Developing, in a Pool Near You…

Every child should have mud pies, grasshoppers, water bugs, tadpoles, frogs, mud turtles, elderberries, wild strawberries, acorns , chestnuts, trees to climb…and any child who has been deprived of these has been deprived of the best part of education.

~Luther Burbank

The arrival of spring is a stop and go affair here in central North Carolina. Warm, sunny days, rain, then a windy cold front, and back again. But, the early harbingers of spring (spring wildflowers, the first pollinators, lusty amphibians, etc.) have a duty, and so they persist. Among the most dutiful are the upland chorus frogs, Pseudacris feriarum. I shared an intimate froggy moment of amplexus in an earlier post a few weeks ago. In case you missed it, here it is again…

Upland chorus frogs in amplexus

Upland chorus frogs in amplexus in mid-February (click photos to enlarge)

These tiny songsters have been calling and courting since early February in various pools at work (NC Botanical Garden). They normally prefer temporary (vernal) pools that often dry up in summer, making them unsuitable for fish. This year they are also breeding in our Turtle Pond, a permanent small pond that is loaded with tadpole predators, especially mosquitofish. So, I pulled one of the egg masses out and brought it inside to photograph, with plans to release them in one of the nearby vernal pools before they transform into frogs.

Upland Chorus frog eggs

Upland chorus frog egg mass

This species utilizes a wide variety of breeding sites, from natural vernal pools to water-filled tire ruts and roadside ditches. Females lay several small egg masses, each containing 50-100 eggs on average (this can vary greatly) for a total of about 1000 eggs each season. She usually attaches them to vegetation or a twig under the water.

Upland chorus frog egg mass near hatching

Tadpoles almost ready to emerge

The eggs hatch within about a week, with the embryos transforming rapidly from a round blob to elongate stylized tadpoles. The ones in my office window started hatching on a Friday afternoon.

Newly hatched tadpole

Hanging out after hatching

When I went in that Saturday, most were hanging vertically in the small aquarium like tiny cream-colored mummies. Look closely and you can see some tiny filaments off one side of the lower edge of the head region. I assume these are the external gills, which only last a few days after hatching in most tadpoles.

Upland chorus frog tadpoles after 2 days plus copepod

Two days old

On Monday, the now two-day old critters were changing color and looked a lot more like tiny tadpoles. Note how the head region has enlarged, and how you can now clearly see their insides, darkening eyes, and mouth (the photo above is of their ventral side). Also note the tiny zooplankton (a copepod with egg sacs) swimming just to the right of the upper tadpoles’ tail tip. I am amazed at how much tiny life I collected when I dipped up a small bucket of water from Turtle Pond.

Upland chorus frog tadpole 1 week old 1

Four days old and growing

Another couple of days go by and they are changing rapidly – darkening in color, adding subtle gold flecking, getting larger, and swimming more vigorously. These tadpoles should transform into juvenile frogs in 6 to 8 weeks, depending on temperature and food availability.

Upland chorus frog egg 4 days after hatching 1

Grazing on algae

I will probably let most of them go this coming week, and hang onto just a couple in hopes of watching the rest of this amazing metamorphosis.

Upland chorus frog tadpole 6 daysold

Six days old and counting

Trending Now…Spring

No matter how long the winter, spring is sure to follow.

~Proverb from Guinea

It has been a busy couple of weeks, both at the office, and in the Garden outside. Temperatures have swung widely – 60+ degrees a couple of days ago, a nice fire in the fireplace last night, a pretty typical February in North Carolina. But the natural world has its own schedule, its own to-do list. It starts start slowly, and then erupts – it is the arrival of spring. One of the first signs is an auditory one. On one of the warm mornings last week, I noticed birds starting to sing (especially the Northern cardinals, Carolina wrens, and Eastern bluebirds).

Early saxifrage

Early saxifrage in bloom at the NC Botanical Garden (click photos to enlarge)

The first wildflowers of the season make a quieter appearance. Early saxifrage, Micranthes virginiensis, is easy to miss when walking the paths at the Garden, my mind full of things to check off my to-do list. Luckily, someone alerted me to the first flowers, but I still had to look hard to find them. The generic name means small flower. an appropriate name for a a plant with tiny white flowers less than 1/2 inch across. Ironically, the common name, saxifrage, bestows a more powerful status to these tiny plants. It means stone breaker. Many species of saxifrage are plants of rock outcrops, with the tiny plants often nestled in soil deposits of the cracks and crevices of boulders. People once believed these plants to be responsible for the splits in the rocks where they grew.

spotted salamander egg mass in turtle pond

The first spotted salamander egg masses of the season

Some early spring amphibians are also on the move as the days lengthen. The first spotted salamander egg masses appeared in the pools at the Garden and in my home woods last week. Not a huge run of salamanders as yet, but a sure sign that warmer weather is on the way.

