Sunday, January 29, 2012

Winter and Early Spring Vernal Pool Egg Mass Identification: Pt. 1 Frogs

Vernal pools are teaming with life now that winter rains and snow have filled them with water.

Photo: Linda Ruth

These low areas that usually hold water from winter through early summer are very important ecosystems because this habitat allows certain frogs and salamanders to lay their eggs without the fear of their offspring being devoured by fish. Vernal pools also are the main breeding ground for many insects and fairy shrimp.

Photo: Fairy Shrimp by Linda Ruth

These animals are the main diet of amphibian larva. Many of these frogs and salamanders lay their eggs in mass. I am going to give information on how to identify amphibian egg masses that can be observed from winter into early spring.

First of all, it is important to be able to differentiate between a frog egg mass and a salamander egg mass.

Photo: Salamander egg mass by Richard Bonnett

In the above photo you can see that these eggs have an outer layer of gelatinous material that encapsulates the egg mass. All salamander egg masses in vernal pools will have this outer layer of material.

Photo: Frog egg mass by Ronnie Puckett

Frog egg masses do not have that outer protective layer like salamanders. The outer edge of the mass is made by the eggs. Once you have determined whether the eggs are from salamanders or frogs you can start to try to get the eggs to species. I have included maps from the USGS National Amphibian Atlas that show ranges for each species to county level. The color codes are as follows: Dark Green = Museum record, Middle Green = Published record, Light Green = Presumed presence, no green = no known occurrence.

Wood Frog
Photo: Bill Hubick

Wood Frogs are our earliest anuran breeder. They are very common in most wooded vernal pools. Wood Frogs are found in every state in the Mid Atlantic region.

Egg masses of Wood Frogs will have anywhere from 500 to 2000 eggs and the mass is very cohesive, meaning that the egg mass structure will hold together when taken out of the water.

Photo: Richard Bonnett

Individual eggs, when young, will have a black and white coloration. The white coloring will slowly disappear as the larvae mature. In the above photo the middle eggs are the youngest while the egg mass on the left is the oldest. After the egg mass has been in the water for a few days the distance between the embryo and the edge of the egg starts to expand. You can age a Wood Frog egg mass by how large the distance is between the embryo and the outside of the egg.

Northern/Southern Leopard Frogs

Photo: Southern Leopard Frog by Jim Brighton

Photo: Northern Leopard Frog by Jim Brighton

Leopard Frog eggs are easy to tell apart from Wood Frog eggs by the size of the egg and embryo.

Photo: USGS Amphibian Site

In a Leopard Frog egg mass there is usually twice as many eggs than in a Wood Frog egg mass, but the two species egg mass sizes are virtually the same. This means that a Leopard Frog egg is about twice as small as a Wood Frog egg. Their egg masses appear almost pure black because there isn't as much room between the embryo and the outside of the egg. Young eggs are the same color as Wood Frog eggs, black and white. Even though you can't tell by the above photo, Leopard Frog egg masses are not cohesive, meaning they will easily fall apart when taken out of the water. Often Leopard Frog eggs will be lower in the water than those of Wood Frogs. The eggs sometimes rest on the bottom of the vernal pools which means that the egg mass is often covered in silt and debris. Fortunately, Northern and Southern Leopard Frog ranges do not overlap that often, so getting your egg mass to species shouldn't be that difficult.

Northern Leopard Frog

Southern Leopard Frog

Pickerel Frog

Photo: Jim Brighton

The egg mass of a Pickerel Frog is virtually identical to Leopard Frog eggs. Luckily for us there is one characteristic that saves us from lumping Pickerel Frog egg masses in with Leopard Frogs. The eggs of Pickerel Frogs are brown and yellow not black and white. Unfortunately, I do not have a photo to show the noticeable contrast in colors. There is a nice photograph on the Virginia Herp Atlas webpage that shows the brown coloration of the egg mass. It can be viewed here:

American Toad

Photo: Jim Brighton

American Toad egg masses are the easiest of the anuran vernal pool breeders to identify. They are the only early spring amphibian breeders who lay their eggs in long strings. The egg mass often sits on the floor of the vernal pool resulting in the egg mass being covered in silt.

