American Toads: A Few Wild Days, Then Solitary Again

My walks in Eliza Howell Park in the second half of April always include stops at the “Toad Breeding Pond.”

When the weather gets to be just warm enough, male American Toads, having recently emerged from hibernation, head to the pond to call in females. I expect to hear/see them within a few days of April 20 (either before or after), usually beginning the day following a “warm” night rain.

On April 17 this year, there was a light rain at about 9 p.m. when the temperature was about 51 degrees, which counts as “warm,” and some toads were, in fact, present on April 18. The active breeding did not really begin until April 21, however, because the weather turned colder. The temperature did not get above 44 degrees on April 19 and April 20, too low for these cold-blooded animals to think about breeding.

The next three days (April 21, 22, 23) were warmer and filled with the loud calling of many voices and lots of activity, even in daytime.

      Note: This toad photo and the next 3 below are courtesy of Margaret Weber

For 51 weeks in the year, toads are solitary and nocturnal (and they hibernate in burrows individually from November to April). During the brief breeding season, however, the sexually mature (2 or more years old) return to their natal pond, where the males compete in attempting to attract females by their calls.

Some time is spent, of course, in considering the options or the competition.

In mating, the male attaches himself to the back of the female and, while she lays eggs in the water (in strings), he releases sperm. Fertilization takes place outside the body.

In 3 – 12 days (depending upon the temperature), the eggs hatch and the resulting tadpoles will spend up to 2 months in the pond before they complete metamorphosis and are able to leave the pond. Only a very small percentage survives the first year.

Last year egg-laying was later, followed by cold weather which delayed hatching. Then there was a May hot spell, leading to the drying up of the pond before the tadpoles were able to survive on land. (See “American Toad Breeding Pond: the 2018 Story,” July 23, 2018.)

So I was pleased to hear from another member of the Eliza Howell frog/toad survey team on April 21 this year that toads were calling in a different location in the park, an annually flooded area by the edge of the road, a spot that I am creatively identifying as “Toad Breeding Pond 2.” I don’t know how many years toads have been using this location, but they were present in large numbers this year and will probably continue to do so in the future.

Typically, toads are loud and active in the breeding pond for 3-4 days. On April 24, all was quiet in both ponds. The adults have now gone their separate ways – till next April – catching insects mostly at night (the estimates are that one toad eats about 10,000 insects in the summer season), and hiding under leaves or logs in the daytime.

And I, instead of watching breeding adults, I hope to be watching tadpoles soon.

Thinking April during Winter Walks

I enjoy nature walks in the winter in Eliza Howell Park, especially when there is snow on the ground, but for 2-3 months the seasonal changes are minimal. Plants and many animals are dormant and the number of birds present is the lowest of any time during the year. Nature’s year begins later in the calendar year in Detroit, in March rather than in January.

So, during my quiet winter walks, I sometimes find myself thinking ahead and anticipating some of the special times that will be coming later this year, some of the best times to visit the park to observe, and perhaps to photograph, annual natural phenomena.

The first “don’t miss” days marked on my calendar are late April. (There will be a public nature walk on Saturday, April 27, at 10 a.m.)

In late April, the earliest of the summer breeding birds will have returned from their winter grounds and, like this male Red-winged Blackbird, will be claiming their territories and proclaiming their interest in a mate.

     Photo by Margaret Weber

Sometime in the second half of April (the exact time is temperature dependent), American Toads will return to their breeding pond in EHP and spend a couple of days and nights in loud calling and in mating / egg-laying. In 2018, the weather was too warm in May and the pond dried up before the tadpoles were fully developed, so it will be especially interesting to see what happens this year.

     Photo by Margaret Weber

Late April is also the beginning of the blooming wildflower season in the park, with a variety of small species found along the paths in the woods. The timing of this is also weather dependent, but on the basis of my experience over the last decade, the last week in April is usually a good time to see them. This collage of Violets is made up of pictures taken in 2018.

The Mayapple does not usually bloom as early as April in Eliza Howell, but it is fascinating to observe how it emerges. There are several patches where its progress can be observed in the late days of April.

Of the approximately 30 butterfly species that can be seen annually in Eliza Howell, the first ones usually show up in late April. The tiny Spring Azure, pictured with the wings up here, is a lovely blue when the wings are open.

