Allozyme variability within and divergence among populations of the liverwortConocephalum conicum (Marchantiales: Hepaticae) in Japan

Genetic variation within, and divergence among, populations of the liverwortConocephalum conicum were estimated from the study of 17 populations and 23 putative gene loci. Two additional multilocus genotypes (“T” and “FS”) were detected in Japan, along with the previously reported “J” type. These three multilocus genotypes differed both morphologically and ecologically. All eight populations from western Japan included only the J-type and exhibited low genetic variation within populations: Nei's (1973) average gene diversity (Ĥ)=0.080±0.029. In contrast, co-occurrence of several multilocus genotypes in each population from the Kanto District resulted in much higher levels of genetic variation (Ĥ=0.218±0.037). If the three genotypes are distinguished,Ĥ values are 0.113±0.030 for T-type, 0.107±0.033 for FS-type, and 0.083±0.018 for J-type. UsingC. japonicum, which showed low genetic variation (0.014±0.010) as an outgroup, each genotype formed a monophyletic clade, and the J- and FS-types were more closely related to each other than to the T-type. Populations of western Japan and the Kanto District also differed in the degree of gene diversity among populations, but the reasons for these differences are obscure.     

Hunting for answers: rabbit (<Emphasis Type="Italic">Oryctolagus cuniculus</Emphasis>) population trends in northeastern Spain

Some populations of European wild rabbit (Oryctolagus cuniculus) in Spain have recovered after rabbit hemorrhagic disease, but others (the majority) have not recovered. The European wild rabbit is a keystone species in Spain’s Mediterranean ecosystems, and several factors have been studied to determine what will stabilize populations and possibly propagate recovery. Many of the previous efforts to determine these pivotal factors have been short-term studies focused on few localities. Most management efforts and studies focused on the well-preserved habitats of southwestern Spain. Our objective was to examine spotlight counts from 60 localities over the past 13 years following the arrival of rabbit hemorrhagic disease in Aragón, northeastern Spain, to estimate rabbit population trends using linear regressions. The number of rabbits seen was transformed into a rough kilometric abundance index. With this data, we calculated a population trend index only for those localities with 6 or more years of data (n=42). No clear population trends were observed for the study period at a regional scale [±SE, range]; (0.065±0.081 from −0.860 to 0.915). We also examined factors that potentially influence regional rabbit population trends, including vegetation, topography, soil softness, climate, predator population trends, and hunting pressure. Our results indicate that rabbit trends have their strongest positive correlation with low hunting pressure and are negatively affected in areas of hard soils. In Aragón, the best populations of endangered raptors are concentrated in the Central Valley, which is the same area where rabbit populations are currently increasing.     

Development of subcutaneous fat in Spanish and Latin American children and adolescents: Reference values for biceps,triceps, subscapular and suprailiac skinfolds

Subcutaneous fat skinfolds represent a reliable assessment instrument of adiposity status. This study provides current percentile references for four subcutaneous skinfolds (biceps, triceps, subscapular, suprailiac) applicable to children and adolescents in Spain and in Latin American countries where data are scarce.The design consisted of a cross-sectional multicenter study performed with identical methods in 5 countries (Argentina, Cuba, Mexico, Spain and Venezuela). Total sample comprised 9163 children and youths (boys 4615 - girls 4548) aged 6–18 years, healthy and without apparent pathologies. Percentiles 3, 5, 10, 25, 50, 75, 90, 95 and 97 were calculated by the LMS method. Sexual dimorphism was assessed using the t-test and age differences with ANOVA. Normalized growth percentile references were obtained according to sex and age for each skinfold. The mean values of four skinfolds were significantly greater in girls than boys (p < 0.001) and, in both sexes, all skinfolds show statistical differences through age (p < 0.001) with different magnitudes.Except triceps in girls, peaks between 11 and 12 years of age are more noticeable in boys than in girls. Although the general model of growth is known, the skinfold measurements show variability among populations and differences of magnitude are presented according to the analyzed population. Therefore, these age and sex-specific reference percentile values for biceps, triceps, subscapular and suprailiac skinfolds, derived from a large sample of Spanish and Latin American children and adolescents, are a useful tool for adiposity diagnosis in this population for which no reference values were available.     

