Garden Biodiversity Challenge #9

Beautiful butterflies

April sees the butterfly season kick off in earnest and there has been a very predictable pattern to the sequence of their emergence. So far this year I have seen seven different species in the garden. The first butterfly was the small tortoiseshell for it overwinters as an adult. It spends the winter months in our house as the old stone, cold walls must provide near perfect conditions for its hibernation. They are a constant companion during the winter months and at one stage I counted 14 hibernating, unmolested, in my daughter’s vacated bedroom. On bright sunny days in February when the sun streams through the windows an occasional one gets fooled into thinking that spring has arrived, rouses from its torpor, and seeks the freedom of the great outdoors. These pioneers perish as the air temperature is still too cold for them to survive.

In late March when we had the first succession of bright sunny days, the holly blue appeared in the garden. I was delighted to see one flying about in March and I noticed that there was both a male and female about. Then one day last week I counted at least four individuals, the most I have ever seen in the garden. Holly blue are unusual in that they have two generations each year and both generations have a different food plant; holly is the preferred food plant of the first generation and ivy of the second.  We have ivy in abundance in the garden as the older trees are laden down with it. When we first arrived here to Bramblestown there was no holly in the garden so we planted some. It has never really prospered but we have three or four scraggly bushes that just might be doing their job for the holly blues.

Then, during the second week of April coinciding with the spell of warm, sunny weather more species emerged. The first peacock was seen on 8th April followed in quick succession by the orange-tip, comma and red admiral. The peacock and comma both overwinter as adults so it just needs the aim temperature to warm up sufficiently for them to fly; a few bright days of around 10 °C will suffice. Peacock is a very common and mobile species so it can be seen almost anywhere. The comma has a more interesting back story. The first comma in Ireland was recorded from the Raven Nature Reserve in Wexford in 2000. Since then its population has grown and its range has expanded. I first recorded it in the garden in 2015 and while it is never abundant, I have seen it every year since. Superficially it looks rather like a dowdy small tortoiseshell, but it has a lovely scalloped profile and a prominent comma-shaped mark on its underwing, hence its name. I also find it a quite confiding butterfly.

Red admiral is also an interesting species. It can be very abundant flying into late autumn. It was the last species I noticed flying in the garden last year, on a very cool day in October. But it is thought that very few if any survive the Irish winter and that the first adults seen in spring each year are immigrants from Europe. The red admiral I saw on the 10th April coincided with a southerly airflow, and later that night I trapped a large yellow underwing moth in the garden, also a migratory species. This would tend to confirm that it was a migrant rather than a resident butterfly.

The last few days saw the emergence of both speckled wood and green-veined white, two of the commonest, most widespread and longest flying species in Ireland. Speckled wood has three generations each year and can be found flying from April to September.  It favours the sun dappled lane and hedgerows where the male takes position guarding a sunspot, pouncing on any passing male or female, either to chase or court depending on the sex.

Butterflies are marvelous creatures and they brighten up any garden. Butterflies can tell us a great deal about how our environment is changing. Each species needs a specific plant species or group of species for their caterpillars to feed on, so their distribution and abundance can be influenced by changes in land use that disrupt the distribution of these plants. They are susceptible too much artificial fertiliser in the environment so modern farming methods are not the butterfly’s friend.  Butterflies also have distinct flight periods that have evolved to coincide with certain seasonal traits, so impacts of climate that mess with these timings can be detected by studying butterflies. Butterflies are good indicators of a changing environment so it is important that we monitor their populations.

Over the years I have seen evidence of these changes here in my garden. I have already mentioned that the comma is a new addition to my garden species list, but another has also been lost. When I first moved to Bramblestown there were still wall browns to be seen, however, these have long since disappeared from the county of Kilkenny.

Species #33 Small tortoiseshell hibernate in our house, and so can be seen year round. Its food plant is nettle of which there is no shortage in our garden.
Species #34 Holly blue is seen daily in the garden and it appears to be more common this spring than in other years. I have been watching individuals settling down for the night on a shrub that we planted in the vegetable garden.
Species #35 Peacock is on of the most spectacular butterfly species to visit the garden. It too finds plenty of nettles in our garden on which to lay its eggs.
Species #36 Orange-tip is one of the most delightful and conspicuous butterflies to be found in the garden. The first male was sighted on 9th April. There is none of its food plant, the cuckooflower, growing in the garden but it does grow in the surrounding fields.
Species #37 Comma is a relatively new arrival to Ireland, having been first recorded here in 2000. I first saw comma in the garden in 2015 and it is now a regular. It overwinters as an adult so is one of the first butterflies to be seen each year. I say it first on 10th April.
Species #38 Red admiral butterflies are most abundant in autumn each year, but few if any are thought to survive the Irish winter. The first red admiral I saw on 10th April was almost certainly a migrant, having arrived here from Europe.
Species #39 Speckled wood has up to three generations each year, consequently it is one of the species that can be seen flying from April to September. The first seen in the garden was on 13th April.
Species #40 Green-veined white is an extremely common butterfly in the garden. The first was seen flying on 16th April. Trying to protect the brassicas from its caterpillars is the bane of many a good gardener – glad I’m a bad gardener!