Double brooding and polygyny in Sedge Warblers Acrocephalus schoenobaenus breeding in north-west England

Sedge Warbler breeding was studied at a site in Greater Manchester, UK, during 1991 and 1993. Birds were individually colour-ringed and, in the 2 years of the study, 18 pairs and 38 nesting attempts were observed. In both years, the majority of pairs (> 90%) attempted a second brood after successfully raising their first. Overall nest survival was 44% and the median reproductive output of individual males was 6.5 fledglings in each year (range 0–10 and 0–15 in 1991 and 1993, respectively). After fledging, one or both parents continued to feed the young for up to 15 days (median 11, range 0–15 days). One male was apparently bigamous in 1991 and in 1993, raising four broods successfully in 1993 and 25 fledglings over the 2 years. These observations suggest that double brooding is the normal strategy for Sedge Warblers in this population and that polygyny may be common, although easily overlooked.     

The status of the Corncrake Crex crex in Britain in 1998

A census of Corncrakes throughout Britain was carried out in 1998. National Grid squares of 10 km in the Hebrides, Northern Isles and the mainland of Highland Scotland known to have held the species during the breeding season since 1988 were searched systematically by night for singing males. A sample of such squares elsewhere in Scotland was also searched. In addition, bird-watchers and the general public were encouraged by press publicity to contribute records of singing birds, which were checked for accuracy. A total of 589 singing males was counted in 93 10-km squares. Ninety percent of the population was in the Hebridean Islands. The total count was 23% larger than in the previous census in 1993 and 3% larger than in 1988. All surveys of distribution and censuses between the late 19th century and 1993 recorded a progressive decline in the national population and range. The average rate of population decline between 1988 and 1993 was 3.5% per year, but between 1993 and 1998 the population increased by an average of 4.2% per year. However, annual counts from 1993 to 1998 in core areas that held more than 90% of the population, showed that this overall increase resulted from four successive annual increases of 4–16% followed by a decline of 15% between 1997 and 1998. There was considerable variation among islands and areas in the rate of change of their Corncrake numbers.     

Chaos in percepts?

Multistability in perceptual tasks has suggested that the mechanisms underlying our percepts might be modeled as nonlinear, deterministic systems that exhibit chaotic behavior. We present evidence supporting this view, obtaining an estimate of 3.5 for the dimensionality of such a system. A surprising result is that this estimate applies for a rather diverse range of perceptual tasks. Received: 22 April 1993/Accepted in revised form: 6 August 1993     

A winter's tale: Among-year variation in bird community structure in a southeastern Australian forest

Abstract The bird community structure of an undisturbed forest (Olinda State Forest) east of Melbourne, Victoria, varied greatly among the winters of 1993, 1994 and 1995. Increases in the total density of all diurnally active species were as much as 66% between winters [381 versus 633 birds per 50 ha (the density unit used throughout)]. Community structure differed significantly among all three winters, although 1993 and 1994 differed most (1995 was intermediate). One of the striking features was the heterogeneity in patterns among species, families and foraging guilds over the three winters: some taxa (guilds) showed significantly higher densities in the middle year (1993 < 1994 > 1995), others increased monotonically (1993 < 1994 < 1995), while others increased from 1993 to 1994 and maintained those densities in 1995. The species showing significantly higher densities in 1994 were mostly nectarivorous, which seemed to accord with profuse and sustained flowering by Eucalyptus cypellocarpa in 1994 alone. The results are discussed in the context of non-equilibrial community dynamics, large- versus small-scale processes, and the implications of this magnitude of variation in unperturbed forests for environmental monitoring and impact assessments.     

