Thread by @SteB777

1) Early this morning I saw large numbers of Manchester Treble-bar Moths on Whixall Moss NNR flying just after sunrise. This is the behaviour I described here, which seems to be undocumented. @gmtord @savebutterflies @Buzz_dont_tweet @pebo22 @EntoProf
…nsandwhixallmossdiaries.wordpress.com/2018/07/13/man…

2) This morning I remembered to take my fold up sweep net to confirm what I was seeing flying around were in fact Manchester Treble-bar (Carsia sororiata). This is because at this time they are flying endlessly and only occasionally settle.

3) I caught in excess of 15, and all those I thought looked liked Manchester Treble-bars, were indeed this species.

4) The impressive thing is the sheer numbers of them. In the area I was in, there must have been hundreds of them on the wing. They appear to be male moths patrolling around patches of Cranberry in very wet and boggy areas.

5) I think the mistaken assumption given how few turn up in traps, and are disturbed when you are looking from, that they must occur in quite low numbers. This proves not to be the case.

6) They are only active for about the first 1 1/2 hours after sunrise, with the numbers on the wing rapidly reducing after this. Whilst they do cross the drier path, most of the activity is confined to these very wet boggy patches.

7) This would explain why only small numbers get disturbed, fly up and are seen during the day. The wet areas they frequent are too wet to walk on, so you are only seeing outliers away from the main centres of their activity.

8) There were also good numbers of Purple-borded Gold (Idaea muricata) on the wing. Their activity seemed to be very similar to MTB, in the same areas. Apparently confirming that on Whixall Moss at least, that Cranberry is their main larval food
…nsandwhixallmossdiaries.wordpress.com/2018/06/24/pur….

9) Presumably MTB and PBG are really night flying moths, that continue to fly into the first hour or two of light in the morning. And not really day flying moths, as they only fly when disturbed.
butterfly-conservation.org/moths/manchest…

10) I think an understanding of this behaviour will make it easier to locate them and to estimate their numbers, because other sampling methods produce low numbers detected, which is misleading given the numbers they actually seem to live in.