Fewer than 3500 tigers (Panthera tigris) remain in the wild. Habitat loss and fragmentation, and depletion of prey are key factors contributing to their decline, prompting investigations on prey ...requirements needed to sustain their dwindling populations. To estimate prey requirements from consumption rates, the non‐consumed portion of a carcass (NCP) or degree of carcass utilization is required as, depending on prey size, part of the kill might not be consumed. Because NCPs for tigers have never been systematically estimated, the aim of this study was to develop a model to calculate NCPs based on prey body mass, and to determine whether the NCPs used in current tiger literature were accurate. Additionally, we applied the model to two tiger reserves to test if our results improved prey requirement estimates calculated with current NCPs. The study took place at Laohu Valley Reserve (South Africa), where four male and five female tigers were fed fresh carcasses of six ungulate species. Each prey carcass was weighed prior to feeding to tigers and once abandoned, the remains were weighed allowing the weight consumed minus the gastrointestinal contents to be calculated. We observed a strong positive relationship between prey body mass and NCP. For large prey, prey requirement estimates obtained with the NCPs yielded by our model were very similar to those obtained with the NCPs used in current tiger literature. However, differences increased for smaller prey, and for those species that comprised a high percentage of the tiger diet. In summary, we provide a model to calculate NCPs based on prey body mass, and demonstrate the importance of using specific values of NCPs in calculating prey requirements from consumption rates. These results could be useful for other large carnivores, as well as for calculating feed portions for large predators in captive settings.
In carnivores, the degree of carcass utilization is needed when estimating prey requirements from consumption rates, as depending on prey size part of the kill might not be consumed. In this study, we developed a model to calculate the non‐consumable portion of a carcass or ‘NCP’ based on prey body mass to assess carcass utilization in tigers (Panthera tigris). Results showed a strong positive relationship between prey body mass and NCP. When we applied the model to two tiger reserves, NCPs calculated with our model improved accuracy over other studies in calculating tiger prey requirements for prey under 100 kg. Additionally, in the absence of empirical values for other carnivore species, our equation may be useful in the conservation and management of other large carnivores.
Bioenergetic modeling is employed to estimate the energetic demands of many cryptic carnivores and their kill rates needed to meet their energetic requirements. We tested two prevalent assumptions ...driving energetic modeling of predator kill rates: (1) morphological and physiological information (weight, energetic demands of activity patterns) of individual predators are sufficient to accurately predict their kill rates, and (2) kill and consumption rates are equivalent (meaning that carnivores consume all of what they kill). We did this by testing whether two independent energetic models accurately predicted puma (
Puma concolor
) kill and consumption rates in three study systems in North and South America with variable ecology, including climate and prey assemblages. Our results demonstrated that current puma energetic models drastically underestimate actual puma kill rates quantified through intensive field monitoring. We concluded that puma energetic models more realistically estimate puma consumption rates needed to meet metabolic requirements. Puma kill rates determined from field efforts were not explained by puma weight (in kg) or activity patterns (in distance traveled), which were the variables used in energetic models. Our kill rates in kg/day determined from field investigations of GPS clusters were the highest reported to date and statistically equivalent across three distinct ecosystems, a range of puma characteristics, variable lengths of monitoring, variable daily distances traveled, and across systems with 1-3 ungulate prey. In contrast, puma kill rates in ungulates/week differed across study areas, suggesting that kill rates described in kilograms per day are better suited for comparing puma kill rates across systems while kill rates in terms of ungulates per unit time are better suited for modeling predator-prey dynamics for a particular ecosystem. Based on these results we concluded that energetic models using morphological and physiological variables alone were insufficient to predict kill rates, and proposed that rather than focusing future research on refining current energetic models, future research should be directed at understanding the behavioral ecology driving carnivore kill rates.