Lake Erie sport and boat show patrons rank Great Lakes ecosystem health issues in 1993 and 1994

In 1993 and 1994 patrons of the Mid-America Boat Show and the American-Canadian Sport, Travel and Outdoor Show, both held in Cleveland, Ohio were asked to respond to an Ohio Sea Grant survey on Great Lakes issues. In 1993 and 1994, a list of issues, identified from previous surveys and citizen advisory groups, were presented to show patrons at the Ohio Sea Grant exhibit. They were asked to rank the importance of each issue on a scale of 0 to 6. A total of 1,751 and 987 boat show and sport show patrons responded in 1993 and 1994 respectively. The four highest ranked issues and their arithmetic means and standard deviations in 1993 and 1994 respectively, were: Lake Erie water quality (5.60±0.79 and 5.53±0.81); Eliminating persistent toxic substances in the Great Lakes (5.54±0.88 and 5.49±0.89); Protecting the Great Lakes ecosystem (5.49±0.87 and 5.51±0.80); and Toxic contaminants in fish (5.49±0.97 and 5.36±1.00). A t-test was used to compare means of 1993 and 1994 responses. Significant differences (0.05) occurred in mean responses for 9 out of 14 issues common to both the surveys. Factor analysis of 1993 data suggested that patrons of the 1993 shows: (1) have a strong concern for the Great Lakes ecosystem; and (2) recognize that individual actions count. Factor analysis of the 1994 data indicated that show patrons continued to have a concern for the Great Lakes ecosystem. Boat and outdoor show patrons (recreational resource users) are a constituency that can, if politically active, validate and support efforts to protect and preserve the Great Lakes ecosystem.     

Career preferences of doctors who qualified in the United Kingdom in 1993 compared with those of doctors qualifying in 1974, 1977, 1980, and 1983.

OBJECTIVE--To report the career preferences of doctors who qualified in the United Kingdom in 1993 and to compare their choices with those of earlier cohorts of qualifiers. DESIGN--Postal questionnaires with structured questions, including questions about choice of future long term career, were sent to doctors a year after qualification. SETTING--United Kingdom. SUBJECTS--All medical qualifiers of 1993, comparing their replies with those from earlier studies of the qualifiers of 1974, 1977, 1980, and 1983. MAIN OUTCOME MEASURES--Choice of future long term career and certainty of choice expressed at the end of the first year after qualification. RESULTS--Questionnaires were sent to 3657 doctors. 2621 (71.7%) replied. Of the 2621 respondents, 70.5% (1849) stated that their first preference was for a career in hospital practice, 25.8% (677) specified general practice, 1.0% (25) specified public health medicine or community health, 1.4% (36) specified careers outside medicine, and 1.3% (34) did not state a choice. By contrast, 44.7% (1416/3168) of the doctors in the 1983 cohort had specified that their first preference was general practice. Among the 1993 qualifiers, general practice was the first career choice of 17.5% of men (227/1297) and 34.0% of women (450/1324). Only 7.4% of men (96/1297) stated that they definitely wanted to enter general practice. Only 7.8% (103/1324) of women qualifiers in 1993 expressed a career preference for surgical specialties. Within hospital practice, comparing 1993 with 1983, choices for the medical specialties and for accident and emergency medicine rose and those for pathology fell. Women were less definite than men about their choice of future long term career. CONCLUSIONS--If the 1993 cohort is typical of the current generation of young doctors, there has been a substantial shift away from general practice as a career choice expressed at the end of the preregistration year. General practice was much more popular among women than men. Few women opted for surgery. The sex imbalance in the percentage of doctors who choose different mainstreams of medical practice seems set to continue.     

Changes in prevalence of herpes simplex virus type 1 and 2 antibodies from 1973 to 1993 in the rural districts of Japan

Using the gG-capture ELISA, changes in the seroprevalence of HSV-1 and HSV-2 from 1973 to 1993 were studied for 614 sera collected from general adults living in rural Japan. The HSV-1 seroprevalence for men and women decreased from 75.3 and 80.6% in 1973 to 54.4 and 59.6%, respectively, in 1993. The HSV-2 seroprevalence also decreased from 10.2 and 9.9% in 1973 to 1.8 and 1.2%, respectively, in 1993. Although the decrease in HSV-2 prevalence seemed to be correlated with the general decrease of sexually transmitted diseases in Japan since the 1950s, these findings should not be interpreted as typical, as HSV-2 infections are particularly known to distribute unevenly among populations, according to sexual activity and cohorts.     

