Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
We mailed survey questionnaires to 62 upland game bird managers in the United States and Canada in 2004. We received questionnaires from 47 of the 62 (76%) upland game bird managers that were contacted and 43 (91%) respondents provided information on how monitoring data were used. Responses indicated monitoring programs (population trends and/or harvest monitoring) for 23 species of Galliformes, with 145 ± 208 personnel days/year devoted to monitoring. Estimating general population trends (e.g. up or down) was the most frequent objective (N = 41; 95%) of survey data. Other applications of data included assessments of hunting activity, evaluations of regional programs and reviews of conservation status related to Endangered Species Act petitions. The majority of respondents (i.e. 63%) with monitoring programs considered the programs within their states to be effective with respect to their objectives. Many states rely upon hunter surveys, harvest data or road counts to access demographic and population data to address major conservation and management issues. The relevance of these issues is growing and agencies must respond with management recommendations, but often must do so with limited data on the status of their populations. Comprehensive monitoring should be a major component of conservation and management planning for upland gamebird populations particularly as a tool to track and evaluate the effectiveness of management actions and inform management options.
Information on waterfowl survival during the overwintering season (i.e. autumn and winter), when hunting seasons occur, is important for making harvest management decisions. However, the relationship of overwintering survival to hunting season structure, weather and body condition are not well understood. We measured survival of 235 radio-marked adult female and male mallards Anas platyrhynchos along the South Platte River corridor in northeastern Colorado, USA, during the overwintering seasons of 2005/06 (pilot year), 2006/07 and 2007/08, and we determined the primary factors affecting survival. Hunting was the most important factor affecting survival. Of mortality, 67% were direct results of hunting, and survival was lower during hunting periods compared to non-hunting periods. Within hunting periods, survival was lowest during the first 2-3 weekends of the hunting periods. During the seasons 2006/07 and 2007/08, survival of radio-marked mallards was monitored during September-February. The estimated survival was 0.65 (95% CI = 0.50 - 0.78) for females and 0.54 (95% CI = 0.39 - 0.68) for males during 2006/07, and 0.55 (95% CI = 0.40 - 0.69) for females and 0.42 (95% CI = 0.28 - 0.58) for males during 2007/08. We did not observe a strong correlation between body condition index and survival ( = 0.36, SE = 0.43). Accumulated snowfall and daily minimum temperature were unimportant variables for predicting survival. Of hunting recoveries, 89% occurred in our study area, and 15% and 18% of radio-marked mallards went missing during 2006/07 and 2007/08, respectively. Our results suggest that split hunting seasons are an effective management tool to increase hunter harvest and affect overwintering survival. Given a set bag limit and season length, managers may be able to increase hunter harvest by: 1) having hunting periods of at least three weeks in length, 2) including as many weekend days (i.e. Saturdays and Sundays) within hunting periods as possible and 3) interspersing hunting periods with non-hunting periods of at least 2-3 weeks.
In black grouse Tetrao tetrix the survival of juveniles from hatching until recruitment is a critical determinant of population growth. The proportion of juvenile survivors from hatching until recruitment declines continually, but juvenile mortality rates are commonly highest during approximately the first 10 days after hatching. Likely causes of mortality include adverse weather, predation and availability of food. Little is known, however, about how individual properties, such as body mass of hen or chicks and properties of the brood rearing environment (e.g. vegetation characteristics or weather conditions) interact with each other and/or with fluctuating levels of predator abundance in determining early brood survival, simply because such data are very scarce. Using an information-theoretic approach, our paper identifies determinants of early daily survival rates of black grouse chicks in a managed forest landscape of central Finland. During the three years of our study, the proportion of hens losing their broods within 10 days after hatching varied between 0.08 and 0.36.The variation in daily survival rates of chicks was largely mediated by a combination of four key explanatory variables. Brood survival clearly increased with the extent of bilberry Vaccinium myrtillus cover, and was further affected by interactions of temperature and hatching date as well as temperature and chick body mass. Low temperatures consistently resulted in lower daily survival rates. An increase in temperature, however, was more beneficial for early hatchers and heavy chicks. There was no difference in survival between broods from yearling and adult hens and we found no effect of predator density, be it as main effect or as interaction with other variables, on the daily survival rates of chicks. Improving black grouse breeding success can be regarded as a key management target which may be critical for their recovery. Our results suggest that such management should favour protection or local recovery of bilberry, as well as integrate weather and climate changes into the equation of hunting management.