Determining minimum ultimate size, setting size limits, and developing trophy standards and indices of comparable size for maintaining quality muskellunge (Esox masquinongy) populations and sports fisheries

Growth and ultimate size can provide important population insights and a sound biological basis for setting length limits, which can be the best single regulation for preventing overexploitation of muskellunge (Esox masquinongy) populations. A system was developed, using cleithral age and total length at age confidence limits (CL) data, to determine reproductive and growth potential (ultimate size) for calculating and setting increased size limits based on minimum reproductive size (upper 99% CL at age at first maturity + 2 year) and minimum ultimate size (MUS) calculated from the lower 99% CL—minimum ultimate size limit (MUSL). MUS also provides a trophy standard and an index of relative size for comparing trophy potential of individuals within and among populations. Guidelines are provided for determining minimum sample size (mean ± 95% confidence interval = 12 ± 4) and minimum age (8–10 ± 2.0 year) required to produce valid von Bertalanffy growth trajectories. MUS, MUSL, and trophy standards for both length and estimated weight are provided for female and male muskellunge from 14 Ontario sources. Mean MUS, or trophy standard, for females was 115 ± 10.3 cm (MUSL range 75–135) and 11.1 ± 2.6 kg (2.5–17.5) and for males was 95 ± 7.5 cm (66–110) and 6.1 ± 1.3 kg (1.9–9.2). These indices can precisely define growth and growth potential for muskellunge populations and individuals and can be used to better manage and maintain or improve the quality of muskellunge populations and fisheries. Dedicated to the late Dr. E.J. Crossman.     

Threatened freshwater pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> L. in NW Spain: low and very structured genetic variation in southern peripheral populations assessed using microsatellite markers

A genetic analysis of freshwater pearl mussel Margaritifera margaritifera populations from NW Spain, a peripheral area of its European distribution, was carried out using microsatellite markers. These populations were formerly reported as genetically differentiated on the basis of growth and longevity studies. Ten loci previously characterized in populations from central Europe were used to comparatively analyze the genetic variability at the southern edge of the species’ range. Iberian pearl mussel populations showed very low genetic variability and significant high genetic differentiation. Half of the total genetic diversity observed appeared to be distributed between populations, which suggested a highly structured adaptive potential in pearl mussel at the southern peripheral distribution of the species. Population distinctiveness was evidenced by assignment tests, which revealed a high accuracy of individual assignments to their population of origin. All data suggested low effective population size and major effects of genetic drift on population genetic structure. In order to avoid further loss of genetic variation in biologically distinctive populations from NW Spain, prioritization of genetic resources of this species is required for conservation and management.     

Manual therapy as a conservative treatment for adolescent idiopathic scoliosis: a systematic review

Background

Studies on adolescent idiopathic scoliosis have well documented the differences between natural history of male and female patients. There are also differences in responses to nonoperative treatment, but the results of operative treatment in male patients compared with females have not been widely reported. Only few studies had compared the outcomes of operative treatment between male and female patients with different results.

Methods

We retrospectively reviewed the outcome of 150 (112 girls and 38 boys) consecutive patients with diagnosis of adolescent idiopathic scoliosis who were managed surgically between May 1996 and September 2005. Next, male radiographic parameters were compared with female ones pre- and postoperatively. Then, a subgroup of 38 matched girls was compared regarding the age, curve type, curve magnitude, and the instrumentation we used.

Results

In comparing male patients with unmatched girls, the boys had greater mean age (17.3 ± 2.3 vs. 16.3 ± 2.9; p = 0.049), greater primary curve (71.4 ± 21.3° vs. 62.7 ± 17.5°; p = 0.013), less flexibility (30.1 ± 13.5% vs. 40.3 ± 17.8%; p = 0.01), and less correction percentage (51.3 ± 12.9% vs. 58.8 ± 16.5%; p = 0/013). The loss of correction was comparable between the two groups. In the matched comparison, the flexibility in boys was less than girls (30.1 ± 13.5% vs. 38.1 ± 17.5%; p = 0.027). Also, the boys had a smaller correction percentage compared to the girls, but this finding was not statistically significant.

Conclusion

There was similar distribution curve pattern between male and female patients with AIS. Males had more rigid primary curves compared to females but a similar degree of postoperative scoliosis correction. Male AIS patients were older at the time of surgery. These preoperative gender differences, however; did not compromise the radiological outcomes of surgical treatment and the results were comparable between the genders.     

