How to find amphibians during their spring breeding migrations

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Every spring in the Northeast, as the snows melt and the ground begins to thaw, frogs and salamanders move out of their upland overwintering habitat into wetlands to breed and lay their eggs. Unfortunately, when roads pass between breeding wetlands upland forests, many of these amphibians are killed during their seasonal back and forth travels. If a road has enough traffic, entire populations of amphibians can be lost over time as even a single vehicle can kill dozens, or even hundreds of amphibians in one night. In areas with very light traffic, roads also open the door for people to witness the migrations with their own eyes and get a close look at some species that will spend the rest of the year hiding underground. For children especially, getting a close look at a large salamander on a rainy spring night can be a life changing experience and has inspired many, including myself, to pursue careers in conservation. In recent years, more people are venturing out to see the salamander migrations for themselves, but most people don’t know where to start. If you’re going to do it, you might as well do it right! In this post I will walk you how to find a good spot to witness these remarkable amphibian migrations for yourself, but first we have to go over some safety and ground rules.

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Throughout the northeastern United States, Spotted Salamanders will be one of the species you are most likely to encounter during an amphibian night time road search. Photo by Kiley Briggs

SAFETY:

In order to find an amphibian on a road, that means you will be walking on roads. Wear a reflective vest and never look for amphibians on busy roads. Never run out in front of traffic to save a frog or salamander. The risk is too high. Lots of amphibians are killed every rainy spring night. You need to be prepared to see dead frogs and salamanders and you may see even see them get hit by passing cars with your own eyes. Don’t add yourself to the list of animals that are killed on a given night by putting yourself at risk. The objective here is to find a rural low traffic area to safely look for amphibians. One your way there, you might see some hopping across busier roads. If you find a high traffic area with lots of amphibian activity, avoid using that road on rainy nights in the future and report your observation to your state wildlife agency. If you cannot get to a rural area without driving over large numbers frogs and salamanders to get there, you might just want to stay home or consider traveling to the area earlier in the day. This will be most challenging for people residing in urban and suburban areas. People who live in the country should be able to find a good spot and avoid driving through a high traffic amphibian hot spot with relative ease.

Other Ground Rules:

Do not collect amphibians you find. They are not pets and it is likely illegal in your state to collect without a permit. Plus, keeping a wild animal as a pet and later releasing it can introduce disease that can devastate wild populations. 

Also, be mindful about people’s property and try to avoid getting out of the car in front of people’s houses. Dogs will bark then lights in the house come on. Remember, if you’re walking around at the end of someone’s driveway in the middle of a rainy night with a flashlight, your behavior will be suspicious and alarming to a sleepy homeowner. Some people may call the police or come out to see what you are doing and not everyone is friendly about it. On major highways it is often unlawful to pull over on the side of the road and walk around and is not safe to do so anyway. Some states, like Texas, have very strict laws about looking for animals on roads and many require permits or a specific type of reflective vest. If you are unsure, you can always call your local police department or fish and wildlife agency for guidance. 

You are responsible for your own safety, and common sense applies. With that, here’s how to find a good spot.

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Reflective safety outerwear is a must when conducting an amphibian night time road search. Photo by Chris Slesar

Stage 1: Find a spot

Predicting where amphibians will cross roads is pretty easy if you know what to look for. Because most of these early spring breeders overwinter in woods and breed in wetlands, such as Blue-spotted Salamanders and Wood Frogs, all you have to do is open a road atlas or browse Google Maps and look for a place where a road passes directly between woods and water. Amphibians like marshy habitat with a lot of vegetation, so look for that instead of a manicured lake or pond with open beach front. The earliest amphibian movement will typically happen at lower elevations below south and west-facing slopes, but that will not be relevant later in the season. Once you arrive at a potential spot, you will be looking for the animals on foot, so you need to find a rural low traffic area to do this; safety is the number one priority. You can use topographic maps or even road atlases (such as the Gazetteer), but online services such as Google Maps are also very helpful. 

Below is an example of the sort of places to look for on a topographic map. I have never been to this site but based on its location in southern New Hampshire, would guess that it might have Wood Frogs, Spring Peepers, Blue-spotted, Spotted, and Four-toed Salamanders all crossing in the early spring. The two pins mark places where a rural road passes between a wetland or pond. And if you are not comfortable reading topographic maps, you can learn here, or just use maps that have aerial imagery.

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Looking at the zoomed in areal imagery of the more western site you can see that there appears to be a wetland, possibly a beaver meadow, below the road.

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The same is true of the more eastern site marked on the first map.

