Program Notes from the April 24, 2007 Meeting of LKWA

April 24, 2007 at 6:00 pm

Fair Meadows, Vogel Road

Rick Persson called the meeting to order at 6:05 pm. There were 23 persons in attendance.

A short business meeting was conducted.

Susan Yates reported that the next program is on May 29 at Fair Meadows, the Shackelford home. NOTE: AT THE TIME OF THIS WRITING, THE MAY MEETING HAS BEEN CANCELLED. Our next meeting will be on June 26 at 6:00 pm at Fair Meadows (Shackelford home). We will have a business meeting followed by a prairie walk.

The business meeting adjourned at 6:20 pm.

Bob Hay, Cold-blooded Biologist (also known as herpetologist) with the DNR presented a program on amphibians of Rock County. Bob brought a tape recording of the different frog and toad calls so we could learn to distinguish the calls we might hear along the Koshkonong area roadsides. He also had live specimens of a chorus frog and central newt. His enthusiastic, fact-filled presentation continued until dark. We plied him with questions throughout until about 8:30 pm when the calls of the frogs drew us out for a stroll along the drive and out onto Vogel Road.

During our exploration, we actually caught a glimpse of the tiny but beautiful creature (chorus frog) responsible for the loud call sounding like “running your fingernail along the teeth of a fine-toothed comb”. The spring peepers and chorus frogs are about an inch long although they sound like they should be the size of a soccer ball! We also saw green frogs (who are not singing yet), and heard, but did not see American toads. The toads make a musical trill and the various individuals harmonize at different pitches.

Here is a partial list of the fascinating facts we learned about the amphibians of the Koshkonong area.

  1. There are 12 species of frogs in Wisconsin. Actually, now there are 13 species because the taxonomists have divided chorus frogs into two species.
  2. Do not pick up amphibians if you have mosquito repellent on your hands. The chemical is toxic and amphibians will absorb it through their skin and die very quickly ( within 30 minutes).
  3. The wood frog is the first to begin calling in the spring. They migrate from the woods to a pond to breed and lay their eggs. Often many frogs will lay in a communal egg mass. The call of this frog sounds like a quacking duck. They have a black mask. Their distribution in this area is unclear.
  4. Spring peepers are also early spring breeders. Their call is a clear high-pitched peep and sounds very loud for their size (about 1 inch). They have a dark X on their back.
  5. A very interesting fact is that several frog species that winter on land under leaves and woody debris actually freeze in the winter. Their metabolism changes and they produce a glycol-like antifreeze that prevents their cells from freezing. However, many frogs do not survive a very cold winter without snow.
  6. Many turtles also die during cold winters when the water table is low. The following spring one often sees floating turtles. These animals have damaged limbs and are unable to escape predators. They also are susceptible to bacterial infections that kill them.
  7. Leopard frogs also breed and call early in the spring. Their call sounds like rubbing a finger across a balloon. These frogs will travel long distances from water (up to two miles) after breeding. They live in prairies, farms and lawns. Leopard frogs had a huge die-off in the 70s. The cause was never clear. They continue to decline and it has been determined that their life span has been shortened and their reproduction is decreased by 50%.
  8. Pickerel frogs are a species of special concern because of their declining numbers. Their call is like a continuous snore. They have blotches like a leopard frog, but the blotches on their back are in 2 rows rather than randomly scattered like a leopard frog. They are often found in cold streams around watercress. Because of the special concern for this species, the DNR would like to hear if you find one.
  9. The American toads are now beginning to call. They have a musical trill. Their different pitches of call create a kind of harmony when many individuals are calling. Female toads prefer to mate with males with a deeper tone.
  10. Because of the early warm weather is our area, the early spring breeders (leopard frogs and wood frogs) have finished calling. They have already hatched although many of the young may have been frozen into the top of the ice when the early warm spell was followed by the hard freezes. Bob has found egg masses with the top portion frozen but with live tadpoles on the bottom of the mass, apparently insulated by the frozen gel above them.
  11. In the early spring when the weather warms the adult frogs that have over-wintered in the woods and fields migrate to small ponds to call and breed. Salamanders also begin to move when there is a warm evening rain (around the 20th-30th of March). The frost and snow need to be gone. They avoid frozen ponds and go to those where at least the edges are melted. The grass must be wet for their migration so they don’t get dehydrated. They are very faithful in returning to the site where they originated.
  12. Ephemeral ponds are very important to the life cycle of amphibians. These are ponds that are fed by snowmelt and early spring rains and are used for breeding, egg laying and maturation to tadpoles. It is important, however, that the pond dries out by late summer so that they remain fishless. Fish love to eat eggs and tadpoles.
  13. Because migrations and small ponds are so critical to the reproductive success of amphibians, they are declining because of fragmentation of habitat caused by roads and drainage of wetlands. They are helped by the creation of farm ponds and wetland scrapes. They need about 300 feet of upland areas around the wetland for the remainder of their life cycle. It is important to consider the migration paths for these creatures when planning roads and development. Bob noted that it is like the movie “Field of Dreams” – “if you build it, they will come”. He had even observed eggs and tadpoles in wet tire ruts. Another major problem for amphibians is sedimentation and chemical pollution of their habitat.
  14. The Eastern tiger salamander requires more permanent ponds. Normally these animals are herbivores as tadpoles and carnivorous as adults. However, if the pond starts to go dry, the larvae undergo a fascinating change. Their mouths become hyper-enlarged and they begin eating each other! The tiger salamander gets quite large – up to 7 inches and live well into their teens. There is one record of a tiger salamander living 32 years in captivity. Bob showed us a very handsome live specimen.
  15. The central newt is also a fascinating creature. It has strong powers of regeneration. For example, if its eye is removed, cells in the back of the eye can differentiate and form a new eye. It can also replace its tail and legs and some of its internal organs.
  16. Finally, Bob answered a question about the cause of the malformed frogs that are being found with increasing frequency. He reviewed the history of the observations and some of the theories about the cause including a parasitic infection and various chemicals. The most recent evidence seems to suggest that the cause is a combination of “stressors”. One investigator (Tyrone Haye) has shown that no one specific chemical causes the abnormality. Rather a combination of 7 chemicals is required and it can be any of a number of combinations or permutations of 31 different chemicals.

The next meeting will be at Fair Meadows on June 26 at 6:00 PM. We will have a business meeting followed by a prairie walk.

Respectfully submitted,

Penny Shackelford, secretary