This is the entry page for the Natural History section

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EXPLANATION

Birds: Species list linked to gradually growing content. Mainly sound recordings -- only photos are on Swifts page.

Tawny Owls: A big section. Click on the green" button to get to the section navigation page.

Insects: Just started August 2007. Only Beetles and Dragonflies open at the moment.

Apologies for this raw-looking page, but it'll be needed to navigate the Natural History section later.

In the meantime, some useful links:

UK Butterflies This is a marvellous, beautifully designed site, packed with info and superb pics of all our butterflies. A one-stop resource -- so complete you're unlikely to need more. Don't miss the contributors' galleries. There's a forum too.

British Dragonfly Society Excellent photos here, with several pics per species from different angles and exuvia. I haven't found a site yet with pics of all the British species on one page (probably because there are quite a lot). A pity, because this would speed identification considerably. We have a lot of dragonflies locally in August and September.

British Reptiles A nicely presented site about our snakes and lizards. Sadly small as there are so few species.

Reptiles and Amphibians of the UK (RAUK) This link takes you to the identification pages of RAUK, where amphibians as well as reptiles are covered. Good descriptions and again some quite useful photos.

I'm interested in the reptile side of things as in all our wanderings we've never seen a snake or lizard (Corinne once came across a dead snake in a lane which she swears was an Adder, though I think it's much more likely to have been a Grass Snake). There is also a small colony of Slow Worms in one part of the owl wood, though again we only ever find dead specimens, probably hauled (and mauled!) out on to the path by foxes or badgers. (Aug 2007: None now seen for two summers, so they may be presumed wiped out.) Fortunately there are reports by locals of Grass Snakes in two locations, and indeed one beautifully marked mature individual is occasionally seen in Corinne's mother's garden. I saw it myself two years ago when it came to investigate my budgie in his cage! And we are hoping to check out one local wood where we have been told there are Adders.

But basically the snake and lizard picture is depressing, My distinct impression is that there were more when I was young, and that the Grass Snakes -- which I used to catch and keep for a while -- were bigger. Now on the rare occasions I've seen them they've been slender youngsters little more than 15 inches long, suggesting a high mortality. Lizards just seem to have vanished.

Couple of sites where others are recordng their local natural history

15 Acres in Kent -- Wildlife in the High Weald Small website by John Webley with impressive photos of a wide range of critters in his local patch near Goudhurst, a really beautiful part of the Weald. There's no text, but every species from mammals and birds to insects is nicely photographed and named. The dragonflies and insects sections are particularly impressive. For example, 12 species of grasshoppers and crickets are shown. Also well represented are bees and wasps (including bumblebees), flies, beetles (and bugs), and ladybirds. No ants or moths yet, but a very good butterfly page.

Judy Woods Heritage Site Some good stuff here -- lots of pics and useful for id. Judy Woods is a group of woods in Bradford, West Yorkshire.

Mersea Wildlife Dougal Urquhart's blog about wildlife on Mersea Island, Essex. Dougal has been the ranger at Cudmore Grove Country Park in East Mersea since 1983, and his blog has been going since January 2007. Beautiful photos here, all clickable for larger versions, of a wide range of creatures, including adders and lizards (lucky island!). There's even a Tawny Owl living on this tiny island, which doesn't have much that could be called a wood! Also very atmospheric scenery shots. For once a blog where you can quite easily locate past topics as they all have a name that indicates what the entry's about. A pleasure to look at as well as being informed and authoritative -- all species are identified.

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Islandisation, habitat fragmentation, or the effects of isolation

My feeling is that the reptiles and amphibians, as well as some other species/groups, are a good illustration of the effects of "islandisation", or just call it isolation. It's a phenomenon we first heard of in Costa Rica. If species that are not very mobile end up in pockets of terrain that may be favourable but are isolated from populations in other favourable areas, the result can be the local extinction of that species. If this happens in all the pockets, that's it -- regional or even global extinction. Species become much more vulnerable when their habitat is chopped up into small areas by development.

Isolation can be due to sheer distance, or to intervening unfavourable terrain (including farmed land), busy roads or urbanised areas. A motorway is the equivalent of an ocean for many species, and many busy country roads -- including secondary roads -- are now almost as lethal and isolating. Attempts by terrestrial (non-flying) species to cross a road may end in death, reducing the population on the "island". It's quite a surprise to think of our english countryside as becoming like a sprinkling of small Pacific islands dotted in an ocean, with only flying creatures (birds and insects) able to move freely between islands. But that seems to be what is happening. In Costa Rica, despite the setting up of numerous wildlife reserves, the same problem has arisen of small, isolated communities of a particular species struggling to maintain their numbers.

For a limited discussion see the Wikipedia page "Habitat Fragmentation". Search on this more accepted term as well as "islandis/zation" to find other web pages on the topic.

