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.

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 18^th and 19^th centuries. The oldest breeding record that I can find for Norfolk is for 1808 but by the end of the 19^th 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.

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.

HIbernating butterflies

Although winter can be a difficult time, there are species that manage to avoid the worst of its ravages by going into hibernation. Many are familiar to us: newts that retreat into the spaces under log piles, hedgehogs that bury themselves in last autumn’s leaves or ladybirds that squeeze into the cracks of a window frame. Most of these creatures will spend the winter unnoticed by homeowners and gardeners, but others may be chanced upon as logs are brought in from the woodpile or something is fetched from the garden shed.

This winter, a small tortoiseshell butterfly has chosen my shed and it is interesting that this butterfly should choose to overwinter as an adult. Very few of our resident butterflies overwinter as adults; the majority spend the winter as caterpillars, although nine species overwinter as eggs and eleven as pupae. It is also interesting to note that, with the exception of the speckled wood, the hibernating phase is always the same in a given species. The speckled wood can hibernate as either a caterpillar or a pupa. Along with the small tortoiseshell, the other species to overwinter as adults are comma, peacock and brimstone. To these can be added large tortoiseshell (though now thought to be extinct as a resident species), red admiral (though only in the extreme south of the country does overwintering appear to be successful) and Camberwell beauty (which overwinters occasionally). Many of these species will spend the winter in hollow trees or outbuildings but the beautifully camouflaged comma prefers to overwinter on exposed branches or among dead leaves and the brimstone hibernates deep within an evergreen shrub. During hibernation these butterflies must be vulnerable to predation by birds and this may be why many have evolved their camouflaged underwings. The peacock goes a step further and has evolved a warning display. If disturbed, the peacock will open its wings to their fullest extent to reveal the large ‘owl-like eye’ pattern on its wings. At the same time it produces a hissing sound by rubbing its wings together, something that is usually enough to scare off a would-be predator.

Once we receive a run of several days of warm, spring-like, weather many of the butterflies will emerge from hibernation to seek out nectar sources to replenish reserves lost over winter. None of the species is able to mate immediately on waking but needs to feed and bask in the sun to develop the eggs or sperm needed for the reproductive act. The butterfly can always re-enter hibernation if spring has not really arrived, although it will have lost vital reserves and be less likely to survive the remaining winter period.

Winter songsters

There have been a few warmer days of late, premature hints of a spring that is still a number of weeks away. Such teasing glimpses make February burdensome – winter can’t still be upon us. I want to get out and watch nature springing into life. I am not the only one eager to get going, for outside in the early morning darkness a song thrush is singing; its strident notes striking out above the plaintive winter song of a robin. The robin is one of the few birds to defend a territory year round and this is why its wistful tunes can be heard throughout the winter months. But the song thrush is a less regular songster at this time of the year and its performance is an optimistic sign that winter will soon be over.

The impression ones gets when listening to a song thrush is of a singer that enjoys the act of performance, something that is reflected in the bold clarity of the delivered phrases and the deceptive simplicity of structure. Each song thrush will have a repertoire of some 100 or so different phrases and appears to select from these almost at random, putting several together and often repeating a sequence a number of times over. This fondness for a rhythmic repetition of repeated phrases may be one of the reasons why the song thrush features so prominently in poetry. One of the best examples of this comes in Tennyson’s ‘The Throstle’ but others, including Thomas Hardy, Robert Browning and Edward Thomas, all draw on this English songster. Edward Thomas, undoubtedly the least well-known of these poets, featured our various thrushes in 15 or so of his 142 poems and his use of colloquial speech rhythms is well-suited to the repetitive nature of the song.

The presence of repeated phrases is characteristic of the song thrush and very useful for separating this species from another late winter songster, the mistle thrush. The latter species has a song that is more reminiscent of a blackbird, though harsher in tone with a faster tempo. This is delivered from the upper branches of a tree and is loud and far-carrying. Many authors have commented upon the feeling of sadness that derives from the mistle thrush song. Perhaps this is added to by its habit of singing on bleak, overcast days or during periods of wind and rain, a behaviour that has earned it the local name of ‘stormcock’. Although I admire the mistle thrush for singing, indifferent to the harsh backdrop of a late winter storm, I prefer the optimism offered by the song thrush: “Spring is coming, spring is coming, spring is coming”.

