Just as a follow-up to Neil’s post on 18th Jan. and his enquiry about 2016 results from other areas of the county. I’ve at last completed my records for my area in the north of VC25 (Waveney Valley) which includes some on adjacent sites on the VC27 side of the border. Whereas Neil’s records are for 2 sites, mine are across 20 or more sites which I trap regularly every year, several with Keith on his Somerleyton estate sites. On the sites we trap together we will run 7 or 8 lights and on those I trap alone I run 5 lights on average. All the records are over 12 months of the year and include my garden which accounts for a very small percentage of the totals except the number of nights the traps are run. One thing to keep in mind is that on all these sites except my garden, the lights are not run all night, but for 2 to 3 hours after dusk. So this may affect final totals compared to sites where lights are left on all night.
Year Sites Nights No. of records Species No. of moths counted
2012 26 150 4172 653 14494
2013 22 139 4743 709 16943
2014 20 136 4446 706 16950
2015 27 165 5013 703 15248
2016 25 154 4005 653 15217
So the species count for 2016 was down by about 50, similar to 2012 but in that year I did not run as many lights as I did in 2016.
I have selected a few of the more obvious winners and losers from the 2016 list. These are moths I record regularly on my sites and usually in good numbers. The % figure is based on the average over the previous 4 years.
Winners Losers
E. postvittana (569) up 90% [mostly in my garden] Diurnea flagella (30) down 60%
Drinker (142) up 60% Agapeta hamana (26) down 50%
Small Fan-footed Wave (61) up 70% Ditula angustiorana (15) down 60%
Common Marbled Carpet (125) up 60% Aleimma loeflingiana (5) down 150%
Clouded Border (480) up 80% C culmella (109) down 50%
Pale Tussock (122) up 60% C pascuella (9) down 150%
Dingy Shears (22) up 150% July Highflyer (18) down 75%
Fen Wainscot (160) up 120% May Highflyer (23) down 100%
White-mantled Wainscot (14) usual average is 2 Flame (74) down 60% Large Y Underwing (342) down 30% Lesser Y Underwing (21) down 60% Double Square-spot (41) down 50% Bright-line Brown-eye (28) down 50% Dark Arches (130) down 60% Vine’s Rustic (8) down 100%
Some that I have recorded every year but did not see at all last year included Varied Coronet, Light Brocade, Blair’s Shoulder-knot, Red Underwing and Six-striped Rustic.
Clouded Border, May Highflyer and July Highflyer all live in similar habitat, so it’s interesting to see how the former had such a good year and the 2 Highflyer’s such a poor one.
So there were a lot more losers than winners and the figures back up the feeling you had when out on site recording that even though many nights were very promising for trapping, the moths just did not turn up in the usual numbers.
Brian
Very interesting Brian. I think your results back up Neil and the general feeling. I have been thinking in the intervening time between Neil’s post and yours why I might have higher species numbers. I have come to the conclusion that the only reason is that I have changed the design of my traps. They have been my new design for all of 2016. I feel the design of the vanes and position of the bulb and collar makes the traps more efficient especially for micros. Possibly because this design also allows me to trap in the rain with no ill effects might also be relevant. There is nothing else changed. I have trapped fewer days in 2016 too. I am just two traps and only in my garden for the data I gave.
Thanks for the report Brian, very interesting. I see that many of the common grassland moths had a bad year with you, certainly something that was very noticeable last year. Most overwinter as larvae so the mild winter did for them probably for several reasons – increased predator activity in the mild conditions, increased fungal diseases caused by damp and warmth. Things are looking a bit better so far this year numbers wise hopefully it will continue the same way all year. The cold spell in January must have done some good.