By the middle of March the days are getting longer and the equinox, when there’s 12 hours between sunrise and sunset, is not far off. The first indications of new life were already visible where I live on the Moray Firth coast at Findhorn, with daffodils getting ready to flower and pussy willows appearing on the willow trees, so I headed out to Glen Affric to see if spring was also making its presence felt there. Situated inland, amongst the mountains to the west of Loch Ness and at a higher elevation, Glen Affric is always behind Findhorn with the return of life each year, but nevertheless I hoped there would be something to see already.
Arriving in the glen, my intuition was proved correct immediately, when I saw catkins on some hazel trees (Corylus avellana) beside the road between Badger Falls and Dog Falls. I’d been out with a group in the glen about 10 days previously, and there had been no sign of the catkins then, but they had been visible along the shore of Loch Ness, on the way to the glen. Because of its size and depth of water, Loch Ness acts as a great climate moderator, and the milder winter temperatures there mean that the phenomena of spring are always more advanced there than they are in Affric, sometimes by two or three weeks.
The study of this variation in the timing of annual natural phenomena, such as leaf burst in spring or the nesting of a specific bird species, is known as phenology, and has become a subject of more popular interest in recent years. The annual variation in events such as the first flowering of primroses (Primula vulgaris) has intrigued me for many years, and is due to a combination of factors, such as seasonal temperatures, amount of snow and rainfall, severity of winter frosts etc.
This means that every spring is unique and different to those preceding or following it, with the exact timing of specific biological events varying from year to year, and the specific sequence of events within each year varying from other years as well.
This annual variation is apparent in the flowering of hazel catkins, which varies both in its exact timing from year to year, and in the number of catkins produced by the trees.
2014 was an exceptionally abundant year for hazel catkins, and I wrote an entire blog about them then, which can be read here. By contrast, last year there were comparatively few catkins on the trees, but this spring there are more again, although they are not as prolific as in 2014. They are also a little later in opening than some other recent years, and have yet to reach their peak of flowering. Thus, some of my photographs show a combination of fully open and partially open catkins, and I also spent a while taking a high magnification image of one of the female flowers – these are tiny red-tufted buds that are easy to overlook on the twigs.
Inspired by seeing these catkins, my thoughts went to what other signs of spring might be visible, and wood ants came to mind immediately. They are dormant during the winter, staying underground in their nests, but by this time of year, on warmer sunny days they can often be seen massed on top of their nests. With this in mind, I drove further into the glen, to where I knew there are several wood ant nests beside some large Scots pines (Pinus sylvestris) next to the road.
Reaching the site, I approached one of the nests and even before I got close to it I could see the black mass of large numbers of wood ants clustered together on top of it. These are the northern or hairy wood ant (Formica lugubris), the commonest species in the native pinewoods to the west of Loch Ness. When they first emerge in the spring, they often cluster together on top of their nest like this, and the reason for doing so is to absorb the heat of the sun. Their mostly-dark bodies are good for this, and the thermal energy they gain thereby helps them to become active. They also use the sun’s heat to regulate the temperature inside their nest. Once they have warmed up, they go inside where their bodies radiate the heat in the nest chambers, and this helps to regulate the temperature there, keeping it at an optimum level for the development of their larvae.
I watched the ants for a few minutes, but my presence caused a disturbance to them. Their view of the sky must have been darkened by me leaning over the nest, and they began moving around rapidly, so I retreated to give them the freedom of their own space. In a few minutes they settled down again, but weren’t as densely massed as before.
Out of curiosity, I looked at the trunk of the large Scots pine nearest their nest, to see if any ants were on it. I didn’t really expect to see any at this time of the year, as the ants seemed to be focussed on staying on the top of their nest, rather than foraging and bringing food back for their young. However, I did spot one or two individuals moving down the trunk – in previous summers I’ve watched columns of them going up and down this tree, presumably to ‘milk’ honeydew from aphids that were feeding high up in the branches. There would be few if any aphids feeding this early in the season though, so I suspect the ants that had climbed the tree probably hadn’t been successful in their forays.
Although there weren’t many ants on the tree, the trunk of the pine drew my attention, as it was a particularly good example showing the different layers of bark, each composed of organically shaped pieces, and forming a three dimensional jigsaw puzzle-like pattern.
A few months ago I wrote another blog all about the bark of some Scots pines in Glen Affric, and the remarkable natural artwork they exemplify. It may seem somewhat repetitive therefore to feature pine bark again in this blog, but I make no apologies for that, as I constantly find different and beautiful patterns on the trunks of these old trees in the forest. For me it’s a similar experience to that of discovering that every snowflake is individual and different to all others, except that with the pines, because of the large surface area of their bark, there’s scope for huge amounts of variety amongst them all.
I was very close to the eastern of Loch Beinn a’Mheadhoin, so I walked a little way to an overlook, where there was a view down to the water. Looking through a stand of downy birches (Betula pubescens) I could see some more pines nearer the edge of the loch and the canopy of an area of birchwood off in the distance. This latter displayed another sign of imminent spring, because the twigs of the birches turn a vivid colour of reddish-purple as the buds swell, prior to bursting open into the new season’s leaves.
This is one of my favourite times of the year, when there’s a pregnant quality to all of Nature, with the imminent re-emergence of life being like a new birth waiting to happen.
The lengthening days and warming temperatures call forth the rising sap and awaken the invertebrates that have been dormant over the winter. In addition to the wood ants, I saw a few spiders and some small flies in the air, but there still weren’t many insects to be seen yet – their main emergence time is still a few weeks away.
There’s a great sense of anticipation for me in the forest at this time, in these last days and weeks before the exuberant explosion of new life, which always seems to happen too quickly, once it gets going!
Here’s a couple of further images of the bark of one of the Scots pines in this area, followed by some video footage of the wood ants and some sequences showing the overall patterns of the pine bark.
PS: After using the video head on my tripod to shoot the footage above with the camera movements in it, I changed back to the ball and socket head for taking some more still photographs. In doing so I left the video head on the ground and forgot about it! Returning to the glen a week later, I retrieved it from amongst the heather at the base of one of the pines, and whilst in Affric, I found some more signs of spring, namely freshly-laid frog spawn in a pool near the bridge at the Dog Falls car park.
I visit this pool every spring, and there’s always frog spawn, and later on tadpoles, in it, so I was delighted to see the phenomenon again this year. It’s obviously a favoured spot for frogs to reproduce, and I wonder if perhaps the frogs are like salmon (Salmo salar), and remember their birth place, so that they return there themselves, to lay their eggs and continue the cycle of reproduction in the same pool?
Last year, on almost exactly the same day (22nd March 2015) I visited this pool, and the frog spawn was a little more abundant and perhaps slightly more advanced in its development. I also saw the frog which must have been responsible in another section of the pool nearby.
I’ll return to this pool later on in the spring to check on the progress of this frog spawn … watch this space…