Froggy goes a-courtin’

wood frog

.[Reprint from February 2011]

My mole Tboy (mole as in spy, not insectivore) tells me Valentine’s Day has its intended effect on the wood frog population in southwestern Virginia. Mid-February is when the first early-bird males usually appeared at area ponds, floating patiently in anticipation. Within a few days the gene pool is getting crowded, and the boys are warming up for karaoke and the start of happy hour. Once the ladies arrive and joint be jumpin’!

The watering holes have been silent for the last few months. Winter is a time for amphibians to lie low. Really low. Aquatic frogs hibernate on or partially submerge in the mud at the bottom of ponds and lakes. Terrestrial frogs, including the wood frog, hibernate on land. Some burrow down below the frost line, but wood frogs are not adept diggers so they seek out crevices in rocks, crawl beneath a log, or just huddle in the leaf litter.  Their hibernacula don’t always make for cozy inglenooks. When the temperatures drop below freezing, so do the wood frogs. But not to worry—wood frogs have what it takes to best Old Man Winter.

Antifreeze.

No, I’m not talking about well drinks. A high concentration of glucose keeps a frog’s vital organs from freezing, so even though the animal may stop breathing and doesn’t have a heartbeat, it’s not dead. As soon as things heat up again, the frog thaws and life goes on.

wood frogs in amplexis

Wood frogs in amplexis—male is on top (Photo: Richard Bonnett, Creative Commons license)

The wood frog club scene is cool. That’s because it usually begins in late winter, sometimes before the ice has disappeared from vernal reproduction pools. The whole rave lasts for about two weeks. A female steps onto the dance floor—I mean into the water—and a male grabs her and holds on tight. The process is called amplexis. That’s Latin for embrace. Yeah… kind of like the way sumo wrestlers embrace.  Because once the male has her in his arms, he’s not letting go without a lot of… persuasion. Sometimes not even then.

The process is highly competitive and not without hazards. “Satellite” males hang out beyond the water’s edge so they can grab a gal while she’s in transit. In this way, he avoids jostling with the boys at the pool while also scoring a ride to the party. Male wood frogs are stimulated by movement so they;re not always discriminating about who they grab. Sometimes it’s the wrong species of frog, and sometimes several males will grab the same female, which can cause her to be squeezed to death or drown. Club life has its ugly side, too.
wood frog egg masses
But, assuming there aren’t any bar brawls, the female will lay large masses of 1500+ eggs, choosing a site where they receive sunlight and protection from predators. When she releases her eggs, the male—who has been waiting for this opportunity and is now in the perfect position—fertilizes them with a sperm-containing fluid and soon the eggs begin to develop.wood frog metamorphosing

Eventually, the tadpoles hatch and begin their metamorphosis, absorbing the nutrient reserves in their tails to fuel their makeover.wood frog metamorphosingTime to head for the forest and get on with the serious business of making a living. Last call! (Until next year, that is).

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Start your day with a little Next-Door Nature—jump to the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!

© 2011 Next-Door Nature— no reprints without written permission from the author. Cover photo by Garrett and Kitty Wilkin; egg mass photo by Richard Bonnett; metamorphose photos by Brian Gatwicke. Thanks to all these photographers for making their photos available for use under a Creative Commons license.

Hops-itality

pacific tree frog (photo: jacki dougan, creative commons license)

Frogs, including this Pacific tree frog, could use a little help as they try to survive in the 21st Century (Photo: Jacki Dougan, Creative Commons license)

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Fifty years ago, Rachel Carson asked the world to consider a simple question: imagine springtime without birdsong.

Silent Spring addressed an unlikely subject for what was to become a best-selling book—the effect of DDT and other pesticides that persist in body tissue, becoming more and more concentrated as they move up the food chain (a process known as biomagnification). Yet nearly everyone could easily understand that their own quality of life would be diminished should they step outside one sunny May morning to find the dawn chorus had been replaced with a deafening stillness.

green treefrog (Photo: sarowen, Creative Commons license)Thanks to Carson’s courageous stand—and the subsequent public outcry—songbirds and other avian species dodged a bullet.* Now there’s another set of wild voices in the spring choir who could use a hand—the amphibians.

More specifically, frogs.

There are now over 1,800 threatened amphibian species. At least 168 species have gone extinct in the last two decades due to factors such as habitat loss, water pollution, disease, climate change, and invasive species. Additionally, many areas in the U.S. have recently experienced severe drought, and England is currently experiencing its worst drought in decades.

Many frog species depend on ephemeral (temporary) water sources for breeding since they don’t support fish that would eat the eggs and tadpoles. If the ephemeral pools dry up before the young amphibians have time to metamorphose, or if there isn’t enough rain to create pools in the first place, it can result in a missed generation… and a fragile future for frogs.

Poison Dart Frog Sitting on a Leaf (Photo: MoleSon2, Creative Commons license)Kermit the Frog spoke from experience—it isn’t easy being green… or yellow, or red, or black, or blue.

Frogs are essential to the health of wetland, riparian, and coastal ecosystems. Tadpoles feed on algae, preventing blooms that can reduce oxygen levels. Frogs consume millions of insects each year, including mosquitoes and ticks carrying diseases that threaten the health of humans, their companion animals, and livestock. A wide variety of wild mammals (raccoons, opossums), birds (herons, hawks, geese), and reptiles (snakes) rely on frogs as part of their diet.

