resource based on the award-winning nature guide

Frogs

Wood Frogs Awakening and Thawing

4-17-14 wood frog IMG_1377The duck-like quacking of recently-emerged, courting wood frogs is slightly miraculous considering that only days ago these amphibians were frozen practically rock solid. At some point in late fall or winter, as temperatures drop, they flood their bodies with blood sugar that acts as antifreeze in their circulatory system. Activity in their brains stops, their heart stops, and 45 – 60% of their body can freeze. Yet within hours of being exposed to the spring’s warming temperatures, wood frogs thaw out and start moving towards a body of water to breed.

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Young Pickerel Frogs Underfoot

9-6-13 young pickerel frog 049If you remember visiting a pond last April or May and hearing a low, snoring sound (the mating call of the male Pickerel Frog) you might see the end results of those snores if you re-visit the pond now. Young Pickerel Frogs the size of quarters are currently abundant on the banks of the ponds in which they grew up, as well as in nearby vegetation. After emerging from the water sometime between July and September, many of these first year frogs move into nearby fields, meadows and damp woods. They are only a few weeks away from burying themselves in mud at the bottom of the pond, where they will hibernate all winter.

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Young Spring Peepers Now The Size Of Your Baby Fingernail

8-28-13  spring peeper & Jap. beetle 066It takes roughly two months for Spring Peeper tadpoles to metamorphose into adults, and unlike other frogs, they don’t complete this process in the water. Young Spring Peepers leave their ponds at an earlier stage of development than most frogs – they have four legs and lungs when they come out of the water, but most of them also still have a tail which is absorbed shortly after they become land dwellers. Adult Spring Peepers measure roughly ¾” (males) to 1 ½” (females) in length. As you can see in this photograph, this fully metamorphosed young Spring Peeper is hardly bigger than a Japanese Beetle, and it has completely lost its tail, so it was even smaller when it hopped out of the water!

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A Frog’s Tympanum

8-15-13  green frog tympanum  051A frog’s tympanic membrane, or tympanum, is the circular patch of skin directly behind its eye that we commonly call its eardrum. It functions much like our eardrum does –the tympanum transmits sound waves to the middle and inner ear, allowing a frog to hear both in the air and below water. In addition, this membrane serves to keep water and debris from entering a frog’s ears. In some species of frogs, such as the Green Frog, American Bullfrog and Mink Frog, their gender can be determined by the size of their tympanum relative to their eye: the male’s tympanum is larger than its eye, the female’s is equal in size or smaller than its eye.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Pickerel Frogs Calling

5-2-13  pickerel frog IMG_9431If you’ve spent time at a pond recently and heard what sounded like someone snoring, you weren’t hallucinating! Male pickerel frogs have started calling to attract mates, and each species of frog, just like birds, has its own distinctive call. Spring peepers peep, wood frogs clack and pickerel frogs snore. Their snore isn’t long – it only lasts a second or two — but it’s unmistakable. Pickerel frogs call from under water, as well as on top of mounds of vegetation, so if you hear one and then search for it, it’s very possible you may not find it. (My sincere apologies-computer failure prevented me from posting on the previous two days.)


Spring Peepers Mating & Laying Eggs

spring peepers mating DA8A0504The mating season for spring peepers lasts two months or more, and judging from the sound that is coming from ponds and woodlands these days and nights, it is in full swing. Once a singing male is successful in attracting a female, he mounts and clasps her while depositing his sperm on her eggs. She lays up to 800 eggs, either singly or in small groups, on plants within the male’s territory. The frogs remain joined (a position known as “amplexus”) for up to four hours. After egg-laying and fertilization is completed, the female peeper returns to the woods; the male remains at the pond and resumes singing.


Frog Vocal Sacs

4-16-13  vocal sacs“Peeps” and “quacks” fill the air these days.  How is it that these frog calls travel so far?  It’s all thanks to a thin membrane , or sac, that most frogs have. Note the single inflated sac of the spring peeper, and the paired sacs on either side of the wood frog’s head. These vocal sacs act as resonating chambers, causing the male frog’s mating call to be amplified and carried far (some species of frogs can be heard over half a mile away). Most frogs have one of three basic types of vocal sacs: a single throat sac (the most common), paired throat sacs (partially separated by connective tissue) and paired lateral sacs (completely separate chambers on either side of the head). Vocal sacs are outpocketings of the floor of the frog’s mouth. When calling, a frog closes its mouth and nostrils, and expels air from its lungs through the larynx and into the vocal sacs. The vibrations of the larynx emit a sound which resonates within the vocal sacs. The frog continues calling as muscles within its body wall force the air back and forth between the lungs and vocal sac. The thickness of the vocal sac wall in frogs varies. Typically, small frogs that call in the air (spring peeper) have thin vocal sac walls, whereas those that call in the water, particularly large species (green and bull frogs) often have thick-walled vocal sacs that appear swollen, not inflated like a balloon, when filled with air.


Spring Peepers Emerging

4-8-13 spring peeper2 IMG_7463Sitting on top of the snow, still as a statue, a spring peeper gathers strength to make the long trek to open water, where, if it is a male, it will exercise its voice for the first time in many months. Like the gray treefrog and wood frog, spring peepers can freeze as solid as a rock for several months during hibernation and then, on a warm day, thaw out in a few hours and resume a normal, active life.  The formation of glucose and ice crystals that form outside of cells enable this phenomenon to occur.  Once hibernation has come to an end, peepers seek out wetlands, vernal pools and ponds to breed and lay eggs before they return to their home on the forest floor.


A Great Christmas Present!