An illustration -- the Capercaillie

The Capercaillie in Scotland is a high-profile bird that's identifed as facing this problem of shrinking and fragmenting sub-populations leading to local extinction, among many other threats, in a recent issue of Bird Study (published by the British Trust for Ornithology). Although a recent dramatic decline appears to have been halted by concerted conservation efforts in the core ranges, one projection suggested that if the decline had continued at the rate estimated from two surveys done in the 1990s the hen population would have been down to 40 by 2014 -- an unsustainable level. (The current total Capercaillie estimate is about 2,000 birds.) Interestingly, a recent genetic study has shown that "movement between these [fragmented] populations is restricted". The authors of the Bird Study paper comment gloomily: "Given the fragmented nature of suitable habitat and the pressures on the Capercaillie population, recolonization after local extinction may not be feasible. Hence, despite encouraging signs in Strathspey, there must be real concern over the possible extinction of local populations of Capercaillie." As Strathspey (with Badenoch) has the largest and most sustainable population, it appears they mean that local extinction is a risk in some of the less populated clusters. There are just four clusters with confirmed Capercaillie left. (From Eaton, Marshall and Gregory, Status of Capercaillie Tetrao urogallus in Scotland during winter 2003/04. Bird Study 54(2), July 2007, pp. 145-53.)

September 2007 -- CPRE publishes maps illustrating fragmentation of english countryside

Three maps showing the increasing fragmentation of the english countryside since the early 1960s have been published by the Campaign to Protect Rural England (CPRE). (The CPRE is an independent UK charity that campaigns for a sustainable future for the English countryside and is one of the longest established environmental organisations in the country.) The maps show the relentless growth of "areas disturbed by urban development, major infrastructure projects and other noise and visual intrusion" over the past 50 years or so.

The maps and an account of the associated campaign start on this page on the CPRE website, and there's a good summary news story on this Daily Telegraph page (10 Sept 2007).

Click on the thumbnail below to see a comparative montage of portions of the three maps for southeast England. From these it is evident that while urbanisation continues its outward creep from town and city perimeters, the factor responsible for cutting up the countryside into a patchwork of isolated fragments is the busy road corridors. This is especially evident in the Weald, which appears as an area of continuous green on the map for the early 1960s but has become divided into about 20 separate patches by the early 1990s. Particularly evident are the development of the M20 corridor along the northeastern edge, the A21 down the middle and the A22 near the southwest edge.

These selections from the "intrusion" maps published by the CPRE in September 2007 illustrate all too clearly the fragmentation of southeast England by the growth of traffic on the road system. The M20 in particular, running ESE from near London to the Channel ports, must now be an almost total biological barrier for non-flying wildlife, cutting off the northeast of Kent from the Weald to the southwest. Even many "minor" roads now carry quite heavy traffic for about 18 hours of the day. Another notable feature of the secondary road system is the twice daily rush hour, reflecting increasing economic activity in the countryside and smaller urban centres and resulting in an almost continuous, fast-moving traffic flow. The hazard this presents to wildlife is evident from the corpses, including those of birds, that line such roads. According to the CPRE the southeast is one of the worst affected areas of England by this urban and infrastructural growth.

(Map selections reproduced by kind permission of the CPRE.)

The statistics given in an accompanying pdf are alarming. Kent has an area of 3,639 sq km. In the early 1960s 1,132 sq km, or 31.10%, were "disturbed by noise and visual intrusion". By the early 1990s the area affected had risen to 1,963 sq km, or 53.95%, and in 2007 this had risen again to 2,327 sq km, or 63.94%. (Pdf page of statistics, download is third item from bottom; direct pdf download). At this rate, the CPRE warns, much of the remaining undisturbed countryside could be lost in a generation, or 45 years (see news release for the southeast region). Not least, the CPRE are aware of the effect on wildlife, warning that "new roads slice through undisturbed landscapes shattering their calm and disrupting habitats and wildlife" (from news release linked above), although the fragmentation and isolation of previously connected habitats are not specifically mentioned. Nevertheless, these new maps provide a graphic illustration of how less mobile wildlife populations are divided up by road network development into smaller entities that have difficulty interbreeding or restocking depleted areas, a process that for some species may result in the eventual collapse of the entire population.

Even birds may be affected. The low-flying Barn Owl is almost as vulnerable to trunk road traffic as terrestrial wildlife. BTO maps show the dramatic collapse of the english Barn Owl population in recent decades. Studies by the Devon Barn Owl Trust have established that fast traffic on major roads is a significant factor in this decline. (More on this later; in the meantime refer to the Research page on the Barn Owl Trust website for research reports. I cannot find the BTO distribution maps online -- I saw them in a leaflet distributed with other printed literature I receive.)

This unfortunate outlook is only made more likely by current central government demands on southeastern regional authorities to increase their quota of new housing stock, with associated infrastructure, to take the pressure off existing stock (my comment).

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