ON THE SOUTH AFRICAN RACE OF THE LITTLE SPOTTED WOODPECKER

Discriminant analysis functions have previously been determined for sexing Mediterranean Yellow-legged Gulls Larus michahellis michahellis from the western Mediterranean basin. However, data from eastern Mediterranean populations are lacking. In this work, we used morphometric data from a sample of 81 Mediterranean Yellow-legged Gulls (39 males and 42 females) breeding in the Gulf of Gabès in south-eastern Tunisia to (1) determine a discriminant function useful for sex discrimination, and (2) assess the accuracy of previously published functions in sexing Mediterranean Yellow-legged Gulls from our study area. Our results showed marked sexual differences in all morphological measurements, with males being significantly larger than females. The best discriminant function included head length, bill depth and wing length, and accurately classified 93% of sampled birds. We also found that Mediterranean Yellow-legged Gulls from the Gulf of Gabès could accurately be sexed using discriminant functions determined for another North African population, but not with a function determined for a South European population, although distances between sites are almost the same.     

Determination of Sex from Footprint Dimensions in a Ghanaian Population

The present study sought to verify the utility and reliability of footprint dimensions in sex determination in a Ghanaian population. Bilateral footprints were obtained from 126 Ghanaian students (66 males and 60 females) aged 18–30 years at Koforidua Polytechnic using an ink pad and white papers. Seven dimensions–length of each toe (designated T1-T5) from the most anterior point of the toe to the mid-rear heel point, breadth at ball (BAB) and breadth at heel (BAH)–and the heel-ball (HB) index were obtained from each footprint. Some footprint dimensions (i.e. T2, T3, T4 and T5) showed statistically significant bilateral asymmetry in males only. All the footprint dimensions, except HB index, were significantly greater in males than females (p<0.001). Applied singly in discriminant function analysis, the footprint dimensions allowed 69.8%-80.3% of cases to be correctly classified into their sex groups; the accuracy of sex classification was higher using left footprints than right footprints. With all dimensions subjected to stepwise discriminant function analysis 80.3% and 77% of cases could be correctly classified, combining both T5 and BAH for left footprints and T1, BAB and BAH for left footprints respectively. The present study has demonstrated, for the first time among Ghanaian subjects, the utility and reliability of sex determination standards developed from footprint dimensions. The results thus provide the baseline for elaborated studies in the future.     

Migration of Walruses (Odobenus rosmarus) in the Svalbard and Franz Josef Land area

Thirty-four walruses ( Odobenus rosmarus ) were fitted with satellite transmitters (PTTs) from 1990 to 1993 in order to study the distribution of the population in the Svalbard area. Twenty-eight were caught at Svalbard and six at Franz Josef Land. All were males except one female caught at Franz Josef Land. At Svalbard, one walrus was caught on the west coast of Spitsbergen, while the others were caught at southern Edgeøya. All walruses were caught in the period from mid-July to early September. The PTTs provided information on location for periods ranging from 0 to 212 days. The results of the satellite trackings show that there is a migration of male walruses between most of the walrus areas at Svalbard and Franz Josef Land. In particular, it seems that migration of males from southern Edgeøya to Kvitøya, Viktoria Island, and Franz Josef Land is common. The walruses winter in the southern parts of Svalbard, as well as within the winter pack-ice of north-eastern Svalbard, which contains numerous open leads. The only walrus at Franz Josef Land that was followed to mid-winter stayed in the area and therefore supports the view that walruses also winter in that area. It is assumed that the majority of walruses at Svalbard are males from one common Svalbard-Franz Josef Land stock. The walrus in the Svalbard-Franz Josef Land area today belong to a recovering population. Their current distribution and behaviour may therefore differ from that found in Svalbard in former times.     

