Ask Maine Audubon: Be Part of the Big Night of Amphibian Spring Migration

Small nocturnal large amphibians crossing Range Road in Cumberland. Ariana van den Akker/Maine Audubon

One of the most anticipated March events for naturalists is the amphibian migration known as the “big night.” With each warm evening, we believe we are getting closer to the main event, and while sometimes a big night turns out to be a small one, when the big night rolls around, it’s an event not to be missed.

The big night usually occurs on the first warm, rainy night of spring (45 degrees or warmer) when the majority of amphibians – frogs and salamanders – emerge from the burrows where they overwintered and return to the vernal pools in which they were born, to reproduce. (A vernal pool is a small, temporary wetland that fills with water in the spring or fall.) Conditions for the big night may not arrive until April, but it’s a good idea to be prepared. because you often don’t know if the weather will be right until a few days before it happens.

The journey might not seem very long geographically, until you consider the fact that these cold-blooded animals are only a few centimeters long. Their migrations are made even more difficult because the roads intersect with many routes that the animals must follow. Slow-moving land animals that cross roads on nights with poor visibility unfortunately result in high mortality rates. Maine Big Night, a community science project that was launched to collect data on these frog and salamander movements, reported that 31.89% of the 5,732 amphibians detected in 2021 surveys – at 185 sites with 737 hours of effort – were found dead.

But you can help. Maine Big Night is always recruiting volunteers to come out on hot, rainy nights to conduct surveys and help amphibians get across safely. You can find out more about the project at vernalpools.me/big-night. Maine Big Night also has a very active Facebook page where you can learn more and stay up to date on the big night schedule: facebook.com/groups/bignightmaine. Shameless Take: Maine Audubon is hosting a show with Greg LeClair, the founder of Maine Big Night, who will talk about the project and how to get involved, March 25 at 7 p.m. This is a free online show (register at maineaudubon.org/events). From becoming a volunteer to simply driving more carefully and watching out for amphibians in the spring, any extra help can go a long way in helping these endangered animals.

ARRIVAL OF THE BECASSINE

American Woodcock. Pam Wells/Maine Audubon

A little easier to predict than the big spring night is the arrival of the woodcocks and the start of their elaborate sky dances. Male woodcocks perform these courtship ‘dances’ in the sky, usually in the evening, displaying themselves to watching females in an attempt to win one.

If you’re lucky enough to see one, it’s quite a memorable experience, which brings us to a very common question we get: Where can I go to see woodcock demonstrations? The surprising answer: almost anywhere.

It helps to start by knowing exactly what you are looking for. American woodcocks, colloquially known as timberdoodles, are a species of shorebird (think sandpipers and plovers), except they don’t live near the shore. Instead, they live in young forests where they use their long beaks to probe the ground for invertebrates like earthworms. Spending so much time with their heads down and bills in the ground, they have evolved to have their eyes far back on their heads, giving them near-panoramic “rear-view binocular vision.” To achieve this (and I’m going to oversimplify for the brevity of this article), the woodcock’s anatomy has changed so much that its ears (which are obscured by feathers) are below (not behind) its eyes, and its brain basically rolled over. .

All this to say that they have a unique look. In the spring, after migrating from their wintering grounds in the southeastern states, the males waste no time in beginning their courtship displays by seeking clearings in the forest or open fields.

The displays begin with a nasal “peent” that the bird calls while standing on the ground, often given for about a minute before launching into the air. From the air, a variety of chirps and chirps can be heard, but this is not vocalization, it is made of air passing through specially modified outer primaries (the outermost flight feathers). Think of how you can whistle by blowing with a glass slide in your hands. Likewise, their rapid wing beats produce these unique noises. The aerial dance lasts about a minute, with the final notes becoming more accentuated as the bird descends rapidly to the ground, landing very close to where it took off from. These dances are usually performed at dusk and dawn for a 30-40 minute window, beginning 30-45 minutes after sunset and 30-45 minutes before sunrise.

To underscore my point that woodcocks can be found almost anywhere (assuming you have a small forest with a clearing nearby), we can look at our Maine Bird Atlas results down to here. The Maine Bird Atlas is a project of the Maine Department of Inland Fisheries and Wildlife to document the breeding and wintering grounds of Maine birds.

It is quite difficult to ‘confirm’ that woodcocks are breeding in an area, but if you hear them performing their courtship displays, this is considered a ‘probable’ breeding status. An atlas volunteer, Jeff Cherry, became a bit obsessed with proving that woodcocks were more widespread than most people appreciated, and has since documented woodcock breeding (mostly in display) in each block (a 9 square mile survey area in the Maine Bird Atlas) in Lincoln County.

You can view our preliminary results, including the Lincoln County Giant Swath, for American Woodcock records at: ebird.org/atlasme/map/amewoo. Get outside this spring for some wood and report your findings to the Maine Bird Atlas via ebird.org/atlasme.

Do you have a nature question for Doug? Email questions to [email protected] and visit maineaudubon.org to learn more about backyard birding, native plants, and Maine wildlife and habitat programs and events. Maine Audubon hosts free bird walks Thursdays, 8-10 a.m., at Gilsland Farm Audubon Sanctuary in Falmouth. (Walks will start at 7 a.m. starting in April.)


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