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For species that overwinter in rivers and lakes and breed in floodplains, such Northern Leopard Frogs, or species that live in the water and forage on land during rain (like Green Frogs and Bullfrogs), you would want to look for a place where a road lies between a river or lake and flat valley fields or wetlands. Roads that bisect wetlands and flood planes are good too. Aside from some Leopard Frogs, these sites usually don’t have much action in the early spring, but are pretty froggy on rainy summer nights.

Below is a good example of a site where a road bisects a river and floodplain.

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And again, look for a low traffic area. Busy highway = bad. Dirt or lightly traveled paved town road = good.

As far as finding a spot, that’s pretty much it! Some of the spots you pick out will be duds, so try to pick a few so you’ll have a backup if the first doesn’t work out. 

Stage 2: Know when to look.

Ok. You’ve found some spots to check out. Then what? Wait to go out until a rainy night when the snow has mostly melted (at least 50% ground visibility). Amphibians can move whenever roads are wet and temperatures are above freezing (even when it is snowing), but the busiest amphibian nights generally have steady rain and air temperatures above 40F. Usually, in Vermont, that’s late March through mid April depending on temperatures and snow cover. Once the season starts, amphibians will be out on roads whenever it is raining, but as the year progresses the species change and the amphibians you will find might be foraging rather than moving to or from breeding habitat.

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This Blue-spotted Salamander was found crossing a road during a light snowfall. While it is uncommon to see large numbers of amphibians moving in snowy conditions, they might be out any time the air is above freezing and the ground is wet. Photo by Kiley Briggs

Stage 3: Do it.

While in a car it is very difficult to spot certain species, and it will take you a little while to develop a search image for amphibians, especially small ones like Four-toed and Red-backed Salamanders. The truth is that really small amphibians cannot be seen from a parked car, let alone one traveling at 35-50 mph. The idea is to go to the spot you picked ahead of time and search on foot, but you might find a good spot on your way there. Larger salamanders that are not moving often look like broken sticks that point up at one end, and frogs that are not moving can look a lot like rocks or leaves. While driving around, if you notice a couple large amphibians close together, you may want find a place to park so you can check the road on foot with your flashlight if traffic is light enough to do so safely. Don’t forget to wear reflective vests so passing vehicles can see you, and also to turn on your car’s hazard lights.

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It is not uncommon to find frogs already paired up during the migrations. If a male finds a female en route, he might hitch a ride increase his chances of mating in the wetland. Photo by Kiley Briggs

While driving around, roll down your windows if it’s not raining too hard and turn off the radio so you can listen for frog choruses. Loud choruses close to the road mean it’s a good spot to slow down or get out of the car, even if you haven’t seen anything on the road yet. Once you are on foot, you can walk back and forth on the road scanning for frogs and salamanders with a flashlight. If there is any traffic at all, stay on in the road margins and only venture into the road to observe or move amphibians if there are no approaching vehicles. Never run out in front of traffic to save an amphibian from an oncoming car. If you want to move animals off the road, move them in the direction they were headed and make sure your hands are clean of any oils, lotions, and bug spray as that can be absorbed through an amphibian’s skin and can be very painful (if you don’t like getting it in your eye, assume an amphibian won’t like it on their skin).

Some amphibians, such as Spotted Salamanders, secrete toxins from their skin that are very sticky and may sting for several minutes if you get it in your eyes, so be very careful not to touch your eyes after handling amphibians.

Keep track of the how many of each species you find and where. The data you collect can be used by states and conservation organizations to prioritize habitat restoration and road mitigation. You can use apps like iNaturalist and HerpMapper, or submit directly to your local herp atlas or state wildlife agency over email.

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A waterproof field notebook will help you collect valuable data in the rain, but putting a regular notebook in a ziplock bag and being very careful works too. Photo by Chris Slesar

Be prepared to see some sad stuff. You’ll probably find dead and dying amphibians. Finding a dead salamander is one thing, but finding a severely injured animal thrashing around in the middle of the road can be really difficult to witness. Some people choose to put them out of their misery, others don’t. I won’t tell you what to do here, and laws vary from state to state, just be prepared to see it and put some thought into what you might do ahead of time so you are prepared when the time comes.

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One major downside to looking for amphibians on roads is that you will find many that are dead or dying, such as this fatally wounded Leopard Frog. Photo by Kiley Briggs

If you want to hold/observe a frog or salamander for a few minutes, put it in something like a Tupperware container so you can look at it or show children without stressing the animal too much. Do not let amphibians become dry! They breathe through their skin and some do not have lungs, so if their skin is dry it is very bad news. If it is not raining and you need to rehydrate an amphibian, dechlorinated or bottled water is best.

