Little Night

Spotted salamander waiting for love. Photo by Burne

In the northeastern US, we’re getting ready for the big start to the spring, as marked by the salamander and frog migrations we've come to refer to as “Big Night.”

The animals that rely on vernal pools for breeding (we’ll do a post on this topic someday and link back to this, we promise) are putting their offspring in something they know is going to dry out. Hurry up or die, kid. This is what makes a vernal pool what it is. Relative safety from a big predator (fish) with the down-side risk that you’ll die a slow, painful, air-soaked death.

To improve chances for little Johnny and EmmaMay, salamanders and frogs get going on breeding as soon as humanly possible…so to speak. They get started on their breeding migration as soon as the ground is thawed and they get a nice, rainy night with temperatures around 40 F (4 C). This results in a highly synchronized breeding migration – lots of animals out and about when conditions are perfect. We’ve come to know this as Big Night. Check out Sarah Lamstein’s book of the same title – we love it.

Salamander thinking "this is not what I meant."

Here’s the thing: lots of people get excited about Big Night, and anxious and stressed over not missing it. In point of fact, it’s a bit of a myth. To be sure, migration in the spring is highly synchronized among vernal pool breeding amphibians, and in some years when conditions are spot-on: wow; it’s something to experience. But if you were just too tired to get out last Thursday night, or you had tickets to the theatre, don’t sweat it: there are opportunities yet to see the salamander stampedes.

North of Boston, there are salamanders in vernal pools (see the first picture, taken last Thursday). I’ve heard reports of wood frogs calling north of Boston on a sunny day early last week. There are even reports of egg masses (whaaa?!). But we haven’t seen the bulk of the migration yet; it’s still early. What we will actually see over the course of a typical spring is a number of “Little Nights” when animals are arriving at their breeding pools and joining the party.

So don’t fret! Get out and check out your local vernal pools regularly through the early spring, monitor roads that have high crossing mortality (be careful, please!), and see the great annual amphibian migrations that mark the start to the spring! ~ MR Burne

Boing! Goes Spring

All of that snow on the ground does make spring feel a long way off, even though we’ve passed the equinox. While we wait for the snow to melt and frogs to get hopping, some interesting things are already out and hopping about.

Collembola are about 3 mm long - tiny! Photo by Kenney

Collembola, a.k.a. “springtails,” can be found on the forest floor and near wetlands where they’re beginning their annual breeding congregations. Springtails are closely related to insects but in their own taxonomic class (or subclass, depending on whom you talk to). They are tiny – really tiny – measuring much less than 6 mm in most cases. Around Boston, most of our Collembola are 2 or 3 mm. They are all black, have a distinct head with jointed antennae, a thorax with three pairs of legs, and an abdomen with no legs.

Breeding congregation on a small puddle. Photo by Burne

What makes Collembola particularly unique is an appendage on the end of the abdomen called a furcula. This forked appendage is held against the bottom of the abdomen, and when released, causes the animal to be launched several centimeters, giving them their moniker. Since they’re often found at the end of winter on snow, they’re also known as “snow fleas.”

In a funny sort of symmetry, Collembola have a mating strategy very similar to our favorite vernal pool vertebrate, the Spotted Salamander. Males deposit a stalked spermatophore that females gather; there’s no contact between the two.

Most Collembola are terrestrial and will be found throughout forested areas. There are many species that are semi-aquatic, though, and these will often be found around vernal pools, especially in spring. They utilize the water surface for breeding and feeding; they will often be seen bounding around the surface of a pool with all of the other organisms that are busily going about their business.

Wee little snow fleas on the trail. Photo by Burne

So take a close look around you on trails in the woods as you’re waiting for the snow to melt. There’s a lot to see, especially if you get low and look closely! ~MR Burne

Happy Vernal Equinox!

As in years past (maybe every spring that I've found myself looking closely at vernal pools), I am so happy to see half a foot of snow on the ground at the vernal equinox. There's so much to do in planning for this year's field work - workshops to organize, field trips to plan, priorities to set, &ct - and so little time to do it all!

So sleep, my slithery and hoppity friends, sleep under the warm blanket of fresh snow. I hear there's more on the way later this week. As Mr. Burns would say, "Eeexxcellent." There is much planning to do. ~ MR Burne