Population parameters and harvest risks for polar bears (<Emphasis Type="Italic">Ursus maritimus</Emphasis>) of Kane Basin,Canada and Greenland

We estimated demographic parameters and current harvest risks for a population of polar bears (Ursus maritimus Phipps) inhabiting northern Smith Sound and Kane Basin, Canada and Greenland. Our demographic analysis included a detailed assessment of age- and sex-specific survival and recruitment from 141 marked polar bears, using information contained within the standing age distribution of captures and mark-recapture analysis. Total survival rates for females were: 0.374 ± 0.180 (cubs), 0.686 ± 0.157 (ages 1–4), and 0.967 ± 0.043 (ages 5+). Mean litter size was 1.67 ± 0.08 cubs. Females did not reproduce until at least age 6, which is late compared to other populations of polar bears. The model-averaged, mark–recapture estimate of mean abundance (±1 SE) for years 1994–1997 was 164 ± 35 bears. We incorporated demographic parameters and their variances into a harvest risk analysis (i.e., a stochastic, harvested population viability analysis, PVA). Results suggest that polar bears in the region were severely over-harvested during the mark–recapture interval (1992–1997). The current status of the population is unknown.     

The influence of glacial epochs and habitat dependence on the diversity and phylogeography of a coastal dolphin species: <Emphasis Type="Italic">Lagenorhynchus albirostris</Emphasis>

In this paper we use mitochondrial and microsatellite DNA variation to investigate the mechanisms that underlie the evolution of population structure in a highly mobile marine mammal, the white-beaked dolphin. We found moderate genetic diversity (h) at mtDNA, but low nucleotide diversity (π) (0.7320 ± 0.0031 and 0.0056 ± 0.0004, respectively), consistent with expectations for a recent expansion. Analyses based on mismatch distributions further suggested a demographic expansion in the Norwegian-Barents Sea population and a spatial expansion in the British isles-North Sea population, implying distinct demographic histories. F _ST values showed clear differentiation among these two populations, but no difference was found between putative populations separated by the English Channel. Our data suggest a stepwise pattern of expansion, dependent on available coastal habitat. The conservation implications are a need to protect local populations isolated by an expanse of deep water, and in particular, a population along the British coasts and in the North Sea as separate from the North Norway-Barents Sea population. It is also evident that overall diversity was reduced, probably during the last glacial epoch.     

Comparison of quantitative genetic parameters between two natural populations of a selfing plant species, Medicago truncatula Gaertn.

 In this paper we compare mean values, heritability estimates, coefficient of genetic variation, and genetic correlations among several fitness components of two natural populations of a selfing plant species, Medicago truncatula L. It is shown that the population that had been found most polymorphic for molecular markers in a previous study was also the most variable for quantitative characters. Depending on the traits, the larger heritabilities in this population were due to either larger coefficients of genetic variances or smaller coefficients of environmental variances. Whereas genetic and phenotypic correlation matrices were very similar within each population, they were quite different between populations. In particular, although a positive correlation between age and size at maturity was found in both populations, the correlation between age at maturity and reproductive success was negative in the more variable population (late flowering plant, with a larger size at flowering, produced fewer pods), whereas no correlation was observed in the less variable population. We suggest that while in the less variable population all individuals have a high reproductive effort, several strategies coexist in the more variable population, with some early-flowering genotypes showing a high reproductive effort and other late-flowering genotypes showing a larger competitive ability through increased vegetative growth. Received: 25 June 1996 / Accepted: 11 October 1996     

Rural populations of the red fox Vulpes vulpes show little evidence of reproductive senescence

The ageing theory predicts fast and early senescence for fast-living species. We investigated whether the pattern of senescence of a medium-sized, fast-living and heavily-culled mammal, the red fox (Vulpes vulpes), fits this theoretical prediction. We used cross-sectional data from a large-scale culling experiment of red fox conducted over six years in five study sites located in two regions of France to explore the age-related variation in reproductive output. We used both placental scars and embryos counts from 755 vixens’ carcasses aged by the tooth cementum method (age range: 1–10), as proxies for litter size. Mean litter size per vixen was 4.7 ± 1.4. Results from Generalized Additive Mixed Models revealed a significant variation of litter size with age. Litter size peaked at age 4 with 5.0 ± 0.2 placental scars and decreased thereafter by 0.5 cubs per year. Interestingly, we found a different age-specific variation when counting embryos which reached a plateau at age 5–6 (5.5 ± 0.2) and decreased slower than placental scars across older ages, pointing out embryo resorption as a potential physiological mechanism of reproductive senescence in the red fox. Contrary to our expectation, reproductive senescence is weak, occurs late in life and takes place at an age reached by less than 11.7% of the population such that very few females exhibit senescence in these heavily culled populations.     

