An online resource based on the award-winning nature guide

Amphibians

Pickerel Frogs “Snoring”

4-28-16  pickerel frog IMG_9429Pickerel Frogs emerge early in the spring from their muddy, pond bottom hibernacula, and mate in April and May in the Northeast. As part of the mating ritual, males call to attract females, with the calls resonating inside their internal vocal sacs located between their tympanum (ear drum) and foreleg (unlike Spring Peepers and American Toads, whose vocal sacs are located directly under their mouths).

These low-pitched calls resemble short “snores.” Occasionally Pickerel Frogs call from under water, but even when they are above water, their calls do not carry very far, frequently making it difficult for human ears to hear them.  Their call is similar to that of the Leopard Frog’s but lacks the short grunts of a full Leopard Frog call.  You can compare these two calls (and several others) by going to http://langelliott.com/calls-of-frogs-and-toads-of-the-northeast/ (Sound recording © Lang Elliott – langelliott.com)

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.

 


Wood Frog Egg Matts

wood frog egg mass IMG_2760Now that normal spring temperatures have returned, the air around vernal pools is once again filled with the clacking/quacking calls of male wood frogs hoping to attract females. Once this has been accomplished, most paired wood frogs head to the same general area in the pool to mate.  The resulting egg masses, each consisting of several hundred eggs, form a communal cluster, or “egg matt,” on the surface of the water.  Eventually algae will start growing on the jelly-like substance surrounding the eggs, causing them to resemble pond slime – an effective camouflage.  The gelatin covering, the size of the communal cluster, and exposure to the sun all help the eggs to be warmer than the surrounding water and they develop quickly – a necessity if one is to metamorphose into an adult before the vernal pool dries up.

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.

 


“Big Night” Hazard

big night 2016 IMG_7612Every year in early spring on a rainy night spotted, blue-spotted, Jefferson and four-toed salamanders, wood frogs, and spring peepers leave their leaf litter and subterranean winter hibernacula and migrate to their ancestral breeding pools to mate.  Sometimes there are roads between these two sites.  Vehicles driving these roads inevitably kill thousands of salamanders, wood frogs and spring peepers every year.  Concerned citizens have set up teams to try to scoop up these nocturnal travelers and escort them to the side of the road in which they were headed.  While this action definitely helps, it is hard to find enough generous volunteers to man every crossing on every road all through a rainy night.

In Monkton, Vermont, Jim Andrews, Steve Parren and Chris Slesar, along with the Lewis Creek Association and the Monkton Conservation Commission, spear-headed an effort this past year to do something about the mortality of hundreds of migrating frogs and salamanders. Grants, plus a large number of organizations and citizens, provided the manpower and finances to construct two concrete culverts under a road in a location where the road separates the breeding pools of amphibians from their upland wintering grounds.

In the past, hundreds of migrating amphibians were killed in this location by automobiles during every spring and fall amphibian migration, and it is doubtful whether the population would have been able to sustain itself over time. (In the past month, 673 salamanders and 329 frogs have safely passed through the tunnel.  In addition, a few early migrators (16) have already started coming back up hill.) Hopefully, these will be the first of many such culverts in the Northeast. For further information on the Monkton underpasses, go to:  http://www.burlingtonfreepress.com/story/news/2016/03/28/hundreds-saved-new-vermont-salamander-crossing/82336084/.  (photo:  spotted salamander)        

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.


Wood Frogs & Spring Peepers On The Move

3-29-16 road frogs 015Although the temperature hovered around 32°F.  last night in central Vermont, wood frogs and spring peepers were on the move.  Usually it is above 40° or 45° before you see the earliest of our breeding amphibians, but a few hardy souls ventured forth to their breeding pools and ponds under cover of darkness and  rain yesterday.  Those that breed in vernal pools are in a hurry to take advantage of every day, as the eggs they lay must complete metamorphosis by the time their pool dries up, often in mid- to late summer.

Both of these species of frogs are freeze tolerant.  Wood frogs are coming out of a state in which they haven’t taken a breath and their heart hasn’t beaten for several months.  Prior to hibernation they convert glycogen in their bodies into glucose, a form of antifreeze that helps prevent the water within their cells from freezing, which would kill them.  However, the water outside their cells does freeze.  Amazingly, wood frogs can survive having up to 65% of this water frozen, yet when warm weather arrives, they thaw and move about in a matter of hours.

If you rescue these woodland amphibians that are crossing roads (where so many of them get run over at night) during their migration to their breeding pools, take note of the temperature of their body.  Often they are still quite cold to the touch — colder than the air, even – which fortunately makes it difficult for them to move fast enough to escape your helping hands. (Photo: Amorous wood frogs getting a head start as they cross a road to get to breeding pool.)

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.


Spring Peepers Peeping

12-16-15 spring peeper IMG_7853The sound of a peeping Spring Peeper in December (yes, this occurred in Vermont this week) conveys to one and all that climate change is not a figment of our imagination. Amphibians are extremely sensitive to small changes in temperature and moisture due to their permeable skin and shell-less eggs. Certain species, including Spring Peepers, Grey Tree Frogs, Wood Frogs, American Bullfrogs and American Toads, are emerging and mating earlier in the year than they did historically. Causal relationships have been found between irregular climate conditions (drought, increasing frequency of dry periods and severe frosts) and decreasing (extinction in some cases) of certain amphibian species.

Behaviorally and physically, warming temperatures are having an impact on amphibians. A recent laboratory study investigated changes in amphibian metamorphosis time due to pond desiccation and whether amphibian immune systems become compromised as a result of these changes. They found that amphibian immune responses became increasingly weaker and white blood cell counts were increasingly lower with higher desiccation. As a result of climate effects, immune systems are weakened, making it more difficult for amphibians to fight off diseases.

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.


Green Frogs About To Take The Plunge

11-9-15 A. bullfrog 005Most Green Frogs have disappeared over the last few weeks, but this male (eardrum, or tympanum, is larger than his eye) was basking in the last bit of sunshine he will see or feel for the next five or six months. Soon he will take the plunge and bury himself in leaf litter at the bottom of the pond or lay, partially exposed, on the mud beneath the leaves. (Green frogs typically hibernate in water, but occasionally overwinter on unfrozen stream beds or seeps, as well as underground.) Aquatic turtles can shut down their metabolism to a greater extent than frogs, so they are able to survive hibernation buried in mud, where there is little oxygen, but frogs overwintering in a pond must have their skin at least partially in contact with oxygen-rich water. Green frog tadpoles will typically, but not always, overwinter prior to metamorphosing the following spring.

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.


Eastern Red-backed Salamanders Migrating Downwards

11-4-15 eastern red-backed salamander2 091Eastern Red-backed Salamanders reside in the leaf litter throughout the Northeast during the summer months. Here they scent-mark their territories on the forest floor with pheromones and fecal matter in order to convey information concerning their body size and gender to other Red-backed Salamanders. If the temperature soars or the humidity drops, these salamanders do just what they do in the fall – seek deeper, moister protected areas such as beneath stones, under and within rotting logs and stumps, or underground in animal burrows.

Whereas they migrate downwards in summer to avoid the heat and dry air that would impair their ability to breathe through their skin, these salamanders are avoiding the approaching cold when they migrate downwards in the fall. Red-backed Salamanders are not freeze tolerant, and thus must avoid freezing temperatures. Once ensconced in a freeze-free hibernaculum, they usually remain there until snowmelt.

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.


Follow

Get every new post delivered to your Inbox.

Join 4,196 other followers