下颌骨的性别判别分析研究

对183例国人成年下颌骨的统计检验表明,13项测量数据中有12项性别差异显著。其中下颌枝高性别差异最为明显,其单项性别判别率达80％。采用Fisher判别分析法建立了11项判定国人下颌骨性别的判别函数,判别率为85.2％—87.4％。     

Differences in growth,size and sexual dimorphism in skulls of East Greenland and Svalbard polar bears (<Emphasis Type="Italic">Ursus maritimus</Emphasis>)

Size, growth and sexual dimorphism of nine skull traits was studied in 300 East Greenland and 391 Svalbard polar bears (Ursus maritimus). Two traits were significantly larger in bears from East Greenland compared to Svalbard bears, and trait size was smaller after 1960 in five traits. For both localities and both age groups (subadult, adult), mean trait size values were higher in males than females (all: P < 0.05). Gompertz growth models showed trait size increasing with age in seven traits. Depending on the trait, males reached 95% asymptotic trait size at age 3–10, females at age 2–6. The females of both localities matured at approximately the same age, whereas the Svalbard males generally matured years later than their East Greenland peers. The differences found in the present study between the two polar bear subpopulations support the notion that East Greenland and Svalbard polar bears probably should be managed as separate units.     

SEX DETERMINATION OF THE CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS CALIFORNIANUS) FROM CANINE TEETH

Size of canine teeth from California sea lion ( Zalophus californianus californianus ) carcasses is shown to be useful in determining the sex of animals which have missing genitalia or which are otherwise of unknown sex. A total of 267 canine teeth from carcasses of 68 males and 43 females were measured along five axes. Of root and crown measurements of upper and lower canines, males and females overlapped only in root thickness of upper canines. A multivariate ANOVA showed a significant difference in the size of canines between upper and lower canines, and between males and females. Stepwise discriminant analysis produced discriminant functions for upper and lower canines for determining sex of unknown-sexed California sea lions. A separate set of canine teeth from 39 male and 49 female California sea lions was correctly classified without prior knowledge of sex by visual inspection and by the two discriminant functions.     

Geographic morphological variation of Gentoo penguin (Pygoscelis papua) and sex identification: using morphometric characters and molecular markers

Gentoo penguins Pygoscelis papua have sexual dimorphism, which females have smaller morphological measurements than males. P. papua also shows a geographic morphological variation, decreasing in size toward southern latitudes. Therefore, morphological measurements may vary in space and overlap in the distribution of traits between females and males, which could lead to sex misidentification. A total of 300 blood samples and eight measurements and weight were obtained for Gentoo penguins from three localities in the South Shetland Islands and the Antarctic Peninsula. The molecular sex was identified for all individuals using two primer pairs (P2/P8 and PL/PR). We obtained higher success amplification for P2/P8 compared to PL/PR. We used 172 adults to create a morphological discriminant function using the backward stepwise method. We established a discriminant function for sex identification of each locality due to significant morphological differences found between sexes and between the three studied localities for adult Gentoo penguins. Using these functions, the percentages of individuals correctly assigned was 93.87 % in Ardley Island, 88.09 % in Bernardo O’Higgins, and 83.95 % in Gabriel Gonzalez Videla. The most southern locality studied was the most morphologically divergent from the others and with low divergence between sexes. Moreover, we also established a general function for the Gentoo penguin, which can be used to identify the sex of penguins from a broad number of localities. Therefore, molecular and biometric are useful techniques for sexing Gentoo penguins.     

Use of skin biopsies for assessing levels of organochlorines in walruses (Odobenus rosmarus)

Skin and blubber samples of ten adult male Pacific walruses (Odobenus rosmarus divergens) from Alaska were used to investigate the relationship between organochlorine (OC) levels in skin and blubber of individuals. For analyses we selected 11 components that were quantified in the blubber of all individuals: hexachlorocyclohexanes (αHCH and βHCH), the DDT (dichlorodiphenyltrichloroethane) metabolite p,p′DDE, oxychlordane, and 7 individual PCB congeners, 28, 99, 105, 118, 138, 153 and 180. The correlation between the levels in the two types of tissues was significant and the relation was isometric for all components. The regression coefficient between levels in blubber (dependent variable) and levels in skin (independent variable) was different from 1 for only four of the components. The mean levels in the two types of tissues were significantly different for 3 of the 11 chemical components (βHCH, oxychlordane, and PCB28). Although this analysis is based on only ten individuals, we propose that skin samples taken by biopsy darts can be used to monitor OC levels in walruses. In August 1993 skin biopsies were collected from 25 adult male Atlantic walruses (O. r. rosmarus) at haul-out sites in southeastern Svalbard in the Norwegian Arctic and from 28 walruses of different sex and age at haul-out sites at Franz Josef Land in the Russian Arctic. The mean levels of OCs were 2–10 times higher at Svalbard than at Franz Josef Land. The dominant OC component was PCB153 in both areas. A principal component analysis detected differences between areas in OC levels but not in patterns. Since the Franz Josef Land samples were mainly taken from females and young individuals and the Svalbard samples were taken largely from adult males, we believe the differences in tissue OC levels observed from these areas can be explained by differences in sex and age of the walrus sampled. Comparable organochlorine levels in skin samples from walruses from other areas are not available. However, compared to the corresponding OC levels found in walrus blubber in other areas, the OC levels from Svalbard and Franz Josef Land are higher. The high levels of OCs in walruses from Svalbard and Franz Josef Land may be a combined effect of high pollution level in the environment and seal-eating habits. In the present study we show that it is possible to use skin biopsies taken by a non-destructive method to assess OC levels in walruses. Accepted: 24 October 1999     

