Showing papers by "Suffolk University published in 1974"

Rheotropism in fishes

Abstract: Summary (1) The fluid properties of air and water enable animals to orientate to flow and this behaviour in water is termed rheotaxis. Fish, however, have a wide range of responses to currents, extending beyond simple orientation, and the term rheotropism is therefore used as a ‘portmanteau’ word to describe all such reactions. (2) Fish detect currents directly by flow over the body surface or indirectly by other stimuli. Indirect responses are more common and occur in response to visual, tactile and inertial stimuli resulting from displacement of the fish by the current. Reactions to displacement of visual images are called optomotor reactions. The lateral line is not involved except in the detection of small localized jets of water. It has not been demonstrated that any fish can detect the current by electrical stimuli, although it is theoretically possible for some to do so. (3) In the basic form of rhotaxis the fish heads upstream and maintains station by stemming the current. Current detection thresholds fall within the range 0.4 to 10 cm/s for tactile stimuli but may be as low as 0.03 cm/s for visual stimuli. (4) Visual responses have been studied by simulating displacement by the current in optomotor apparatus. Fish respond to a rotating black-and-white-striped background by compensatory movements of the head and eyes - optokinetic nystagmus - or by the optomotor reaction, in which the fish swims with the background. (5) Fish show an orthokinesis in optomotor apparatus, their mean swimming speed increasing with the speed of rotation of the background. The precise form of the relationship varies between species and there is also considerable individual variation in performance. Fish accelerate and decelerate relative to the background, fixating on a particular stripe for short periods. (6) Factors limiting the appearance of the optomotor response are contrast, illuminance, acuity, critical flicker fusion frequency and spectral sensitivity. (7) Fish tolerate retinal image movements equivalent to those received when they are carried forwards by the current but not to those received when they are carried backwards. There are ganglion cells in the optic tectum which are sensitive to the direction of movement of targets across the visual field. In the goldfish there are significantly more units sensitive to movements in the temporo-nasal than in the opposite direction. (8) There are close parallels between the behaviour of fish in schools and in an optomotor apparatus. The optomotor response is apparently innate, occurring in newly hatched fry. (9) Physical and chemical factors can modify rheotaxis. Temperature and olfactory stimuli affect both the sign of the taxis and the kinetic component of the behaviour. (10) Thyroid hormones which are involved in the control of migration have been shown to affect the kinetic component of rheotaxis. (11) Fish show a number of hydrodynamic adaptations to life in currents. Morphological modifications are greatest in fish from torrential streams, which show extreme dorsoventral flattening and have specialized adhesive organs. Other fish select areas of low velocity or decrease their buoyancy with increasing current speed. (12) Rheotropic behaviour plays an important role in the distribution of fish within stream systems, in the maintenance of territory and station and in feeding behaviour. Territory, station and spawning sites in salmonids are all selected in relation to water velocity. (13) Water currents are thought to provide either a transport system or directional clues for fish on migration. The fish either does not respond to the current and is carried passively downstream, or it makes an orientated movement, swimming up- or downstream. (14) Eggs and larvae are known to drift passively downstream from their spawning grounds and some adult fish may also drift passively. In the sea both adult and juvenile fish use a form of modulated drift associated with vertical migration. Fish move up into midwater either by direct tidal selection or in relation to the diel cycle of illuminance. In fresh water the downstream migrations of salmonid fry, and smolts under some conditions, occur by modulated drift. (15) There is no evidence that fish migrating in the sea orientate to the current, but in fresh water the upstream migrations of diadromous fish are clearly orientated movements. (16) Water velocity is a major factor for salmonids migrating upstream. For fry it limits the occurrence of upstream migrations and for adults it can also prevent upstream movement. But migrations are often initiated by freshets, and changing water velocity is thought to be the most important factor associated with a freshet. (17) Both environmental and genetic factors affect the direction of migration in relation to the current. In some sockeye salmon fry direction is determined by temperature, but in others the overall direction of movement is genetically determined and environmental factors only modify the behaviour. (18) Rheotropic behaviour has a number of important practical applications in the capture of fish and in guiding them past dams and power stations. (19) The optomotor response plays a basic role in the capture of roundfish by trawls under conditions when the fish can see the gear. Many fish are caught because they become fatigued after a prolonged period of swimming at the same speed as the trawl. (20) Most success in guiding fish away from hazardous areas and bypassing them round dams has been achieved with mechanical barriers which depend on rheotropic reactions of the fish. (21) Louvre screens are very successful in deflecting juvenile salmonids migrating downstream past small dams but are impracticable at large dams. Instead, the turbine intakes are commonly sited at a considerable depth and fish are bypassed by mechanical screens either at the surface of the forebay or into the gatewells immediately upstream of the turbine intakes. (22) With upstream migrants the basic problem is to attract fish to the lower end of the fishways. An adequate ‘attraction velocity’ is an important feature of fishways, which must be sited so that the fish avoid the high velocity discharges from spillways and turbines.

