Signs of the times: Spring #3

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 Picture 4, below, shows rooks in their rookery in elm trees with, in the background, a flight of rooks mobbing or chasing off a solitary heron.

 

 

As a child, this picture resonated strongly with me as there were lots of rooks and rookeries around the East Lothian farm and woodlands where I lived. The rook (latin name: Corvus frugilegus) belongs to what I think of as the “cheeky chappy” bird family, the crows (or corvids), containing some of the most intelligent of all birds. Rooks are birds of farmlands and grasslands and I always find it slightly pleasing that, even though their linguistic roots are unrelated, the words “raucous” and “rook” sound similar, as the overwhelming experience of a rookery in Spring is one of sound. Yes, rooks are incredibly noisy when they are all together – not for nothing is the collective noun for rooks, “a parliament of rooks.” As shown in this picture, in Spring, pairs of rooks rebuild the nests they used the previous season. Britain’s rook population is in a healthy state, according to the British Trust for Ornithology, with an estimated summer population of 1 to 1.3 million pairs. The counting of nests in rookeries suggests a shallow upward trend in numbers plus, for rookeries, a 40% increase in abundance between 1975 and 1996 (also according to the BTO). it is suggested that this probably reflects the species' "considerable adaptability in the face of agricultural change". Counting of individuals in the Breeding Brid Survey, rather than nests in rookeries does suggest, since 2000, a The BTO does conclude: "There has been little change in breeding productivity since the 1960s but a minor decrease in brood size is now becoming evident."

These rooks are shown nesting in elm trees. I described the cataclysmic effect of Dutch Elm Disease on Britain’s elm trees (since these books were published) in the previous post in this series.

The wonderful wading bird, the heron (or grey heron) only features in this one picture in the “What to Look for in Spring” book (although it does also feature later in the year). I love the heron, one of Britain’s largest birds, with its dagger beak, what I think of as a graceful, slow flapping flight, sentinel-like approach to fishing, and its loud, harsh cries. In his song, Now westlin winds, Robert Burns described the heron as; "The soaring hern", and my old Observer's Book of Birds describes the heron's flight thus: "When it takes to its great grey wings with dark tips, the unusually slow and languid wing-beats are distinctive."

We used to see herons over our house nearly every day when I was a child, flying between the Peffer Burn Estuary on Aberlady Bay Local Nature Reserve and a major heron colony (or “heronry”) located high up in the branches of a conifer plantation a mile or two inland. I recall the courtship of herons in that heronry, and the demands of their chicks for food, being just as noisy and raucous as that of rooks! The heron in Britain is the subject of the longest-running breeding-season bird monitoring scheme in the world, through the BTO Heronries Census which began in 1928. The best idea here is simply to show the results of this survey, as presented by the British Trust for ornithology on its website:

(Figure from British Trust for Ornithology)

Herons are very susceptible to high mortality during harsh winters and this is clear from the graph above. I think the extremely extended and harsh winter we have just emerged from may also create another low point on this graph. Many bodies of freshwater in the UK have been frozen over for up to two months this winter and, while estuarine and coastal waters have been ice-free, inland heron populations are bound to have suffered. You will see, however, that there has been a general upward trend in heron numbers over the course of the 20th Century, levelling off a little  after the turn of the 21st Century. This upward trend is described as "moderate" for the whole Uk and "shallow" for herons in Scotland. It is thought (as reported by the BTO) that the general upward trend may reflect: "reduced persecution, improvements in water quality, the provision of new habitat as new lakes and gravel pits mature, and increased feeding opportunities at freshwater fisheries". Numbers of herons has apparently also increased across Europe since 1980.

It is also stated that: "High rates of nest failure at the chick stage were noted in the late 1960s, but not subsequently", a fact I believe is almost certainly linked to the decline in the concentration of organochlorine pesticide residues measured in herons since that time. This has been studied since then through an annual monitoring contract issued by the Joint Nature Conservation Committee (JNCC, and its predecessor bodies) to the Centre for Ecology and Hydrology (CEH, and ITS predecessors!). The programme was started in the early 1960s, when there were serious concerns over the effects of organochlorine pesticides and organomercury fungicides on a range of bird and mammal species in the UK. High concentrations of these toxic compounds are now well-known to lead to a range of causes of reproductive failure in birds. This early work demonstrated the effects of the organochlorines and eventually contributed to the ban on their use in the UK and abroad. The assessment of a range of organochlorines and also the toxic metal mercury in the livers of herons has revealed significant long-term declines in liver residues of organochlorine pesticides and mercury during the monitoring period. These declines appear now to have largely levelled off.  I have copied the relevant trends in these from the JNCC's website below. You can read the original report here.

