30 Days Wild – Day 27: Location, Location, Location

After several days of the forecast promising rain in a couple of days, it finally arrived, although not yet in great quantity it is none the less welcome, so long as it does not get out of hand.

I have been running two moth traps at Blashford on several recent nights and it is remarkable how different the catches are. On trap is on the open ground beside the Centre and the other about 50m away under some trees. One of the most immediate differences that I notice when opening the traps is that the one close to the Centre has hawk-moths in it, that under the trees does not. Clearly the hawk-moths favour flying over open ground, perhaps their fast flight is just not suited to confined spaces, like trying to drag race around the streets of Fordingbridge. Under the trees there are many more smaller moths, is seems probably that they are actively avoiding the open spaces where their weak flight may mean they lose control over where they are going.  It has certainly been a lesson in importance of exact location in determining what is caught.

As a further illustration of the difference that location made is that the trap in the open caught 34 species, whilst the one under the trees 40 species, but there were only 18 species that were caught in both traps. Both have been run for the same time each night, coming on and going off at the same time, the effect would seem to be due to where they have been running. Open sites might be expected to catch less on windy nights but last night was not windy so this is unlikely to have been a factor and both sites are shaded from the morning sun, which might otherwise warm the moths and means some fly out of the trap, so lost moths can probably be discounted too. Clearly I will need to give more consideration to precisely where I put the trap in future as it would seem to be a very important factor determining what gets caught.

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