The reproductive biology of the horse mackerel Trachurus trachurs (L.) in the North Sea and English Channel

Abstract: In the horse mackerel the gametes develop asynchronously and are released in batches. The maturity cycle is characterized by a rapid post-spawning recovery period and a relatively long period of oocyte maturation. Mean gonad weight reached a peak in June and intraovarian hyaline oocytes occurred from May to August. Determination of fecundity was complicated by resorption of oocytes both before and after spawning, and by the fact that resting and developing oocytes were not clearly separated by size. An estimate of‘potential fecundity‘was obtained by a combination of histology and oocyte measurement. Plankton surveys showed that a major spawning area exists in the Southern Bight of the North Sea, with eggs occurring from May to late August. An estimate of annual egg production was combined with the fecundity data to give an estimate of stock size of about 500 000 tons.

Behavioural studies on the lesser sandeel Ammodytes marinus (Raitt) II. The effect of light intensity on activity

Abstract: The behaviour of the lesser sandeel, Ammodytes marinus (Raitt), has been investigated at light intensities of 1, 10, 100 and 1000 lux, using a photographic method of recording activity. The level of swimming activity was high at 1000 and 100 lux, declining to a very low level at 1 lux. It was concluded that this was due to the limiting effect of light on feeding. The threshold light intensity for swimming activity in the tank was estimated as being approximately 20 lux but it was considered that in the area of the sandeel fishing grounds the threshold might be higher than this, in the region of 100 lux. The number of hours light per day above 20 and 100 lux at a depth of 15 m in the area of the Outer Dowsing sandbank (53°30′N, 01°00′E) was estimated for the various months of the year. It was shown that during the winter the light intensity does not normally reach 100 lux and only exceeds 20 lux for a few hours each day. It is suggested that this could limit swimming activity and accessibility at this time of year. Measurements were made of the penetration of light into sand and it was concluded that fish which are buried might be able to detect light, possibly via the pineal gland.

The settlement, distribution and movements of O‐group plaice Pleuronectes platessa (L.) in Filey Bay, Yorkshire

Abstract: The pelagic larval stages and the demersal O-group stage of plaice were sampled in the immediate vicinity of Filey Bay, Yorkshire (54°12′N, 00°16′W), using a modified Gulf V high-speed plankton sampler and beam trawls. The distribution and movements of these fish were studied from the time of first settlement in May through the period of metamorphosis and the O-group stage. It was found that the larvae settled in water deeper than 5 m and moved into shallow water following metamorphosis. This established a typical distribution of larger fish in shallower water than the smaller fish. When the fish grew over 40 mm they moved out again into deeper water which leads to a reversal of the lengthdepth distribution. Further movements during the winter months and of the I-group fish were studied by tagging. It was found that emigration from the nursery ground did not occur until the I-group stage.

Behavioural studies on the lesser sandeel Ammodytes marinus (Raitt) III. The effect of temperature on activity and the environmental control of the annual cycle of activity

Abstract: The behaviour of the lesser sandeel, Ammodytes marinus (Raitt), has been investigated at 5, 10 and 15° C, using a photographic method of recording activity. The activity patterns at 10 and 15° C were very similar, there being a high level of swimming activity during the light period, which fell to a low level at 5° C. It was also lower at 10° C at the end of the experiment than at the beginning and it is suggested that this might have been due to an increase in the fat contents of the fish. The feeding rate of the fish was measured and showed a Q10 of 2.08 for the temperature range 5–15° C. The annual cycle of activity of A. marinus is discussed in relation to seasonal changes in food availability, light and temperature, and in the fat content of the fish. It is concluded that after spawning in the December–January period the fish remain buried in the sand until April, because of the limiting effect on swimming and feeding activity of the environmental factors in the intervening period. The proportion of fish available for capture at the start of the fishery in April is related mainly to temperature, but food (as measured by numbers of copepods) light intensity and photoperiod are by then increasing rapidly. After July the fishery ceases and it is thought that this is because the fish have entered an overwintering stage, during which they remain buried in the sand. This phase is also thought to be associated with the maturation of the gonads in readiness for the winter spawning. The factors causing the fish to enter this stage are as yet undetermined but may be related to the attainment of a certain level of fat content.

