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Thursday, 11 March 2010
Signs of the times: Spring #1
The "What To Look For In..." series of books by Ladybird paint us a picture, season by season of the changing face of the British countryside through a year. But, published, as they were, between 1959 and 1961, the countryside we see around us today, some 50 years later, has been subject to considerable change, both in agriculture and land management practices, and, related to this, in the richness, distribution and overall health of the wildlife (and not all the changes have been negative). We also have lots of bits of evidence that the climate has changed measurably over the last 40 years, with effects on the seasonal timing of natural events (more later). So, here is the first of the posts I will make over the next year, based on the words and pictures of these "What To Look For" Ladybird books. I will be trying to compare the idealised countryside presented to my young self in the early 1970's (itself based on images from some 10 or more years before then) with the countryside around us today and seeing if it is possible to draw any conclusions, in due course, about "the state we are in".
The first picture in the Spring book (click on it to see a larger version) shows a scene supposed to be from the first week of March (so I just missed the chance to coincide with that), with some mallards flying above a lake (or maybe a loch?), alder catkins, pussy willow buds and more waterbirds on the loch - a pair of mallards and a great crested grebe. In the background, a farmer is ploughing up his winter stubble from last year's grain crop.
So, I guess the first thing that's worth saying is that the timing of Spring has changed a bit since 1961. Why do I say that? Well, with all the fuss about the climate change we can expect in the future, we may be conveniently overlooking the fact that it has been happening for a few decades already. The study of phenology, or the seasonal timing of natural events, reveals the annual and seasonal cyclical changes in emergence of flowers and leaves, the hatching of bird chicks, the timing of leaf fall in Autumn, and so on. In 2006, a handbook of climate trends for Scotland was published, covering the years 1961 - 2004. Over the last 50 years, in response to warmer average temperatures and a consequent longer growing season, the average growing season now starts a full three weeks earlier in Scotland than in 1961:
So, in the first picture in this series, it is likely that the timing of the opening of buds of the pussy-willow will now be taking place earlier than in 1961. That said, I spotted the first opening pussy-willow buds of the year that I've seen here in Stirling yesterday, but this has been the coldest January and February in Scotland for 50 years - and that illustrates the need to differentiate between weather (what's happening today) and climate (the long-term average conditions) when thinking about the effects of climate change!
Other wildlife issues worthy of comment in this picture are, firstly, the mallards. There are both paired-off mallards (in the water) and courting mallards (in flight). Mallards are Britain's and Scotland's commonest wild ducks, well-known from and easily observed in city park ponds, local rivers and lochs, estuaries, harbours and canals. There has, however, been a long-term decline in mallard numbers in the UK in winter. Here is the trend in winter mallard abundance between 1961 and 2008, as collated and analysed by the British Trust for Ornithology (BTO) as part of its annual Wetland Bird Survey:
From BTO (2009)
The BTO suggests that this decline in winter mallard numbers may be a result of milder winters on continental Europe leading to fewer mallards arriving in Britain to escape the colder continental conditions and find open unfrozen water in Britain. If the breeding population of mallards is examined, by contrast:
you can see that there has been a big increase in numbers. You can read more about this at the BTO's website. It seems this increase may have been partly brought about by the release into the wild of mallards bred for duck shooting purposes.
The BTO's account for this species, in the Breeding Bird Survey (BBS), says that the "species was believed to be on the verge of extinction in Britain around 1860, when only 32–72 pairs were known in England". A "subsequent increase followed reductions in persecution, aided by statutory protection, and the creation of habitat in the form of gravel pits". An increase in numbers was tracked by special surveys to around 7,000 adult birds in Britain by 1975. The BBS provides the first annual, national monitoring of this species and indicates a shallow increase in numbers since 1994.
The final issue worth commenting on in this picture is the tractor in the background, ploughing, as it says: "wide strips in last year' stubble". First off, a recurrent theme of the agricultural issues in comparing the world of today with the "What to look for" books is the extent to which farm machinery has changed since 1961. The farmer here is driving a small Massey Ferguson-type tractor of the kind I remember from small childhood, with no cab or even a roll-bar to protect the driver (must have been freezing! They bred them tough in those days!) and so totally unlike the massive, soil compacting monsters that are in use on farms these days. I have no idea whether last year's stubble is for wheat or barley, but one of the significant changes in agriculture since the book was published has been a major switch away from the Spring planting of cereal crops, particularly barley, to planting in Autumn. I found one quote: "From the late 1980s, the area of winter-sown barley has exceeded that of spring-sown, whereas as recently as 1970, spring-sown barley acreage was more than ten times that of winter-sown." This change, and with it the ploughing up and subsequent loss of winter stubble and its supply of fallen seed, as well as differences in the usefulness of spring and autumn and winter sown crops as habitats for some nesting birds, has had massive negative consequences for British wildlife, a theme I will certainly revisit in subsequent posts, but it is interesting to see it reflected in the very first of the pictures I have examined in this exercise. So, climate changes, agricultural changes, declines and increases in different bird species. Lots of interesting issues in one simple (but lovely) picture!