Virtual Reality, Ranger Style…

Publish Date: Wednesday April 8, 2020

Whilst getting out on site and conducting surveys may not be possible at the moment, it does give the ideal opportunity to catch up on the analysis of the backlog of data that’s been carefully gathered over time. Each year, from April to June, ten (weather permitting) visits are made to the Nature Reserve at Lochore Meadows for what is known as a Common Bird Census. Originally coordinated by the British Trust for Ornithology, (BTO) it’s what was previously used to give an index of the population numbers of breeding birds across Britain. Eight of the visits starting at silly o’clock in the morning and two evening visits. Each visit is given a letter from A to K. This will be important later!

A fresh 1:2,500 scale map is taken along each time and every bird, including its activity, is plotted on the map. Each species has been allocated a nationally recognised two letter code. For example, Willow warbler becomes WW. There are also codes for each activity; just observing the bird would result in the two letter code being written on the map at the appropriate location, whilst a singing male would have the two letter code then a circle drawn round it. Birds that are definitely known to be different individuals are connected with a dotted line, if it’s the same bird that has moved, then a solid line is drawn between them, and so on. So far so good.

Once all the visits have been carried out, it’s time to create a new set of maps, preferably when the weather’s not so good and being indoors with a cup of coffee is a nicer option, so not like today… The ten maps will be turned into species maps. One for each species. Now’s when those letters A – K come into their own.  Let’s look at our friend WW. Lochore is ideal habitat for Willow warblers and there are lots of them, each male singing his heart out, informing the females that he’s there and telling other males to keep away.  I’ve got two maps in the table in front of me, one from the first visit (in this case 11^th April, 2008. Started at 7.30 am and finished at 10.50. The weather was still, clear and mild. Perfect for shouty Willow warblers). I look at map ‘A’, and each time I see ‘WW’ written down I copy it to the unsullied map, along with any registration of the activity it was doing. But this time, the ‘WW’ becomes an ‘A’. I do the same with map ‘B’, ‘C’ and so on, until I have a representation of the Nature reserve, covered in nothing but Willow warblers. (Picture 1).

Now for the next bit. I have to try and impose some sort of sense onto this bewildering smattering of scribbles and deduce what it means in terms of territories held. Luckily, the BTO provides very definite and helpful advice on how to do this. Clumps or clusters can be seen, hopefully of differing letters and with useful dotted lines radiating out from them. A male, in roughly the same place each time I was there, and known to be different from the other birds.  A circle is drawn round this cluster. In Pencil. That’s very important and a mistake you only make once! Some are easy to sort out, whilst others involve various combinations of registrations with rubbing out and redrawing of circles, until a version of a year’s information is captured on the map. (Picture 2)

As this is being done, I can recall individual days and sometimes birds; the thrill of realising that the plank bridge I was standing on had a foraging Water rail underneath it. Ok, so it extended the visit by some minutes, and suspended the formality and concentration of the survey, but not an experience I’ll forget. What the weather was like, who was or wasn’t with me, (and who fell in the ditch), introducing people to the expanded world that’s there to be found once the veil’s been drawn from identifying birds by song and call, (now you know there’s a Grasshopper warbler nearby, even though you’ll never see it). Getting an idea of just how many Wrens you can hear at once, and having to take a few minutes out every so often as concentration leads to visual and aural overload. Seeing the massive changes wrought by the severe winters in the 90’s, when Wren territories dropped by 30 or so.

The CBC has been surpassed by the Breeding Bird Survey as the method for indexing national bird populations, but we still carry it out at Lochore. The reason is it’s a marvellous tool for site management. Birds react quickly to changes and can indicate what’s happening on site, or act as a trigger point for a management operation. For example, over the years the species have changed from mainly open grassland specialists to woodland birds, as the trees have grown. Along the pond and loch margins, Grasshopper warbler and Reed bunting numbers have gradually declined as scrub has taken over. One of these species is nationally at threat. The CBC information feeds into the site management plan, allowing us to decide where we can take action to improve the habitat for it and evidence for why we made that decision.

The surveys started in 1983 and 1984. I took them up in 1993 and they’ve continued, uninterrupted, since then. It’s probably one of only a tiny few continuous CBC’s in Scotland and I suspect the longest running by some margin. It’s a fantastic set of data, spanning 37 years in total, with a single run of 27 years and has been used in theses, HNC studies and as a baseline for some information, such as the Fife Bird Atlas. So whilst I’m stuck indoors, I’ll be travelling through time to various mornings in the Nature reserve, and compiling vital information whilst I’m doing it. The fascinating thing will be to find out, if possible, what the changes are in response to the lockdown.