Behavioural studies on the lesser sandeel Ammodytes marinus (Raitt) I. The effect of food availability on activity and the role of olfaction in food detection

Abstract: The behaviour of the lesser sandeel, Ammodytes marinus (Raitt), has been investigated using a photographic method of recording activity. Three main states of activity were recognized: (1) swimming, (2) partially emerged from the sand, or (3) completely buried in the sand. When food was present there was a basic diurnal rhythm of activity; during the dark period most of the fish remained buried in the sand and in the light period they emerged to swim and feed. In the absence of food the level of swimming activity during the light period was extremely low, while the level of partial emergence activity increased. The fish appear to be visual feeders and those which were buried in the sand did not appear to be able to detect the presence of food in the water by means of olfaction. There was usually a low level of partial emergence activity during the dark period, which tended to increase in the few hours before the lights were switched on. The timing of this increase was thought to be related to an internal clock. The basic diurnal rhythm of activity shown in the laboratory experiments is discussed in relation to the marked diurnal variation in the catch of sandeels in the fishery. It is concluded that the failure to catch sandeels at night is due to their remaining buried in the sand.

Paracentesis as an aid to the diagnosis of abdominal disease in the horse

Abstract: SUMMARY The technique and interpretation of the results of paracentesis abdominis in the horse are described. Normal values for nucleated cell count, differential cell count, protein and specific gravity are listed. Peritoneal fluid from normal horses is compared with that from horses with colic. Selected case reports illustrate the value of paracentesis as an aid to the differential diagnosis of colic. RESUME La technique et l'interpretation des resultats de la paracenthese abdominale chez le cheval sont exposes. Les valeurs normales pour les cellules nucleees, le compte cellulaire differentiel la nature des proteines et le poids specifique sont indiques. Le liquide peritoneal des chevaux normaux est compare avec celui des chevaux atteints de coliques. Des cas choisis illustrent la valeur de la paracenthese comme aide au diagnostic differentiel des coliques. ZUSAMMENFASSUNG Die Technik der abdominalen Paracentese beim Pferd und die Interpretation ihrer Resultate wird beschrieben. Normalwerte fur die Anzahl kernhaltiger Zellen, fur das Differential-Zellbild, Proteingehalt und spezifisches Gewicht werden angegeben. Peritonealflussigkeit normaler Pferde wird mit Punktaten von Kolikpatienten verglichen. Ausgewahlte Falle dienen zur Illustration des diagnostischen Werts der Paracentese.

Further studies on the use of synthetic prostaglandin analogues for inducing luteolysis in mares.

