A fly in the ointment for butterflies

Springtime heralds the arrival of new flowers and insects
Springtime heralds the arrival of new flowers and insects

How exciting to see the first bumblebees,butterflies and wildflowers of the spring!

Being lucky enough to have long ago turned my pastimes into my profession, I always look forward to summer and a resumption of wildlife auditing.

In the case of butterflies we usually carry out such surveys over the same routes or “transects” at least three times between spring and autumn.

It can be fascinating to see how each year differs, with some favouring certain species over others.

Where one species may be our most common one year, it may be among our rarest the next.

Painted Ladies and Red Admirals are examples, as these migratory butterflies rely upon south and east winds to ensure a good supply to Scotland from Europe and even from as far away as North Africa!

In years when our prevailing westerlies continue throughout, we may see very few migratory butterflies.

Not only weather determines such fluctuations.

In the case of the Small Tortoiseshell Butterfly there is a parasitic fly which can drastically reduce its numbers. The fly does not like Scottish winters and a particularly cold one can be the saviour of the tortoiseshells for a year or more until the flies catch up again.

We have now had two mild winters in a row, assuming there is not going to be a return to winter weather in April, which can happen.

There will be winners and losers among species as a result. I can guess which species might fare better than others, but it is not until well through the summer’s moth, butterfly, botany and other surveys that the full effects will become clear.

It is all fascinating stuff and each year is very different from any other. Bring it on!

By George Hogg, Hogg Estate Services, Wildlife Managment