Sunday, 13 June 2010

Signs of the times: Spring #21 (final post of Spring!)

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 - an experience in immortality."
Henry D. Thoreau

A bit of a bumper post this time, to complete the stories from the Ladybird Spring book with Spring pictures 23 and 24.

(Copyright: Ladybird Books)

Picture 23 shows a turtle dove sitting on a branch of a horse-chestnut which is in full blossom. In the background a crowd of swifts are circling a church tower. The turtle dove (Latin name: Streptopelia turtur), a fairly lovely looking bird is, however, one that I have never seen in over 40 years of observing wildlife in Scotland. I checked with my Dad who, with maybe a further 30 years of bird watching, has never seen turtle doves in Scotland either.

I know they do turn up in Scotland – they are recorded at the bird observatory in Fair Isle and on North Ronaldsay (Orkney) every Spring, presumably on migratory passage (or gone off course on migration!). I say “on migratory passage” because maps of its breeding areas, for example in the Birds of the Western Palearctic, show that it doesn’t breed in Scotland. Even back in 1969, when my old AA Book of Birds was published, it shows only the slimmest of areas of breeding territory in Scotland, in the extreme southeast, stating that, back then, turtle doves had only bred in Scotland in the previous 25 years. I not sure that’s even the case anymore. The poor old turtle dove, for all its loveliness and its role in “The Twelve Days of Christmas”, is in trouble. It has suffered relatively recent and widespread decline in Europe, particularly in the west. According to the British Trust for Ornithology, the turtle dove "is one of the most strongly declining bird species in Europe, having decreased at an annual rate of 4% during 1980–2006.” The above bird book suggests that this is “probably due to drought in its winter quarters [in semi-arid and savannah areas of Africa from Senegal to Ethiopia], shooting and agricultural changes on breeding grounds”, which agrees with what the BTO also suggests. Although the turtle dove population of Britain increased in the 19th Century and up to 1965, there has been a marked decline since the early-to-mid 1980s, as you can see from this BTO plot:

The British population was estimated to be over 125,000 pairs between 1968 and 1972, but only 75,000 territories between 1988 and 1991 and, according to the British Trust for Ornithology, from their Common Bird Census, an 87% decline between 1967 and 2007, putting it on the UK’s conservation “red list” of species suffering a decline of greater than 50%. So, I guess my chances of seeing a turtle dove in Scotland are now even slimmer!

I think that church tower in the picture really suggests that this picture was never intended to represent a Scottish scenario! I’m no architectural expert but it looks much more like a church tower that would be flying the cross of St George! The swifts screaming around the church tower are another of the things I look forward to most about Spring and the move into Summer (nearly there folks!). The swift (Apus apus) is perhaps the most aerial of birds, its short legs generally incapable of sitting it up should it accidentally end up on the ground and its long wings therefore hampering its take-off again. Apart from fleeting contact with water surfaces (while in flight), all of the swift’s normal activity takes place up in the air, from feeding to courtship, even regularly roosting in flight at night. Formerly a bird that nested, in pre-civilisation times, on the edges of crags, sea-cliffs and caves, it has largely moved over to being a species that nests on buildings, often on a flat surface under eaves, or in holes in walls, in a shallow nest of feathers, straw, leaves, etc, cemented together with saliva. So, the swift is a species for which urbanisation and the spread of cities and towns with tall buildings has facilitated the expansion of its range. And rarely can a bird have been given a more descriptive common name. I defy anyone not to marvel at racing flights of large numbers of swifts, with their long, scythe blade-like wings, screaming and screeching around buildings and turning tightly down urban canyons on warm evenings in late Spring and Summer. So, given the importance of urban areas to swifts, it is ironic that one of the proposed explanations for the decline in swift numbers shown in the BTO figure below (in this case, for the UK, but the Scottish picture is similar) is suggested to be the loss of breeding spaces in buildings as a result of redevelopment:

(From: British Trust for Ornithology)

The BTO figure above is based on its Breeding Bird Survey and there is uncertainty over the actual status of swifts. The swift has, however, been placed on the amber list of conservation concern. Other initiatives are also aimed at improving our understanding of the status of swifts (by the RSPB. Look here if you are interested in taking part), and Concern for Swifts, a small private organisation is promoting the deliberate provision of nesting sites for this species.

The final feature of this penultimate Spring picture if the horse-chestnut trees in full flower. The horse-chestnut (Aesculus hippocastanum) is not native to Britain, having been introduced into cultivation in 1612 or 1615, then recorded in the wild by 1870 (all according to the New Atlas of the British and Irish Flora). It is widespread throughout Britain and Ireland, and all over Scotland except for the central Highlands, the far north (blanket peat areas), the Outer Hebrides and Shetland. According to the New Atlas, its distribution has changed little since the 1962 Atlas was published. Richard Mabey, in Flora Britannica, points out that for a relatively new tree in Britain, in ecological terms, the horse-chestnut has made a huge contribution to popular culture. In particular, the glossy red-brown chestnuts or “conkers” are the raw material for what he says is the most widely played children’s game with plants, a game of conkers, with horse-chestnut nuts on strings, taking turns to try to smack the opponents conker into oblivion. But the horse-chestnut has also provided a symbol of “village peacefulness”, the theme of music-hall songs and a 1930s dance craze, one of the commonest elements of street names and gaggle of words and metaphors to enrich our language. There is even a World Conker Championship. Incidentally, as children in East Lothian, we ALWAYS referred to horse-chestnut trees as conker trees. I had a secret and very fruitful conker tree in the Gosford Estate woodland where I lived that no-one else knew about (I think!). We even had one at the entrance to our primary school, inside the front gate. I wonder if it is still there?

