Individual and population growth in the asexually reproducing anemone Aiptasia pallida Verrill

The effects of feeding regime and zooxanthellae on individual and population growth of Aiptasia pallida (Verrill) were studied in a series of laboratory experiments. Individual and population growth were measured as biomass increase. Both individual and population growth were significantly affected by feeding regime while zooxanthellae enhanced growth only at the most infrequent feeding regime. Feeding regime had no significant effect on the number of individual anemones in the population produced asexually by pedal laceration after 8 wk, although there were temporal differences in pedal laceration between feeding regimes during this 8-wk period. Anemones fed three times per wk underwent little pedal laceration prior to week 4 with most individuals produced after week 4. In contrast, anemones fed once per 4 wk produced almost all anemones prior to week 4 with little subsequent pedal laceration. Zooxanthellae significantly increased the number of anemones produced by pedal laceration only among individuals fed at 4-wk intervals. Zooxanthellae had no effect on pedal laceration among individuals fed three times per week.

Population growth, measured as weight change, after 4 wk was greater than individual growth for all treatments except aposymbiotic anemones fed at 4-wk intervals for which there was no significant difference between individual and population percent weight change. These results suggest that zooxanthellae enhance growth only during periods of prey scarcity and that asexual reproduction by symbiotic individuals increases biomass at a greater rate than does individual anemone growth.     

Factors influencing nursing in Macaca fascicularis.

Nursing by two mother-infant pairs in a caged colony of Macaca fascicularis was monitored at 1-min intervals for 8 h beginning 8:30 a.m. BST, once a week for 3 months in the summer of 1973. Nursing occupied about 210 min in 8 daylight hours for the infants at 10 weeks of age, and the time spent nursing decreased at the average rate of 9.4 min per week until the infants were about 6 months old. The time spent nursing by the infants studied here resembles closely the times spent nursing by some other macaques and by baboons. In the course of a day the amount of time spent nursing varies significantly with a diurnal peak. If nursing by one mother-infant pair is independent of nursing by the other pair, then the time the two pairs spend nursing together would be a function of the product of the frequencies of nursing by each pair. The expected times for the pairs nursing together based on the hypothesis of independent events were significantly less than the observed times the pairs nursed together. Nursing, therefore, involves a positive influence or imitation of one nursing pair by the other. Nursing sessions involving both mother-infant pairs were longer on the average than sessions involving only one pair.     

A field experiment on dispersal of newly emerged adults ofMonochamus alternatus (Coleoptera: Cerambycidae)

Newly-emerged adults of Monochamus alternatus aged 1 to 5 days were code-numbered with lacquer paint and released by placing them on the trunks of one or two trees in a Pinus thunbergii stand at weekly intervals during the beetle emergence period from 1980 to 1983. Beetles were captured at weekly intervals from one week after the first day of release. Determinations were made on the distance and direction of beetle dispersal during a week after release and analysed by a method of Inoue (1978). When the stand canopy was closed, the rate of beetle's stay on trees was 0.56 per week. The beetles dispersed at random by walk and flight. When the pine stand was sparse, the rate of beetle's stay on trees was 0.02–0.30 per week. They dispersed at random by flight. The average distances traversed were estimated to be 7.1–37.8 m for the first week after emergence. Using other method, the average distance traversed was estimated to be 10–20 m for each week through the first 3 weeks after release. The results of stepwise multiple regression analysis and a simple field experiment suggested that the dispersal of newly-emerged beetles was affected by stand density, number of beetles emerging from individual dead trees, maximum air temperature, and precipitation.     