Photo: Rob Kirkland

Photo: Rob Kirkland

Southern Toad

Photo: Hunter Desportes

Southern Toads only hit the Mid Atlantic region in the coastal plain of Virginia and North Carolina.

Like the American Toad, Southern Toads lay their eggs in long strings. I couldn't find much information on Southern Toad egg masses but the eggs and egg strings are usually smaller than American Toads.

Photo: USGS Amphibian Site

From photos, like the one above it seems that Southern Toads egg strings lay straighter than the curly strings of the American Toad, but this is just my observation from looking at photos and may not be accurate. Luckily, the ranges of the two species only overlap in a few areas so it shouldn't be to difficult to figure out.

There are a few more frog species whose ranges reach into North Carolina like the Crawfish Frog and various species of Chorus Frogs who also use vernal pools for reproduction. Chorus Frogs normally have very small loose egg masses of between 10 to 50 eggs. Crawfish Frog egg masses closely resemble Leopard Frog egg masses, but you'll only have to deal with separating these species in southern North Carolina. Spring Peepers also use vernal pools throughout the Mid Atlantic region during the late winter and early spring but they normally lay their eggs singularly and not in large masses.

Most of the above photos were used under the Flickr Creative Commons license. I would like to thank all the photographers who made this post possible. Please visit their websites and peruse their wonderful photos.

Bill Hubick:
Linda Ruth:
Richard Bonnett:
Ronnie Puckett:
Rob and Jane Kirkland:
Hunter Desportes:

The range maps I used are found on the USGS National Amphibian Atlas website.

These are the books I used when doing my research.
White, James & Amy. Amphibians and Reptiles of Delmarva. Centerville: Tidewater Publishers, 2002.
Conant & Collins. Reptiles and Amphibians of Eastern/Central North America. Boston: Houghton Mifflin, 1998.
Martof, Palmer, Bailey, Harrison. Amphibians & Reptiles of the Carolinas & Virginia. Chapel Hill: University of North Carolina Press, 1980.
Petranka, James. Salamanders of the United States and Canada. Washington, D.C.: Smithsonian, 1998.

Amphibiaweb is an amazing website. Hours of fun exploration available!
On the USGS website there is a page that has a field key to amphibian eggs of Minnesota, Wisconsin, and Iowa. Luckily, the Mid Atlantic region shares many of the same species. The key is really easy to use.
On Field Herp Forum there was a post that helped me greatly with this blog post. The photos are awesome and his egg mass descriptions are very clear and concise.

Monday, January 23, 2012

Sundews of the Mid Atlantic

Sundews are one of my favorite plant groups. Sundews are carnivorous plants that gain nutrients by trapping insects with sticky secretions that form droplets on the stems and leaves. Tom Muroski on the State College carnivorous plant website states very simply how sundews trap their food.

The Sundew is covered with a series of short hairs, referred to as Tentacles, that each contain a ball of sticky liquid. When an insect touches this liquid, it tries to get out by squirming, but that only makes matters worse, since the little hairs start moving together in order to stick more of the liquid to the bug...Once the bug is caught, the hairs start to make acids and enzymes to break down the bugs. The remaining juice drips onto the leaf where it is absorbed into the plant for food.

Below is a photo I took in Worcester County, MD of a Spatula-leaved Sundew (Drosera intermedia) that has caught a Common Pondhawk.

Photo: Jim Brighton

All sundews belong to the genus Drosera. There are over 190 species worldwide. North America has ten species and the Mid Atlantic region has five species. The Drosera in our region are usually found in moist boggy areas with plenty of sunlight. Below, I am going to describe the five species of Drosera of our region and give enough information that the reader will be able to identify any sundew they stumble upon. First, I am going to give a brief glossary of some of the botanical terms that I will be using in the descriptions.

