FIELD NOTES
FEBRUARY 2003 continued....
ARTICLES
Moth Trapping at Marshalls Heath:
The First Ten Years
Yesterday I completed my first ten years of systematic moth trapping at Marshalls Heath. This has meant operating a Heath trap all night every night when I'm at home, a total of 2631 nights in all.
Numbers of moths of each species are recorded in the morning, together with weather at dusk and dawn, plus daily maximum/minimum temperatures, rainfall etc. After counting, moths are put into the hedge on the other side of the house from the trap and about 80 feet from it, so as to minimise re-trapping. At the end of each year, totals are corrected for nights missed, by simple interpolation. Some preliminary findings are as follows:
92,646 moths were trapped altogether, comprising 605 different species, though 918 moths (nearly 1 percent) were not identified, either because they were too worn, or flew away during counting, or are still awaiting identification. 15 species had totals exceeding 1000 individuals in the ten years, and one species exceeded 10,000. The "top fifteen" moths, together with corrected 10-year totals, are as follows:
| Chrysoteuchia culmella: | 10,304 |
| Large Yellow Underwing: | 5472 |
| Agriphila tristella: | 5198 |
| Common Wainscot: | 4017 |
| Agriphila straminella: | 3486 |
| Common Footman: | 2451 |
| Heart and Dart: | 2388 |
| Hebrew Character: | 2314 |
| Square-spot Rustic: | 2063 |
| The Rustic: | 1937 |
| Lesser Common Rustic: | 1792 |
| Agriphila geniculea: | 1739 |
| Smoky Wainscot: | 1544 |
| Dun-bar: | 1095 |
| Blastobasis lignea: | 1069 |
At the other end of the scale, exactly 100 species of moth appeared only once in the ten years, and a further 63 Marshalls Heath species never entered the Heath trap. The latter include day flyers, leaf miners, and some species that have only been attracted to the house lights or the Mercury Vapour trap.
Among the most variable moths in terms of annual numbers are the following:
Small Square-spot: Totals up to 335 per year (in 2000), but no moths at all in 1996
Rush Veneer: Highest total 284 in 1996, but none in four out of ten years
Ingrailed Clay: 211 recorded in 1997, but none in three out of ten years.
Finally, the corrected annual totals for the ten years are:
| 1993: | 3343 (191 species) Probably low due to learning curve and only 190 nights of operation caused by teething troubles with the trap |
| 1994: | 5114 (254 species) |
| 1995: | 14634 (351 species) |
| 1996: | 12604 (348 species) |
| 1997: | 12115 (353 species) |
| 1998: | 8090 (346 species) |
| 1999: | 7532 (322 species) |
| 2000: | 11167 (284 species) |
| 2001: | 10732 (284 species) Poorly recorded: 203 nights only, many summer weeks missed |
| 2002: | 7315 (362 species) |
John Murray
Page Five >>
|