April is also the month when the earliest bird nests can be found (the Red-tailed Hawk nest earlier). Most song birds build their nests later (the annual Detroit Audubon field trip to Eliza Howell to observe nesting bids is in early June), but I often find a couple by late April.

These pictures were taken in April, 2018. The one on the left, a nest on the ground, is Killdeer. The one on the right, in a shrub, is Northern Cardinal.

My walks continue all winter and I usually find something noteworthy each time, but the changes from one week to the next are nothing now like they are when spring has fully arrived. To avoid missing special developments – such as first butterflies, first wildflowers, first bird nests – it’s time to mark the calendar.

Six Hibernating Animals: See You in April

Animals have different ways of surviving winter in locations like Michigan where temperatures fall below freezing and the usual food sources are scarce or absent. Some (especially birds and mammals) find sufficient food options and remain active all winter. Some (especially insect-eating birds) migrate to a warmer climate for the season. Some (especially insects) survive only in the egg or pupa stage that will grow into the next generation of adults in the spring. And some hibernate.

I am using the term “hibernation” here to mean an adult remaining in an inactive or dormant condition, in the same sheltered location, all or most of the winter. Mammals (such as bears or groundhogs) may be the hibernators that we think of first, but many “cold-blooded” animals like reptiles, amphibians, insects, and crustaceans also hibernate.

On a recent walk, I started thinking of species that I find every year in Eliza Howell Park that are now hibernating. They include these six.

1.Eastern Chipmunk

While tree squirrels remain active all winter, often relying on the food (especially nuts) that they stored in the fall, the chipmunk, the only ground squirrel in EHP, hibernates. It stores some food for the winter in its winter burrow and eats when it awakens from time to time during the winter, before returning to its dormant winter condition.  It will emerge in the spring, when I often see the first of the year near the path by the river on a sunny day.

2. Common Garter Snake

I was walking in the park in the afternoon on December 2 this year when I was surprised to see a Garter Snake. My first thought was “I thought you would be hibernating.” They usually are in their den well before December, but this was a warm day (68 degrees), so it may not have been quite ready to settle down for the winter.

The non-venomous Garter Snake, with its three stripes along its roughly 2 feet length, is the only snake species that I encounter with any regularity in Eliza Howell Park.

3.Mourning Cloak

Photo by Margaret Weber

The Mourning Cloak is the first butterfly species I expect to see in the spring. Different from almost all other butterflies in our region, it overwinters as an adult rather than in a developing stage or by migrating – and this is the explanation for its early emergence. It finds a hidden location, such as under bark, seeking protection from the birds that forage for insect life all winter. The location may not protect it from freezing temperatures, but it can survive them.

4.Land Snail

In early October, these (Brown-lipped?) land snails were common in the wild flowers, climbing plants to consume dying leaves. Around first frost they settle down for the winter. They use their mucus to close the shell mouth and protect themselves from the cold. Before they seal themselves in, they find a location under rocks or ground litter protected from the cold and stay there until it is time to emerge in the spring. (Note “The Snails Have Returned,” April 18, 2018.)

5.Groundhog

This picture, taken in June, is of a half-grown immature Groundhog. Adults mate shortly after they emerge from hibernation in the spring. Groundhogs use burrows throughout the year, but they sometimes dig a separate one for the winter. They settle in below the frost line, rely upon their stored body fat, and sometimes lose half their weight during the months of winter. I don’t know if any of the Eliza Howell groundhogs check the weather on February 2, but, if one does, no one is there watching.

6.American Toad

Except for gathering at the breeding pond for an intense couple of days in April (See “American Toad Breeding Pond,” July 23, 2018), adult American Toads live quite solidary and nocturnal lives. In the Fall, they dig winter burrows with their feet, sometimes up to three feet deep. When the weather begins to warm and the insects become more active, they emerge and soon after, when the air temperature and the body temperature are right, the males will head to the breeding pond and call the females. (Some of us toad watchers will be listening.)

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While the dates vary somewhat, I usually see each of these species for the first time in April. Until then, I wish them a peaceful winter.

 

American Toad Breeding Pond: The 2018 Story

It was on February 28, I think, that I posted comments on the “Grassland Spring Pond,” where American Toads breed in Eliza Howell Park, and about my looking forward to what I might observe this year. The 2018 story is not what I had hoped for, but it is a story to be told.