Cuneate -- wedge shaped
Glabrous -- smooth, a surface without hair
Glandular-pilose -- covered in fine soft hairs with secreting glandular ends
Obovate -- egg shaped and flat with the narrow end attached to the stalk
Petiole -- the stalk of the leaf that attaches to the stem
Pilose -- covered in fine soft hairs
Spatulate -- broad at the apex and tapered to the base

Round-leaved Sundew (Drosera rotundifolia)

Photo: Bill Bouton

In our region Drosera rotundifolia is found on and off the coastal plain. It is the only sundew that is found in the mountainous region of the Mid Atlantic.

The leaves are round, broader than long and shorter than the petioles. The petiole is very glandular-pilose.

Photo: Bill Bouton

The flower of the Round-leaved Sundew is normally white but can be pink.

Photo: Bill Bouton
Pink Sundew (Drosera capillaris)

Photo: Wiki commons

The Pink Sundew is the common sundew of the southeastern coastal plain. It's northern most range is on the Delmarva Peninsula. Unfortunately, the Delaware population is extirpated and according to the Maryland Natural Heritage website there are only three populations left on the Eastern Shore of Maryland.

The petioles of the Pink Sundew are sparsely glandular-pilose and the leaves are broadly spatulate.

Photo: Barry Rice

The flower of the Pink Sundew is pink, but very rarely can be white.

Photo: Wiki commons

Spatula-leaved Sundew (Drosera intermedia)

Photo: Chris Moody

Spatula-leaved Sundew is the common sundew on the Delmarva Peninsula and the coastal plain. Off the coastal plain it can be found in northeastern Pennsylvania, northern New Jersey, and throughout New York. Only a few populations exist in Virginia, all on the coastal plain. It's range in North Carolina is limited to the southeastern portion of the state.

Drosera intermedia petioles are glabrous. This feature is diagnostic to the large sundews in our region. Its leaves are oblong spatulate or obovate.

Photo: Lisa Lawley

Dwarf Sundew (Drosera brevifolia)

Photo: Barry Rice

Dwarf Sundews are found in the southern region of the Mid Atlantic. It is found on the coastal plain of Virginia and North Carolina. It can be easily overlooked because of its very small size and is generally not as common as the Pink Sundew. The two species can be found inhabiting the same areas.

Dwarf Sundews are easily identified by their small size. While the petioles are glabrous like Drosera intermedia, the petiole only measures 5-10mm compared to the 2-5cm of Drosera intermedia. The leaves are cuneate shaped and usually longer than the petioles.

Photo: Barry Rice

The flowers of the Dwarf Sundew range from pink to white.

Photo: Barry Rice

Thread-leaved Sundew (Drosera linearis)

Photo: Travel Stuffies

Thread-leaved Sundews have the smallest range of any of the sundews in our region. The largest populations are in the New Jersey Pine Barrens. Smaller populations are located on Long Island and the southeastern portion of North Carolina. Maryland has a population at Suitland Bog in Prince George's County, but this population is not native and the plants have not been observed in recent years. Drosera filiformis is extirpated from Delaware according to BONAP's North American Plant Atlas.

Thread-leaved Sundew looks nothing like any of our other sundews. The leaves of the plant are long and erect and the glandular hairs are purple colored.

Photo: Natalie McNear

Photo: John Brandauer

The flower of Drosera filiformis is a purplish pink.

Photo: Anita Gould

The sundews and many other carnivorous plants are becoming scarcer as the wetlands where they live are drained for urban development and agricultural uses. While habitat destruction is the leading cause of these plants demise, collecting plants is also a serious problem. Many people do not realize that wild transplanted plants are very difficult to keep alive and most often die. For someone who would like to try to keep a carnivorous plant there are many breeders who raise captive bred plants which are much more likely to survive in a domesticated setting.

I would like to thank Barry Rice whose website is the best site on web for carnivorous plants. He has more photos of species and varieties than any other website I have found. The information that is available on his site is amazing.

All of the other photos I used for this post were gleaned from the Flickr Creative Commons or Wiki commons. Below are links to the photographers photo sites.
Anita Gould --
John Brandauer --
Natalie McNear --
Travel Stuffies --
Lisa Lawley --
Chris Moody --
Bill Bouton --

For the descriptions of each species I relied heavily on the website
On the website is a key to the North American Drosera.