An effective method for freezing White Italian gander semen

Efficiency of freezing method, worked out for the White Italian gander semen was evaluated by comparing motility, morphology and fertilizing ability of spermatozoa in fresh and frozen-thawed semen. A part of pooled semen, collected from 25 White Italian ganders by dorso-abdominal massage was used immediately for artificial insemination of 10 geese (the control group) with a dose of 80 microl. This insemination was performed six times at weekly intervals. The remainder of the semen was diluted 1:0.5 (v/v) with EK diluent, equilibrated for 15 min at +4 degrees C, mixed with 6% (v/v) of dimethylformamide (DMF) and frozen to -140 degrees C at a rate of 60 degrees C/min. Frozen semen was thawed in a 60 degrees C water-bath and inseminated twice weekly in a dose of 100 microl (10 females of the experimental group, 12 inseminations were made). The freezing process affected spermatozoa motility and morphology, but had no effect on their fertilizing ability. Positive movement was observed in 50-60% of the spermatozoa in fresh semen and about 40% of the frozen-thawed cells. The average percentage of total live and live normal spermatozoa decreased due to freezing from 92.2 to 68.4% and from 34.7 to 14.1%, respectively. After the fresh semen insemination with average 12 million of the live normal spermatozoa per week average fertility was 88.24%; hatchability of set eggs was 80.88% and hatchability of fertile eggs was 91.67%. For frozen-thawed semen inseminated with average 9.5 million of the undamaged spermatozoa per week, the average fertility and hatchability rate was 83.78, 73.87, and 88.17%, respectively. Fecundity rates obtained after insemination with the frozen-thawed gander semen allow for the application of the freezing technique into breeding practice, in place of natural mating or to assist natural mating in periods of lowered fertility level.     

The effectiveness of steers and heifers treated with oestrogen or testosterone to detect oestrus in cattle

Two experiments were carried out to determine the effectiveness of steers and heifers, treated with oestrogen or testosterone, in the detection of oestrus in cattle.In the first experiment 17 steers castrated at birth and 16 castrated at 6 months of age were randomly allocated to three groups and received an 800 mg subcutaneous implant of testosterone, subcutaneous injections of 10 mg oestradiol benzoate per week for 16 weeks or no hormone (controls). In addition, six heifers were injected subcutaneously with 10 mg oestradiol benzoate per week for 16 weeks while six untreated heifers served as controls. Animals were observed in a standardised libido test 2, 4, 8, 16, 20 and 24 weeks after treatment commenced. The time to first mount and the number of mounts per animal responding in the presence of oestrous heifers were recorded. Both steers and heifers treated with oestradiol benzoate were superior at detection of oestrus in cattle than animals treated with testosterone or those receiving no hormone. Oestrogen-treated animals generally detected heifers in oestrus in less than 3 min after introduction and mounted these animals between 20 and 30 times in one hour. This response was consistent throughout the duration of the experiment. There was no effect of age at castration of steers on development of male behaviour.The second experiment determined the rate and degree of development of male behaviour in steers in response to weekly subcutaneous injections of 0, 2, 4, 8 or 16 mg oestradiol benzoate per 250 kg body weight, 250 mg testosterone or 150 mg dihydrotestosterone for a period of 15 weeks. Steers treated with oestradiol benzoate again proved to be more successful than untreated or testosterone-treated steers at consistently detecting and mounting oestrous heifers. The best response was obtained from steers treated with 8 mg/250 kg body weight per week. The practical application of this work is discussed.     

Effects of temperature and diet on the growth rate of year 0 oyster toadfish, Opsanus tau

The effects of temperature and diet on the growth of captive year 0 specimens of Opansus tau were examined for two consecutive year classes. The 2001 year class was raised at about 23, 26, or 29 degrees C and provided with live brine shrimp, frozen butterfish and squid, or commercial food pellets (45% protein, 19% fat, and 3% fiber) three times per week. Maximal growth was achieved with the pellet diet, and fish raised at 29 degrees C attained the highest mean wet weight (84.0 g +/- 14.6 g SE) and fastest instantaneous relative growth rate (IRGR, 1.79% body weight/d). The 2002 year class was raised on the same pellet diet at 31.5 degrees C and fed 3, 5, or 7 times per week. Although more frequent feedings led to significantly greater mean wet weight in the first half of the year, by month 12 there was no significant difference between the three feeding frequencies. These fish weighed approximately 68 g and had an average IRGR of 1.74% body weight/d. The pellet diet during both years was correlated with high survival (> 75%).     

Observations on agonistic behaviour of Clarias gariepinus larvae and juveniles under different densities and feeding frequencies in a controlled environment