Quality of recently used foraging areas is likely an important predictor of fidelity to specific locations in the future. We monitored movement and habitat use of 58 adult female American woodcock Scolopax minor at three study areas in Minnesota, Wisconsin and Michigan, USA, during autumn 2002 and 2003, to assess the relationship between foraging habitat use decisions and environmental conditions at previously used foraging locations. We assessed whether habitat variables which related to food and weather were related to distance between locations on subsequent days of individual woodcock that choose diurnal foraging locations when they return from night-time roosting locations. We predicted that woodcock would return to foraging locations used on the previous day (i.e. shorter distances between daily foraging locations) when environmental conditions on the prior day were favourable. Woodcock generally made short (i.e. 48% < 50 m and 91% < 400 m) between-day movements, but also occasionally (∼ 7%) abandoned prior foraging areas. The primary determinants of woodcock movements during autumn (prior to migration) were low local food availability and potential for increased food availability elsewhere. The quality of foraging locations was an important predictor of future foraging habitat use for woodcock, consistent with the hypothesis that woodcock movement behaviour balances the risks associated with movement with the potential benefits of increased energy intake in new foraging areas.
Conservation and management of animal populations often require knowledge about the age structure, but this information is usually difficult to discern. We propose a method to estimate the age of carnivores based on dental condition and body size measurements, and we apply the method to populations of brown-nosed coatis Nasua nasua and crab-eating foxes Cerdocyon thous in the Brazilian Pantanal. We sexed, weighed and measured 31 coatis and 45 foxes of known-age, and characterized and quantified their pattern of dental eruption and wear for the construction of a teeth condition index. Scores of the first factors of a principal component analysis including data on six body size measurements and the teeth condition index of the individuals were then used in a discriminant analysis to generate functions that can be used for estimating age of animals of unknown age. Models were validated using subsets of individuals of known age through a 3-fold cross validation process. The first functions accounted for over 90% of the discriminatory power for both species. Whereas in coatis, the first function was mainly explained by the body size measurements, in crab-eating foxes it was represented mainly by the teeth condition index. During model validation, individuals were on average classified with 88 and 80% average confidence for coatis and foxes, respectively. Our method is as accurate as other methods that are commonly applied to assess age, but less subjective. While it requires animal capturing, it is less invasive than methods requiring tissue removal such as analyses of teeth cementum annuli. The method we outlined can be used for age estimation of other populations, as long as the models are validated with a subset of animals from the region studied. It could also be useful as a model for estimating age of other carnivore species.
Modern farming practices in the midwestern United States have drastically altered the landscape. Most wetlands have been drained, and small streams are channelized to transport excess water away from tile-drained agricultural fields. Loss of critical wetland habitat has shifted the distribution of muskrats Ondatra zibethicus, an economically important furbearer in the region, to highly altered riparian habitats with unstable flow regimes. However, information regarding home-range size and space use for muskrats occurring in these linear habitats is lacking. We used location data from 26 radio-marked muskrats to estimate home-range size and space use in riparian habitats in an agroecosystem in east-central Illinois, USA. Home ranges were highly linear and confined to stream bank edges. Contrary to our prediction, muskrats did not freely move to upland habitat (e.g. row-crop agriculture) adjacent to stream edges to forage. Linear home ranges were longer for adults than for juveniles. Home-range size also was related positively to number of burrows used by individuals. As expected, muskrats used space non-randomly within linear home ranges with most movements aggregated around established bank burrows. Muskrats in riparian habitat are multiple central-place foragers. Our study provides insight into how muskrats, a semi-aquatic species affected by large-scale landscape change, use space within highly restricted linear habitats.
Adaptive management of wild populations requires good knowledge of the population status. The main way to evaluate management performance is through recurring surveys, which often also serve as a decision basis for harvest quotas. We evaluated the effect of different survey reliabilities and frequencies during 1-4 years on management performance using a stochastic age and stage-specific population model for an Eurasian lynx Lynx lynx population. As a proxy for management performance, we looked at the proportion of time that the population remained within a preferred interval, the proportion of time with no harvest, the average harvest number and the total number of surveys during the 50-year period in the simulation. In general, management performance increased with increased monitoring accuracy. More interestingly, a more reliable survey performed less frequently performed better than a less reliable survey performed every year. The management performance was not perfect even with complete knowledge of the population size at the survey, as annual variation in reproduction and survival between the survey (decision based on year t) and harvest (performed in year t 1) sometimes cause the population to be outside the preferred interval. If financial resources are limited, we recommend managers to minimise the error in the survey rather than to increase the frequency of surveys.