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To observe amphibians for more than a minute, place them in a tupperware container with a small amount of dechlorinated water to prevent them from drying. If it's raining, that is easy! Photo by Jim Andrews

Here’s a short material list of what you’ll probably want to bring during your road searches. It’s not all required, but it’s what I bring. At the very least bring a flashlight, reflective vests, some sort of map or map app, and something to write on. If you aren’t aware already, a smartphone’s touchscreen may not work well in the rain or when your fingers are wet.

A strong flashlight – These days strong LED flashlights are cheap and easy to find. Head lamps are useful but most are not strong enough to spot things well up the road. Most people who use a head lamp on their first road search switch to a more powerful flashlight on their second. The light on your phone is NOT going to cut it.

Reflective vest – You need to wear reflective vest so you can be more easily seen by oncoming traffic. Even if you do not think you will need one due to sparse traffic, the vest is a courtesy to drivers who will appreciate being able to see you from greater distances.

Extra batteries – this is especially important if you’re not using an LED light, but even if you are. Most people use their house flashlight once in a while and only for a minute or a two at a time, so years go by between changing batteries. Take that same flashlight on an amphibian hunt and it is dead after an hour of use. Bring extra batteries.

Road atlas – This is optional if you prefer to use an app on your phone for finding and navigating to spots, but road atlases such as a state Gazetteer really comes in handy. If you don’t have or can’t find a good road atlas, you can use your phone or Google Maps, but you’ll probably miss some spots. Online topographic map services such as this one are great and include all the same info as a Gazetteer. Many atlases and road maps do not show wetlands other than lakes, large ponds, rivers, and streams. Gazetteers show marshes and differentiate between woods and open fields on a large scale. You can also print maps from google (the areal imagery helps a lot!), but if you plan on driving around larger areas nothing beats a good atlas. Vehicle GPS units help as well, especially if you don’t know where on a map you are, but they aren’t very useful in finding road crossing sites.

Notebook – A good field notebook is the best friend of anybody wanting to record their findings or submit reports to a conservation institution. Keep in mind that it will be raining so you will want a way to protect your notebook from the water or use one that is made with rain-proof paper. The brand, “rite in the rain” is great and you can get a decent notebook that fits in most back pockets for about $6 on Amazon. As a bare minimum, the sorts of data you might want to write down include the date, location, time, species, and quantity. Other useful information might include weather conditions, the sex and size of each amphibian, and GPS coordinates. 

GPS unit or app – Coordinates are about the best kind of data you can record. Some phones will embed coordinates into the data of every photo you take, but free apps such as US Topo Maps are great, as are standalone handheld GPS units if you have one. If you cannot collect coordinates, write down approximate distances from nearby intersections for each area you find amphibians so someone can put a pin on the map afterward.

Tupperware container – These are useful to temporarily store amphibians to show other people or to observe while you identify the species. It allows for you to easily see the underside of salamanders and can be especially useful if you want to show a small salamander to kids, some of which do not have gentle hands. If you need to hold onto a salamander for more than a minute you should put it in a container with a little bit of rainwater to minimize stress. Bottled or spring water is ok too. Chlorinated tap water can be harmful to amphibians. 

Field guide – Having a good field guide to help you identify the amphibians you find is very useful. It does not have to be a book; there are plenty of online resources to help you with ID, and apps such as iNaturalist will attempt to identify animals in pictures for you. Apps are not completely reliable, though, and they do not teach you field marks necessary to ID species on your own. The Peterson guide to the reptiles and amphibians of the eastern United States will get you by pretty much anywhere in eastern half of this country, but I like guides that are specific to smaller regions because they only show species in your area and provide more details about each species. For Vermont, I recommend the New York guide, but The Great Lakes guide is awesome too. In Vermont, we also have a waterproof pocket guide for amphibian ID.

Friend – having a friend along to help makes a trip much more enjoyable, and if you are driving,  they can help you navigate and get out of the car faster to catch a frog that is hopping across the road.

Submitting Data

While witnessing the amphibian migrations can be a very rewarding experience, it is even more rewarding if your observations help your state plan habitat restoration projects or develop amphibian road mitigation plans. Feel free to print out and use this datasheet to record your observation. Where you submit the data will be specific from state to state, but here are a few good places to start if you are in the northeast:

Vermont Herp Atlas

North Branch Nature Center Amphibian Crossing Guards Program (Vermont only, contact ahead of time to get a site code)

Pennsylvania Herp Survey

New Hampshire Reptile and Amphibian Reporting Program

Massachusetts Herp Atlas

HerpMapper (all states)

iNaturalist (all states) 

Looking for amphibians during the spring migrations is a very rewarding experience and can be especially fun for children who will benefit greatly from being exposed to such things early on in life. Good luck out there, I hope I have provided you with enough information to get you started in your quest for migrating amphibians. And remember, your safety comes first.