Temporal changes in the relationship between observed and expected sex-investment frequencies, social structure and intraspecific parasitism in Leptothorax tuberum (Formicidae)

The proportional investment in females (IF0) was observed in three Dorset (UK) populations (Portland, Holworth and St Alban's Head) of the ant Leptothorax tuberum during 1993 and 1994. The workers' optimum investment in females predicted by kin selection theory (IF_E) was calculated for these populations from relatedness values estimated from an isozyme polymorphism. Although a previous study at Portland in 1992 found IF_o and IF_E not to differ, in 1993 IF_o and IFE were significandy different from each other at Portland and St Alban's Head. In 1994 the difference was significant at Portland only. IF_o was lower than IF_E at all three sites in both years. The differences between 1992 and 1993 and 1994 were consistent with either an unresolved conflict between workers and queens for control of the IF or change in an environmental factor that affected all sites. Relatedness values showed that at Portland most nests were founded by one singly-mated queen. However, at St Alban's Head relatedness values were consistent with some serial polygyny in 1993 but not 1994, while at Holworth there was some egg-dumping by queens unrelated to the colony queen. The differences in nest structure between sites may have been related to habitat differences. In 1993 there was evidence of a split sex ratio. However, unlike 1992, the female biased nests did not have a higher relatedness asymmetry than the male biased nests.     

War in Guatemala and Exile in Florida

Book reviewed in this article:
Unfinished Conquest: The Guatemalan Tragedy . Victor Perera. Berkeley: University of California Press, 1993. 382 pp. Maya in Exile: Guatemalans in Florida. Allan F. Burns. Philadelphia: Temple University Press, 1993. 208 pp.     

Seasonal variation of fatty acid content in natural microplankton from the Tumpat coastal waters of the South China Sea

In the search for better understanding on the nutritional quality of natural tropical plankton, samples were collected from shallow coastal waters facing the South China Sea during the dry monsoon (May-September) and the wet monsoon (November-April) seasons from March 1993 to July 1994. The total fatty acid content of the predominantly phytoplankton communities (25-200 microns sieve nets) varied four to fivefold with the lowest value occurring during the dry monsoon when blue-green became predominant. Saturated fatty acid content (SAFA), polyunsaturated fatty acid (PUFA) and total omega 3 (sigma omega 3) showed the same seasonal pattern as the total fatty acid with high values in October to December 1993. When species of the dinoflagellate Peridinium and Ceratium were present in considerable amount, the docosahexaenoic acid DHA content was high, especially from March to May 1993. The maximum content of eicosapentaenoic acid EPA, total omega-3 fatty acid, PUFA and sigma omega 3 in phytoplankton occurred during the pre-monsoon period (October and November 1993) when the diatoms were present in large amounts. The larger fraction sample (> 200 microns sieve nets) which consisted predominantly of zooplankton had high amounts of PUFA from September to November 1993.     

Reproductive biology of the mosquitofish in a permanent natural lagoon in south-west Spain: two tactics for one species

Introduced Gambusia holbrooki in a natural lagoon of southern Spain consisted of two age groups: 1992 cohort, 7-11 months old and 1993 cohort, <4 months old. In the 1992 cohort, females grew even during the gestation period at about 0·30 mm day^-1. In the 1993 cohort, females displayed a high growth rate (0·55 mm day^-1) and reached reproductive size in a few weeks, but stopped growing when they matured. All the 1992 cohort reproduced from mid-May to mid-June, but only 50% of the 1993 cohort reproduced, from mid-August to mid-September. Reproducing females were significantly larger in the 1992 cohort (39·8 mm) than in the 1993 one (34·8 mm). The largest 1992 females cohort had reproduced previously; the 1993 cohort had not. The mean dry weight of intra-ovarian embryos decreased to a minimum immediately before birth. These metabolic costs represented 29·8 and 31·4% of the initial weights of the 1992 and 1993 embryos, respectively. Mean dry weight of full-term embryo was significantly higher in the 1992 cohort (0·80 ± 0·129 mg; 95% CL) than in the 1993 one (0·70 ± 0·086 mg; 95% CL). With more females in 1992, cohort fecundity was considerably higher (number of embryos=7151; 63%) than in the 1993 (4193; 37%) cohort. The population completed two generations each year (spring and summer). The spring stock grew slower than the summer one but continued to grow during the gestation period, reaching larger final lengths, with more synchronous reproduction and clearer evidence of a second reproductive event. Each reproductive stock displayed its own life-history characteristics, with significant differences between mean length of reproducing females, growth rate, mean brood size, offspring size, standard fecundity and minimum length at reproduction.     

