Saturday, 11 March 2006

Help needed for misunderstood Adder

Over the next few weeks we will see more spring-like days and increasing daytime temperatures. A run of such days will trigger the emergence of adders from the sites in which they have spent the last five months. These sites are known as hibernacula and each one is likely to hold a number of adders, wintering communally. Although some individuals may have already made a brief appearance, the peak emergence in Norfolk spans March and April. Initially, the adders will emerge on warm days to bask in the sun, something they will do on and off over a period of days or weeks, before dispersing away from the hibernaculum in search of a mate. This period of ‘lying out’ provides an ideal opportunity to study these wonderful creatures. I have watched and photographed adders around Thetford for the last couple of years. This year, however, I will be taking a more detailed interest in these snakes by collecting information for a survey being coordinated by the Herpetological Conservation Trust. The Trust wants to monitor the fortunes of this species by carrying out counts at sites across the country. By doing so, they hope to find out if, as has been suggested, adder populations are in decline. If you have a piece of heathland near you, why not get out and see if you can locate and monitor a hibernaculum.

Hibernacula are usually located close to a fallen tree, within a root ball or an embankment. Within Thetford Forest, it is the old snag lines that seem to be favoured. Newly emerged snakes will bask close to the hibernaculum, out in the open on bare ground. This makes it possible to observe the snakes without having to approach them too closely and I find that a pair of binoculars is ideal for the task. The adder is a rather short and stocky snake, the males reaching up to 60cm and the females 75cm. They almost invariably show a clear wide zig-zag pattern along their back and a ‘V’ or ‘X’ marking on their head. There is a clear difference in colour between the two sexes (best seen in adults). Males are usually light-grey or cream with a jet black zig-zag, while females are sandy or pinky-brown in colour with a dark tan zig-zag. Both sexes show the characteristic red eye and vertical black pupil.

As our only venomous animal, the adder has had an undeserved bad press. Like all wildlife, they should be treated with respect and valued as part of our natural fauna. Why not do your bit to help them by taking part in the survey. For more details: phone 01986-872016 or email

Friday, 10 March 2006

Ocean giant washed ashore

The dead sperm whale whose body was washed ashore at Scolt Head on 19th February has, understandably, attracted many people to view its carcass. At 50ft in length, the sheer size of such an animal is something to behold and even in death, there is a resonance that exists between ourselves and such giants of the ocean. I remember seeing my first stranded whale, also a sperm whale, that had been washed ashore at Heacham some ten or 15 years ago. I was not the only one on the beach, staring in awe at the great bulk, the square head and the low hump set high on the back in place of a fin. I was struck by the disproportionately small mouth and the row of conical teeth set in the lower jaw. It was on these teeth that sailors used to practise scrimshaw during long voyages ­– the sperm whale was one of the most heavily exploited species by the whaling industry. Although the upper jaw appears to lack any matching teeth, there are tiny vestigial teeth that rarely break through the gum.

There have been a number of sperm whales washed ashore on the Norfolk coast in recent years and, like these, the individual beached at Scolt Head is likely to have entered the southern North Sea by mistake, becoming disoriented and trapped. Sperm whales are a species of deep water, where they feed on squid, and so are most commonly reported from the areas of deep water that lie to the north and west of Britain and Ireland.  It is thought that a group of these whales may have entered the North Sea from more northern waters and this may explain why three other individuals have recently been washed ashore in Lincolnshire and Humberside. It is just possible that more may follow.

Of course, the sperm whale is not the only species of cetacean (whale or dolphin) to have been washed up on our shores. The Norfolk Mammal Database holds records for a range of other species including: minke whale, fin whale, false killer whale and northern bottlenose whale. The latter species is the one that caused quite a stir when an individual found itself in central London having swum up the River Thames. Fortunately, not all encounters with cetaceans involve animals that have become stranded. Harbour porpoises can be seen feeding close inshore off Sheringham, Waxham and Walcott. These small cetaceans rarely reach 6ft in length and feed in small pods, lured inshore by feeding opportunities. Encounters are usually brief and it tends to be birdwatchers scanning the sea for migrating seabirds that see the porpoises but if you have the patience it is well worth the effort.

