What a staggering month May was for rarities on the PWC!
by Mark Lewis
In May 2013, as well as all of the usual scarcities there were four BB rarities recorded as finds on PWC – namely Spotted Sandpiper, Black-winged Stilt, Bonaparte’s Gull, and Thrush Nightingale. Not a bad haul, especially as it was backed up by a really great selection of classic late spring quality. Conversely, 2014 May saw 15 self found BB rares for hard-working patchers, which included multiple Black Storks, Citrine Wagtails and Savi’s and Blyths Reed Warblers, and single Collared Flycatcher, Bonapartes Gull, Broad-billed Sandpiper and best of all, Alan Tilmouths Eastern Bonelli’s Warbler. On the face of it, one month was obviously a lot better than the other!
But we can look a little deeper than that. In 2013, those 4 BB rares were part of 118 score submissions – which works out as 1 rarity for every 29.1 patches. In comparison, this May’s tally of 15 BB’s came from 168 submissions, coming in at 1 rarity for every 11.2 patches (of course, this assumes there is only one submission per patch – this might not be the case as occasionally folk submit more than one score per month. I haven’t checked for this, but if there are any duplicates it’s very unlikely that they’ll have any impact on the overall scenario) So, what this essentially means is that this May, you had a 1 in 10 chance of finding a BB rare on your patch, compared to a 1 in 30 chance last year. Which according to my logic makes this year three times better! Lets hope it felt that way for all of you!
It certainly will have done for some. Assessing the quality of a month by the number of rarities per patch is slightly perverse, as obviously some patches are better for rarities than others. Last year we singled out Rob Fray, at the Pool of Virkie in Shetland, as having had a particularly good month. Rob notched up a Thrush Nightingale, and backed it up with Buff-breasted Sandpiper, Red-backed Shrike, Common Rosefinch and Grey-headed Wagtail, to take the ‘Patch of the month award’ – which is something we really out to sort out more formally! If you thought that was good though, check out what John Bowler managed in May on Tiree this year. His Collared Flycatcher tops the tree, but along with that he found Red-rumped Swallow, Rustic Bunting, Red-backed Shrike, Marsh Warbler and Common Rosefinch. I think that’s a haul that most of us would be happy with over the course of a year!
So, all this begs a question of me. Is May the best spring month for birding on patch? In terms of number of rarities the answer is undoubtedly yes, but there’s more to patching than that. I can only really answer that with the info from my own patch, so here’s a look at how Girdle ness has been faring so far this year.
The red line on the graph above charts my cumulative species total through the course of this year. It’s at it’s steepest (i.e. the most species were added) in April, which fits in nicely with the tallest of the blue bars, denoting the number of species recorded in each month. So variety wise, April comes out on top so far. However, I was on holiday for more than half of May, so simply comparing the number of species in each month is not sensible, as the effort was completely different. If instead we look however at the green bars, they show a nice progression that peaks in May. These bars represent the number of species per complete list (good old BirdTrack!) – so essentially it shows that when I go out in May, I’m likely to see more species than on a trip to the patch in any other month. So if the number of rarities can’t be used as a measure of ‘month quality’, this assessment of diversity certainly backs up the assumption that May really is the best month in the first part of the year.
Although to rule out June would be foolish of course…