北方稻田蒸散需水分析及其作物系数确定

利用Penman-Monteith方程估算了中国北方下辽河平原地区52年(1951～2002)的潜在蒸散量,分析了潜在蒸散的年际动态变化规律;在中国科学院沈阳生态实验站的水田实验地上,利用非称重式蒸渗仪对充分供水条件下同一水稻品种稻田蒸散量进行了测定,在此基础上确定了水稻作物系数.结果表明,在北方下辽河平原地区稻田蒸散量变化在581～695 mm之间,年际变率为24%.无论是湿润年还是干旱年,由于受降雨量及其时间分配不均的影响,在该地区水稻生产中都需要有灌溉水补充.整个生育期水稻作物系数多年(1993～2002)平均值为1.32,水稻生育期内作物系数基本符合二次曲线趋势变化.     

Coastal residence periods and reproductive timing in southern right whales, Eubalaena australis

The duration and timing of coastal residence of individually identified southern right whales at a principal aggregation area on the southern Australian coast differed markedly between females with calves and unaccompanied whales. The mean residence period of females that calved within the aggregation area was 70.9 days, with mean residence mid-points of 20 August in 1993 and 22 August in 1994. In contrast, unaccompanied adults remained resident for an average of only 20.4 days with mean residence mid-points of 27 July and 11 August in 1993 and 1994, respectively. Whales have been sighted at this aggregation area from mid May to late October (approx. 160 days), although the effective calving season (95-100% of calves born) lasted only 88 days in 1993 and 96 days in 1994. The mean birth date based on first sighting with neonatal calf, and corrected for sightability bias, was 15 July in 1993 and 17 July in 1994, with 100% of calves born before 31 August 1993 and 23 September 1994.
The time between birth and dispersal from the aggregation area, at or just prior to the commencement of the southward migration, was highly variable. Calves bom before the mean calving date averaged 80 days within the aggregation area, twice as long as those born after the mean (40 days). The large number of calves estimated to be less than 14 days old at first sighting, combined with the sighting of 26 pregnant females prior to parturition, suggests the majority of births occurred within, or very near to, the aggregation area.     

Some taxonomic corrections in the subtribe Bulbophyllinae (Orchidaceae)

Garay, Hamer and Siegerist (1994) propose numerous new taxa and combinations in the genus Bulbophyllum . Their opinions are often contradicting those expressed in Vermeulen (1991, 1993a. 1993b). A reason for this can be sought in the different basic principles both authors apply when delimiting species and higher taxonomic entities. Some of the taxa proposed by Garay, Hamer and Siegerist (1994) are analysed, and taxonomic changes are proposed.     

Annual variations in the reproductive traits of Pomatoschistus microps in a Mediterranean lagoon undergoing environmental changes: evidence of phenotypic plasticity

The spawning period of the common goby Pomatoschistus microps from 1993 to 1997 in the Vaccarès lagoon did not vary, except in 1997 when it was longer due to the reproduction of the young-of-the-year. Egg size and number, and reproductive allocation varied greatly with one year to another. Female common gobies increased both their fecundity per spawning act and their egg size from 1993 to 1995. The annual variation in the reproductive effort suggests a high phenotypic plasticity of reproductive traits in P. microps , in the face of environmental perturbations. In winter 1993–1994, a centennial flood of the Rhône River caused major hydrological changes in the lagoon in less than 1 week, affecting many invertebrates and fish for several years. The reproductive investment of the common goby increased, possibly as a consequence of those environmental changes.     