On the trail of the Otter

There have been more signs of otter activity locally in recent weeks, encouraging news for a species that is recovering from a decline that began fifty years ago. The introduction of persistent organochlorine pesticides was part of a post-war drive towards agricultural self-sufficiency. The otter population suffered the consequences of our lack of understanding of the impacts of these toxic chemicals on the wider environment. Now that the use of such chemicals has ceased, we are seeing a recovery in the otter population, albeit with something of a helping hand in the form of a reintroduction programme. Even though the signs are encouraging, many of the Norfolk rivers that may once have supported otters have yet to be reoccupied. Periodic surveys, together with the conservation efforts of the Otter Trust and the Anglian Otters and Rivers Project, show that the population is recovering and expanding slowly.

Seeing an otter is a rare occurrence. The species is secretive and mainly nocturnal and this is one of the main reasons why encounters are so rare. Here is a creature perfectly adapted to its riverine existence and well able to slip away unnoticed if disturbed. Roger Deakin, in his wonderfully evocative book Waterlog, writes of a momentary encounter with an otter while he was swimming in the River Waveney. Deakin describes the otter’s “puckish, Dionysian habit” of veiling itself from view, something to which I can relate from my own encounters with these spirits of the river. While Deakin’s otter slipped from the floating log on which it had been sunning itself to disappear from sight, my most engaging encounter was with an otter that seemed positively curious about what I was doing. The otter was hunting in a deep pool that I often scan for pike and I saw its dark silhouette below the surface. I waited patiently and then the otter surfaced. It was clear that it had seen me against the sky but, nonetheless, it seemed inquisitive, almost pleasantly surprised by the creature that stood staring down from the bridge above. Having given me a rather prolonged once over, the otter slipped away into the deep of the pool and was lost in the shadow of the bridge.

I walk along this stretch of river everyday, to and from work, and yet I have only seen the otters themselves on a handful of occasions over the last five years. Their droppings, placed at prominent locations to advertise their residency to other otters, are more commonly encountered so I know they are still there. Knowing this, generates a sense of anticipation each time I walk along the river and I wonder if I am being watched from the shadows under the bank.

Norfolk home to grey geese

Norfolk has a reputation for its wintering geese. This winter, the reputation seems particularly well-deserved, with huge numbers of geese to be seen at sites across the county. Holkham, in particular, has exceptional numbers this year, with tens of thousands of pink-footed geese present. The sight of huge skeins of geese moving between their roosting and feeding grounds is one of the most sensational experiences for any birdwatcher. The numbers of pink-feet wintering here are internationally important. The entire breeding population of Iceland and eastern Greenland winters here, representing more than 85% of the World population. Favoured roosting and feeding areas have become established over the years, with the birds choosing to roost on secure sandbars and shingle ridges off the North Norfolk coast. Their principal diet during the winter months is sugar beet tops, a food they first began to utilise in 1966. At Holkham, the remaining sugar beet tops tend to be ploughed in during February and the geese switch to feed on permanent pasture and winter cereals.


Pink-feet are wary birds and favour sites where disturbance is minimal. They prefer large fields and avoid those with tall surrounding hedges. If undisturbed, feeding will continue throughout the day, with the birds returning to the roost at dusk. However, on moonlit nights they may remain in the fields, making the most of feeding opportunities and good visibility. Although the birds tend to use a small number of favoured roosts, the roosts themselves are not self-contained and individuals may shift between them. A very small number of individuals from the Svalbard breeding population, which winters in the Netherlands and Belgium, is known to join our wintering flocks.  These are not the only geese to mix with the pink-feet, since small numbers of white-fronted geese (of two distinct races) and genuine wild barnacle geese may also be present.


Norfolk is also fortunate in having wintering bean geese. Two different races, known as tundra bean goose and taiga bean goose, winter within the county. In recent winters, some 100-150 taiga bean geese have used the marshes on the northern side of the River Yare, typically at Cantley and Buckenham, and are the only regular wintering flock of these geese in England. Individuals of the tundra race were first recognised as wintering here in 1987 when up to seven individuals visited Buckenham Marshes, remaining separate from the local taiga flock. Small numbers are reported annually, often mixed in with the flocks of pink-feet at sites on the North Norfolk coast. The different ‘grey’ geese can represent something of an identification challenge but, even if you just view them as ‘grey’ geese, they make a spectacular sight.