Amphibian mass migration in the Netherlands

This video from the USA says about itself:

On warm early spring nights amphibians across Vermont are on the move. Unfortunately, in many areas these migrations take them across heavily traveled roads resulting in high mortality rates. However, a dedicated group of volunteers has been keeping an eye on the spring weather. When conditions are right these salamander saviors descend on known crossing sites both to ensure a safe migration and to learn more about some of Vermont’s most delicate and rarest residents.

After a slow start, amphibian spring migration in the Netherlands has started seriously. According to Dutch daily De Stentor, in the Kuinderbos nature reserve on the border of Overijssel and Flevoland provinces, on 18 March 1570 amphibians have been helped by people to cross dangerous roads.

The helpers included government forest service people, conservation education people, and schoolchildren.

The amphibians helped across the roads to their mating waters included 1335 toads, 161 frogs (probably common frogs) and 64 newts.

Last year, less than ten thousand amphibians were counted during the whole spring migration. Two years ago they were 17,550.

Kuinderbos update: on 26 March, amphibian #10,000 was helped to cross safely.

See also here about amphibian migration in Amsterdam.

Moor frogs: here.

Amphibian migration in the USA: here.

Spotted Turtle and Wood Frog Celebrate Saint Patrick’s Day: here.

This is a video about spring in the Netherlands in 1953.

USA: Amphibians — frogs, toads, salamanders, and newts — are disappearing worldwide, but the stream salamanders of the Appalachian Mountains appear to be stable. This region is home to the largest diversity of salamanders in the world (more than 70 species reside here), and scientists want to understand what contributes to the stability of these salamander populations: here.

Spotted Salamander Eggs Mature in Abandoned South Coast Cranberry Bog: here.

“Spotted salamander near state symbolism –”: here.

‘Toad tunnels’ for amphibians looking for love in Powys: here.

A new species of newt of Paramesotriton (Salamandridae) from SW Guangdong, China: here.

7 thoughts on “Amphibian mass migration in the Netherlands

  1. Maine Audubon seeks volunteers for frog survey

    March 22, 2010

    FALMOUTH, Maine—Maine Audubon is looking for volunteers to survey the state’s frog population.

    The group’s Maine Amphibian Monitoring Project is now in its 14th year.

    The program is seeking “citizen scientists” to conduct two-hour roadside surveys three times this spring and summer to document the sounds and locations of the nine different kinds of frogs that live in Maine.

    The surveys take place in early spring for spring peepers and wood frogs, in late spring for American toads and northern leopard and pickerel frogs, and in early summer for bullfrogs as well as gray tree, green and mink frogs.

    Volunteers are needed for routes in northern, western and central Maine.


    On the Net:

    © Copyright 2010 Associated Press.


  2. Pocono Outdoors
    John Serrao

    Top Photo
    The jefferson salamander has been known to emerge from hibernation as early as the first week of March in the Poconos.John Serrao

    March 21, 2010

    Every year, as winter finally begins to relax its hold on our environment, we anxiously look for the first signs of spring. Some of us search for songbirds returning from the south; others watch for the earliest wildflowers emerging in the forests.

    A few, including me, venture out on the first mild, rainy nights in March to witness an annual event that has been carried out for thousands, if not millions, of years in the northern climates — the migration of amphibians from the woodlands to the wetlands.

    In the Poconos, several species of frogs and salamanders perform this ancient ritual and deposit their egg masses in the water at night, only to re-emerge onto the land and return to the woods just a few days later.

    Two frogs — the wood frog and the tiny spring peeper — announce their presence with their distinctive voices. The salamanders, however, are silent and must be sought with flashlights as they travel across the forest floor and cross dangerous roads to find the swamps and vernal ponds where they themselves were born a few years ago.

    Once in the water, they perform underwater courtship “dances” before the egg masses are attached to branches and twigs that become surrounded by these clumps of jelly.

    The salamander most commonly associated with this early spring breeding activity in the Poconos is our largest species, the 8-inch spotted salamander — a robust, black amphibian with big yellow spots.

    A second species is the red-spotted newt, an abundant salamander which actually breeds through the spring and into the summer, and is very familiar to people as its bright reddish-orange, immature land stage, the eft.