Population structure and loss of genetic diversity in the endangered white-headed duck, <Emphasis Type="Italic">Oxyura leucocephala</Emphasis>

The white-headed duck is a globally threatened species native to the Palaearctic with a range extending from Spain in the west to the western edge of China in the east. Its populations have become fragmented and undergone major declines in recent decades. To study genetic differences between populations across the range and change in genetic diversity over time, we sequenced a portion of the mitochondrial DNA control region from 67 museum specimens (years 1861–1976) as well as 39 contemporary samples from Spain and seven from Greece (years 1992–2003). In the historical sample, we found a lack of significant genetic structure between populations in different areas. We found evidence that the species experienced a rapid expansion in the past, perhaps from glacial refugia centred around the Mediterranean following the last ice age. In Spain, the population went through a dramatic bottleneck in the 1970s and early 1980s, when only a few dozens individuals remained in the wild. Although population size has since recovered to a few thousand individuals, we found a highly significant loss of mitochondrial haplotype diversity between the historical and contemporary samples. Given ongoing declines in other areas, losses in genetic diversity that may reduce the adaptive potential of white-headed ducks in the future are a continuing concern throughout the geographic range of this species.     

Genetic Variability and Genetic Structure of Wild and Semi-domestic Populations of Tasar Silkworm (Antheraea mylitta ) Ecorace Daba as Revealed through ISSR Markers

The genetic diversity in the wild and semi-domestic populations of Daba ecorace of Antheraea mylitta was studied to ascertain the distribution of variability within and among populations of semi-domestic bivoltine (DB), trivoltine (DT) and nature grown wild populations (DN) with inter-simple sequence repeat (ISSR) markers. A total of 138 markers were produced among 56 individuals of the three populations, of which 98% were polymorphic. For the individual populations, the percentage polymorphism was 58.69, 52.9 and 77.54 for DB, DT and DN, respectively. Average number of observed (1.791 ± 0.408) and effective alleles (1.389 ± 0.348) was also high in the wild populations in comparison to the bivoltine and trivoltine semi-domestic populations. Genetic diversity (H_t) in DB, DT and DN was 0.180 ± 0.033, 0.153 ± 0.032 and 0.235 ± 0.033, respectively and within-population genetic diversity (H_s) ranged from 0.166 to 0.259 with a mean of 0.189. Mean gene differentiation (G_ST) was found to be 0.25. Shanon’s diversity index was 0.278, 0.237 and 0.361 for DB, DT and DN and overall it was 0.391. Gene flow (N_m) among the populations was 1.509. The dendrogram produced by UPGMA with Dice’s genetic distance matrices resulted in the formation of three major clusters separating the three populations. Considerable intra- and inter-population variability is found in all three populations. The population structure analysis further suggests that the semi-domestic populations of Daba ecorace are at the threshold of differentiating themselves. The high genetic variability present within wild Daba population of A. mylitta is of much importance for conservation as well as utilization in systematic breeding program.     

A replication study confirmed the <Emphasis Type="Italic">EDAR</Emphasis> gene to be a major contributor to population differentiation regarding head hair thickness in Asia

Hair morphology is a highly divergent phenotype among human populations. We recently reported that a nonsynonymous SNP in the ectodysplasin A receptor (EDAR 1540T/C) is associated with head hair fiber thickness in an ethnic group in Thailand (Thai-Mai) and an Indonesian population. However, these Southeast Asian populations are genetically and geographically close, and thus the genetic contribution of EDAR to hair morphological variation in the other Asian populations has remained unclear. In this study, we examined the association of 1540T/C with hair morphology in a Japanese population (Northeast Asian). As observed in our previous study, 1540T/C showed a significant association with hair cross-sectional area (P = 2.7 × 10⁻⁶) in Japanese. When all populations (Thai-Mai, Indonesian, and Japanese) were combined, the association of 1540T/C was stronger (P = 3.8 × 10⁻¹⁰) than those of age, sex, and population. These results indicate that EDAR is the genetic determinant of hair thickness as well as a strong contributor to hair fiber thickness variation among Asian populations. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Reproductive performance of wild boar females in Portugal

