Other May pages: Woodland, meadow and field flowers • Wayside flowers • Downland and seaside flowers • Trees and shrubs • Birds • Weather
Put your cursor over any photo on this page to see its caption, or click here to see more May butterfly and insect photos. For more information on butterflies and moths see the Butterfly Conservation website.
May starts well for butterflies, with the ones that hibernated over the winter and appeared in late March and April being joined by others newly emerged. Towards the end of the month there can be a marked dip in numbers, however, as the overwintering generations die out and before the summer ones reach adulthood.
Of the overwintering butterflies, small tortoiseshells are still quite common at the start of May but tend to be gone by mid month: the same is true of peacocks, though you can see the occasional one (looking rather worn out by now) right till the end of May. Both look almost black in flight due to their dark underwings, but have a handy habit of landing for a rest on paths, making their colourful upperwings easy to see.
The striking yellow brimstone can last longer, appearing throughout May and into June. Note that the female brimstone is a very pale yellow and can be mistaken for a large white butterfly: the key is its lack of black wingtips and the shape of its wing if you see it at rest.
Another overwintering butterfly is the comma, though it is less common at this time of year than during its second generation later in the summer. This is because overwintering ones may not have survived, but those that do lay eggs and produce more numerous young who emerge in July. Look out for them early in the month particularly near bramble bushes and hedgerows.
Also early in the month (all month in 2015 and 2016) you can see the lovely orange tip. It usually as long as the flowers of garlic mustard, one of its favourite plants for laying eggs on. Again, the female can be mistaken for a small white butterfly as it does not have the orange tips to its wings: the key to identification is a mottled green pattern on its lower underwing.
You can only make this identification if the butterfly comes to rest, however, and that is a problem for all the white butterflies, which seem to be especially restless. They are commonly grouped together as "cabbage whites" but in fact there are three different species - large white, small white and green-veined white. All are usually about in May, but it is almost impossible to tell them apart as they flutter past. If you do get a look, then large whites have more extensive black wing tips, extending down the edge of the wing, while small whites have smaller grey tips. Green-veined whites also have grey tips, but descending down the wing edge in a series of blobs. If you see their underwings their green veins are also obvious. All three overwinter as pupae, though large and small whites also migrate from the continent in May.
Another butterfly that can overwinter as a pupa is the speckled wood, though some also spend the winter as caterpillars. This means it has less of a pronounced season than other butterflies and so is reasonably well spread throughout May. If you see a brown butterfly in a wood or on a shady verge then it is almost certainly a speckled wood. They are relatively placid and happy to settle on a leaf, so are not hard to identify.
You may also see a red admiral or painted lady during May. The red admirals are migrant females who have already mated on the continent and lay eggs here immediately on arrival, while the painted ladies mate once they arrive in the UK. In both cases, their offspring go on to make up a much more numerous summer generation, boosted by further migrants. Both species then travel back southwards in the autumn. Some red admirals also overwinter but scientists have not yet decided if they then go on to breed.
Rarer butterflies include the wall, which has brown on orange markings somewhat similar to those of the comma. Once a common farmland butterfly, it is now only found on coasts. It likes to sunbathe on paths (and also supposedly walls, hence its name) but is quite flighty when disturbed.
Look out also for tiny blue butterflies during the month. Near brambles, ivy bushes or hedgerows early in the month these might be holly blues, which have a pale blue underside and look a bit like a silver flash as they fly past. Later in the month and on grassland you may well be seeing the common blue, which can be distinguished by its brown underside with black spots.
Also later in the month, on south-facing downland slopes with horseshoe vetch growing, there is a possibility that you may be seeing an adonis blue - a fairly remote one as these are rare and localised butterflies. Telling them apart from the common blue is in any case a big challenge. The adonis is a lighter blue, but the common blue looks fairly light in flight too; the adonis has black lines through the tiny white borders on its wings, but the common blue has the beginnings of lines; the adonis blue male's underwing is darker than the male common blue's and with only the faintest of blue blushes near its body: and there are also slight differences in the arrangement of the black underwing spots between the two species. But unless you manage to take a good quality photograph you are unlikely to see these details. To make matters worse, when their markings fade adonis blues look a lot more like common blues.
The female of both these two species are brown with orange chevrons around the outside of the wing (practically invisible on the forewing of the adonis, but its female is also very rarely seen). However if you see a very small butterfly with these markings, the brown argus is also possible. Its male is smaller than the female common blue but its female looks pretty identical. Again, the minute details of the black spots on the underwing are the guide to identification. Just to make life extra confusing, you sometimes you also get common blue females which are substantially blue in colour.
Once you start looking for butterflies this small, all sorts of wonders open up. May is the best month to see both dingy skippers and grizzled skippers, but you might easily mistake these tiny brown-patterned butterflies for minor day-flying moths, so small and inconspicuous are they. Both are found in downland or short, rough grassland but they are quite localised - that is to say, only found in a few places (the slopes of Pitstone Hill near Tring is one location).
Equally small but more brightly coloured are the small copper, with its bright orange markings, and the small heath, which looks orange in flight but always closes its wings when at rest. Both like reasonably short grassland. Much harder to spot is the green hairstreak, whose green underwing means it blends in with its downland habitat. (Try Aldbury Nowers near Tring.)
It is easy to mix all these small butterflies up with various tiny day-flying moths that also appear around this time. These include grass veneer moths, which look like tiny white butterflies as they flit around grassland but then close their wings tight to almost completely disappear when at rest on a blade of grass. On a slightly larger scale are the burnet companion and the silver Y. Other day flying moths look for all the world like small butterflies - see the green carpet or the speckled yellow.
April has already seen quite a lot of tiny insects emerge (it is one reason those summer visiting birds come to our shores), and this continues into May.
One that can be very prominent and even rather sinister-looking in early May is the St Mark's fly, whose legs trail below as it flies and which can be found in large swarms. They look alarming, but are in fact quite harmless. Their name, incidentally, refers to the 25th of April, the feast of St Mark, when they traditionally appeared.
Otherwise, there are bees and tiny wasp-like insects to be found polinating flowers (they are in fact hoverflies, which have evolved to look like wasps to avoid being eaten). Notice also the bee fly, which is, as its name suggests, a fly that looks like a bee. But you almost never see actual wasps yet, and flies are not a nuisance until later in the month, if then.
Instead, the kind of insect common in May are the tiny ones that fly into your mouth when you are running or cycling, or produce mysterious insect bites on your arms and legs. There are soldier beetles and other tiny bugs crawling about on flower heads and crane flies flitting about in the grass.
As the month goes on you can also see dragonflies and bright blue damselflies, including the beautiful banded demoiselle with its hypnotically patterned double wings. By a river towards dusk, look out for swarms of mayflies, which dance up and down in the air. A clue to idenfication are the three long tail filaments, easily visible as they float downwards in their dance, and the striped black and white tips to their abdomens. They actually metamorphose twice when they emerge from the water - once into a dull brown sub-adult and then into a more highly decorated full adult. They live in this form for just one night - long enough to mate. You can see them even in early May and indeed later in the summer, but late May or early June is supposedly the peak time.
This is also the month that you see cuckoo spit - the saliva-like liquid on plants that is actually produced by the froghopper.
More May pages:
- Woodland, meadow and field flowers
- Wayside flowers
- Downland and seaside flowers
- Trees and shrubs
© Peter Conway 2006-2016 • All Rights Reserved