Lancy, Fair Isle

Lancy, Fair Isle

As our first week on Fair Isle draws a close, this seems a suitable point to review what we have seen. In more or less chronological order the scarce or rare species have included: Barred Warbler, Common Rosefinch (at least 2), Short-toed Lark, Red-throated Pipit, Yellow-browed Warbler (peak of 54 on 20 September, of which I saw at least 17), Little Bunting (2), Bluethroat (2), Lanceolated Warbler (a very satisfying bird to find, and very obliging for all the visiting birders), and Olive-backed Pipit.

The spectacle of migration, and the chance to see birds in the hand as well as in the field, deliver a birding experience which would be hard to beat.

Rosefinch, Fair Isle

Rosefinch, Fair Isle

The under-appreciated Small White, Rutland

The under-appreciated Small White, Rutland

As temperatures climbed towards an unseasonal 30 degrees, I managed to fit in a couple of hours looking for butterflies this afternoon. The most numerous was Small White, which is Rutland’s most widespread butterfly. Other species, including Vanessids, were only seen in small numbers. Of note were Common Blue and Brown Argus.

A covey of eight Grey Partridges near Clipsham Ford was also notable.

White's Thrush - what do those words mean to you?

White’s Thrush – what do those words mean to you?

September is a magical month for birdwatchers. Autumn migration is under way throughout the month, and the mix of migrants changes as the month progresses from birds which originate in Europe to those from further away. White’s Thrush, like this 1944 specimen from Fair Isle, is a good example. Possible from late September onwards, most records involve brief visits to one or other of the northern isles. In over 45 years of active birdwatching I cannot recall a single east coast record south of Spurn, which is one reason why I have never had a sniff of one in Britain.

Throughout my adult life September has been dominated by work, with relatively little time free to follow the wonders of migration. This year will be different…

Small Tortoiseshell caterpillars

Small Tortoiseshell caterpillars

In common with many other species, numbers of Small Tortoiseshell have been low so far this year. In recent weeks I have seen clusters of caterpillars, however, and the adult butterflies are now beginning to appear in more promising numbers.

Other butterflies on the wing today included several Painted Ladies, better numbers of Common Blue, a late Silver-washed Fritillary still at Ketton, and Small Heath.

Fresh Small Tortoiseshell

Fresh Small Tortoiseshell

Holly Blue, Rutland

Holly Blue, Rutland

There was a distinctly autumnal feel in the air today. Some of our summer butterflies are coming to the end of their season, and numbers generally seem low.

Two species which are having a good year are Holly Blue (still) and Brown Argus. To date I have seen more second brood individuals of the latter than Common Blue, which is unusual.

Brown Argus, Rutland

Brown Argus, Rutland

Double-crested Cormorant: the rarer the bird, the more significant each record

Double-crested Cormorant: the rarer the bird, the more significant each record

There has been some misinformed discussion about records committees on birding discussion groups recently, so this seems a good time to set out my experiences of the committees for which I have served: many years on a county records committee (L&R), many years on a national records committee (BOURC) including a term as secretary, and attendance at a European (AERC) records committee meeting in 2009.

Without exception, these committees have worked hard and done a good job. Perfection is of course an unattainable target – committees are groups of people who by nature sometimes make mistakes – but the vast majority of their decisions stand the test of time.

Europe At a formal level the AERC has not been entirely successful, partly because of its nature and the logistical problems associated with such a large and varied body. At an informal level it has been very successful. For example, conversations I had at the 2009 meeting contributed to subsequent reviews of controversial records of Slender-billed Curlew and Louisiana Waterthrush.

Britain During my time as secretary of BOURC I saw every file on a first for Britain up to my retirement in 2013. The standard of almost all files was very high. Although the committee was sometimes criticised for being slow, it is the case that decisions taken too quickly are more likely to be problematic. In maintaining the British List, BOURC has to consider taxonomy, identification and provenance. Contrary to some statements any previous record can be reviewed, including those placed in Category E.

Determining the status of species on the list also requires occasional reviews of historical records: the rarer the bird, the more significant each record, and we have a lot more information available to us than many previous assessors. At both county and national levels it is clear that determining first records of rare species is important. The alternative ‘voucher’ system sometimes proposed would quickly prove unworkable.

County The LROS records committee maintained consistent high standards, and undertook a review of historical records as part of the preparation for publication of BLR in 2009. As committees should, it erred on the side of caution.

Do we need committees? Although committees have their critics, it is unclear that there is a better alternative. Collective decision-making by a body of experienced individuals has a proven track record, and as already noted the vast majority of their decisions stand the test of time. One of the problems with many historical records is that they were assessed by individuals, not committees.

How many? Many countries manage with one committee, and the same might be possible in Britain (though Britain does attract relatively large numbers of rare birds, so assessing their records involves a significant workload). It is still unclear what BOU will decide about its approach to taxonomy, which is an unfortunate vacuum. The assessment of historical records is an area which should preferably be informed by dedication and experience. I have occasionally heard suggestions that we should simply disregard all Category B records, which would be irresponsible.

In the absence of a better alternative, we should support those who serve on our records committees. I’d go further: we should applaud them.

Peacock, Rutland

Peacock, Rutland

Since my last update there have been a few more changes in the fortunes of our local butterflies.

The second brood of Small Copper appeared  at the end of July, but Common Blue has been scarce and did not begin to appear until 5 August. Holly Blue continues to have a good year, but I have not yet heard any reports of Chalkhill Blue from Bloody Oaks – if the colony has died out it will have appeared and disappeared again within the short period of the RBA.

Purple Hairstreaks are having a good year, and Painted Lady has appeared in small numbers (though as last year I have not yet seen a Clouded Yellow).

Fluctuations in populations are to be expected – numbers of many species seem relatively low this year. As national statistics show, however, the general trend for many species is disappointingly downwards.