Ten-day-old African catfish larvae, Clarias gariepinus , were stocked in aquaria at 5, 13, 22, and 30 larvae per liter with fish at each density being fed three and six times per day over 35 days. Fish were fed with an artificial diet in excess of their satiation requirements at each feeding. Every week total length was determined for samples of 25 fish per tank and all fish were counted at weekly intervals. Behaviour patterns were categorized into timed behaviour (i.e. resting, swimming and browsing), and frequency events e.g. number of contacts, aggressive contacts and number of head or body attacks. Fish at the lowest density grew faster than fish at the other densities. Feeding frequency had no effect on growth. With increasing densities fish less frequently changed timed behaviour patterns while spending a greater percentage of the time swimming. Aggressive behaviour was highest at the lowest density but remained uninfluenced at densities greater than five fish per litre. The high feeding frequency provoked a higher rate of aggressive contacts than the low feeding frequency. A suggested explanation was that these fish were more often in anticipation of food and consequently more active between feedings. In summary, it was shown that density had an effect on duration behaviour patterns such as resting and swimming, while feeding frequency significantly influenced frequency events, in particular the rate of aggressive behaviour. The study contributes to an understanding of factors influencing C. gariepinus juvenile behaviour and suggestions for follow-up experiments are discussed.     

Assessing reproductive cycles and pregnancy in cheetahs (Acinonyx jubatus) by vaginal cytology

Vaginal cytology was used to monitor ovarian cycles, two pregnancies, and three pseudopregnancies. Vaginal smears were collected two or three times per week from three adult females; smears plus blood samples were collected once per week from a fourth, adolescent female. Mean cycle lengths, based on intervals between onset of leukocyte infusions, were 11.9 ± 4.9 days (n = 43 cycles), 10.8 ± 5.1 days (n = 49), and 12.3 ± 6.3 days (n = 7) for the three females. Weekly hormone data from the adolescent female revealed a correlation between serum estradiol and percent anuclear cells, suggesting that these cells may be indicative of estrus. The fourth female experienced two sustained, 6-week increases in serum progesterone, one spontaneous and the other following follicle-stimulating hormone (FSH) administration. Leukocyte infusions continued during these periods of increased progesterone secretion. However, leukocyte infusions ceased during the two pregnancies of one adult female and during two FSH-induced pseudopregnancies of another. © 1992 Wiley-Liss, Inc.     

Attainment of puberty in female pigs: Influence of boar stimulation

The object of the present study was to investigate whether the presence of a boar is of importance for the age at puberty and the expression of external heat symptoms in female pigs. Altogether 60 crossbred gilts were purchased at an age of 12 weeks and grouped, three or four per pen, in three separate barns (treatment groups A, B and C). Treatment group A: Boars were kept in adjacent pens to the gilts during the whole period. One vasectomized boar was penned with the gilts daily for 20 min during the experimental period, which started at a mean age of 142 days. Treatment group B: Boars were kept in adjacent pens to the gilts during the whole period. Treatment group C: No boars were kept in the barn at any time.The study was performed six times. Daily heat control was carried out during the experimental period, which was terminated when the gilts had passed at least two oestrous cycles. Blood samples for progesterone analysis were taken once a week. Laparoscopy was performed in all gilts after their first observed heat. The gilts were slaughtered after their third or fourth heat. The effects of treatment group were estimated by the method of least squares analysis.All gilts except one showed external heat symptoms at regular intervals during the experimental period. A few gilts did not stand for the boar at each oestrous period, regardless of oestrous number. Gilts belonging to group A showed their first oestrus on average 20 days earlier than gilts in group B and 35 days earlier than gilts in group C. These differences were highly significant (P < 0.001). The stimulatory effect of the boar on the age at puberty varied between the six experimental groups and the interaction between treatment and experimental groups was significant (P < 0.01).     

Effect of duration of melatonin treatment on the onset and duration of oestrous cyclicity in ewes.

Forty-two Scottish Blackface ewes that lambed outdoors in March were removed from their lambs at the end of April and housed under natural daylength at 57 degrees N. Treatments (n = 7 ewes per treatment) commenced on 1 May and comprised daily oral dosing at 15:00 h with 3 mg melatonin dissolved in water and ethanol (4:1, v/v) for 30, 60, 90, 120 or 150 days. Control ewes received the vehicle alone. Ovarian activity was assessed by laparoscopy at monthly intervals with an additional interim observation in mid-July. Blood was sampled three times a week by jugular venepuncture and assayed for progesterone, prolactin and follicle-stimulating hormone (FSH). Luteinizing hormone (LH) was determined in blood samples collected at 15 min intervals for 10 h on days 28, 60, 91, 119 and 150. Thirty days of melatonin treatment delayed (P < 0.01) first ovulation by about 1 month (mean interval +/- SEM from 1 May to progesterone > 1 ng ml-1, 165 +/- 4.5 days versus 132 +/- 9.2 days for controls). None of the ewes that received melatonin for 60 days ovulated before the end of melatonin treatment, but subsequently six of them did; the mean interval from 1 May to increased progesterone concentration was 75 +/- 1.2 days. All ewes receiving melatonin for 90, 120 and 150 days ovulated with corresponding mean intervals of 83 +/- 2.7, 85 +/- 1.3 and 87 +/- 2.2 days, respectively (P < 0.001 compared with controls).(ABSTRACT TRUNCATED AT 250 WORDS)     

Introduction of a partial shift system for house officers in a teaching hospital.