April 28th was the 4th Annual Save the Frogs Day, established to raise awareness and funds for amphibian conservation. Since many frog species are comfortable living in cities and suburbs, I thought I would pass along suggestions for homeowners who would like to offer some hoppin’ hospitality, courtesy of yesterday’s event organizers:

1.    A Wet Welcome Mat

Fall and spring are the best times to create a permanent oasis for frogs. Kits are available at many garden and home improvement stores, or simply use a container or dig a hole that is deep enough (at least 1 foot at one end) and line it with sand or a flexible plastic liner before adding water.  Keep in mind, you must provide a sloped ramp so the frogs can get out easily.  Slope the liner or build one out of rocks to gradually allow the frogs to get to ground level or out of the pond. (Some nurseries also have floating devices for swimming pools that can allow amphibians who might jump in a way out.)

Don’t clean the water. In fact, add floating plants such as lily pads or leaves to provide cover. Refill slowly and carefully if water levels get low.

Don’t put fish in your pond, as they will munch on your tadpoles and frogs.

2.    Shade & Shelter

Place your pond in a shady spot, preferably surrounded with native plants to attract a tasty bug feast of ladybugs, bumblebees, and other pollinators to also help beautify your yard. You can stack some rocks or turn over a half of a flowerpot beside the rim of the pond to give your frogs a place to sit and eat their lunch as it flies or crawls by.

glass frog (Photo: Josiah Townsend, Creative Commons license)3.    Go Organic

Don’t use pesticides or weed killers. Amphibians absorb water—and any chemicals in it—through their skin. Pesticides and weed killers can run off from land into water and can be lethal to amphibians. Certain weed killers also can alter hormones, changing male frogs into females and reducing the potential of frogs to perpetuate thriving populations.

4.    Patience, Grasshopper

Don’t be tempted to relocate frogs from other areas or stock your pond from pet stores. You may introduce diseases or invasive species and domestically raised frogs will not necessarily adapt to wild habitats. If you build it, frogs will come.

5.    Look & Listen

Become a frog watcher. You will appreciate these wonderful animals more if you can see them in action, and you can help their conservation in the process. The National Wildlife Federation’s Wildlife Watcher program allows citizen scientists to contribute to a growing database of North American wildlife, learn about the animals living in their region, and build a printable checklist of sightings.

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* Although the focus of this post is frogs, wild birds still face many challenges and threats to their long-term survival. You can check out one such hazard here. Others will be addressed in upcoming NDN posts.

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Life is better when you have Next-Door Nature—click the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!
© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work; all you have to do is ask). Thanks to these photographers for making their work available through a Creative Commons license: [from top to bottom] Jackie Dougan (Pacific tree frog in rose); sarowen (green treefrog); Sascha Gebhardt (poison dart frog); ucumari (bullfrog); Josiah Townsend (glass frog).

Froggy goes a-courtin’

wood frog

The wood frog has a large North American range (Photo: Garrett and Kitty Wilkin, Creative Commons license)

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My mole Tboy (that’s spy, not insectivore) tells me Valentine’s Day has had its intended effect on the wood frog population in southwestern Virginia. On February 18th the first early-bird male appeared at a nearby pond, floating patiently and quietly. Four days later, 50 guys had found their way to the gene pool and were warming up for karaoke and the start of happy hour. Any time now, the ladies will arrive and that joint be jumpin’!

The watering hole has been silent for the last few months. Winter is a time for amphibians to lie low. Really low. Aquatic frogs hibernate on or partially buried in the mud at the bottom of ponds and lakes. Terrestrial frogs, including the wood frog, hibernate on land. Some burrow down below the frost line, but wood frogs are not adept diggers so they seek out crevices in rocks, crawl beneath a log, or just huddle in the leaf litter.  These hibernacula don’t always make for a cozy inglenook. When the temperatures drop below freezing, so do the wood frogs. But not to worry—wood frogs have what it takes to best Old Man Winter.

Antifreeze.

No, I’m not talking about well drinks. A high concentration of glucose keeps the frog’s vital organs from freezing, so even though the animal stops breathing and doesn’t have a heartbeat, it’s not dead. As soon as things heat up again, the frog thaws and life goes on.

wood frogs in amplexis

Wood frogs in amplexis—male is on top (Photo: Richard Bonnett, Creative Commons license)

The wood frog club scene is cool. That’s because it usually begins in January or February, sometimes before the ice has disappeared from vernal reproduction pools. The whole rave lasts for about two weeks. A female steps onto the dance floor—I mean into the water—and a male grabs her and holds on tight. The process is called amplexis. That’s Latin for embrace. Yeah. Kind of like the way sumo wrestlers embrace.  Because once the male has her in his arms, he’s not letting go without a lot of… persuasion. Sometimes not even then.

wood frog egg massesThe process is highly competitive and not without hazards. “Satellite” males hang out beyond the water’s edge so they can grab a gal while she’s in transit. In this way, he avoids jostling with the boys at the pool while also scoring a ride to the party. Also, male wood frogs are stimulated by movement so they’re not always discriminating about who they grab. Sometimes they grab the wrong species of frog, and sometimes several males will grab the same female. This can cause her to be squeezed to death or drown.

But, assuming there aren’t any bar brawls, the female will lay large masses of 1500+ eggs, choosing a site where they receive sunlight and protection from predators. When she releases her eggs, the male—who has been waiting for this opportunity and is now in the perfect position—fertilizes them with a sperm-containing fluid and soon the eggs begin to develop.

wood frog metamorphosing

Eventually, the tadpoles hatch and begin their metamorphosis, absorbing the nutrient reserves in their tails to fuel their makeover.

wood frog metamorphosingTime to head for the forest and get on with the serious business of making a living. Last call! (Until next year, that is).

.
.
Start your day with a little Next-Door Nature—jump to the “subscribe”  link in the upper right-hand corner of this page and receive notifications of new posts!
© 2011 Next-Door Nature— no reprints without written permission from the author. Egg mass photos by Richard Bonnett; metamorphose photos by Brian Gatwicke. Thanks to all the photographers featured in this post for making their photos available for use under a Creative Commons license.