In this study we present empirical data on predator numbers, movements and area usage, and predation obtained from tracking transient killer whales Orcinus orca throughout the inland waters of ...southeastern Alaska, USA. During 1991-2007, we documented 155 transient killer whales via photo-identification methodology within the large study area (27,808 km2). Transient killer whales were distributed throughout southeastern Alaska and were present during all seasons, although not all individuals were seen every year. Resighting data suggested that within southeastern Alaska, maternal groups may partition area usage of their environment. By following whales for 1,467 km, we calculated a mean travel speed of 7.2 km/hour with mean daily movements of 134 km ± 88 km/24 hours and ranging within 59-240 km/24 hours. Photographic matches demonstrated that most of the transient killer whales (86%) identified in southeastern Alaska also utilized British Columbia and Washington State waters. In contrast, photographic matches between whales in southeastern Alaska and whales seen off of California, USA, were rare, suggesting that different transient killer whale stocks occupy these two regions. Transient killer whales preyed upon Dall's porpoise Phocoenoides dalli, Pacific white-sided dolphins Lagenoryhncus obliquidens, harbor porpoise Phocoena phocoena, minke whales Balaenoptera acutorostrata, Steller sea lions Eumetopias jubatus, harbor seals Phoca vitulina and seabirds. Potential prey species that were available, but not targeted, included humpback whales Megaptera novaeangliae, elephant seals Mirounga angustirostris and sea otters Enhydra lutris. Prey-handling techniques varied depending on the prey being targeted with no evidence of prey specialization. During 114 encounters totaling 332.5 hours of direct observations of transient killer whales, we documented 36 predation events for a calculated kill rate of 0.62 prey items/24-hour period/whale. The data we present in this article provide a foundation of transient killer whale ecology aimed at improving our ability to understand the impact of transient killer whale predation on southeastern Alaska prey populations.
Spinning-wing decoys are strong attractants to ducks and increase kill rates over traditional decoying methods. However, it is unknown whether all duck species are attracted similarly to ...spinning-wing decoys and whether the effectiveness of these decoys changes with latitude. We examined the effectiveness of spinning-wing decoys for 9 species of dabbling ducks during 545 experimental hunts in California (1999–2000), Minnesota (2002), Manitoba (2001–2002), Nebraska (2000–2002), Missouri (2000–2001), and Arkansas (2001–2003). During each experimental hunt, we systematically alternated between 2 paired decoy treatments every 15–30 min (depending on study site): traditional decoys only and traditional decoys with a spinning-wing decoy. Overall, 70.2% (n = 1,925) of dabbling ducks were harvested (shot and retrieved) when spinning-wing decoys were turned on, ranging from 63.6% (n = 187) in Missouri to 76.4% (n = 356) in Minnesota. Effectiveness of spinning-wing decoys increased with latitude of study sites. Proportions of ducks shot when spinning-wing decoys were turned on differed among species, from a low of 50.0% (n = 8) for cinnamon teal (Anas cyanoptera) to a high of 79.0% (n = 119) for American wigeon (A. americana). The probability of being shot when spinning-wing decoys were turned on increased with annual survival rates among species; for example, spinning-wing decoys were more effective for American wigeon and mallard (A. platyrhynchos) than they were for cinnamon teal and American green-winged teal (A. crecca). Effectiveness of spinning-wing decoys did not differ consistently by age or sex of harvested ducks. Our results indicate that the effectiveness of spinning-wing decoys differs among duck species and changes with latitude; thus, consideration of these effects may be warranted when setting harvest regulations and methods of take.
Methodology for targeted defect reduction and inspection optimization Skumanich, A.; Ryabova, E.
13th Annual IEEE/SEMI Advanced Semiconductor Manufacturing Conference. Advancing the Science and Technology of Semiconductor Manufacturing. ASMC 2002 (Cat. No.02CH37259),
2002
Conference Proceeding
Recenzirano
A methodology is outlined to establish the prioritization of defects under conditions of low sampling statistics based on the deliberate introduction of defects at specific process points. Probe ...results from electrical test structures are correlated with optical defect inspection data to determine the kill rates of various defects. The methodology generalizes from a standard approach that typically relies on a high statistical sampling plan with significant wafer area coverage. In this case, the probed area coverage is reduced to 1-3% of the wafer surface but still provides defect impact prioritization for targeted defect reduction and optimized inspection strategies for optical capture and SEM review.
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