    There are two other salamanders, however, that also breed in early spring but are hardly ever encountered because of their rarity in our area. One, the Jefferson salamander, is a close relative of the spotted salamander. It’s slightly smaller, lacks the yellow spots and is almost uniformly dark brownish-gray except for tiny bluish flecks along its sides. This species has been known to emerge from hibernation as early as the first week of March in our region.

    It occurs in just one or two breeding colonies in Delaware Water Gap National Recreation Area and is completely absent from the Pocono Plateau. It is, however, also found in several places in nearby Luzerne and Lackawanna counties. When I was a graduate student at Cornell University and ventured out on my first nightly amphibian explorations around Ithaca, N.Y., the Jefferson was almost as common there as the spotted salamander. It’s always been a mystery to me why this species is so rare in the Poconos — perhaps it’s one of those amphibians that still hasn’t completely reclaimed parts of its northern range from which it was eliminated during the last glacial era.

    The second spring-reproducing salamander that’s almost never witnessed is our state’s smallest species — the four-toed salamander. Only 3 or 3½ inches long and more slender than a nightcrawler, this cinnamon-brown salamander with a porcelain-white, black-dotted belly inhabits sphagnum bogs and swamps throughout the Poconos, from the Delaware River to the top of the plateau. Its distribution, however, is very spotty, with localized populations spaced miles apart from each other because of its habitat requirements. Other than naturalists and biologists who seek out this species, very few people have ever seen one of these salamanders.

    One of the four-toed salamander’s unusual traits is its delayed reproduction. Adults mate in late summer or autumn. (Like other salamanders, “mating” is characterized by the male depositing a packet of sperm or “spermatophore” and then luring or stimulating the female to walk over and take it into her genital opening in order to fertilize her eggs internally.) But they don’t lay their eggs until the following spring, in cavities inside mounds of sphagnum moss near the water. The female stays with her eggs until they hatch into tiny, gilled, aquatic larvae almost two months later.

    I’ve seen relatively large numbers (10 to 15) of four-toed salamanders only a few times in my life, in early to mid-April at the edges of bogs and swamps, usually beneath small logs and fallen limbs. These were probably females getting ready to enter the wetlands to lay their eggs.

    For most of the remainder of spring and summer, this tiny but fascinating amphibian is one of our most elusive and mysterious species.


  3. Wednesday, 24 March 2010 4:31AM

    Plenty of Toads on Local Roads Leave Volunteers Scrambling

    by KYW’s John Ostapkovich

    Don’t look now (although actually maybe you should), but toads are on their annual migration near the Roxborough Reservoir. Watch your step, and your driving.

    Detours for through traffic on a couple of streets in Upper Roxborough were scheduled to take effect on Friday night, which was the best guess when American toads who’d wintered in the woods would head for the waters of the reservoir. Unfortunately, Lisa Levinson, Toad Detour Coordinator, says the toads began showing up on Monday:

    “They have their own schedule so they did a toad surprise on us and for that reason we had limited volunteers out in the rain and mud and we did have many casualties.”

    Among toads, not volunteers. But still, it wasn’t a toad-al loss:

    “We found over 600 toads that we were able to save in one night so we do believe that there are many more toads out there than we at first anticipated.”

    But overall success in maintaining the population from steel-belted predators won’t be known for years.

    For toad detours, go to


  4. Fri, Mar. 26, 2010

    How does a toad cross the road? If lucky, by hand

    By Sandy Bauers

    Inquirer Staff Writer

    Oh, to be a toad crossing the road in Roxborough!

    Like toads everywhere, they obey a timeless rite of spring, emerging from their muck at the first warm rain to hop straight for the nearest nuptial pond to breed.

    In this case, that would be the Roxborough Reservoir.

    But also in this case, Port Royal Avenue – with its steady car traffic – amounts to a sort of no-toad’s-land blocking their path.

    All too often, where the rubber meets the road, it also meets the toad.

    To the detriment of the latter. As if their cousins weren’t in enough trouble – up to one-third of amphibian species worldwide are in danger of extinction – the toads used to suffer a high death-by-squishing rate on this stretch.

    But now, a curious thing happens.

    On rainy spring nights, patrols of a dozen or more volunteers, with flashlights and reflector vests, walk the Roxborough road, picking up hopsters and carrying them across the blacktop.

