Thursday, 25 March 2010

Signs of the times: Spring #5

More comparisons between the British countryside of today and that from 1959-1961 in the paintings of Charles Tunnicliffe in the Ladybird "What to look for..." series of books.

“Spring is nature's way of saying, "Let's party!"” (Robin Williams)

As the “What to look for in Spring” book crams a lot of activity into supposedly a short period of Spring, I’m producing these posts as thick and fast as I can – just like the real world outside where, now that the frosts and snow and below zero temperatures have been replaced by 10 degree heat and mild rain, everything is bursting out all over (remember the “unexploded season” of a couple of days ago?). So it seems very appropriate that picture 6 in this Spring series is all about sex. Yes, that’s right - sex. Everything in this picture is making a mad dash for the reproductive start-line. Every last part of the picture. Two male coots are engaged in a chase after a potential female mate (off the picture). A pair of beautiful great crested grebes are engaged in their elaborate mating display. The little male reed bunting in the top of the picture is setting out his stall for the ladies, and marking out his pitch for other male birds, singing from the top of a pussy-willow tree. Even the pussy-willow, which appeared with unopened buds in the first picture in the series, is in full flower, the male flowers yellow with pollen and the smaller female flowers a paler greenish-white and awaiting fertilisation by wind-blown pollen grains.

I wrote, in the first post, both about the advance of Spring dates, such as flowering of willow, since these books were published between 1959 and 1961. I also wrote about the great-crested grebe (Latin name: Podiceps cristatus) and its close link to the early story of nature conservation in Britain, the formation of the RSPB and its subsequent recovery from near-extinction in Britain. So, I won’t say more about this species here, except to encourage you to take a look at a Youtube film, showing stills from their amazing mating display (from about 1 minute 30 into the film).

The coot (Latin name: Fulica atra) is a largish member of the rail family, distinguished by its large white featherless forehead patch (the proverbial “bald as a...” being one reason I feel a filial attachment to this species...). In the picture, you can see the partially-webbed feet that are features of the two aquatic rail species found in Scotland, the coot and the waterhen (or moorhen – it will make an appearance in the Summer book).

Coots are one of the success stories of the British bird world. Since these books were published, or at least since the late 1960s, the coot population of the UK appears to have doubled in size, up to estimated population of 22,600–28,800 pairs in 2000. The increase was most marked in the 1960s on birds living on smaller water bodies, but has continued since then. Perhaps an increase in fresh standing waters through the creation of gravel pits and new reservoirs has resulted in increased availability of breeding sites? Here is a plot from the British Trust for Ornithology, combining data from its Wetland Bird and Wetland Breeding Bird Surveys, which shows the estimated increase in coot numbers over the last 35 or so years:

Finally, to the reed bunting, the smallest bird in the picture. The reed bunting (Latin name: Emberiza schoeniclus), can be seen in Britain all year round, although it is only a summer visitor in the most northerly part of Scotland. As its name suggests, it inhabits reedbeds, as well as scrub habitats in river corridors and, according to RSPB information, is predominantly a farmland and wetland bird. It is typically found in wet vegetation but has recently spread into farmland and, in winter, into gardens. When singing, the male usually perches on top of a bush, or reed, so Charles Tunnicliffe got it right in this picture! Its population history since the 1960s is varied and interesting and suggests the possibility of it having adapted to changing habitat circumstances. The British Trust for Ornithology provides a graph, based on its Common Bird Census and Breeding Bird Survey, showing firstly a rapid decline of reed buntings in Britain during the 1970s, with the population then stabilizing and, in recent years, showing a significant increase.

As an interesting aside on reed buntings, I said earlier that this picture is all about sex - over half of Reed Bunting chicks are not fathered by the male bird in the pair, but are the result of an adulterous liaison, the highest recorded rate of any bird.

The decline is thought to be due to the intensification of agricultural practices at the time, while recent increases may be due to the high value of oilseed rape as a food source for this species, and the increase in the planting of this crop. The BTO reports that densities are four times higher in oilseed rape than in cereals or on set-aside land and that “this crop is crucial in reducing the dependency of the species on wetlands” [which have declined in area as a result of agricultural intensification over this period]. Its present status in Britain could probably be characterised as improving: “The initial decline placed Reed Bunting on the red list but in 2009, with evidence from waterways and from BBS of some recovery in numbers, the species was moved from red to amber.”

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