OBJECTIVES--(1) To introduce a partial shift system to reduce the hours of work of preregistration house surgeons to an average of 64 a week to comply with the New Deal for junior doctors; (2) to test linking the partial shift concept to an existing structure of "on call" firms. DESIGN--Formal assessment after three months of a pilot partial shift system for eight house surgeons on three firms instituted on 1 November 1991, followed by questionnaire and interview evaluation at three and six months of a revised system implemented on 1 February 1992. SETTING--Department of general surgery at St Bartholomew''s Hospital, London. SUBJECTS--24 house surgeons attached to three surgical firms. RESULTS--In eight weeks each house surgeon worked one week (five shifts) of night duty, one week of "cover" (afternoon and evening) duty, and six weeks of normal daytime hours. Each weekday a house surgeon from the firm on call worked an extended daytime on call shift until 10 pm. Weekend duties were split between two house surgeons from the firm on call. A computer generated graphical display of the rota was used to facilitate leave planning. Average working hours were reduced to below 64 per week, including prospective cover, without detriment to patient care and educational standards. Within the shift system individual house surgeons could be on call with their own firm by day and at weekends. Opinions were equally divided among junior staff as to their preference for either on call or partial shift systems. CONCLUSIONS--The principles of this partial shift system are generally applicable and the model can readily be adopted by district general hospitals.     

Cytokinins,donor plants and time in culture affect shoot regenerative capacity of American elm leaves

Cytokinins, donor plants and their time in vitro as well as basal media were investigated for their influence on shoot regenerative capacity of American elm (Ulmus americana L.) leaves. Leaves excised from six 2-year-old seedlings formed adventitious shoots when placed on Driver and Kuniyuki Walnut (DKW) medium supplemented with 7.5, 15 or 22.5 M of benzyladenine (BA) or thidiazuron (TDZ). Thidiazuron induced significantly higher regeneration percentages on elm leaves than BA, regardless of concentration used. Donor plant also affected the efficiency of shoot regeneration, with certain seedlings having 1.5 to 7 times more explants forming shoots as compared to other seedlings tested. By subculture 15, the average number of shoots per regenerating explant increased at least 3-fold for leaves on media with BA or TDZ for the one donor plant that survived continued subculturing. Leaf explants from donor plants with the highest regenerative capacity had a higher percentage of shoot formation on DKW than MS medium. Explants from productive donor plants should be placed on DKW medium supplemented with TDZ to improve shoot regeneration efficiency from American elm leaves.     

The repeatability of superovulatory response and embryo recovery in sheep

Over an 8-year period, a total of 328 Scottish Blackface donor ewes were involved in a MOET program. They were synchronized with fluorogestone acetate sponges and superovulated with ovine FSH. After the onset of estrus, ewes were hand-mated and laparoscopic artificial insemination was performed with fresh semen 44-46 h after sponge removal. Embryos were recovered semi-laparoscopically on either Day 5 or Day 6 after insemination. Of the 328 donor ewes used, 222 ewes were supervoulated only once, while the remaining ewes were superovulated either twice (73 ewes), 3 times (26 ewes) or 4 times (7 ewes) at yearly intervals to generate a maximum of 474 records for subsequent analysis. There was no significant change in either mean ovulation rate or the mean number of embryos recovered per donor ewe at successive treatments. However, significant (P < 0.05 at least) effects of both year and donor ewe age existed for superovulatory response and number of embryos recovered, though only the effect of year was significant (P < 0.001) for percentage embryo recovery. Repeatability was significant (P < 0.05 at least) for both superovulatory response (r = 0.55, s.e. 0.055) and number of embryos recovered (r = 0.38, SE 0.074), but not for percentage embryo recovery (r = 0.04, SE 0.102).     

Embryological study on gynogenesis in onion (Allium cepa L.)