Books

Book reviewed in this article: Berndt , R.K. & Busche , G. (eds). 1993. Vogelwelt Schleswig-Hoisteins. Band 4: Entenvagel I1 (Kolbenente-Ruderente). Bildstein . K.L. 1993. White Ibis, wetland wanderer. Birkan , M., Pm , G.R., Aebischher , N.J. & Dowell , S.D. (eds). 1992. Perdix VI. First International Symposium on Partridges, Quails and Francolins. Gibier Faune Sauvage. Birkhead , T. 1993. Great Auk Islands. A field biologist in the Arctic. Butler . D. & Merton , D. 1992. The Black Robin: Saving the world's most endangered bird. Clancey , P.A. 1992. Kingfishers of Sub-Saharan Africa. Standard edition. Committee on the Scientific Bases for the Preservation of the Hawaiian Crow . 1992. The Scientific Bases for the Preservation of the Hawaiian Crow. Cramp , S. & Perrins , C.M. (eds). 1993. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palearctic. Sonograms reprinted from Volume VII. Flycatchers to Shrikes. De Blieu . J. 1991. Meant to be Wild. The Struggle to Save Endangered Species through Captive Breeding. Einarsson , P. 1991. Guide to the Birds Iceland. A Practical Handbook for Identification. Eldredge , N. 1992. Systematics, Ecology and the Biodiversity Crisis. Gosler , A. 1993. The Great Tit. Hammond , N. & Pearson . B. 1993. Birds of Prey. Knystautas , A. 1993. Birds of Russia. Lack , P. & Ferguson . D. (eds). 1993. The Birds of Buckinghamshire. Lindsey , T.R. 1992. Encylopaedia of Australian Animals. Birds. Mac Kinnon , J. & Phillipps , K. 1993. A Field Guide to the Birds of Borneo, Sumatra, Java. and Bali. Mc Farlane . R.W. 1992. A Stillness in the Pines. The Ratcliffe , D. 1993. The Peregrine Faicon. 2nd ed. Shrubb . M. 1993. The Kestrel. Sinclair . I., Hockey . P., Tarboton , W., Hayman . P. & Arlott , N. 1993. Illustrated Guide to the Birds of Southern Africa. Andrews , J. & Carter . S. (eds). 1993. Britain's Birds in 1990–91: The conservation and monitoring review. Bond , J.T & Hume . K. 1993. Birds: An artist's view. Carter , R.M. 1993. Finding Birds in South Carolina. Choremi . J., Choulis . D. & Spnhakis , V. 1993. The Birds of the Island of Chios Greece. Dennis , N. & Tarboton . W. 1993. Waterbirds. Birds of Southern Africa's Wetlands. Duckworth . D., Genoways , H.H. & Rose . C.L. 1991. Preserving Natural Science Collections: Chronicle of our environmental heritage. Epple , W., Holzinger , J. & Schmid , G. (cds). 1992. Artenschutzsym-posiuni Wendehals. Lambert , F.A. 1993. The Status of and Trade in North Moluccan Parrots with Particular Emphasis on Cacatua alba. Lorius garrulus and Eos squamatn. Moser . M. & van Vessem , J. (eds). 1993. Wetland and Waterfowl Conservation in South and West Asia. Olney . P.J.S. & Ellis , P. (eds). 1992. International Zoo Yearbook. Perrins , C.M., Le Breton , J-D. & Hirons , G.J.M. 1993. Bird Population Studies: Relevance to conservation and management. Ruge . K., Heidinger , C. & Havelka , P. (eds). 1993. Artenschutzsym-posium Spechte. ?tastny , K. & Bej?ek , V. (eds). 1990. Bird Census and Atlas Studies. Taylor . M. & Canberra Ornithologists Grow . 1992. Birds of the Australian Capital Territory, an Atlas. Walraven . E. 1992. Rescue and Rehabilitation of Oiled Birds: Field manual. Wilson , R.T. (ed.). 1993. Birds and the African Environment. Proceedings of the Eighth Pan–African Ornithological Congress. Won , P. 1993. [A Field Guide to the Birds of Korea]. World Conservation Centre . 1993. World Checklist of Threatened Birds. Jeffery Boswall     

Trends in the Incidence of In Situ and Invasive Cervical Cancer by Age Group and Histological Type in Korea from 1993 to 2009

Objective

Our study aims to describe changes in carcinoma in situ (CIS) and invasive cervical carcinoma (ICC) in Korean women diagnosed between 1993 and 2009.

Methods

All cases of CIS and invasive cervical carcinoma diagnosed from 1993 to 2009 in the Korean National Cancer Incidence database were analyzed. Age-standardized rates (ASRs) and annual percent changes (APCs) in incidence rates were compared according to age and histological type. Additionally, we used Korea National Health and Nutrition Examination Survey (KNHANES) to know the association between screening rate for cervical cancer and incidence rate of cervical cancer.

