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No. 46 NEWSLETTER Summer 2000

WEST MIDLANDS BRANCH, BUTTERFLY CONSERVATION

 

1999
WEST MIDLANDS
BUTTERFLY AND MOTH
ANNUAL REVIEW (3)

Butterfly Roundup

Certainly not the best of years to round off the old century with no real highlights in what was on the whole a fairly depressing year for the region’s butterflies. Although as always there were sites and species which bucked the trend. Perry Wood in Worcester, for example, turned in its highest ever butterfly count (PAW) as did Rodborough Common in Gloucestershire (MTO), although the latter can be mainly explained by the phenomenal numbers of Chalkhill Blues, while in Perry Wood the standout species were Ringlet, Gatekeeper and Speckled Wood. Generally, the Satyrid family had a reasonably good year especially Meadow Brown, although this fact was rather overlooked at the time. Transect figures don’t lie, however, and the numbers recorded were almost 75% up on the previous year providing ample justification for making this species butterfly of the year. Last year’s winner, the Holly Blue, was nowhere to be seen, collapsing in its first generation and almost invisible in its second. Sadly some of our rarer species fared much less well and their flight season often seemed to coincide with the worst of the weather. With the notable exception of Haugh Wood, Pearl bordered Fritillary did abysmally with very low numbers at its few remaining sites. Haugh Wood, in contrast, thanks to some sterling work by Forest Enterprise, produced its best figures since the early nineties (JA) proving once again the importance of beneficial management even in a generally poor season. Of interest was a report east of the Severn near Bewdley (MEW), the first in about ten years. If anything, Small Pearl bordered did even worse than their larger cousins with the only saving grace coming from the Stiperstones where they were reported locally in some strength (JJ). Silver-washed numbers were also nothing to write home about but did show some recovery on the previous year. There was a report from Monkwood (via CET) which was pleasing after a blank in 1998. Dark Green Fritillary certainly did better in places, with some really good numbers at some Cotswold sites but poorer elsewhere, with a very disappointing performance on the new transect at Ewyas Harold (SY). A new report for this species came from a site near Bishop’s Castle (AN).

I can hardly bring myself to report on High Brown Fritillary which again did appallingly. If 1998 was an “unmitigated disaster” for this species, as described in last year’s report, I’m not sure what words are left to describe its performance in 1999 with none seen at all at Chase End and the lowest ever totals at its other remaining sites (DJW, BP, PHy et al). Despite all our efforts, extinction is staring this butterfly in the face as far as the West Midlands are concerned. We can but hope that the new initiative on the Malverns reported in our last newsletter and continuing management efforts at other sites may be in time to turn the situation around but there is little room for optimism.

On a brighter note, at least one species of Fritillary did well within the region with the most successful year since monitoring began at the Marsh Fritillary site in Gloucestershire. Good spring larval accounts were followed by the highest adult emergence on record and evidence of very good breeding success, despite sometimes dubious weather conditions during the flight season (MTO). There was some evidence of possible dispersal with reports from Rodborough Common. The introduced colony in Worcestershire also survived another season with similar numbers of larval webs in the autumn as the previous year suggesting that they will survive another season.

Other species to do reasonably well in the Spring included Green Hairstreak which was out before the end of April and was reported from a number of new locations on the Malverns (C&HD) as well as its usual haunts. For the first time, it turned up inside the boundaries of Monkwood NR after the sighting on Monkwood Green in 1998. There was also confirmation of a small colony at the Floggin in Halesowen (DWh) proving once again the increasing value of old industrial sites in urban areas. Grizzled Skipper continues to thrive under sympathetic management in a small area of Wyre Forest (FL et al) and a more surprising report came of a new site near the base of Ankerdine Hill (TS). Dingy Skipper was in fairly short supply in 1998 and is another species for which urban settings are becoming increasingly important. Strenuous efforts are being made to conserve the newly discovered colony at Anchor Meadow in Walsall (see newsletter). Wood White figures were similar to the previous year with some encouraging new records from Herefordshire near Aconbury and Checkley (JA) and a few reported from near the Royal Ordnance site in Wyre Forest (TBu). The status of Wood White within Wyre is rather baffling with specimens being seen in widely scattered locations for a few years, only to then disappear and reappear elsewhere. There was a reasonably strong second brood at Monkwood with several August sightings (CET, DWh et al.).