Thursday, 9 March 2006

Add some golden glamour to your garden

At this time of the year I see increasing numbers of goldfinches visiting my garden. With their red faces, white cheeks and black and gold wings, these endearing little birds used to be popular as cagebirds, a Victorian fashion that put great strain on their population. With the passing of this particular fashion, the goldfinch population recovered only to be hit again in the late 1970s, when changes in farming practices reduced the availability of the weed seeds that were an important food during the winter months. Fortunately, goldfinches are mobile feeders and have been able to move into gardens, initially to feed on weed seeds, but more recently to take sunflower hearts and nyger seed. The increasing use of gardens has been charted through the BTO/CJ Garden BirdWatch, a year-round study of birds using gardens and involving some 17,000 people. The latest results from this project have just been published and show that goldfinches are now reported from just over 50% of gardens, increasing from 23% ten years ago. Researchers believe that the provision of food in gardens has been a major factor in helping the population to recover, highlighting the contribution that we, as individuals, can make by providing suitable food in our gardens.

If you watch goldfinches feeding you will notice that their bills are quite long and thin, something that enables them to extract seeds from plants that are usually unavailable to other species. For example, the goldfinch is the only finch able to extract seeds from teasels, although it is usually only the males that are able to do this because the female bill is slightly shorter than that of the male. The males and females are almost identical in appearance. However, the red on the face extends behind the eye in the male but remains in front of the eye in the female. Young birds are more easily distinguished for, even though they have the same wing and tail markings as the adults, they lack the red, white and black head pattern.

If you don’t have goldfinches using your garden at the moment then you should find that you can attract them by providing hanging feeders with either sunflower hearts or nyger seed. While the sunflower hearts can be provided in a standard seed feeder, you will need to buy a special nyger feeder if you wish to provide this very fine seed. Because the seed is so fine it will ‘pour’ out of a normal feeder like liquid. Although I provided nyger initially, I now just provide sunflower hearts and they seem to do the job. A free leaflet giving more advice about attracting goldfinches is available from the British Trust for Ornithology.

Wednesday, 8 March 2006

Rookeries buzz with activity

I have noticed a great deal of activity in the local rookeries over recent days, as pairs add sticks to their nests and indulge in a spot of petty theft from those left unattended. There is a real sense of excitement, with the first eggs likely to be laid within the next two weeks. Since Norfolk is a county dominated by agriculture it should come as no surprise that we have such a large population of breeding rooks. The most recent survey, carried out by the British Trust for Ornithology in the mid-1990s, estimated that there were 17,600 nests located in 340 rookeries spread across the county. This represents an increase on previous figures, perhaps a reflection of a run of mild winters, coupled with the ban on stubble burning and the increasing number of outdoor piggeries. These last two changes will have increased the amount of food available to these farmland specialists. My own impression is that they have continued to increase and that there are now many more rookeries to be found within the county. Some of these are small, numbering a few pairs, such as the one alongside the B1108 just outside Watton or that close to the heart of Wymondham. Most rookeries sit high in tall deciduous trees and at this time of the year, before bud-burst, the large nests are obvious. Others are in conifers and I recall one in hawthorn scrub at Bunwell. I have also heard of a few rooks nesting on the pylons that run alongside the Norwich southern bypass at Keswick.

Although rookeries may seem noisy, disorganised affairs, there is a structure and hierarchy to them. Dominant birds, typically well-established pairs that have bred together over several seasons, will occupy nests at the centre of the rookery. Presumably this gives them the greatest protection from predators and the elements. Less-experienced pairs, usually young birds, are forced to nest on the periphery of the colony and these are more likely to fail through a combination of position and lack of experience on the part of the birds themselves. Although both members of the pair construct and defend the nest, it is the female who incubates the eggs and broods the chicks. During this period, as Gilbert White noted in his journal of 1775, the male provides the female with food. Although the breeding season diet is dominated by invertebrates, the rook is omnivorous and has developed a reputation for taking grain. Despite this, rooks are tolerated across much of the county, though some are still shot each year and the loud thump of a gas gun remains commonplace. Not that such measures seem to have halted the increase of this wonderful bird.