Results

Between 1993 and 2009, 72,240 cases of ICC were reported in Korea. Total incidence rate of ICC was 14.7 per 100,000 females. ASRs of ICC declined 3.8% per year, from 19.3 per 100,000 in 1993 to 10.5 per 100,000 in 2009. Although the overall incidence rate of adenocarcinoma remained stable, invasive squamous cell carcinoma showed a decreasing trend (APC −4.2%). For women aged 60–79 years, ASRs for squamous cell carcinoma increased from 1993 to 2001, and decreased from 2001 to 2009 (APC: −4.6%). Total 62,300 cases of CIS were diagnosed from 1993 to 2009. Total incidence rate of CIS was 12.2 per 100,000 females. ASRs of CIS increased 5.7% per year, from 7.5 per 100,000 in 1993 to 19.0 per 100,000 in 2009. Adenocarcinoma in situ increased 13.2% per year. There was a strong positive correlation between screening rate for cervical cancer and incidence rate for CIS (p-value = 0.03) whereas screening rate showed a strong negative correlation with incidence rate for squamous ICC (p-value = 0.04).

Conclusions

The increasing trend in CIS, coupled with a decreasing trend in ICC, suggests the important role of cervix cancer screening. The incidence of adenocarcinoma showed a plateau, but the incidence of adenocarcinoma in situ showed an increasing trend.     

House mice and wood mice in and around an agricultural building

Wood mice Apodemus sylvaticus and house mice Mus domesticus are two of the commonest and most intensively studied British mammals. However, relative to the vast literature on non-commensal and laboratory house mice (Berry, 1981, 1991), and woodland wood mice (Flowerdew, Gurnell & Gipps, 1985; Flowerdew, 1991) little is known of the ecology of either species in and around farm buildings. Farm buildings and their surroundings are particularly important for house mice, which are a major stored-product pest (Meehan, 1984). In Britain they live largely indoors but also make limited use of hedges and fields in the summer (Rowe & Swinney, 1977; Montgomery & Dowie, 1993). Wood mice are very abundant on agricultural land, and occasionally use buildings (Green, 1979; Montgomery & Dowie, 1993; Tew & Macdonald, 1993).     

Reform and Revolution in Mexico

Book reviewed in this article:
Spent Cartridges of Revolution: An Anthropological History of Namiquipa, Chihuahua . Daniel Nugent. Chicago: University of Chicago, 1993. 225 pp. Planificación Regional y Reforma Agraria . Angel Palerm. Mexico: Universidad Iberoamericano, Gernika, 1993. 420 pp.     

Recent trends in infant mortality rates and proportions of low-birth-weight live births in Canada

OBJECTIVE: To identify spatial patterns of changes in infant mortality rates and proportions of low-birth-weight live births observed in 1994. SETTING: Canada. SUBJECTS: Live births and infant deaths in Canada between 1987 and 1994. Data for Newfoundland were unavailable for 1987 through 1990. OUTCOME MEASURES: Annual infant mortality rates (crude and after excluding live newborns weighing less than 500 g); proportion of live births by low-birth-weight category (500-2499 g). RESULTS: Nova Scotia, New Brunswick, Quebec and Manitoba had lower crude and adjusted infant mortality rates in 1994 than in 1993. Newfoundland, Saskatchewan, Alberta and British Columbia had higher rates in 1994 than in 1993. The crude rate in Ontario was lower, and the adjusted rate higher, in 1994 than in 1993. A downward trend in the proportion of low-birth-weight live births was observed in Quebec (chi(2) for trend = 29.2, p < 0.01). Conversely, an upward trend was observed in Ontario (chi(2) for trend = 241.3, p < 0.01). However, the increase may have been due to data errors, especially in 1993 and 1994, involving truncation of ounces in 2 digits to 1 digit (e.g., 5 pounds 10 ounces became 5 pounds 1 ounce). CONCLUSIONS: Although the marginal increases in infant mortality observed in several provinces could be the result of random variation, future trends should be closely monitored. The proportion of low-birth-weight live births in Canada (excluding Ontario) appears to be stable, with Quebec showing significant reductions. The errors in data for Ontario need to be corrected before trends can be estimated for that province and for Canada as a whole.