    These aren’t the only do-gooder toadies. Similar amphibian rescues occur from the country roads of Chester County to the green vales of England.

    The Brits are so enamored that they’ve mapped 700 toad-crossings on Google Earth, and “toad patrols” regularly converge to handle the blitz.

    At the Delaware Water Gap National Recreation Area, officials actually close a road to allow salamanders, frogs, and toads to cross unscathed.

    It keeps things safe not just for the critters, but also for the parents and kids who show up to witness this slimy Serengeti of animals.

    “It’s a special moment,” said spokeswoman Deb Nordeen.

    Near Sumneytown, Montgomery County, science teacher Kathy Leber and some of her students walked Swamp Creek Road recently, carrying 68 salamanders to safer ground.

    Then on Monday, she joined a group in northern Chester County that for several years has been safeguarding the spring hop across St. Peter’s Road in North Coventry Township.

    The scene resembles a kind of amphibian flash mob. Salamanders were already heading back to the woods, while “frogs and toads seemed to be going in both directions,” Leber reported. “Their voices were an amazing cacophony of trills, grunts, and croaks.”

    To be sure, this can all get a tad nutty, drawing its share of smirks – and even angry responses from drivers.

    But amphibians have been hit hard by humans. Only half of the wetlands that existed before Europeans arrived in America remain today.

    Their waters have been fouled with pesticides, introduced species outcompete them for food, and their skin can get scorched by sunlight streaming through a thinning ozone layer.

    Compared with such perils, the automobile was once deemed incidental. But scientists began to accord it new status as an amphibian death machine after two researchers tallied the carnage along a country road – averaging 3,207 vehicles daily – in northern Denmark.

    Writing in 2001, they found that an amphibian attempting to cross had a one-in-three chance of being flattened. And that was on a lucky day.

    “A lot of us looked at that and said, ‘Yeah, maybe we ought to be paying more attention to this,’ ” said Michael Adams, a research ecologist with the U.S. Geological Survey.

    In a subsequent U.S. project involving spotted salamanders, researchers found that if more than 10 percent wound up as roadkill every year, the local population could crash.

    That seems to have happened in North Jersey at one of three crossings that researchers from the state and two conservation groups have been monitoring since 2002. One is on the well-forested Shades of Death Road.

    On a busy night, a thousand or more amphibians can try to cross these spots, said MacKenzie Hall, a biologist with the Conserve Wildlife Foundation. Some are listed by the state as threatened or endangered species.

    But during just one two-hour period, with only 34 cars going by, as many as 71 percent of crossers were killed.

    For a while, traffic was detoured, but then the researchers realized they were sending cars through another migration area they hadn’t known about. So they went back to being crossing guards.

    Still, within a matter of years, they shut down one of the survey spots; few amphibians were left.

    What ups the risk for creatures like toads, frogs, and salamanders is that they’re so-called explosive breeders. Instead of willy-nilly breeding over a matter of weeks, the first few warm and rainy nights of spring will bring most of the population out en masse.

    In this region, it often happens in late March. So last weekend’s warm weather surprised everyone.

    In Roxborough, Lisa Levinson, an animal activist and artist who started the toad project, was just setting up a schedule, intending to start patrols tonight.

    But during Monday evening’s warm showers, toad mayhem erupted.

    Fortunately, someone checked, and the call went out. Volunteers raced to the area and began stuffing them into wet sacks for mass transport.

    Within several hours, they saw or helped 600 toads cross the road. Meanwhile, about 200 wound up under the tires. By morning, the group knew, the carcasses would be gone, cleaned up by possums and other predators.

    Most of what had crossed Monday night were males, and the next night they were trilling loudly from the phragmites-thick water of the abandoned reservoir.

    Within moments of starting down Port Royal, Nicola Baker, 19, of North Wales, bent to pick up a toad that had hopped in front of her.

    She was with her father, Brett. Citing their pet cane toad at home, they said they wanted to help.

    Starting today, the group has a permit from the Streets Department to close portions of several roads when needed. Meanwhile, they waved flashlights to slow motorists.

    Many in the neighborhood know what’s up. One driver rolled down his window and called out, “Frog time?”

    Jessie Zahner of Roxborough, on her way to the gym, pulled over and declared it “cool to see so much nature in a big city.”