Reproductive tracts of 214 female wild boars collected in Central Portugal between October and February over the period 1997 to 2001 were examined. From this material, we were able to determine reproductive phenology (conception and birth periods) as well as age and weight of sows at puberty, ovulation rates of adults, foetal sex ratio, levels of intrauterine mortality, final litter size and postnatal mortality. Differences between year, region, age and body weight were analysed. A total of 66.8% of the females examined were gestating or lactating and 96.3% of these weighed >40 kg. The highest proportions of pregnant sows were found in the adult age/weight classes (74%). None of the juvenile females (1 year old and younger) were lactating and only 7% was pregnant. The average number of foetuses/female (4.1 ± 1.2SD) and that of corpora lutea per female (4.6 ± 1.7SD) increased from lighter and younger to heavier and older wild sows. Foetal sex ratio was biased towards males (1.3:1). Observed intrauterine mortality rate (9.7%) and postnatal mortality (6.3%) were among the lowest recorded in European wild boar populations. The productivity rate of the Central Portuguese wild boar population was calculated as 1.1 young per individual in the population. Conception and birth periods did not differ significantly between the considered 4 years. Birth synchronisation was pronounced in all the years, with a peak of births occurring in March.     

Assessing the genetic divergence of Pinus leucodermis Ant. endangered populations: use of molecular markers for conservation purposes

 In this study, 23 previously identified Mendelian RAPD markers and 16 polymorphic allozymic markers were used to assess divergence among two Greek populations and five Italian populations of Pinus leucodermis. Confidence intervals of observed genetic divergence were obtained using bootstrap analysis. Divergence among Italian populations was found to be about as large as that between Italian and Greek populations. Since it is likely that the split of two nuclei took place more than 10,000 years ago, a larger differentiation between, rather than within, the above nuclei was expected. If genetic drift was responsible for the larger divergence of Italian populations, large randomly generated disequilibrium between alleles at neutral, unlinked loci was expected. Indeed, the proportion of pairs of loci showing a non-random association of alleles within each of the Italian populations was larger than what was expected by pure chance (7.95–10.88%). Effective population size based on randomly generated disequilibrium was quite small for three out of the five populations considered (N _e =17.31±1.88, 16.57± 1.73, and 31.41±7.26, respectively). The implications of the results with respect to the conservation of endangered species of trees are discussed. Received: 27 April 1997 / Accepted: 14 June 1997     

Frequency of micronuclei in the cells of buccal epithelium in Ukrainian schoolchildren of various age and sex

The frequency of micronuclei (MN) has been studied in 266 schoolchildren, participants of All-Ukrainian school competitions on biology and ecology. The distribution of MN frequencies was Poissonian with λ = 2.5. The mean MN frequency was 2.4 ± 0.15‰ in boys and 2.7 ± 0.14‰ in girls; the difference is not statistically significant. The individual MN frequency varied from 0 to 8.3‰ and on the average was 2.5 ± 0.11‰ which does not exceed known mean population values. We have shown differences in the MN frequency between sexes in some age groups: MN frequency was significantly higher in girls than in boys aged 16 years. The dynamics of age-related changes in the MN frequency of boys and girls also differed in the period studied (14–18 years of age).     

Body size varies with abundance,not climate,in an amphibian population

Body size variation among animals has many possible correlates, temporal as well as geographic. Adult male body size was analysed over the course of 23 yr (1989–2011) in a population of Fowler’s toads Anaxyrus fowleri at Long Point, Ontario. We used an information theoretic approach to identify the most likely models to explain body length variation in relation to abundance, age and environmental variables, including temperature. Male toads overall averaged 53.6 ± 0.1 (SE) mm (n = 1976) but average body length from year to year varied from 50.9 ± 0.2 to 61.4 ± 1.3 mm (n = 23 yr), a difference of 18.7%. Abundance was the only variable significantly correlated with body size variation (R²= 0.713, p = < 0.001). A significant 10‐yr trend in increased body size (R²= 0.874, p = < 0.001) was coincident with a previously detected negative trend in abundance. A 0.05°C yr^?1 increase in environmental temperature over the course of our study was not significantly correlated with the toads’ body size. Body size variation in these toads is likely related to density‐dependent resource availability for growth in the terrestrial stage. Temporal changes in average body size within populations in relation to density may be a significant component of phenotypic variation.     