Sex determination of African Penguins Spheniscus demersus using bill measurements: method comparisons and implications for use

African Penguins Spheniscus demersus are sexually dimorphic; on average, males are larger than females but measurements overlap making sex determination difficult through observations alone. We developed a discriminant function, using bill length and depth from a sample of birds sexed from gonad visualisation during post-mortem, which correctly classified 93% of the individuals. Cross-validation correctly assigned 90% of DNA-sexed birds and 91% of birds sexed by partner measurement comparisons. The use of discriminant function score cutpoints, while leaving 16% and 29% of birds unclassified, improved accuracy of birds sexed by DNA to 97% and of those sexed by partner comparison to 99%. Bill depth was found to be a discriminating variable. However, two techniques for measuring bill depth are currently in use for African Penguins. While these measurements are correlated (r = 0.85), they differ on average by 1.4?mm hindering accuracy of sex determination when using a discriminant function developed from the other bill depth measurement. Exploration of adult bill morphology of birds sexed from DNA at different colonies suggests the discriminant functions can be applied throughout the African Penguins’ South African range.     

Effects of population structure and density on calf sex ratio in red deer (<Emphasis Type="Italic">Cervus elaphus</Emphasis>)—implications for management

There is ongoing interest to assess what factors affect offspring sex ratio, especially in ungulates. Wildlife managers might be interested in influencing this sex ratio for two reasons: either in order to limit population growth more effectively by reducing the proportion of females born or to increase revenues by a higher proportion of trophy bearing males in the population. While previous studies mostly focused on how maternal traits affect offspring sex ratio, we included here also male traits in our analysis. We achieved this by investigating data from 30 areas covering entire Lower Austria, collected over the past 12 years from both hunted red deer and those killed in road accidents. We focused our analyses on parameters that can be easily assessed by managers on the population and individual level, i.e. the numbers of animals culled in different age/sex classes and their body mass. We found that the proportion of females among calves increased with population density. Furthermore, we found that calf sex ratio (i.e. the proportion males among calves aged between 2 and 7 months) increased with increasing proportions of adult females and males older than 10 years, independent of the density effect. We conclude that wildlife managers interested in the effective reduction of red deer abundance and/or increasing the proportion of males among offspring should select a culling regime leading to a low population density dominated by adult, prime-aged females and males. This can be achieved by over-proportional removal of young females and warranting that a high number of strong males reach an age of at least 10 years.     

Sex differences in body size and body condition in breeding Temminck’s Stints Calidris temminckii

There have been very few reports of body size measurements of live Temminck’s Stints, but earlier studies have shown sex differences in body mass and tarsus length. Here we use molecular techniques to determine the sex of Temminck’s Stints from a Norwegian breeding population. In total, we report measurements of body weight, wing length, tarsus length, bill length, skull length and keel length from 17 males and 30 females. We found significant sex differences in all of these variables, with the exception of tarsus length. The differences in skull length disappeared after the bill lengths had been subtracted from the measurements. A discriminant function analysis based on wing length and bill length correctly classified 86% of the cases (12/16 males, 25/27 females). Female Temminck’s Stints are known to regularly lay more than one clutch of eggs per season and could therefore be expected to be physiologically deprived of bodily energy stores. Nevertheless, we found females to be in better body condition than males.     