Abstract: SUMMARY ICI-81008, a synthetic prostaglandin analogue structurally related to Prostaglandin F2α, was shown to be a safe and effective luteolytic agent in mares. It consistently induced luteolysis in Welsh Pony mares at a dose of 125 μg and only produced detectable adverse side effects when given at more than six times this dose. Of 63 Thoroughbred mares in prolonged dioestrus which were treated with ICI-81008, 55 returned to oestrus and ovulated; 40 per cent of the mares covered during the induced oestrus conceived. A total of 144 Thoroughbred mares in prolonged dioestrus were treated with another prostaglandin analogue, ICI-79939; 134 returned to oestrus and ovulated and 46 per cent of those covered during the induced oestrus conceived. However, ICI-79939 produced marked adverse side effects in mares when given at only three to four times the normal therapeutic dose. This study supported previous findings that the majority of non-pregnant mares which are not showing regular oestrous cycles during the breeding season are in prolonged dioestrus rather than anoestrus. RESUME On a demontre l'innocuite et l'efficacite du produit, ICI 81,008, un analogue synthetique de la prostaglandine et qui est structurellement apprente avec la prostaglandine F2α, comme agent luteolytique chez les juments. En administration dans une dose de 125 mcg (microgrammes) la substance induit une repons luteolytic constante chez les juments de la race poney gallois. Des effets collaterau nefastes sont decelables seulement apres l'administration des doses 6 fois plus grandes. De 63 juments pur sang en dioestrus prolonge, qui ont recu ce traitment avec l'ICI 81,008, 55 sont revenues en oestrus avec ovulation ulterieure. 40% des juments couvertes pendant cet oestrus induit ont concu. Un total de 144 juments pur sang en dioestrus prolonge ont recu un traitement avec un autre analogue de prostaglandine (le compose denomme ICI 79,939); 134 sont revenu en oestrus, avec ovulation; 46% des juments couvertes pendant cet oestrus induit sont devenues gravides. Pourtant le compose ICI 79,939 produisit des effets collateraux indesirables marques chez les juments meme dans les doses qui ne depassent le niveau therapeutic normal que par un facteur de 3 a 4. Cette investigation confirme les observations anterieures; elle montre que la plupart des juments non-gravides qui ne presentente pas des cycles d'oestrus regulaires pendant la monte se trouvent en effet en dioestrus prolonge, plutot que dans un etat d'anoestrus. ZUSAMMENFASSUNG Es wurde gezeigt, dass ICI-81008, ein synthetisches Prostaglandin, strukturanalog zum Prostaglandin F2α ein sicheres und wirksames luteolytisches Agens fur Stuten darstellt. Eine Dosis von 125 μg loste bei Welsh-Pony-Stuten durchweg Luteolyse aus und verursachte nachweisbare nachteilige Nebenwirkungen erst nach einer sechsfachen Dosierung. Von 63 Vollblut-Stuten mit verlangertem Diostrus, die mit ICI-81008 behandelt wurden, kamen 55 in Brunst und ovulierten: 40% der Stuten, die wahrend dieser induzierten Brunst belegt wurden, konzepierten. Weitere 144 Vollblut-Stuten mit verlangertem Diostrus wurden mit einem anderen Prostaglandin-Analog (ICI-79939) behandelt; von diesen zeigten 134 Tiere eine ovulatorische Brunst und 46% der wahrend dieser so ausgelosten Brunst belegten Tiere konzepierten. Jedoch verursachte ICI-79939 deutliche nachteilige Nebenwirkungen bei Stuten schon nach der Applikation einer drei- bis vierfachen Menge der therapeutischen Dosis. Diese Untersuchungen erharten vorangegangene Ergebnisse, namlich dass die Mehrzahl aller nicht-tragender Stuten, die keinen regelmassigen Zyklus wahrend der Paarungssaison zeigen, sich eher in einem verlangerten Diostrus befinden als in einem Anostrus-Stadium.

Delinquency and the Family

Abstract: Michael Power trained as a psychiatric social worker. He is now on the staff of the M.R.C. Social Medicine Unit, London School of Hygiene and Tropical Medicine, and Co Chairman of Hackney Juvenile Court. Patricia Ash is a social worker who was on the staff of the M.R.C. Social Medicine Unit and is now a Probation Officer in Suffolk. Elizabeth Shoenberg is part-time Psychiatric Consultant to the M.R.C. Social Medicine Unit and a Consultant Psychiatrist at Claybury Hospital. Catherine Sirey was a statistician on the staff of the M.R.C. Social Medicine Unit.

Clactonian and Acheulian Industries in Britain—their chronology and significance

Abstract: Three sites are considered, where controlled archaeological excavations have been conducted of levels containing both Clactonian and Acheulian flint industries in primary contexts. The sites are Clactonon-Sea, Essex; Hoxne, Suffolk; and Swanscombe, Kent. All are on the fringes or just within the area covered by the till of the Anglian Stage. The sedimentary record at each of these sites is complex, and it is stressed that at none of them can it be certain that there is a complete record of any one period of time; in fact, discontinuities can be demonstrated. In spite of this it seems likely that the three sequences do overlap in time somewhere and correlations are possible. The Anglian till is used as a marker horizon and the pollen profile of the Hoxnian interglacial is regarded as the best available method for correlating some of the post-Anglian deposits at all three sites. The pollen profile at Clacton has been equated with that from Hoxne, and if this is accepted, it raises important archaeological implications concerning the relationship of the Clactonian and Acheulian industries. The conclusion is that the Clactonian has a long history, dating back in time to the latter part of the Anglian, and continued to at least the Early-temperate zone of the Hoxnian, Ho. IIb. Both the Acheulian and Clactonian industries were produced by people with preference for occupying river, marsh or lake environments. The Acheulian first appears at Hoxne in zone Ho. IIc, close in time to the Clactonian. Coupled with the disappearance from the archaeological record of the Clactonian after this period, it is suggested that there may have been territorial infringements to cause this disappearance. New evidence from Hoxne also demonstrates that different traditions of hand-axe manufacture existed side by side in Britain during the Hoxnian and Wolstonian stages. The Swanscombe sequence cannot be fitted with much certainty into the framework suggested by Clacton and Hoxne, but new pollen evidence from the Lower Loam suggests that either the Lower Gravel and Lower Loam are pre-Hoxnian, or the Middle Gravels belong to the Wolstonian.