The High Prevalence of Overweight and Obesity in Mexican Children

Objective: To establish the prevalence of overweight and obesity in Mexican children 10 to 17 years of age according to the percentiles from both the Centers of Disease Control and Prevention (CDC) and the International Obesity Task Force (IOTF). Research Methods and Procedures: Heights and weights were measured in children from nationally representative, randomly chosen households in the Mexican National Health Survey 2000. The study population consisted of 7862 boys and 8947 girls, 10 to 17 years of age. Measurements used were the percentage of children in the corresponding BMI categories for overweight and obesity specified by the CDC and the IOTF BMI percentiles. Results: The children were short, with mean Z scores for height by age varying from ? 0.62 ± 1.26 to ?1.12 ± 1.06 in boys and from ?0.45 ± 1.25 to ?1.19 ± 1.12 in girls. CDC‐based overweight prevalences varied by age from 10.8% to 16.1% in boys and 14.3% to 19.1% in girls, with obesity prevalences from 9.2% to 14.7% in boys and 6.8% to 10.6% in girls; these prevalences did not relate to stunting. IOTF‐based excess weight prevalences were similar, with higher overweight rates (boys, 15.4% to 18.8%; girls, 18.4% to 22.3%) but lower obesity rates (boys, 6.1% to 9%; girls, 5.9% to 8.2%). Discussion: Mexican children have one‐half the overweight/obesity prevalences of U.S. Mexican‐American children; however, there are higher rates in Northern Mexico, which is closer to the U.S. These escalating rates of excess weight demand new prevention, as well as management, policies.     

Analysis of Genetic Diversity of Chukar Partridge (Alectoris chukar) Populations in Khorasan-e-Razavi Province of Iran by RAPD-PCR

RAPD markers were used to investigate population genetic parameters of an endangered partridge, Alectoris chukar, in four areas of Iran, as a part of a genetic conservation program. The aim of this study was to analyze the genetic similarity among these populations. Blood samples from 75 birds were used for DNA extraction and RAPD-PCR analysis of 67 loci, with 28 polymorphic bands (41.79%). The populations of Kalat-e-Nader and Mashhad were found to be closely related, as were the Torbat-e-Jaam and the Quchan populations. Mean heterozygosity for all populations was 0.4405 ± 0.0755. The results indicate that chukar partridge genetic diversity in Khorasan-e-Razavi province is sufficient and the amount of gene flow among populations is acceptable.     

Factors influencing reproductive performance of northern bobwhite in South Florida

Reproductive success is a critical component of individual fitness, and also an important determinant of growth rates of populations characterized by early maturity and high fecundity. We used radiotelemetry data collected during 2003–2008 to estimate reproductive parameters in a declining northern bobwhite (Colinus virginianus) population in South Florida, and to test hypotheses regarding factors influencing these parameters. The overall clutch size was 12.10 ± 0.22, but females laid more eggs in their first clutch (12.43 ± 0.24) than in subsequent clutches (10.19 ± 0.53) within a nesting season. Daily nest survival was higher for first (0.966 ± 0.003) than subsequent nests (0.936 ± 0.011). Hatchability (proportion of laid eggs that hatched conditional upon nest survival to hatching) was 0.853 ± 0.008, but was higher for nests incubated by females (0.873 ± 0.009) than those incubated by males (0.798 ± 0.018). The proportion of individuals attempting a second nest was 0.112 ± 0.024 and 0.281 ± 0.040 when the first nest was successful and failed, respectively. Hatchability was lower when the nesting habitat was burned the previous winter. We found no evidence that food strip density (a management practice to provide supplemental food) influenced any of the reproductive parameters. Mean summer temperature affected hatchability, nest survival, and proportion of nests incubated by males. Overall, the reproductive output in our study population was lower than that reported for most other bobwhite populations, indicating that low reproductive performance may have contributed to bobwhite population declines in our study site. These results suggest that current management practices, particularly those related to habitat and harvest management, need careful evaluation.