Haploid induction in onion can, to date, be induced only via gynogenesis by culturing unfertilized flowers, ovaries or ovules. The process of haploid embryo induction has been macroscopically well studied, but only limited data exist from microscopic examination of ovule development status at the inoculation stage and of the origin of gynogenic embryos. Microscopic studies were carried out using individual donor plants with relatively high embryo induction frequencies (45.9 embryos formed per 100 flowers, on average, for 2 years). Ovaries from flower bud culture were fixed at 1 week intervals up to the 7th week of culture. These were compared with pollinated ovaries at 1 or 2 weeks after pollination. In total, 1428 unfertilized embryo sacs were examined. The results indicate that, at the time of inoculation, ovules within ovaries 2.0–3.0 mm in diameter contained two- or four-nucleate embryo sacs in the smallest ovaries to mature embryo sacs in the largest ovaries. It seems likely that the embryos are actually induced from ovaries cultured at the immature stage. After 1 or 2 weeks in culture, the egg apparatus primarily consisted of distinctly enlarged synergids and the egg cell, which was often detached from the micropylar pole. But free nuclear endosperm was also formed. From the 2nd to 7th week in culture, formation of haploid embryos (from globular to the almost mature cylindrical stage) was detected in 5.7% of the ovules. Their origin, for several reasons, was most likely the egg cell. In addition, ovules containing endosperm only (3.6%) and ovules containing the egg apparatus (0.5%) or both endosperm and embryo (0.4%) were detected. This observation is probably unique and has not yet been reported in other species studied. Received: February 2001 / Revision accepted: 20 April 2001     

Repeated surgical embryo recovery and embryo production in rabbits

The purpose of this study was to assess the embryo production after repeated surgical recovery of embryos in Gigante de Espa?a does. A total of 195 ovulatory treatments and embryo recoveries were performed from 1995 to 1999. Ovulation was induced by an intramuscular injection of 20 microg GnRH immediately after mating. Each doe was induced to ovulate up to four consecutive times at intervals of at least 50 days. Embryos were surgically collected from oviducts 68-69 h post-coitus. An average of 8.6 corpora lutea and 6.4 recovered embryos (90% of them classified as viable) were recorded from the 195 treatments. The process seemed to be less efficient in the fourth treatment, with a drop of more than two recovered and viable morulae with reference to the third (P<0.05 for both parameters) or the second recovery (P<0.1 and P<0.05, respectively). More than 20 recovered embryos and 18 viable embryos per donor doe were recorded considering the three first ovulatory treatments performed in 33% of the does (30/90). Results indicate that the methodology used in the present study could be an efficient way to maximize in vivo embryo production from rabbits.     

Regulation of Haemonchus contortus populations in sheep exposed to continuous infection

Groups of sheep were infected three times weekly for 15 weeks with infective larvae of Haemonchus contortus at four rates ranging from 600 to 4800 larvae per week. At 3-weekly intervals, sheep from each group were killed for total worm counts after receiving a dose of radiolabelled larvae which enabled a direct measurement of establishment of incoming larvae during the continuing infection. Peak H. contortus burdens were reached between 6 and 9 weeks of infection, and were related to infection rate. In the groups receiving 2400 and 4800 larvae per week, worm numbers then declined rapidly and by the end of the experiment were lower than those in the groups given 600 or 1200 larvae per week. Establishment of incoming larvae was not influenced by infection rate, and declined from 45% in the first 4 weeks of infection to insignificant levels during the final 6 weeks. The proportion of incoming larvae arrested in their development increased as the infection progressed. It was concluded that H. contortus numbers were regulated by development of resistance to infection and by a loss of established worms which was related to the current rate of larval intake, and to the host's previous experience of infection.     

Sleep problems and computer use during work and leisure: Cross-sectional study among 7800 adults

Previous studies linked heavy computer use to disturbed sleep. This study investigates the association between computer use during work and leisure and sleep problems in working adults. From the 2010 round of the Danish Work Environment Cohort Study, currently employed wage earners on daytime schedule (N?=?7883) replied to the Bergen insomnia scale and questions on weekly duration of computer use. Results showed that sleep problems for three or more days per week (average of six questions) were experienced by 14.9% of the respondents. Logistic regression analyses, controlled for gender, age, physical and psychosocial work factors, lifestyle, chronic disease and mental health showed that computer use during leisure for 30 or more hours per week (reference 0–10 hours per week) was associated with increased odds of sleep problems (OR 1.83 [95% CI 1.06–3.17]). Computer use during work and shorter duration of computer use during leisure were not associated with sleep problems. In conclusion, excessive computer use during leisure – but not work – is associated with sleep problems in adults working on daytime schedule.     