Moving into Summer, White Admirals generally did badly with the lowest numbers on the Monkwood transect since 1989 and poor numbers elsewhere. Ringlet and Gatekeeper, in contrast, did better and it was encouraging to also see an improved performance from Small Skipper. The fact that there were more Small Skippers around also improved the chances of finding Essex amongst them and so it proved with reports, this time backed up by photographs, from Windmill Hill and Redditch (GF). Although there is obviously more work to be done, it is looking increasingly as if the main penetration into Worcestershire is coming from the east. Speckled Wood also did well at some sites although overall numbers fell back slightly on 1998. White-letter Hairstreak numbers were generally similar to the previous year and once again there were further outbreaks of Dutch Elm. New records came from Hill Croome and West Sugarloaf Hill on the Malverns (C&HD). There were also new reports of Purple Hairstreak from the same recorders at Clenchers Mill and Cold Elm and also a September record from the Floggin (DWh). It is always difficult to judge how this species performed overall but most of the transects where it is well represented showed a decline. The spread eastwards of Marbled White seems to be continuing with a first record from a site near the Clent Hills (DWh). Northern Brown Argus appeared to have a very good season if the numbers at Castern Wood on the July field trip were anything to go by.

Of the doubled brooded species, it was a pretty poor year for Large White with the lowest figure since 1985 on the transect at Perry Wood (PAW). Green-veined White also did poorly although there was an interesting report of ab. Sulphurea near Bridgnorth (RSw) in July. It was generally a disappointing year for Small Heath although there were one or two new records for Worcs (PD, DWh, C&HD). Brimstone, while reasonable in the Spring, did badly in the Autumn and overall showed a decline on 1998. Small Tortoiseshell again were very thin on the ground but Comma did much better and it was good to see the West Midlands branch symbol finish the old millennium with a bit of a flourish. Very few reports were received of Brown Argus, although the one seen on Monkwood Green (CET) was the first report from this location for seven years. Common Blue appeared to do worse regionally than nationally and numbers were generally low with the worst season in fifteen years of monitoring at Perry Wood (PAW). The same might be said of Small Copper which showed an overall decline of 40% on West Midlands transects (ID).

Migrants were generally poor with no records of Clouded Yellow from the region, very few Painted Lady, and generally low numbers of Red Admiral although once again a number of the latter species appeared to get through the winter. Several species lasted quite well into the Autumn with some very late sightings for Painted Lady, Holly Blue, Red Admiral and Speckled Wood. Brown Hairstreak was again fairly hard to come by but the subsequent egg count around Grafton Wood showed a slight improvement on the previous year.

Mike Williams

 

A year of improvement

Most of our garden butterflies showed an improvement on the somewhat dismal results of 1998. There were no spectacular increases, except for the Marbled White which visited an extra 11% of gardens in 1999 compared with 1998 and showed its highest percentage ever. Gains of 5-10% were quite common, including Brimstone, Comma, Gatekeeper, Large White, Meadow Brown, Ringlet, Small Copper, Small Skipper and Speckled Wood. Even the Wall showed a modest gain of 5%, although still far below its abundance in 1995. The most serious loss was the reduction by 28% in the number of gardens recording the Holly Blue, but we know that this is part of the cyclic nature of this species' abundance and no cause for alarm. In fact 1999 set no alarm bells ringing, in my ears at least!

Is the Peacock a Midlands speciality?

This was the question I asked in 1996 and 1997, when the answer appeared to be, “Yes”, the Peacock being recorded in more Midlands gardens than nationally. Although reduced to 96% in 1998, the 1999 result of 99% is yet more evidence that the midlands is a stronghold for this species, as far as garden visits are concerned.

The ups and downs over five years

In this report I have compared the results for the past five years, 1995-1999. There is very little of significance when comparing the data for the common garden butterflies, mostly just a gentle rocking! However, the Large White appears to be increasing its visits, possibly not a welcome finding for vegetable gardeners!
The cyclic nature of visits is plain to see from Table 2: Brimstone begins and ends the five years almost at the same value and all the species show a regular pattern of up and downs.

In 1997 I stated that if the Wall Brown continued its decline in the Midlands at the present rate it will no longer be a garden visitor by the time we reach the millennium. Happily I was wrong, as after reaching an all-time low in 1998 a modest increase was recorded in 1999. Hopefully, this will continue, but beware a severe summer drought. In fact if you are one of the lucky people to have a Wall visit your garden it could be worth trying to discover where the species is breeding and watering the grasses gently in a drought. I also stated in 1997 that the Marbled White was behaving in the opposite way to the Wall, as it was showing a gradual increase in garden visits, which had more than doubled since 1993. There was a dramatic drop in 1998, but this was more than compensated for with the rise in 1999 (Table 3).

Most of the species in this table show a similar cyclic pattern, but Large Skipper seems to have settled at 23%, while variations in Small Heath visits are small, indicating stable breeding populations in the few places where this butterfly visits gardens.

Altogether Midland gardens recorded 35 species in 1999. Rare visitors included Clouded Yellow, Essex Skipper, White Admiral, Silver-washed Fritillary, Dark Green Fritillary, Pearl-bordered Fritillary, Chalkhill Blue, Wood White and Green, Purple and White-letter Hairstreak. There was even an authenticated Large Tortoiseshell!

Thank you to all Midlands recorders who make this garden survey so interesting.

Margaret Vickery

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