(From JNCC Report No. 391)

A final issue for the heron in Britain that is worth identifying here as it is directly relevant to Spring-time is that, since 1968, presumably in response to the general warming of the climate and the advance of Spring, the average egg-laying date for herons in Britain is now some 29 days earlier than it was back then, as shown by the BTO here.

Signs of the times: Spring #2

More comparisons between the the British countryside of today and that from 1959-1961 in the the paintings of Charles Tunnicliffe in the Ladybird "What to look for..." series of books. Spring pictures 2 and 3.

"There is a flower, the lesser Celandine

That shrinks, like many more, from cold and rain;

And, at the first moment that the sun may shine,

Bright as the sun itself, 'tis out again!"

(The Small Celandine, William Wordsworth)

The way these Ladybird seasonal “What to Look for...” books work is to start with examples in the early part of the season and work through the season towards the next one. So, obviously, the second and third pictures from the Spring book show scenes from early Spring. The second picture in the Spring book (below) is a simple little tableau showing two displaying hedge sparrows in among early Spring flowers and a molehill.

The comments about the earlier Spring season nowadays compared with 1959-1961 in the previous post also apply here. The average dates on which these early Spring flowers appear have moved earlier in the year. The lesser celandine (latin name: Ranunculus ficaria, hence, a buttercup species), the smaller of the yellow flowers in the picture and an early source of nectar and pollen for insects, generally flowers about 2 weeks later in Scotland, on average, than in England. The average flowering date in the UK has, however, moved about 2 weeks earlier between 2001 and 2009. I couldn't find any earlier records for the flowering dates of this species, but there is clearly a change in timing taking place.

The text for the picture reports on the pair of Hedge Sparrows or Dunnocks (latin name: Prunella modularis) in the following very innocent and sweet way: "With flirting and jerking of wings, two hedge-sparrows are displaying to each other in a kind of springtime dance. It is a form of love-making." Bless!


The population story for the dunnock or hedge-sparrow (although it is not a species of sparrow) is, however, not so pleasant. Although present all year round in Britain, including most of Scotland, and breeding here, the abundance of dunnocks in Britain fell substantially between the mid 1970s and mid 1980s, after a period of population stability. Some recovery has occurred throughout the UK since the late 1990s, but the species is still "amber listed", meaning that it is thought to have had a population decline of between 25 and 50%. The figure showing its decline is quite dramatic:

(from British Trust for Ornithology)

It is suggested by the British Trust for Ornithology that the decline may be due to wide mis-management and deer-overgrazing of the woodland habitats for this species. One other thing about this relatively undistinguished looking bird - it has a very complex sex life!  I quote: "This unobtrusive little brown bird doesn't form pairs (like most birds), but breeds in groups of up to three males and three females, with two males and a female being the most common." It's always the quiet ones, isn't it?

Finally, the picture has a molehill (or “mole-heave”) in the foreground. Moles (Talpa europaea) belong to the same mammal family as hedgehogs and shrews, the insectivores (“insect eaters”, although moles mostly eat earthworms). You might have noticed lots of small molehills appearing in parks and grass fields in early Spring. As I understand it, this is the result of male moles heading out in search of females, digging new tunnels presumably in the hope of an encounter with a tunnel containing a potential mate. If anyone has a better understanding of this, I’d be pleased to learn what they know. Moles can be found everywhere in Britain where the soil is deep enough for their tunnelling. In a review of British mammals published by the Joint Nature Conservation Committee (JNCC), an amazing population estimate is provided for moles in Britain: total pre-breeding population of about 31,000,000; 19,750,000 in England, 8,000,000 in Scotland and 3,250,000 in Wales!

The trend in mole numbers is unknown; although persecution (trapping, posioning) of moles may have reduced (I no longer see fence lines with loads of dead moles hanging from them, which I used to see when I was young), according to the JNCC report, some current agricultural practices, particularly deep plouging, are detrimental to moles and the removal of hedgerows and areas of rough land eliminates the sanctuary areas from which moles could recolonise an area following cultivation. So the loss of set-aside land due to the removal of farming subsidies may affect mole populations adversely in arable areas (but who knows by how much?).