Tuesday, 7 March 2006

Early nesting proves risky

There has been rather a lot of noise coming from the river over recent days. Two pairs of Egyptian geese are attempting to lay claim to the same stretch of river, no doubt because of the nesting opportunities that it provides. The loud braying call can best be described as ‘donkey-like’, nasal in quality and of great volume. There can be little doubt that these birds mean business.

The Egyptian goose is something of a Norfolk speciality within Britain. An introduced species, native to large parts of Africa, it became a favourite addition to many estates during the 18th and 19th centuries. The oldest breeding record that I can find for Norfolk is for 1808 but by the end of the 19th Century, it was well established at Blickling, Gunton and Holkham. Unlike many other introduced wildfowl, for example the Canada goose, the Egyptian goose has failed to become established over large parts of the country, the small population in Norfolk expanding very slowly and populations elsewhere going extinct. The most recent survey suggests a population of about 900 birds, about 90% of which are to be found in Norfolk. The highly territorial nature of this species is one possible reason for the low rate of increase; another is the exacting nesting requirements. Egyptian geese typically nest in very large tree cavities, although they may also nest in the bowl created where a large branch arises from the main trunk or in the thick of a gorse bush. It is the ownership of a tree cavity over which my two local pairs seem to be arguing. Perhaps the most important factor in the slow rate of spread is that each pair will only manage to raise an average of 1.6 chicks per year. This may have something to do with the fact that these birds start nesting early in the year. With nests recorded as early as December, it is little wonder that nesting pairs often lose out to periods of bad weather.

Despite its name, the Egyptian goose is not a true goose. Instead it is more closely related to the familiar shelduck, a species with which it shares its hole-nesting habit. Both species undertake a moult migration after the breeding season has ended. While most of our shelduck fly to secure moulting sites off the north coast of Germany (an area known as the Heligoland Bight), Egyptian geese make shorter movements, typically remaining within the county. One of the best known of these sites is at Holkham Park, where 200 birds may gather during July and August each year. However, it is the sight of pairs engaged in territorial display that shows these birds off to their best.

Monday, 6 March 2006

Late winter greenery

The first small glimpses of spring are always reassuring, splashes of colour as early flowers poke above ground. Amid the dull browns and greys of the winter’s leaf litter are dotted the white of snowdrops and the yellow of winter aconite. Strictly speaking these are late winter-flowering species but nevertheless they point to future stirrings that will herald the true arrival of spring.

One of the plants best able to lift me from the winter gloom is the cuckoo-pint, whose bright, green shoots first break through the soil during February. By now, these shoots have unfurled to reveal broad leaves, shaped like arrowheads and with a waxy texture. Along a major section of my riverside walk to and from work, these newly emerged leaves can be seen. Over the next few weeks, a new shoot will rise from the centre of each plant, lighter green in colour and destined to form a simple flower spike. By this stage other plants will have put on growth and the cuckoo-pint will be far less obvious than it is now. The flower spike will unfurl to form a tapering hood, within which a short column can be seen. Small flies are attracted to the flower spike and are effectively imprisoned overnight, during which time they are fed with nectar and covered with pollen before being released to pollinate another flower. With pollination complete, the plant fades and by July disappears altogether. However, towards the beginning of September the plant re-emerges, pushing up a stout spike carrying scarlet berries, agents for seed dispersal.

Cuckoo-pint has the distinction of being known by more local names than any other British plant. Two of the most familiar are ‘Lords and Ladies’ and ‘Cuckoo-pint’ – the latter being of Anglo-Saxon origin and phallic in nature. All parts of the plant are poisonous, including the walnut-sized tuber from which it grows. This tuber was used as a source of starch and proved popular in Elizabethan England. However, production and use of the starch was not pleasant, the needle-like crystals of calcium oxalate contained in the tuber blistering hands.

The plant has a particular association with Breckland and the River Little Ouse, along which I walk to work. There is a tradition that the nuns who built the covenant at Thetford brought the plant with them from Normandy. When the monks of Ely stole the body of St. Withburga from East Dereham and paused at Brandon, it is held that the nuns of Thetford came down to the riverside and covered the saint’s body with the flowers of Cuckoo-pint. It is uplifting to imagine that the plant has been established here all this time.