Spring has sprung and love is in the air!

Many consider the arrival of robins or a famous groundhog and his shadow as the official start of spring. But, don’t overlook one very important ambassador group to spring – amphibians!

As soon as the first warm rain occurs, amphibians begin emerging and trekking to small, temporary pools, known as seasonal pools, as well as stormwater wet ponds and other wetlands.

Seasonal pools are sensitive areas that provide critical habitat for invertebrates, amphibians, reptiles, birds and mammals. These small, productive, and important wetlands are critical for maintaining many species. The quality of the pools is directly related to the surrounding land use – changes to the landscape can cause pools to dry prematurely, fragment the habitat and natural corridor between pools, and introduce contaminants and toxins. And, because pools are smaller bodies of water, problems with water quality can show up within them prior to being evident in streams and rivers and even drinking water.

Seasonal Pool in Little Bennett Regional Park in early March 2009. The clucking of wood frogs could be heard before even arriving at the water’s edge. (Photo credit: Rachel Gauza)

In early spring, the pools are bursting with activity and the air is filled with choruses of “love songs” produced by male frogs advertising their availability.

Listen carefully, especially in the evening and at dusk, and you may be treated to calls of:

1. Wood Frogs – The first to advertise with a chicken or duck-like clucking. Identify them visually using the dark eye patch resembling a “burglar’s mask” which goes across their eyes and extends down over their ear drums and upper lip. Also look for signs that wood frogs had visited the pool: clusters of clear eggs that have a grape bunch appearance. These clusters will appear just below the water surface and may be laid singularly and attached to pool vegetation or twigs, or may be present in large sheets if deposited communally. Once the eggs hatch, look for small tadpoles with darker bodies flecked with gold spots and tails that are lighter in color than the body. 

Adult wood frog (Photo credit: Jennifer St. John)

 
 
Communally-laid wood frog egg masses in a woodland pool in Little Bennett Regional Park. (Photo credit: Jennifer St. John)

 
 
Wood frog tadpoles in a riparian woodland pool. (Photo credit: Rachel Gauza)

2. Northern Spring Peepers – Little frogs about the size of a quarter with a big voice. As the name suggests, they make a clear peep when calling which can change to a more agitated rattle (preeeeep) if two males are competing for a calling area or a female. If you give these pint-sized frogs a whistle, they might just respond! Look for these small treefrogs calling from the water and clinging to vegetation.

Northern spring peeper (Photo credit: Rachel Gauza)

3. Pickerel Frog – Often calling individually, these frogs will emit a lazy snoring sound. Identify them by the two lines of squarish spots down their back and the yellow under their legs.

Pickerel frogs (Photo credit: Rachel Gauza)

4. Eastern American Toad – Emit a lengthy hum that can last upwards of 30 seconds. It can be mimicked by humming and whistling simultaneously. Toads differ from frogs in that they have warty skin and two large paratoid glands on the neck behind each eye. When not visiting pools to mate, toads tend to be more terrestrial, navigating the forest floor as well as people’s yards looking for insect prey. Eastern American Toads have one to two warts in each dark spot and a mottled breast.

Eastern American Toad pair in amplexus (mating position) (Photo credit: Rachel Gauza)

5. Fowler’s Toad – Call similar to that of its close relative, the Eastern American Toad, but a shorter, less musical waaahhh, lasting only one to three seconds. Fowler’s toads have three or more warts in each dark spot and a white breast, sometimes with a single central spot. 

Fowler’s Toad (Photo credit: Rachel Gauza) 

As the season grows later, more sounds join the chorus: trills of gray treefrogs, rattling/clicking of eastern cricket frogs, the banjo pluck of northern green frogs, and the mewing or “mooing” of American bullfrogs.

Keep an eye out for Spotted Salamanders! These secretive salamanders are most active in early spring as they emerge from their underground hiding places, searching for a mate. They are large (6-8”), gray to black salamanders with two rows of irregular yellow to orange spots down their back. In addition to their charismatic appearance, these spectacular salamanders return to the same pools annually, traveling hundreds of meters and even bypassing foreign pools. Additionally, these salamanders and can live more than 20 years. Once mating is completed, spotted salamanders disperse into the pool’s surrounding forested areas. Be sure to also look for egg masses: globular, relatively firm jelly encased eggs beneath the water. Gilled (aquatic) larvae may also be visible.

Adult male spotted salamander (Photo credit: Rachel Gauza)

You may also have the good fortune to find small crustaceans called Fairy shrimp. Fairy shrimp resemble brine shrimp (often referred to as “sea monkeys”) and can be seen swimming upside down along the bottom or in the water column of the pool using their delicate paired swimming legs. Fairy shrimp are obligate taxa to seasonal pools and cannot survive in any other environment. They spend their entire life cycle in the pools; feeding on microbes and detritus in the water column or substrate. Some species of fairy shrimp produce two types of eggs – one type hatches immediately while the pool is holding water, the other may lay dormant through the dry season, surviving many years before hatching. These dormant eggs may be transported by mammals, birds, insects, and amphibians visiting the pool as well as by the wind.

Fairy shrimp (Photo credit: Jennifer St. John)

Many other invertebrates are also busy in the pools. Take a closer look and you’ll find daphnia (“water fleas”), crayfish, dragonfly nymphs, aquatic beetle larvae and adults, worms, caddisflies, isopods (resembling terrestrial “pill” or “potato bugs”) and much more.

White River Crayfish (Procambarus acutus acutus) in seasonal pool (Photo credit: Rachel Gauza)

 
Head out to your local “watering hole” and have a look and a listen! If you a visit a pool, walk around the edge and look carefully. Do not walk in the pools since these environments are very sensitive. Biologists that monitor pools follow a strict boot and equipment sanitization routine so not to introduce diseases and pathogens. Also, please keep in mind that many amphibians are on the move, particularly at night time, so take care when driving not to injure or kill migrating wildlife.

For more information, please visit the following:

Amphibian Ark – www.amphibianark.org

FrogWatch USA - http://www.nwf.org/FrogwatchUSA/frogs_state.cfm?showstate=md#frogs

Herps in the Backyard Brochure – www.pwrc.usgs.gov/neparc/Products/Backyard.htm

Maryland Amphibian and Reptile Laws and Regulations: http://www.dnr.state.md.us/wildlife/captive.asp

Mid-Atlantic Turtle & Tortoise Society, Inc. – www.matts-tutles.org

North American Amphibian Monitoring Program – http://www.pwrc.usgs.gov/naamp/

Partners in Amphibian and Reptile Conservation (PARC) – www.parcplace.org

Towson University Herpetology – http://wwwnew.towson.edu/herpetology/Amphibians.htm

US EPA Seasonal Pools – http://www.epa.gov/bioiweb1/html/vernal_pools.html

USGS ARMI Atlas – http://igsaceeswb00.er.usgs.gov:8080/mapserver/naa/