Upland chorus frogs in amplexus

Upland chorus frogs in amplexus

While salamanders and saxifrage can appear without fanfare, the frogs of spring can’t be missed. Last week, we heard the first trills of our earliest frog breeder, the upland chorus frog. Instead of the vernal pool, their favorite dating hot spot last year, they were calling from the artificial “stream” at the back of the herb garden. This species is normally quite shy, and will quickly cease calling as you approach their breeding habitat, disappearing beneath the leaf litter or vegetation in the shallows. But at this location, the water is contained within concrete stream banks with little leaf debris, making it harder for these cryptic callers to vanish. You can usually locate one by a slight ripple in the water when they duck under the surface. Indeed, they all quit calling as I walked over, so I scanned the water’s edge, and found a pair in amplexus (the mating position of frogs and toads, in which the male clasps the female about the back and fertilizes the eggs externally as she deposits them). Unfortunately, I only had my macro lens with me, but I eased closer anyway, hoping to get at least one image. To my surprise, I was able to creep up, kneel down and get a close-up portrait without disturbing them The next evening I could hear more calling as I walked to my car. Then, two nights ago, the first spring peepers of the season were calling in the vernal pool in the woods next to the parking lot. It is coming…the eternal march of the seasons is quickening its pace. Get ready, the great greening of the landscape is not far off.

Woodland Chorus

What is the earliest sign of spring? The motion of worms and insects? The flow of sap in trees and the swelling of buds? Or are there earlier signs in the water? – the tortoises, frogs…

Henry David Thoreau, March 7, 1853

I think the sounds of the coming spring are amongst the first things I notice. The bird songs, the whir of insect wings, the busy rustling of leaves as squirrels begin making their spring nests. Even the breeze sounds different on a warm, late winter day. But one of the surest signs of the warmth to come are the calls of our early amphibians. Here in the forests of the Piedmont of North Carolina, that role is usually handled by Spring Peepers and Upland Chorus Frogs. I started hearing the chorus frogs a few weeks ago, before the last snow and deep freeze. They took a break while their world turned white, but now they are back on duty, proclaiming a change is in the air. I have spent some time over the past several years trying to photograph various species of frogs and toads as they fill the air with their distinctive mating calls. I have had some good success, but one species has managed to elude me – the Upland Chorus Frog, Pseudacris feriarum. I find it both difficult to approach and difficult to observe when calling. They tend to call from shallow water in vegetated pools, often hiding amongst the vegetation as they sing. At my approach, they invariably fall silent, requiring a quiet sit and wait strategy on my part before they call again, if at all. So, I was determined to try again this week after hearing a fair number of them calling in several woodland pools while on my walk this past Sunday. Using binoculars, I watched a few calling at a distance of 30 or more feet in one large pool. I also found several of their small egg clusters attached to some twigs and grasses in the water.

Upland Chorus Frog eggs

Upland Chorus Frog eggs  (click photos to enlarge)

I even saw a pair in amplexus, that amphibian embrace where the male clasps the female from above and fertilizes the eggs externally as she releases them. But, the calling frogs were either too hidden in thick vegetation or too far out in the pool for a good photograph. Walking down through the floodplain I soon heard another loud chorus coming from behind a ridge line that angled toward the stream. As I climbed over the top for a look, I saw a small pool that contained a dozen or more calling frogs.

Woodland pool

Woodland pool with Upland Chorus Frogs

I sat and watched and decided this pool had potential – there was a large tree on one edge that wold provide a bit of cover. The pool was small and the sun would be coming over my shoulder late in the day, so the chances for good photographs seemed likely. Even though the frogs had started calling again shortly after I initially walked up, I was a bit concerned that when sitting against the tree trunk, I might be too close, and that might really spook them. So, the next afternoon I brought my Kwik Camo blind ( I thought it would allow me to better blend in, so the frogs might start calling again even after I brazenly walked into their concert hall. The blind fits nicely in a belt pouch and is lightweight, so it is easy to strap on and carry for long hikes. Plus, it drapes over my camera, tripod, and my human form, and turns me into an amorphous bush that hopefully looks less threatening than a person armed with photography gear.

As suspected, my approach and settling in quickly silenced the almost deafening chorus, so I got situated under the blind, leaned against the tree trunk, and waited. And then waited some more. About thirty minutes went by without a sound except for leaves blowing in the wind. And I could still only see one frog in the pool, and even that one was low in the water and partially hidden by a stick. I decided to try to coax a reaction by using my phone to search the web and play a recorded call. I used the Amphibians and Reptiles of North Carolina web site created by Davidson College at I played the call twice. No response. I looked through my viewfinder at the one visible frog and played the call again. This time, that frog raised up so that the top half of its body was out of the water. I suppose he was trying to figure out where this caller was hiding. But he did not answer.

Upland Chorus Frog checking the scene

Upland Chorus Frog checking the scene

So, I waited some more. Another 15 minutes went by and I was beginning to wonder if I had simply tried to get too close and they were having nothing of it. Then a sound – a partial call. The call of the Upland Chorus Frog sounds something like the noise made by running your fingers over the teeth of a comb – a regularly repeated “crrreek”. This was just one crrreek. But that was enough to stimulate another, then another, and soon the pool sounded like a bunch of busy fingers in a comb factory. Ten or more heads suddenly appeared from the pool and started calling, with the tell-tale enlargement of their vocal pouch keeping time with their crrreeks. The first few callers were partially hidden, either barely out of the water or using some nearby object as cover.

Upland Chorus Frog calling barely out of water

Upland Chorus Frog calling while barely out of the water

Upland Chorus Frog calling 2

Upland Chorus Frog calling with a leaf shelter behind it

But, in less than a minute, it was a frog calling cacophony.

Upland Chorus Frog calling side view with stick

Upland Chorus Frog calling

Upland Chorus Frog calling with foreground leaf

Upland Chorus Frog calling out in the open water of a shallow pool

Here is a short video so that you can share in the amazing sights and sounds of this anuran symphony.