The influence of three rapeseed meals and a mustard seed meal on egg and broiler production

Abstract: Synopsis A mustard seed meal free of oxazolidinethione and three rapeseed meals of low (C), medium (D) and high (E) oxazolidinethione contents were included at a rate of 12% in the diets of laying birds and of broilers. The control diets contained a similar quantity of protein as soyabean meal. In each experiment a further control group was given a suitable commercial diet. The mustard seed meal and rapeseed meals D and E caused large and significant mortalities among laying birds. Macroscopic observations suggested that the main cause of death was probably liver haemorrhage. Egg production, after correction for mortality, was significantly decreased by rapeseed meals D and E, and egg weight by the mustard seed meal. There were no significant treatment effects on food intake and therefore the weight of food needed for each egg produced followed fairly closely the pattern of egg production. Overall egg production was depressed by mustard seed meal and by rapeseed meals D and E. Rapeseed meal C decreased pr...

Imantonia rotunda gen. et sp. nov., a new member of the Haptophyceae

Abstract: Imantonia rotunda, a new member of the Haptophyceae, is described and records of its distribution are given. It is characterised by a distinctive “bicycle-wheel” type of scale and does not bear a haptonema.

The effect of plant spacing, nitrogen fertilizer and irrigation on the appearance of symptoms and spread of virus yellows in sugar-beet crops

Abstract: Satisfactory comparisons of the incidence of virus yellows in sugar-beet fields or experimental plots with different amounts of N fertilizer can be made from visual symptoms early in the growing season, but not later because dressings of N fertilizer may then mask or delay the appearance of symptoms. Sugar-beet plants in the field infected with beet mild yellowing virus (BMYV) are less likely to show symptoms than those with beet yellows virus (BYV), and plants with BMYV in the glasshouse often fail to show clear symptoms.Crop yield will be affected by the spread of viruses and colonization of plants by aphids, which in turn are affected by such factors as plant density, nitrogen supply and irrigation. The presence or absence of virus diseases and of aphids should therefore be considered during studies on the effects of these agronomic factors on the growth and yield of sugar beet. Where ample rather than little N fertilizer is used a small increase in the percentage of plants infected with yellows can be expected, and aphids will be more numerous, if plants are not treated with insecticide. Irrigation may also increase yellows incidence (e.g. from 16% to 20% of plants at Broom's Barn in 1967), but any loss of potential yield from increased virus incidence will be small compared with that gained from the use of fertilizer or irrigation. However, plant density can appreciably affect yellows incidence. For example, at Broom's Barn in 1972, 51% of plants in crops with 17500 plants/ha contracted BMYV but only 15 % of plants in crops with 126500 plants/ha. The less dense crop lost 3–4% more of its potential yield due to yellows than the dense crop; this represents a difference due to virus of about 0·25 t sugar/ha.

Reproductive physiology in relation to deer management

Abstract: One of the more important aspects of deer management is the regulation of the number of animals in the herd. It is the fertility and fecundity of the female, rather than the male, that affects the rate of increase and the number of female deer that affects the size of the population. The various parameters of reproductive physiology of female deer are discussed and the information available with regard to the species of deer occurring wild in Britain is reviewed and summarized. The time of year to cull deer and the importance of the female as well as the male for selection for breeding are briefly discussed.

Grey seals, Halichoerus grypus, of the Dee Estuary and observations on a characteristic skin lesion in British seals

Abstract: Grey seals on the West Hoyle Bank feed on a variety of fish and have a high incidence of dermal lesions, often associated with emaciation and nematode parasite infection. Corynebacterium phocae has been isolated from an active lesion. The significance of large numbers of seals in the Dee Estuary bearing lesions is discussed and the occurrence of seals with lesions elsewhere in British waters is reviewed. No evidence was found to associate the dermal lesions with any environmental factor and it is probable that lesions develop as a result of infection of minor wounds.