Site fidelity of Svalbard polar bears revealed by mark-recapture positions

Quantifying the degree of site fidelity in polar bears’ (Ursus maritimus) use of denning and mating areas in spring is of considerable interest for both basic and applied purposes. We analyzed 276 spring-to-spring movements (displacements) of 178 polar bears obtained from mark-recapture in the period 1987–2010 in Svalbard, Norway. Male and female subadults and adults showed site fidelity (only subadult females non-significantly) when their movements were compared to a scenario of random movements between all capture locations. The median observed displacement was 47.6 km (bootstrapped 95 % CI: 38.6–57.8 km), significantly smaller than the median potential displacement for random movements of 206.3 km (bootstrapped 95 % CI: 187.3–219.6 km). Subadult females tended to have the longest displacements, followed by adult males and adult females. However, large individual variation both in displacement distances and recapture frequency tended to blur age and sex differences. Analysis restricted to one movement for each bear showed that the difference between adult males and adult females was small and non-significant. This indicates that findings based on telemetry, which is almost always restricted to females, may be relatively representative of the whole adult Barents Sea population in the spring season.     

Mortality in Svalbard reindeer

Mortality rates in Svalbard reindeer followed the "U"-shaped pattern, with higher mortality rate among calves and old animals than in middle aged individuals. Assuming a stable population size, the mortality data predict a 16.2% annual mortality and recruitment rate among 6 months and older animals, and a male:female sex ratio of 48.5:51.5 among 1-yr old and older. Both predictions are supported by field data. Female mortality rate increased and differed from the male rate in the age interval 2-4 yr, while the male rate increased sharply and differed permanently from the female rate in the age interval above 6 yr. First and last breeding are thought to cause the increased mortality among 2–4 and 11–13 yr-old females. Increased involvement in rutting activities with age associated with lower grazing activity and depletion of fat reserves probably cause the increasing mortality rate among the 6+ yr males. Maximum life span was 17 yr in females and 12 yr in males. Apart from the unknown but possibly high neonatal calf-mortality, only few animals died during summer or during the rut in autumn. Death among calves, yearlings and most of the females occurred before antler-shedding in May-June. Most of the 2-yr and older males died after antler shedding, which occurs from December among the oldest and during April-May among the younger males. Hence, the major part of the mortality takes place in spring. The lack of visible subcutaneous and femur fat in most carcasses indicated starvation as the major mortality cause.     

Amplitudes of visually evoked potentials to patterned stimuli: Age and sex comparisons

Electrophysiological age and sex differences in visual pattern responsivity were investigated. Pattern reversal evoked potentials (PREPs) and visual evoked potentials (VEPs) to patterned and unpatterned flashes were recorded from 20 normal subjects in each of 4 groups: young females and males aged 25–35 years and older females and males aged 55–70 years. PREP waves N70-P100 and P100-N150 from the older women were significantly larger than those from subjects in the other groups; mean amplitudes for the young females, young males and older males were not different. A similar effect, unusually large potentials for the older women, was obtained for VEPs, but only for VEPs elicited by patterned flashes and recorded from occipital scalp, i.e., an area overlying visual cortex which is sensitive to lines and edges. Our findings suggest that the visual system of older females is unusually responsive to patterned stimuli.     

Prevalence of antibodies against Toxoplasma gondii in polar bears (Ursus maritimus) from Svalbard and East Greenland

Serum samples from 419 polar bears (Ursus maritimus) from Svalbard and the Barents Sea (collected 1990-2000) and 108 polar bears from East Greenland (collected 1999-2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test. Antibody prevalences were 3.6% among cubs dependent on their mothers and 21.4% among subadults and adults. Among subadults and adults there was an interaction between population and sex, with similar prevalences among females (Svalbard = 19.5%, Greenland = 18.0%), but a high frequency among Svalbard males (28.7%) as compared to Greenland males (5.8%). The pattern was also significant after correcting for differences in age distribution. The sex-population interaction term is believed to be connected to area- and sex-specific feeding ecology. The prevalences of antibodies against T. gondii in Svalbard and Greenland were high compared to previously reported findings in polar bears from Russian and Alaskan areas.     

