Friday, 4 April 2014

Butterfly Survey

Insects have got off to a good start this year, especially various bees, midges and butterflies. We thought it was time to re-instate our butterfly transects.
Small tortoiseshell

For several years, Steve May, one of our volunteers, recorded butterflies along the same section of path on a (roughly) weekly basis as part of Butterfly Conservation's national scheme. After a couple of years off, (and a good prod from Ranger Rob Martyr) we have started doing them again.

The procedure could not be more simple. We start at the Visitors' Centre, follow the Meadow Trail to the river and then join the Heronry Trail near the new dragonfly platform. The path then leads past the two hides to rejoin the Ouse Valley Way, ending at the south side of Island Pit. We record all the butterflies we see without leaving the trail.

This standardised procedure, where you cover the same route every time, at the same pace, is more useful than casual recording because you can use the data to compare year on year.

The fortunes of our butterflies at Paxton have gone up and down over the years. We virtually lost all our small tortoiseshells two years ago, probably due to a parasitic wasp. There was a national decline, but they seem to be returning. About 12 years ago we were colonised by marbled white butterflies, but they seem to have gone in the last three years, possibly because their habitat deteriorated through drought. On the plus side, we saw a purple emperor and purple hairstreaks on the haul road in 2013.

This spring we have already seen a lot of peacocks, tortoiseshells, commas and brimstones and we expect the first orange-tip butterflies this week.

The scheme us so easy to do, you could do one yourself along a favourite walk. The information is to be found on Butterfly Conservation's Website. We will be starting a similar survey at Barford Road Pocket Park too.

Bee fly
Apart from it's simplicity, the great thing about this survey is that it gets you in amongst nature and makes you focus down onto the little bugs and beasties by the path. Some butterflies such as brown argus and small blue are relatively small so you have to be observant and so you will spot no end of strange creatures. This week we have seen a lot of bee flies. Like a lot of early insects such as bees, they have "hairy jumpers" to keep them warm.  The long proboscis is not for stinging you, but for obtaining nectar from trumpet-shaped flowers such as primroses and cowslips.