A bit misty

I carried out the ‘late’ visit to one of my two Breeding Bird Survey squares earlier this week – on a rather misty Monday morning. But it’s a good job I did because the next morning it was tipping down with rain and the next two mornings I was either heading to London (for a World Land Trust trustees’ meeting) or to Yorkshire (for an interview with BBC Countryfile).

I usually do the second visit to this square in early June but it’s not wholly exceptional for it to be late June. There weren’t that many birds around and that might be because of the lateness of the visit (well within the survey protocol, of course), or the mistiness of the day or observer error, or just because birds are fading from our countryside. I should think it’s a little of all four.

I enjoyed watching a party, presumably a family party, of 9 Long-tailed Tits. Over the 15 years I have surveyed this particular square for the BBS I’ve seen LTTits in eight years, but I don’t recall seeing a group like this before. That brought home the lateness of the visit but the 9 birds went down as 2 birds because you don’t count the obviously fledged young (otherwise the date of the visit would matter even more!).

I don’t think that the mist made much difference really. Early morning mist is a seasonal hazard in times of high pressure and I may have missed an odd Carrion Crow or so in the distance because of it but the main impact of the mist (dew is the same) is that walking to the survey square my jeans were soaked to above the knees which makes the rest of the walk a bit less pleasant than otherwise.

Observer error? There is bound to be some. I’ve often wondered how my records would compare with someone else’s if we had walked around together, noting, separately, what we saw, and importantly, heard. I’m sure you would judge the distance bands slightly differently from me, you might be more or less tuned in to various calls and songs than I am and although the bird identification on my square doesn’t feel very taxing, I bet I make some errors. I’d feel happier if my errors were more of omission (missing some birds) than commission (misidentifying some birds) but who is to know?

Observer errors are expected to come out in the wash. With squares like mine, which I have surveyed for 15 years, any consistent errors attributable to this observer won’t matter too much as the comparisons are mostly from year to year, so if i am a bit hopeless and record only half of the birds that were really there and record all the Mistle Thrushes as Song Thrushes and can’t judge 100m to save my life then there is still value in the year-on-year comparisons. And because others will be recording twice as many birds as there really were, and all the Song Thrushes as Mistle Thrushes and have a different idea of 100m then it probably doesn’t matter. By the way, don’t take any of that as an admission of error on my part, I’m sure my record-keeping and judgement of birds and distance are all absolutely spot-on – it’s all the rest of you we should be worried about.

In the previous paragraph the word ‘consistent’ is quite important. And one of the slight worries in that regard is the ageing process. So are my errors now the same as they were when I was 46? It’s difficult to tell isn’t it? Conceivably, over that period my knowledge of the site has improved over time (so now I expect to hear a Lesser Whitethroat in a particular spot – does that make it more likely that I do?), I may walk quicker (because I am more familiar with the site) or slower (because my back hurts), my hearing and/or sight may have improved but it’s rather more likely that they have deteriorated. Of course, none of this applies to me really – it’s all the rest of you we should be worried about.

But even if I am not changing at all, the birds are. I added a species to the list this year – Rook. Although there are plenty of Rooks around in the general area, I’ve never recorded them on this survey square before. Yellow Wagtails are hanging on but in the first 7 years of my surveys here I recorded them every year and had 19 records (actually, ‘records’ isn’t quite accurate but it’s good enough shorthand and would take too long to explain) whereas in the last 7 years they have been recorded in only 6 of them and amount to only 9 records. I’ve recorded Reed Bunting in 5 of the 15 years, but not in any of the last 5 years – that’s now looking like a long gap.

But my records, perfect though they are, form only a well-recorded and standardised local picture of what is happening; of course the strength of the BBS is in the fact that there are over 4000 such squares surveyed by volunteers like, or very different from, me.

Anyway, I’ve still got my second visit to my second BBS square to carry out before the end of the month. I’m glad to say the wether forecast looks quite good.

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