In this article we show that the population of Serengeti Masai giraffes Giraffa camelopardalis tippelskirchi is extremely female biased, particularly among newborns. Our results suggest that this might be a response to heavy illegal hunting and the continuous disturbance such activities cause on giraffes, as sex ratios were more female skewed in all age groups in areas with high risk of illegal hunting. Giraffes were also more vigilant and fled at longer distances in such areas. Such female skewed sex ratios have also been found in other Serengeti species such as the ostrich Struthio camelus, the impala Aepycerus melampus and the wildebeest Connochaetus taurinus. In all studies, the sex ratio was more female skewed in areas in which illegal hunting is common. We found that sex ratio in giraffe calves, particularly in areas with high risk of illegal hunting, were more female skewed than in subadults or adults, indicating a female biased sex ratio at birth. If wildlife species react to a constant human disturbance by conceiving female offspring, this might cause serious conservation challenges. Conservation managers must anyway take this into account when developing future hunting regimes, not only for giraffes but also for other ungulate species under constant stress. We discuss various hypotheses aiming at explaining the female biased sex ratio in giraffes. However, further studies are needed to disentangle the causes of the skewed sex ratio observed in our study.
Biologists tasked with managing cervids could benefit from models predicting physical characteristics. Differences in white-tailed deer Odocoileus virginianus morphometrics across soil resource areas in Mississippi, USA, provide opportunity to test the predictive capacity of soil chemical and forage quality variables. Using principal components analysis (PCA), we modeled variation in body mass and antler score of ≥ 1.5-year-old male deer against seven soil chemical variables and 12 forage quality variables to elucidate potential nutritional factors corresponding with physical variation among 21 deer populations. We developed separate sets of models at the levels of state and soil resource area (Delta, Thin Loess and Lower Coastal Plain) and compared statewide models with general linear models (GLM) that related deer morphometrics to nominal classification variables representing the three soil resource areas. PCA distinguished a gradient of increasing soil fertility and forage quality that explained 58% of body mass and 52% of antler score variation statewide. However, the GLM using soil resource area as the explanatory variable explained 78 and 61%, respectively, indicating that management models should use soil resource area to designate areas with broadly similar nutritional planes. Within soil resource areas, the region with the greatest soil fertility and forage quality (Delta) did not model successfully for either body mass or antler score. The Thin Loess was successfully modeled for antler score, but only the Lower Coastal Plain, which had the lowest level of soil and forage quality, was successfully modeled for both morphometric variables. The Delta may have represented an area with habitat quality sufficiently high to render small variations non-influential. In contrast, the generally poorer soil quality of Thin Loess and Lower Coastal Plain soils and forages may act as a limiting factor on physical expression, which allowed some response to relatively small fluctuations in range quality. The potential utility of soil and forage metrics within soil resource areas to estimate deer physical qualities appears to be primarily for fine-tuning estimates largely determined by factors such as density and land use.
Many ringing programmes rely heavily on rings returned by hunters, yet the motivation of hunters to participate in such schemes has not so far been examined. A questionnaire survey was launched while French hunters reported hunted teal Anas crecca rings. The main aim was to quantify the proportion of rings returned by different means, to ask hunters about their previous knowledge of the ringing programme and about their motivation to report rings. Hunters reporting rings exhibited altruistic behaviour, sending their data with little knowledge of what they will be used for, and indicated their willingness to help research as their main motivation. They showed little interest in an internet-based ring return system or internet information, but relied mostly on a phone-reporting system when the phone number was indicated on nasal saddles (although the sole presence of a nasal saddle in addition to a metal ring also likely improved the reporting rate of such marked birds). Considering these sociological aspects in the advertisement of ringing programmes may help improve ring recovery rates of quarry species.
The brown hyaena Hyaena brunnea is a near threatened large carnivore inhabiting sub-Saharan Africa. Like many other species of terrestrial carnivores, brown hyaenas often and repeatedly deposit scats at specific latrine sites as a means of olfactory communication. However, previous studies on brown hyaena latrine use have been constrained to the arid Kalahari region in southern Africa, an area of low resource abundance. To improve our understanding of geographic variation in the biology of this species, we monitored patterns of brown hyaena scat deposition in the Waterberg of northern South Africa, an area of higher net productivity than previous areas for published brown hyaena studies. Defecation rates at latrine sites were low in our study area (median: < 1 defecation in 30 days), but brown hyaenas visited sites significantly more often than they defecated at them (median: 2.6 visits/30 days). The temporal patterns of activity at defecation sites were significantly related to the overall temporal activity patterns of brown hyaenas on the roads within the reserve, and generally confirmed a nocturnal activity pattern in the species. Our result on brown hyaena scat deposition in the Waterberg region indicates a geographic variation in latrine use, and we suggest that such a variation could be linked to resource-driven variation in social and spatial organisation.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere