Early spring butterflies

Apr 01, 2010

by Steve Blight

Adult Mourning Cloak Butterfly

Why a column on butterflies this early in the season, you may well be asking. While it is true that butterflies are more common in the warmer months, you may be surprised to know that there are a few butterflies in our area that can be seen very early in spring – even when there is still snow on the ground.

I was reminded of this by a reader, Neil Carleton, who reported seeing a Compton Tortoiseshell in early March. Another common butterfly you might see flitting along woodland roads on a sunny day in late winter or early spring is a Mourning Cloak.

Let’s take a close look at these two handsome butterflies. The Compton Tortoiseshell is a fairly large butterfly that is generally richly rust-brown on the upper side with a variety of dark and golden bands and spots. The underside is marbled grey and brown, with a small white V in the centre of the hind wing.

The Mourning Cloak is a familiar butterfly with a unique pattern. The ground colour of the upper surface is a rich maroon or purple brown. There is a bright yellow band along the irregular wing edges bordered by a row of bright, iridescent blue spots on the inside. The underside is a dark brown with wavy thin black lines. The blue spots and wavy black lines are often difficult to see when the butterfly is on the wing, but the maroon and yellow pattern is unmistakable.

Both of these butterflies are woodland butterflies. Compton Tortoiseshell caterpillars feed on willows and poplar. They are probably Canada’s longest living butterfly, flying in July and August and often surviving to the following June. Mourning Cloak caterpillars feed on the leaves of a wide variety of trees including elms and poplars and have been recorded in flight in the Ottawa area every week from late March to early November.

The reason one might see these two butterflies so early in spring is that they share one important characteristic – they both overwinter as adults. They spend the winter as fully formed butterflies in sheltered places including tree cavities, under eaves, or in garages, outhouses, and cottages.

There are very few butterflies that overwinter as adults. Most use other strategies to survive the harsh conditions of winter. For example, the familiar Monarch doesn’t spend any time here at all during the winter – they migrate to a few groves of fir trees in mountainous areas of Mexico, where they spend the winter clustered in the millions until spring. At that point they begin the long trek back to breeding areas in the southern US and then on to Canada.

Recall that butterflies have four stages to their lives – egg, larva (or caterpillar), pupa (or chrysalis) and adult. Butterflies that overwinter here do so at all different stages. In addition to the few that overwinter as adults, some butterflies spend the winter as eggs, waiting to hatch into caterpillars once the warmer weather returns.

Others, like the Northern Pearly Eye and most of the fritillaries, spend the winter as caterpillars, emerging in the spring to finish their time as larvae and continue to develop into adult butterflies. Then there are those like the familiar Cabbage White butterfly that overwinter as pupae.

One cannot help but admire the remarkable hardiness and beauty of two of the early spring butterflies of the Land O’Lakes – the Compton Tortoiseshell and Mourning Cloak.

Please feel free to report any observations to Lorraine Julien at This email address is being protected from spambots. You need JavaScript enabled to view it.  or Steve Blight at This email address is being protected from spambots. You need JavaScript enabled to view it.