The final Spring picture, number 24, takes us down to the coast for the first time proper (we saw some terns in the distance in an earlier post).

(Copyright: Ladybird Books)

We see a beautiful cliff-top scene dominated by flowering sea-pink, white sea-campion, a white flowered stonecrop (in the bottom right) and, above it, kidney vetch, all plants that flourish in this environment and are in blossom as Spring turns in to Summer. The flowers surround the nest of a herring gull containing three eggs, herring gulls are flying about the cliff face, and the flowers are being visited by a red-tailed bumblebee and, on the yellow vetch flowers, a cuckoo bee mimic of a red-tailed bumblebee. The rocks are covered in a range of yellow and grey lichens.

The cliff-dwelling coastal plants all shown in flower here are also found in other related coastal habitats. For example, the pink bauble flowers of the sea-pink or thrift (Armeria maritima) are also common in late Spring – early Summer on saltmarshes and coastal shingle habitats (although it is also found in the mountains and on mossy heaths away from the coast). Ironically, it also occurs inland alongside roads treated in winter with salt, creating ideal salt-influenced conditions for its establishment! This species has not, according to the New Atlas of British and Irish Flora, had much change in its natural distribution since the original 1962 Atlas. Its range in Scotland is stable, perhaps as the habitats where it occurs, such as the sea-cliffs in this picture, remain among the least disturbed of Britain’s natural habitats. Richard Mabey, in Flora Britannica, highlights an interesting wee tale about this species and its cultural influence. Its common name “thrift” may actually come from its “thriving” habit, growing densely where it occurs. However, “thrift” was well-enough known (or popular enough perhaps?) to be used as a visual pun, as the emblem on the rear-side of the pre-decimalisation British twelve-sided (twelve-sided!!!) threepenny bit. Mabey describes this as the coin whose physical awkwardness led to it being the one most frequently consigned to money boxes, i.e. a significant contribution to thriftiness!

Like the thrift, the other three plants shown here are distinctive elements of sea-cliff plant communities and their wonderful Springtime flowering displays. The white flowering sea campion (Silene uniflora) at the top of the picture is very tolerant of high nutrient levels which makes it an ideal candidate for sea-cliffs covered in nesting seabirds, with all the attendant inputs of “guano” that comes with this. The New Atlas reports that its distribution in Scotland, largely confined to (almost) all of the 10km squares covering the coastline, as well as a few inland upland locations, is unchanged since the 1962 Atlas. The white stonecrop (Sedum album) shown flowering in the bottom right is not a native species in Scotland, or probably over most of the rest of Britain, and, as a non-native species, the new Atlas reports that its distribution has increased markedly since the 1962 Atlas. The yellow-flowering kidney vetch (Anthyllis vulneraria), also bottom-right in the picture, is a widespread native species, found all around the coasts of Britain and Ireland, as well as widely inland. Its distribution has been stable since the 1962 Atlas was produced. In Flora Britannica, I noted that it is capable of completely dominating bare ground where conditions are right for it.

I’ve already written about the cuckoo bee parasites of bumblebees here.

The final entry for the Spring element of this series of posts is the herring gull (Larus argentatus), represented here by the nestful of eggs and the adult birds wheeling about the cliffs. This species is definitely the definitive “sea gull” of seaside towns – noisy, aggressive (stealing food from people’s hands), splattering droppings, resting on roofs, and so on. If you follow the coverage of gull stories in the media, you would think we were suffering from a Biblical plague of gulls, rampaging through our coastal holiday resorts. So why is the herring gull now listed as a species on the “red list” of conservation concern for the UK? Truth is, there has been a decline in the breeding population in the UK since 1969 and the non-breeding population since 1981.

The British Trust for Ornithology hasn’t produced its usual detailed summary of trend information and related causes for this species (come on guys! What’s going on?) so I will speculate that the decline arises from a number of sources. My guess is that a principal cause may be the continued improvements in the regulation of landfill sites, which used to be chock-full of delicious waste that attracted huge flocks of herring gulls (plus other gulls, crows, rats , etc) and provided an artificial boost to their populations. Landfills are no longer allowed to have exposed tipping surfaces containing edible wastes, plus measures have also increasingly been introduced to prevent gulls accessing waste (nets) or to scare them off (e.g. use of trained hawks and even eagles to scare off “vermin birds”). Also, there has been a long-term decline in the size of Britain’s inshore fishing fleet which has presumably resulted in big reductions in the amount of discarded by-catch and on-board fish processing waste that used to be available to the gulls following the trawlers. Fewer trawlers = fewer discards = fewer herring gulls? Maybe!

This concludes my comparison of the British wildlife and countryside portrayed in the Ladybird book “What to look for in Spring”, seen particularly from a Scottish perspective. Hopefully it has been an interesting read and I’ll try to keep on going now with the Summer book in the series. If I have time, I’ll try to summarise in a brief post what I think the key changes have been, as seen from the Spring book.

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