After raking to and fro over the Southern Uplands for the past month, I’ve seen a lot of black grouse. The lek season may just have passed its peak and there are still a great deal more leks to visit, but one rather striking theme throughout the entire South of Scotland is that the incredible and much lauded summer of 2013 does not seem to have swelled the ranks of existing leks. Numbers are pretty stable, and with a single exception last night on Langholm Moor (which is relatively unlike most of the other leks in this area), I haven’t seen a single young bird displaying together with old birds on existing leks. The huge majority of birds I have seen displaying at the leks have been mature cocks in their second or third years, and the young birds of 2013 have been conspicuous by their absence.
It was easy in August and September last year to get excited as great numbers of young birds were apparently being recruited to the population after the most perfect breeding conditions for decades, but even considering the birds which didn’t survive the winter, the burgeoning number of cocks in the back end is just not being matched with enlarged leks during this past month. I’d be very interested to hear from keepers or observers who are seeing noticeably bigger leks this spring after 2013, because it just does not tally up with my experiences over the last few weeks.
However, that is not to say that we are facing disaster – the young birds appear to be alive and well; they’re just not at the leks.
One theory for this is that young birds don’t win a place on the leks in their first year, and they stand around on the fringes of the main leks, invisibly calling away now and again but biding their time until their second spring. This would explain why there are plenty of young birds going around without being picked up at lek counts, and is obviously true in some cases, but it is more likely to happen when you have a large, prosperous lek which is firing on all cylinders and there is literally no room for youngsters. Some of the leks I have been seeing are dribs and drabs of four and five, so the argument that there is “no room” for incomers fails to hold water.
Another theory is that young blackcock wander around more widely during their first year and don’t settle on an individual lek. Much is made of the fact that young blackcock are very loyal to their “home turf” and will never stray far from it, but in fragmented habitat where greyhens are few and far between, young birds wander over long distances and may not feel the pull to join in on the lek which conceived them, particularly if it is dominated by one or two hoary old tough guys. They may meet up with other youngsters and initiate a new “pop-up” lek which is absorbed into another group in due course, skewing the figures and making the traditional leks seem dominated by old birds.
There is also the notion that leks can only be a certain size before they collapse and split up, and some people have supposed that so many young birds were recruited last year that the large leks have fallen apart and the various fragments have moved elsewhere, leaving only a hardcore group of old birds on the lek site. The only leks I’ve seen this happen to were made up of more than twenty five cocks, so it is not really applicable to the smaller-scale displays that we are used to in the Southwest. If this had happened, we would also be seeing lots of new leks made up of birds at different ages scattered all over the place, but that is not the case. The old birds are on the same leks as last year, and the young birds are not joining them.
This is all based on marginal ground, and I haven’t yet seen any of the big leks in Perthshire or the North Pennines this year, I would imagine that if direct recruitment was taking place and young birds were being accepted straight onto the leks anywhere, then I would expect it to be taking place in these “powerhouse” areas. I will report back when I’ve had a chance to take a look.
I tend to think that the explanation for this lack of young birds on the lek in marginal areas is a complex mixture of all kinds of reasons. Young birds can be more footloose, and the dynamics of a displaying group of blackcock makes it very hard for a newcomer to join in. Perhaps this has been exacerbated by the fact that it has been a rather odd spring, but I am rather satisfied to find my predictions ringing true of single blackcock turning up in unexpected places here and there throughout the spring.
I’ve had unknown birds on my own ground and have spoken to others who have seen similarly unexpected birds displaying on their own, and in my opinion, these are the young birds coming through; away from the leks and uncounted. What they will do from here is the next riddle – will they return to join the leks next year, or will they set up where they are to create a much looser, more free-form style of lek where single cocks display separately? This is certainly a pattern I’ve encountered in populations recovering from a slump.
The classic close-knit gang of blackcock on the lek is everyone’s idea of “proper” behaviour, but there are a million variations of this theme. Many populations have received a huge boost from the good weather of 2013 and now have a chance to recover after several sustained years of decline. It is hardly surprising that they don’t just spring back into prosperity again after a single good year, and all the hugely complex clockwork mechanisms which go on behind the scenes at a lek may take years to heal and show “classic” growth again.