    Debbie Carr, an environmental educator with Fairmount Park, said the effort had been a “volunteer magnet.” Last year, about 100 people participated.

    Levinson said she had been astonished by the response and could only think it had to do with people finding toads cute and harmless, perhaps associating them with fairy tales.

    She said the group planned to keep coming out every night for the next few weeks.

    For the toads that make it across to the reservoir, it’s a frenzied reproductive moment. The males mount the females so they can fertilize the eggs – up to 20,000 – as they emerge.

    The reservoir will be filled with long, gelatinous strands – each coiled like an old telephone cord – studded with eggs.

    Soon, the water surface will be vibrating with tadpoles. And within weeks, when they grow their leaping legs, they’ll embark on another mission improbable.

    They’ll have to get back across the road.

    Contact staff writer Sandy Bauers at 215-854-5147 or

    Visit her blog at


  5. Salamander crossing in Monkton wins $150,000 grant

    By Candace Page, Free Press Staff Writer • Friday, April 2, 2010

    Unwitting motorists squashed nearly 100 salamanders, spring peepers and wood frogs Tuesday night on a single stretch of Vergennes Road in Monkton, but help for the migrating amphibians is on the way.

    The Monkton Conservation Commission announced Thursday that it has won a $150,000 state grant to install at least one, possibly two, culverts under the road so at least some amphibians, reptiles and small mammals can safely pass between uplands southeast of the road and an important swamp northwest of the crossing.

    When completed in 2011, the project will be the first wildlife-crossing retrofit of a Vermont highway.

    “We are absolutely thrilled,” said Chris Slesar, chairman of the conservation commission. “We understood that funds were limited, and competition would be fierce. I couldn’t be happier.”

    Jim Andrews, the state’s leading reptile and amphibian expert, has described the crossing at Huizenga Swamp as “one of the most important of the known amphibian crossings in the state.” A large number of species try to cross the road. Some, including the blue-spotted salamander, are among the state’s most unusual.

    A group of Monkton residents has monitored the swampside road crossing for nine springs, documenting the number of amphibian survivors and victims.

    “Quite often, we find it is 50-50,” said Steve Parren, a Monkton resident and wildlife biologist who has collected the data.

    Salamanders are particularly susceptible to becoming roadkill because they winter in upland areas but must reach lowland swamps to spawn in the spring. Often, those two habitats are separated by roads.

    Teams of volunteers turn out on some back roads around the state on warm, wet spring nights to ferry migrating salamanders to safety. Vergennes Road is too busy to be safe for a phalanx of volunteers, so the Conservation Commission proposed to add culverts under the road.

    “When people think about wildlife and highways, they think of white-tail deer and smashed cars. That is very, very serious, but just because small critters don’t cause accidents doesn’t mean they aren’t important to the ecosystem. I commend Vermont for recognizing this,” said Trish White, director of the Habitat and Highways program at Defenders of Wildlife in Washington, D.C.

    The award came from $3.8 million in federal funds the state is required to spend on transportation enhancement projects — typically bike and pedestrian paths, landscaping and the like. This is the first time the program has awarded money for a wildlife crossing.

    The Monkton Conservation Commission had applied for $225,000, which is enough, with private matching funds, to install the two highest-priority culverts. Parren said he is hopeful residents can raise enough private funds to meet the two-culvert goal.

    Contact Candace Page at 660-1865 or Read her blog, Tree at My Window, at and follow her on Twitter @candacepage.

    This story appeared on page A1 of Friday’s Burlington Free Press


  6. Frog horde closes major highway in northern Greece

    © 2010 The Associated Press

    May 26, 2010, 11:08AM

    THESSALONIKI, Greece — Greek officials say a horde of frogs has forced the closure of a key northern highway for two hours.

    Thessaloniki traffic police chief Giorgos Thanoglou says “millions” of the amphibians covered the tarmac Wednesday near the town of Langadas, some 12 miles east of Thessaloniki.

    “There was a carpet of frogs,” he said.

    Authorities closed the highway after three car drivers skidded off the road trying to dodge the frogs. No human injuries were reported.

    Thanoglou said the amphibians probably left a nearby lake to look for food.


  7. Pingback: Many amphibians saved from dangerous roads | Dear Kitty. Some blog

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