Pellet morphometry as a tool to distinguish age and sex in the mule deer

By examining the morphometry (i.e., length, width, length‐to‐width ratio, and volume) of pellets in three different categories (adult males, adult females, and yearlings) mule deer (Odocoileus hemionus), we were able to distinguish via discriminant function and fuzzy clustering analyses the age and sex of these animals. To determine a priori the identity of the pellet samples and evaluate the accuracy of our methods, we obtained samples from individuals in captivity. The discriminant function allowed us to correctly assign 100% of adult males, 91.66% of adult females, and 75% of yearlings to an age class, using previous information. The fuzzy clustering method enabled us to correctly distinguish 100% of adult males, 83.3% of adult females, and 75% of yearlings. The methods are based upon different assumptions. An important assumption with the discriminant function method is that the membership of each pellet group must be established a priori. This may be a disadvantage in certain cases, such as when pellet samples are gathered for an indirect population assessment procedure. Despite this drawback, however, both methods appear to be highly accurate. Zoo Biol 23:139–146, 2004. © 2004 Wiley‐Liss, Inc.     

Epidemiology of tattoo skin disease in captive common bottlenose dolphins (Tursiops truncatus): Are males more vulnerable than females?

Clinical and epidemiological features of tattoo skin disease (TSD) are reported for 257 common bottlenose dolphins held in 31 facilities in the Northern Hemisphere. Photographs and biological data of 146 females and 111 males were analyzed. Dolphins were classified into three age classes: 0–3 years, 4–8 years, and older than 9 years. From 2012 to 2014, 20.6% of the 257 dolphins showed clinical TSD. The youngest dolphins with tattoo lesions were 14 and 15 months old. TSD persisted from 4 to 65 months in 30 dolphins. Prevalence varied between facilities from 5.6% to 60%, possibly reflecting variation in environmental factors. Unlike in free-ranging Delphinidae, TSD prevalence was significantly higher in males (31.5%) than in females (12.3%). Infection was age-dependent only in females. Prevalence of very large tattoos was also higher in males (28.6%) than in females (11.1%). These data suggest that male T. truncatus are more vulnerable to TSD than females, possibly because of differences in immune response and susceptibility to captivity-related stress.     

Sex determination using the scapula in medieval skeletons from East Anatolia

Sex determination from skeletal human remains by discriminant function analysis is one of the methods utilized in the forensic and osteoarcheological sciences. The purpose of the present study is to establish metric standards for sex determination for medieval Anatolian populations using scapular measurements. The database for this research consisted of 93 adult skeletal remains (47 males and 46 females) from the Dilkaya medieval collection. Four measurements were taken: maximum scapular height, maximum scapular breadth, glenoid cavity height, glenoid cavity breadth, and subjected to discriminant function analysis. All measurements demonstrated some degree of sexual dimorphism, with the highest accuracy of sex determination (94.8%) obtained using maximum scapular breadth. Overall accuracies of the functions ranged from 82.9% to 95.0%, with a higher accuracy rate obtained for female skeletons than for males. Population specific discriminant formulas were developed using combinations of measurements, which can be used in ancient Anatolian populations.     

Sex determination using the femur in an ancient Anatolian population

Determination of sex from the femur measurements has been attempted in several populations. Numerous studies have also demonstrated the importance of creating population specific standards in the metric assessment of sex. The present study attempts to establish metric standards for sex determination by using femur measurements for ancient Anatolian populations. Osteometric data were obtained from skeletal remains of 130 adults (67 males and 63 females) from the Dilkaya medieval collection. Eight femur measurements were taken and the data were analyzed using t-test and discriminant analysis with the help of Statistical Package for the Social Sciences (SPSS). The basic statistics showed that all measurements were sexually dimorphic. For the univariate discriminant function derived, precision of sex determination was 86.5 % with the condyle breadth. Our prediction values showed that sex differentiation can be done by femur measurements with reliability between 76 % and 88.5 %, with values for female slightly higher than for males. It is suggested that discriminant formulas developed by combinations of femur measurements in this study can be used for sex determination accurately on fragmentary skeletal remains in ancient Anatolian populations.