Exercise endurance 1, 3, and 6 h after caffeine ingestion in caffeine users and nonusers.

The purpose of the present study was to examine the duration of caffeine's ergogenic effect and whether it differs between users and nonusers of the drug. Twenty-one subjects (13 caffeine users and 8 nonusers) completed six randomized exercise rides to exhaustion at 80% of maximal oxygen consumption after ingesting either a placebo or 5 mg/kg of caffeine. Exercise to exhaustion was completed once per week at either 1, 3, or 6 h after placebo or drug ingestion. Exercise time to exhaustion differed between users and nonusers with the ergogenic effect being greater and lasting longer in nonusers. For the nonusers, exercise times 1, 3, and 6 h after caffeine ingestion were 32.7 +/- 8.4, 32.1 +/- 8.6, and 31.7 +/- 12.0 min, respectively, and these values were each significantly greater than the corresponding placebo values of 24.2 +/- 6.4, 25.8 +/- 9.0, and 23.2 +/- 7.1 min. For caffeine users, exercise times 1, 3, and 6 h after caffeine ingestion were 27.4 +/- 7.2, 28.1 +/- 7.8, and 24.5 +/- 7.6 min, respectively. Only exercise times 1 and 3 h after drug ingestion were significantly greater than the respective placebo trials of 23.3 +/- 6.5, 23.2 +/- 7.1, and 23.5 +/- 5.7 min. In conclusion, both the duration and magnitude of the ergogenic effect that followed a 5 mg/kg dose of caffeine were greater in the nonusers compared with the users.     

Water hyacinth (eichhornia crassipes) productivity and harvesting studies

Water hyacinth growth rates were monitored from May through October in two sewage lagoons with different nutrient loading rates. The lagoon receiving the heaviest load sustained the highest average growth rates throughout the summer. The lightly loaded lagoon averaged a 29% increase in weight per week over the six month period with the highest growth rate occuring during June with an average weekly weight gain of 71%. The heavily loaded lagoon sustained an average growth rate of 46% per week for the same six month period with the highest measured growth rate of 73% increase in weight per week also occuring in June. In addition, the performance of three harvesters was evaluated. One harvester, consisting of a chopper and conveyor, was capable of picking up and chopping approximately 2.3 t of plants per hour and delivering them to a waiting truck. The second harvester was a single 1.52 m (5 ft) wide conveyor, and the third one was a modified clamshell bucket attached to a dragline. The average harvesting rate of each of these harvesters was approximately 9.3 t of water hyacinths per hour.     

Songbirds using crops planted on farmland as cover for game birds

We counted songbirds in crops planted on shooting estates specifically for game management purposes on farmland in Britain and elsewhere in Europe. Winter game crops provide cover and feed areas for pheasants Phasianus colchicus and red-legged partridge Alectoris rufa, while summer game crops are designed to provide brood-rearing cover for these species. In central and southern England, 30 plots of winter game crops, either kale, quinoa or cereal up to 2 ha in area, and 30 adjacent arable-field plots, were surveyed for birds up to six times at monthly intervals during the winter 1997–1998. In the Scottish lowlands, six plots of summer game crops up to 4 ha in area, and adjacent arable fields were surveyed in summer 1999 or 2000. The winter game plots contained more than ten songbirds per hectare in most months, while the adjacent arable-field plots contained less than one. In all three winter game crop types, songbird numbers declined significantly in the second half of the winter while numbers in the arable fields did not. Of the 26 species recorded in the winter game crops, 10 have undergone rapid decline over the last 30 years. Considering these declining species alone, the winter game crops still contained more individuals than the adjacent arable fields throughout the winter. Densities in both the kale and quinoa were higher than in the cereal game crop. The six summer game crops sampled in mid-summer contained on average 2.9 songbirds per hectare, while the adjacent arable fields contained 0.4. Of the 14 species recorded in these summer game crops, eight have undergone rapid or moderate declines over the last 30 years. Although winter and summer game crops are planted in relatively small plots and hence concentrate birds, these plots are widely planted and our results suggest that they benefit birds on farmland.