Monday 19 June 2023

Moths in Bognor

This is our first summer in our new house by the seaside!


We have been using our DIY moth trap to sample the local population of moths.

It was a slow start, but now looking very positive.

Our new location is in the built-up district of Bognor Regis, although our estate in Aldwick does contain many trees and relatively large gardens.

We also benefit from the RSPB reserve at Pagham, a mile or two to the west. And our first season with a bird box was successful, although in the absence of a camera, we don't know how many blue tit chicks successfully fledged.

The first 3 or 4 times we deployed our moth trap in May & early June, the results were quite disappointing: the most moths we had was 9 and least was zero (although we did have a large hornet that night!)


However, after a long dry period when daytime temperatures were in the mid 20'C range, the situation dramatically improved. On two consecutive Friday nights (we only use the trap once a week) we had over 70 moths in the trap and another 10 or so outside the box, on the nearby wall and windows. This is a larger number than we have ever seen here or at our previous location near Horsham.

So far we haven't seen a large number of species, just a lot of the same medium sized ones (like Heart & Dart). We did find one Poplar Hawk Moth but should see various large hawk moths here.

As a result I've made a couple of changes to our moth trap.

I should point out that if you do an internet search for 'moth trap' you will see many nasty devices for killing them. Whereas the kind of trap I'm referring to here is for catching, monitoring and releasing them [hopefully] alive and well!

The first change is to increase the capacity of the trap. I've done this by raising the supports that hold the two sloping panels. The panels are now at an angle of about 45 degrees, which appears to be typical for Skinner traps, giving extra space underneath for more egg boxes.

I've also added a couple of modified picture hooks to stop these cardboard side panels from bowing out at the top. I'm hoping this will reduce the number of escapees!


I've also decided to run the trap without the centre infill piece which was originally fitted to reduce escapees, as I think its reducing the gap too much and maybe stopping some of the larger moths from dropping through to the bottom.

One other point to note is that I've managed to wake up shortly after 4am (most trap days) to switch the trap off and cover it with the lid to stop escapees (sunrise is currently about 4:45am but it starts getting light around 4 - 4:15am).

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