The response of sugar beet to potassium and sodium fertilizers

Abstract: The results of 216 field experiments with sugar beet (1957–69), testing K and Na fertilizers, were re-examined There were only small increases in yield with K or Na on peat or peaty mineral soils but on mineral soils, 100 kg K/ha without Na increased sugar yield by about 0·4 t/ha and 100 kg Na/ha without K increased yield by 0·6 t/ha Although the average response per kg of nutrient was approximately in inverse proportion to their atomic weights, K and Na were only partially interchangeable; their relative effects differed from field to field and year to yearK seemed most effective in years with more than 80 mm rainfall in March–April but responses were halved when rainfall was 50 mm or less Sowing date and the interval between giving fertilizer and sowing also influenced response to K; with late-sown crops, K fertilizer given within two weeks of sowing was usually ineffective Response to Na differed much less with season so Na was on average more effective than K, especially in dry springs It seems, therefore, that instances of near-perfect substitution between K and Na fertilizers result from chance combinations of weather and crop husbandrySince in some experiments yields from a combined dressing exceeded those from either nutrient alone, and as the weather is largely unpredictable, both K and Na fertilizers should be given on all mineral soils, except those very rich in K, to be certain of avoiding yield loss Texture and exchangeable soil K and Na also affected both the amount and rate of response, but did not much influence optimal fertilizer dressings and so are not very useful for making differential fertilizer recommendations

Apparatus and methods for contacting gases or vapours with particulate solid material

Abstract: An improved vessel design is provided for contact of gas or vapour with particulate solid material, for example for adsorption systems such as air drying and solvent recovery systems, in which a plurality of trays for containing the particulate material are supported by a pillar structure within the shell of the vessel, the shell serving merely as an envelope which does not provide support for the trays thereby enabling a considerable reduction in material costs for the shell and greater design flexibility for the site where the vessel is to be installed. The pillar preferably forms a manifold for conveying gas or vapour streams to or from each of the trays and deflecting baffles for the gas or vapour streams are also provided. A sparge pipe may also extend along the duct to introduce steam or other purge gas for regeneration of an adsorbent in situ.

The effect of nematicides, applied to the seed rows in spring, on growth and yield of sugar beet in Docking‐disorder‐affected fields

Abstract: SUMMARY Both Trichodorus spp. and Longidorus spp. damage roots of sugar-beet seedlings in sandy soil, causing Docking disorder. Trials in infested fields between 1969 and 1972 tested the effects of fumigation along the rows with different amounts of D-D or Telone applied either two weeks before sowing or immediately before sowing, application of the systemic nematicide aldicarb (Temik) in the furrow with the seed during sowing, and top-dressing with nitrogen. Seedling establishment was often decreased by fumigation immediately before sowing, especially when followed by excessive rainfall, but only rarely by earlier fumigation or by aldicarb; differences in numbers of roots harvested were smaller because hand-singling removed excess seedlings. There was usually little difference between the yield increases given by the most effective treatments, which were aldicarb at 1·12 kg active ingredient/ha and 2·2–6·6 ml D-D or Telone/m of row at either time of application. Nitrogen top-dressing never affected sugar yield significantly. Longidorus spp. and Trichodorus spp. were both controlled well in the fumigated row but much less well at 13 cm, and not at all at 25 cm from the row (i.e. mid-way between two treated rows).

Bird damage to sugar beet

Abstract: SUMMARY Pest damage to sugar beet, including that by birds, has been recorded since 1957. During that time damage by rooks has decreased almost to nil, but some other bird damage has greatly increased, most probably as a result of changing agronomic practices, especially the extensive use of herbicides, the introduction of monogerm seed, and the increasing practice of ‘planting-to-a-stand’. The most severe bird damage in the spring is grazing by several species, and in early summer localized felling of plants by pheasants. Observations in the mid–1960's of causes of seedling and plant losses suggested that birds were then of minor importance; the British Sugar Corporation currently consider that birds are the most serious pest of sugar beet. The distribution of the reported damage does not seem to follow any national pattern. In small-plot field trials possible repellent materials such as anthraquinone, methiocarb or thiram, applied to seed or foliage, did not decrease the extent of grazing.