Despite reasonable overnight temperatures, at least in my garden, numbers of species and moths have reduced considerably recently.
02/08/2019 – min 15.9 C – 50 species / 236 moths.
July Highflyer, Dark-barred Twin-spot Carpet, Chequered Fruit-tree Tortrix, Agriphila geniculea and Udea prunalis all NFY.
03/08/2018 – min 17.1 C – 61 species / 274 moths.
September Thorn. Ruby Tiger, Small Dotted Buff, Ypsolopha alpella all NFY.
04/08/2019 – min 16.8 C – 34 species / 163 moths.
Aethes smeathmanniana NFG was the highlight.
05/08/2019 – min 15 C – 29 species / 140 moths.
White-line Dart and Cameraria ohridella both NFY.
06/08/2019 – min 15.5 C – 19 species / 74 moths.
Pale Prominent and Rosy Rustic both NFY.
07/08/2019 - min 14.5 C - 20 species / 50 moths.
Dusky Thorn and Square-spot Rustic both NFY
Minimum overnight temperatures obviouly affect our catches, in rural areas more so than urban areas, as these locations are usually a degree or so warmer, but will we ever know why these variations occur?
Mel.
Dropping Temperatures can only be part of the Problem.
-
melbellingham
- Posts: 834
- Joined: Tue Jun 14, 2011 7:00 pm
- Location: Great Sutton, Cheshire. Mapmate.
Dropping Temperatures can only be part of the Problem.
Last edited by melbellingham on Thu Aug 08, 2019 9:42 am, edited 2 times in total.
Re: Dropping Temperatures can only be part of the Problem.
Interesting stats Mel, our own trapping returns are similar. from the peak on 23rd July:
23rd July: 299 moths and 74 species
25th: 324 of 71
27th: 338 of 68
29th: 228 of 57
1st August: 233 of 35
2nd: 203 of 49
4th: 270 of 58
6th: 99 of 34 and
8th: 88 of 27
The last two nights I considered significantly cooler than anything in the last two-three weeks but there's also the fact that there's less moths about now we're getting more into Autumn, as can be seen below for our garden...we are currently in week 32.
Cheers,
Steve
23rd July: 299 moths and 74 species
25th: 324 of 71
27th: 338 of 68
29th: 228 of 57
1st August: 233 of 35
2nd: 203 of 49
4th: 270 of 58
6th: 99 of 34 and
8th: 88 of 27
The last two nights I considered significantly cooler than anything in the last two-three weeks but there's also the fact that there's less moths about now we're getting more into Autumn, as can be seen below for our garden...we are currently in week 32.
- Moths by week: Elton 1991- 2014
Steve
-
melbellingham
- Posts: 834
- Joined: Tue Jun 14, 2011 7:00 pm
- Location: Great Sutton, Cheshire. Mapmate.
Re: Dropping Temperatures can only be part of the Problem.
Hi Steve,
I see and understand where you are with your thoughts, but the overnight temperature hasn’t been significantly lower in my garden, compared with recent nights.
Other disruptive conditions such as wind, bright moonlight and heavy rain will affect catches, but my garden hasn’t been affected by these as far as I know. When I made my final inspection last night it was not windy, and there was cloud cover (what happened later, I have no details of…zzzzzz).
The overnight low (07/08/2019) was 14.5 C (down from 15.5 C the previous night) and I recorded 50 moths of 20 species. I see from your latest post that you had 88 moths of 27 species, down a little from your previous trap.
I know that we are rapidly approaching the time of year when numbers of species and individuals fall away, I also realize that some of the moths that I record are only passing through my garden, and many of these moths will be the species that I only record occasionally. So numbers are likely to flunctuate.
In the mists of time these stats will probably have no significance at all, but as last year (2018) was my best ever year for the total macro moth species recorded in my garden, and this year is looking at present that it is likely to be my worst year, I am trying to consider all aspects of why.
Just for info, I usually only consider macro’s when comparing past years totals as I didn’t really start to record micro’s until 2009, and I am still not able to ID them all.
Come to think of it, I still struggle with some macro's
Mel.
I see and understand where you are with your thoughts, but the overnight temperature hasn’t been significantly lower in my garden, compared with recent nights.
Other disruptive conditions such as wind, bright moonlight and heavy rain will affect catches, but my garden hasn’t been affected by these as far as I know. When I made my final inspection last night it was not windy, and there was cloud cover (what happened later, I have no details of…zzzzzz).
The overnight low (07/08/2019) was 14.5 C (down from 15.5 C the previous night) and I recorded 50 moths of 20 species. I see from your latest post that you had 88 moths of 27 species, down a little from your previous trap.
I know that we are rapidly approaching the time of year when numbers of species and individuals fall away, I also realize that some of the moths that I record are only passing through my garden, and many of these moths will be the species that I only record occasionally. So numbers are likely to flunctuate.
In the mists of time these stats will probably have no significance at all, but as last year (2018) was my best ever year for the total macro moth species recorded in my garden, and this year is looking at present that it is likely to be my worst year, I am trying to consider all aspects of why.
Just for info, I usually only consider macro’s when comparing past years totals as I didn’t really start to record micro’s until 2009, and I am still not able to ID them all.
Come to think of it, I still struggle with some macro's
Mel.
Re: Dropping Temperatures can only be part of the Problem.
Hi Mel,
Agreed - I too wonder if last year is a factor on this one being so poor overall but I've no comparable data through being unable to trap for much of May and June.
I generally assume that if its around 10-11C then I won't get many micros, between 11 and 15C ought to result in a good night and above 15C anything goes. I do sometimes reverse engineer these presumptions insofar as if there are no micors to speak of in the trap in the morning then the temperature 'must have' dipped during the night. When I put the trap on last night my breath test was possitive - it was cool enough for me to see it!
As you say, interesting to theorise reasons but will we ever know for sure - I doubt it.
If you are out and about there's currently an influx of Essex Skippers happening, with up to 20 being seen.
Cheers,
Steve
Agreed - I too wonder if last year is a factor on this one being so poor overall but I've no comparable data through being unable to trap for much of May and June.
I generally assume that if its around 10-11C then I won't get many micros, between 11 and 15C ought to result in a good night and above 15C anything goes. I do sometimes reverse engineer these presumptions insofar as if there are no micors to speak of in the trap in the morning then the temperature 'must have' dipped during the night. When I put the trap on last night my breath test was possitive - it was cool enough for me to see it!
As you say, interesting to theorise reasons but will we ever know for sure - I doubt it.
If you are out and about there's currently an influx of Essex Skippers happening, with up to 20 being seen.
Cheers,
Steve
-
PaulHopkins
- Posts: 456
- Joined: Wed Apr 23, 2014 4:11 pm
- Location: Bromborough, Wirral. MapMate Recorder
Re: Dropping Temperatures can only be part of the Problem.
My stats from my last 4 trapping sessions show a precipitous drop, last night was a bit of a shock to the system!
Nice to get only my second Rusty-dot Pearl last night though, to make up for the lack of any larger and more exciting migrant species...
Cheers
Paul
Code: Select all
Date Min Temp Total Species
22/7 17.1 430 81
24/7 17.8 401 80
2/8 15.0 324 62
7/8 12.7 112 28
Cheers
Paul