If you’re looking for a present for someone that will be used year round, year after year, Naturally Curious may just fit the bill.  A relative, a friend, your child’s school teacher – it’s the gift that keeps on giving to both young and old!

One reader wrote, “This is a unique book as far as I know. I have several naturalists’ books covering Vermont and the Northeast, and have seen nothing of this breadth, covered to this depth. So much interesting information about birds, amphibians, mammals, insects, plants. This would be useful to those in the mid-Atlantic, New York, and even wider geographic regions. The author gives a month-by-month look at what’s going on in the natural world, and so much of the information would simply be moved forward or back a month in other regions, but would still be relevant because of the wide overlap of species. Very readable. Couldn’t put it down. I consider myself pretty knowledgeable about the natural world, but there was much that was new to me in this book. I would have loved to have this to use as a text when I was teaching. Suitable for a wide range of ages.”

In a recent email to me a parent wrote, “Naturally Curious is our five year old’s unqualified f-a-v-o-r-I-t-e  book. He spends hours regularly returning to it to study it’s vivid pictures and have us read to him about all the different creatures. It is a ‘must have’ for any family with children living in New England…or for anyone that simply shares a love of the outdoors.”

I am a firm believer in fostering a love of nature in young children – the younger the better — but I admit that when I wrote Naturally Curious, I was writing it with adults in mind. It delights me no end to know that children don’t even need a grown-up middleman to enjoy it!


Immature Common Merganser Diet

Common Mergansers are primarily fish-eating ducks. Young mergansers require over half a pound of food per day during their first summer, and often supplement their fish diet with insects, mollusks, crustaceans, worms, frogs, small mammals, birds and plants. The pictured immature Common Merganser had just downed a crayfish when it spotted a frog which it succeeded in catching and eventually swallowing.


Spring Peepers Still Calling

Although Spring Peepers emerged from hibernation about two months ago, on warm nights the males are still advertising for mates and will continue to do so into June. Let your ears guide you to the peepers as they call repeatedly, often while perched on low vegetation near water. Armed with a flashlight, look for the movement of their vocal sacs as they inflate and deflate as the peepers sing. 


Wood Frogs Arrive at Vernal Pools

After noticing the sudden loud clacking chorus at a nearby temporary woodland vernal pool, I went down to investigate, and there were dozens of wood frogs floating on the surface, as they croaked their duck-like quacks in the hopes of attracting female wood frogs.  As far as I could determine, they were out of luck on this, their first day at the breeding pool, as I don’t believe the females have arrived yet.  One clue was the relatively small size of the floating frogs and it seemed as though every frog was calling (only males call).  Plus, time after time a wood frog would swim up to another wood frog and attempt to grasp it only to have the object of its desire utter a “release” chirp (a call made only when a male clasps another male) and swim rapidly away. 

 


Spring Peepers Calling

I heard my first peeper on March 18th, roughly two weeks earlier than in past years.  These tiny members of the treefrog family begin mating rituals shortly after the end of hibernation. The males gather at small pools by the hundreds. Each male establishes a small territory and begins calling the familiar high-pitched “peep” quite frequently. The louder and faster he peeps, the better his chances are of attracting a receptive female. Males usually compete in trios, and the male with the lowest-pitched call usually starts the vocal competition.  If you look closely at the peeper in the photograph you can see some snow fleas hitching a ride.  


Naturally Curious wins National Outdoor Book Award

I am delighted to be able to tell you that this morning I learned that NATURALLY CURIOUS won the Nature Guidebook category of the 2011 National Outdoor Book Awards.  I’m honored and humbled by this recognition.   http://www.noba-web.org/books11.htm


Spring Peepers Calling

You may well have heard the single “peep” of a male spring peeper emanating from the woods recently.  It does seem odd to hear this call now, often far from water, as we associate it with spring courtship.  This phenomenon occurs so regularly in the fall that herpetologists have given it a name – “fall echo.”  They speculate that peeper calling is spurred by light and temperature conditions, when fall climate conditions are similar to those of spring. 


Gray Treefrog (Hyla versicolor)

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A gray treefrog starts life off as a ¼”, yellow tadpole. Eventually it may reach 2 ½” in length, and its body will have turned olive green with a red tail. Upon metamorphosing into a frog, the gray treefrog turns a bright emerald green and gradually develops into a mottled gray adult. The two color phases of the maturing frog are so different it’s hard to believe that they are the same species. However, a glance at their large, rounded toe pads tells you that they are at least related. All members of the treefrog family (which includes spring peepers) possess these toe pads, which enable them to cling to rough and smooth surfaces, and to climb up verticle structures, from tree trunks to house windows.


Pickerel Frog

Next to the green frog, the pickerel frog is the most abundant frog in New England. It is often confused with the northern leopard frog, which it closely resembles.  The spots on a pickerel frog’s back are squarish and aligned in rows, whereas the leopard frog’s spots are rounded, and randomly scattered over its back.  In addition, the male pickerel frog has bright orange on the inner surface of its hind legs, which the leopard frog lacks.  The pickerel frog is very sensitive to pollution, so its presence is indicative of good water quality.

 


Green Frogs Calling

Male green frogs have recently started calling their rather explosive loose banjo string call. Sometimes there is a single note, or often several are issued. Scientists have actually differentiated six different calls. Green frogs have paired vocal sacs which act as resonating chambers, as do the wood frog, northern leopard and pickerel frogs. Unlike American toads, spring peepers, bullfrogs and gray treefrogs, whose single pouch bubbles out beneath their chins when they call, the inflated pouches of the green frog aren’t that obvious. There is a slight swelling of the throat and sides of its body when it is calling, which you can hopefully detect in the accompanying photograph.


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