"The Mole had been working very hard all the morning, spring-cleaning his little home. First with brooms, then with dusters; then on ladders and steps and chairs, with a brush and a pail of whitewash; till he had dust in his throat and eyes, and splashes of whitewash all over his black fur, and an aching back and weary arms. Spring was moving in the air above and in the earth below and around him, penetrating even his dark and lowly little house with its spirit of divine discontent and longing." (Kenneth Grahame, The Wind in the Willows, Chapter 1).

Time to turn the page again:

The third Spring picture shows an altogether more complicated scene. An agricultural landscape with seed drilling, (by modern standards) profligate levels of rural employment, birds galore and elm trees (guess what we’ll be looking at shortly!). As an indication of how much agricultural expectations have changed since 1960, I quote the first line of text: “The elaborate tilling machine, which can till twelve drills of wheat at a time, is a far-reaching advance on the earlier hand-scattering of seeds.” This suggestion of a memory of hand-sowing really does make a link back to pre-intensification agriculture. Also, the picture harks back to a time when many more people were employed in farming - difficult to think today of three people working to plough and seed a single wheat field. This would all be achieved by one guy in a big modern tractor - no need for a man to stand on the back of the seed drill to ensure that the seeds feed evenly!

In the foreground, a group of black-headed gulls (Larus ridibundus) is seen following the tractor. The text suggests that they are picking up grain seeds, as well as worms and soil grubs. It seems unlikely that they would be taking grain, their diet usually being "worms, insects, fish and carrion". Although there is a large breeding popualtion of over 138,000 pairs of black-headed gulls in Britain, most breeding in colonies in bogs and marshes on hills and moors a long way from the sea, in winter, the population swells to nearly 1.7 million birds, on reservoirs, in estuaries, and on the coast (as well as in coastal towns), with birds migrating here from eastern and northern Europe.

In terms of the breeding population of black-headed gulls, the good old JNCC is able to advise as follows: "There has been a marked spread in northern Europe since the early 20th century and the recent colonisation of Italy (1960), Spain (1960), Greenland (1969) and Newfoundland (1977) would suggest this expansion is continuing. British and Irish populations have also reflected the increases that started during the 1900s ... More recent population changes have only been adequately documented for coastal sites, and these showed a slight increase of about 7% between 1969–1970 and 1985–1987 for Britain and Ireland as a whole ... English coastal colonies showed an overall increase of more than 30%, whereas over the same period, a 55% decrease was recorded on Scottish coasts (particularly south-east Scotland)." The apparent loss of colonies in Scotland is reported to be probably a consequence of agricultural drainage.

The displaying lapwings in the picture – also known as peewits in Scotland – offer a salutory tale under the banner of farmland bird decline but, as lapwings feature in a later Spring picture, I am going to save that for another day. Similarly for the rooks in the background, as they will feature in the next post.

The one remaining issue in this picture, and one of the most significant in rural landscape terms over the past 50 years is the elm trees (It says: "The expanding flower-buds on the elm trees are tinged pink against their dark twigs").

Dutch elm disease is one of the most serious tree diseases in the world. It is caused by two related species of fungi (Ophiostoma), spread by various elm bark beetles. Native British elm species are susceptible to the disease. In lowland central and southern Britain, with predominantly English elm, an epidemic of Dutch Elm Disease took rapid hold during the early to mid-1970s, leading to the death of most mature English elm by the early 1980s.

According to Forest Research (the research arm of the Forestry Commission), Dutch Elm disease's epidemic progress has been much slower on the large predominantly wych elm (Ulma glabra) populations of Scotland and north-west England. The result is that the first wave of the 1970s epidemic is still active and continuing in these areas today. It has moved into U. glabra populations that were not affected by the first epidemic, such as those in the Glasgow area. It is continuing to push northwards, particularly on the east coast north of Aberdeen. The disease is now well-established in an area around Nairn to the east of Inverness, with several hundred trees known to be affected.

Elm trees were never as significant a feature of Scottish rural landscapes as in England, where the loss of entire elm populations in many areas completely changed rural landscapes and their skylines.Nevertheless, elms are still regarded as an important tree in some parts of Scotland, such as North-East Scotland, and local authorities and others remain active in trying to prevent the spread of the disease. Here is Highland Council's information on this.