Toads come to the breeding pond to mate and lay eggs for only about three days each April. I usually expect them slightly later than the middle of the month, but the timing is dependent upon the weather. April was colder than normal this spring, but in order to make sure I did not miss anything, I started checking the pond on April 12.

It wasn’t until late in the month that the weather conditions were right for the males to head to the pond. I first heard their loud trilling mating calls on April 25, loud enough to be heard by the females.

The field was starting to turn green by then.

During these mating days, male toads call both during the day and at night, but toads travel to and from the pond only nocturnally. My frog-and-toad-survey colleagues and I visited the pond after dark on April 26 and listened to their very loud chorus for several minutes.

In the beam of the flashlight, I saw this toad, probably a female just arriving.

April 27 was the last date we heard toads in the pond. American Toads, when they are ready to breed, normally return to the same pond where they were tadpoles. While I don’t know how the numbers compared with previous years, it was great to see – and hear – them in the same location again this year.

How quickly toad eggs hatch is also temperature dependent. The weather remained cool and it was a longer time than usual before the tadpoles emerged. It was not till May 21 that I found them in good numbers, three and a half weeks after the adults left the pond. (By comparison, I first saw many tadpoles on May 6 in 2017.)

This picture was taken on May 24.

Following the long cool spring, the weather became quite warm. Actually, it was hot. The high was in the 80s the whole last week of May, reaching 90 degrees on May 28.

The pond plants grew rapidly and on May 29, the pond looked like this.

The weather was all wrong for American toad breeding in the pond this year. The cold spring delayed mating; further cold weather delayed hatching; hot weather dried up the pond before the tadpoles could develop.

On May 29, the water was gone and I saw dozens of dead tadpoles in the mud. They were still weeks away, it appeared, from metamorphosis, weeks away from being able to leave the water as toadlets.

The Eliza Howell toad population will be smaller for at least a year.

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The 2018 toad pond story leaves me with a question about the future of the pond. While I think one can rightfully point to the long cool spring followed by a very hot late May this year as the basic reason for breeding failure, I also wonder whether the pond is becoming more shallow over the years, whether it will be able in other years to maintain sufficient water into June to serve as a viable toad breeding pond.

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While the grassland pond has been an American Toad breeding hotspot, it is not the only location in or near the park where they breed. Recently, I saw clear evidence of this, two small toads, not much more than an inch in length, in the bottomland by the river. This is one.

Somehow, seeing these new toads made me finally ready to tell the story of the grassland pond 2018 breeding failure.

It will be interesting to see what happens next year.

 

Grassland Spring Pond: The Annual Cycle Begins

The recent late February thaw and rains re-filled the shallow pond that I have come to know as “The American Toad Breeding Pond.” This temporary pond exists each year from late Winter or early Spring until the summer. It is a pond for only about 4 – 5 months, but a lot happens in the months that are beginning now.

The pond is found in the grassy area within the road loop and borders (sometimes overflows) the walking path. This picture is from this week.

When pond appears each year about this time, I modify my wanderings to make sure that I take a careful look at it each time I am in the park. I don’t want to miss the life it attracts.

For most of the year, adult American Toads are solitary, mostly nocturnal, and rarely seen. When they are found, they are typically on land, not in water.

Sometime in April, the exact time probably determined by temperature and rain, breeding adults head to the pond. Then, throughout the day, the males sound forth with their loud trilling mating calls, announcing themselves to the females.

        Photo by Margaret Weber

Dozens, perhaps hundreds, of males and females converge on the pond and engage in what appears to me to be a mating frenzy. The phenomenon is short-lived; in a couple of days, the adults depart and the pond is quiet again. A few days later the eggs begin to hatch and the tadpoles quietly develop over the next several weeks.

Killdeer and a few other “shorebirds,” like Solitary Sandpiper, can occasionally be found at the edges of the pond and dabbling ducks, especially Mallards, frequently forage in the water.

A couple years ago this pond was, over a period of days, the hangout of an odd couple – a male Wood Duck and a female Mallard. They were constantly together and may very well have produced hybrid ducklings after they moved on.

      Photo by Margaret Weber

These are some of my memories when the pond fills again. And I look forward to what I might witness at the grassland pond in 2018.