Ask The Entomologist


True to schedule, the mayflies have returned. Of course, the mayflies didn’t wait for May proper… they’ve been with us for the past month at least.

Here’s the shed skin of one I watched emerging this past week. Note the three tail filaments – this is how you can tell it is a mayfly skin.

It’s hard to get an ID from a cast skin –
I’ll be keeping my eyes peeled for an adult to photograph.

Our pond tends to have the smaller species of mayflies in good abundance – primarily genus Callibaetis. Here are some higher-quality photographs of other mayfly nymphs, so you can get a sense of the variety.

All mayflies belong to Order “Ephemeroptera”, which is Greek for “ephemeral things with wings”. While their winged life-stages may be here today and gone tomorrow, their aquatic young live much longer – a year or more below the surface before taking to the skies.

Mayflies are of an ancient lineage – they were around before creatures with backbones colonized the land. In those early days, the skies were relatively free of predators, far safer than below the water. Far different from the world they inhabit now.

Today, mayflies are a staple food for many creatures – fish, birds, and bats (as well as many insects)… All eat prodigious amounts of mayflies. Fly-fishers are well aware of fish’s dependence on mayflies. Many fly-fishers tend to be insect-watchers, and tailor their flies to match the most abundant mayflies are in their location and season.

We can anticipate our mayflies staying around far longer than the month of May – new adults will emerge all summer long, and can be found well into October, depending on the weather. Their presence can also be used to assess how healthy a body of water is – mayflies don’t do well in polluted areas.

Here’s an adult Callibaetis mayfly that joined me on a walk last fall.
And here’s a writeup on flyfishing to match Callibaetis mayflies’ emergence patterns.

This adult’s size is about right for the shed skin in the top image,
but it’s quite possible that our area contains several species from this genus.

The Goslings Hatched

Each Spring, before the ice thaws in the pond, Goose and Gander return, to make sure that no other goose couple takes her nesting island.  In 2015, they were alone, and Gander worked to chase off all other nesting birds – the next year, some of the year-old goslings returned with them.  By now, he’s an old hand at this – about a half-dozen yearling geese and their consorts hang out in the big pond, and ducks nest along with Goose on her island. 

So we’re watching Goose, Gander, and eight offspring stroll and swim around.  The pond isn’t really ours.  It belongs to the waterfowl that use it as a place to raise their young.  We just get to watch them more than anyone else does.

This year she started her nest 3 days before the ice went out – and the hatching was spread out over two days and a night.  It was easy to observe – Gander came ashore to keep the goslings covered as Goose continued her nesting, and last year’s young geese circled the island and flew patrols overhead.