Bonap's North American Plant Atlas has county level maps of all the North American Drosera

USDA Plant Database, whose maps I used on this post, can be viewed at

Here is a list of reputable carnivorous plant breeders
Botanique --
Carnivorous Plant Nursery --
California Carnivores --

Tuesday, January 17, 2012

Ghost Tiger Beetle (Ellipsoptera lepida)

Last July, Jim Stasz and Ed Boyd took Tom Feild and myself up to the Pine Barrens of New Jersey to look for plants. We found many great plants like the federally endangered American Chaffseed (Schwalbea americana) and the New Jersey state endangered Bog Asphodel (Narthecium americanum).

American Chaffseed

Bog Asphodel

We also saw many cool insects like Martha's Pennant (Celithemis martha)

Martha's Pennant

and my favorite sighting of the weekend, a Ghost Tiger Beetle (Ellipsoptera lepida).

Photo: Ben Coulter

The Ghost Tiger Beetle is a very scarce tiger beetle in the genus Ellipsoptera. These beetles are found only in very sandy habitats like coastal sand dunes and inland sand washes. Most of the New Jersey Pine Barrens is composed of sandy well drained soil. This is just the type of habitat to find Ellipsoptera lepida. Because of their white body and dark thorax if the Ghost Tiger Beetle isn't moving it becomes virtually invisible. It is often said that it is easier to see their shadow than the actual beetle.

Photo: Ben Coulter

The Ghost Tiger Beetle is scattered throughout the northeast and central United States. The map below shows some of the county distribution for Ellipsoptera lepida.

This map was taken from the USGS tiger beetle distribution site. All the Mid Atlantic states have or had Ghost Tiger Beetle populations. Normally these populations are restricted to the coast (North Carolina, Virginia, Maryland, and Delaware). New Jersey has records for eight of its 21 counties and quite a few are inland records. All of the Pennsylvania populations which were centered around Lake Erie are listed as historical. A survey conducted in New York from 1995 - 1998 found 13 populations in five counties.

Photo: Ben Coulter

This photo shows in great detail all the necessary identification points for the Ghost Tiger Beetle. The white elytron (back of the beetle) with dark maculations (markings on the back of the beetle). The head and thorax are bronzy with fine white setae (hairs) and the white legs are diagnostic.

Photo: Ben Coulter

Unfortunately, much of the habitat where these beetles live has been lost due to urbanization and industrialization. In the book A Field Guide to the Tiger Beetles of the United States and Canada, the authors state that they believe,

that 33 (15%) of the 233 named species and subspecies of tiger beetles in Canada and the United States may be declining at a rate that justifies their consideration for inclusion on the U.S. Fish and Wildlife Service's List of Endangered and Threatened Species. At present, only five of these are officially listed, and several others are under consideration for listing.

With our lands being under the constant threat of industry and urbanization it is important to keep an eye on nature. Will there be a significant impact on the ecosystem if the Ghost Tiger Beetle disappears? Probably not, but I feel that these creatures are our responsibility. Groups like the Nature Conservancy who set aside land for species just like the Ghost Tiger Beetle deserve our support. Fortunately, the land is preserved where we saw our lepida and the population is very strong.

All of the photos of Ellipsoptera lepida in this post were taken by my friend Ben Coulter in Ohio. Many more of his fine photographs can be viewed at his flickr site

Below are listed a few books that are relevant to tiger beetles of the Mid Atlantic. All of these books can be purchased on Amazon.

A Field Guide to the Tiger Beetles of the United States and Canada: Pearson, Knisley, Kazilek, Oxford, 2006
A Field Guide and identification Manual for Florida and Eastern U.S.: Choate, University Press of Florida, 2003
The Biology of Tiger Beetles and a Guide to the Species of the South Atlantic States: Knisley, Schultz, Virginia Museum of Natural History, 1997

Here are a few websites that have tiger beetle info:

The USGS tiger beetle site has loads of info and lots of distribution maps

Giff Beaton's tiger beetle site has tons of photos

Bug Guide is the ultimate insect resource for North America. It has photos and informations on all the US tiger beetles.

Mathew Brust's flickr site has awesome photos of lots of pinned specimens and live shots