Applications of an unmanned aerial vehicle and thermal-imaging camera to study ducks nesting over water

Finding and monitoring nests are key components of avian research, but they are often expensive, time-consuming, and inefficient operations. This is certainly true for diving ducks that nest in wetlands with thick emergent vegetation where nests are typically located by teams of technicians that wade through a marsh and beat vegetation with sticks, hoping to flush incubating females or encounter nests without a female present. Taking advantage of recent advances in both unmanned aerial vehicles (UAVs) and thermal-imaging cameras, our objectives were to (1) compare our ability to locate duck nests using a UAV and using traditional on-foot searching methods, and (2) determine if nests monitored remotely with the UAV had different survival rates than nests monitored with traditional nest-site visits. We searched for nests with a UAV system in southern Manitoba during the springs of 2018 and 2019. Using the UAV, we located 48 nests not found by ground crews, ground crews found 164 nests not found with the UAV, and 71 nests were found using both methods. Overall, nests were less likely to be detected with the UAV (0.34) than by ground crews (0.71), but surveys were completed approximately four times faster with the UAV. Detectability of nests varied among duck species (range = 0.55–0.04). We found no difference in nest survival between nests monitored with the UAV (0.95) and those repeatedly visited by ground crews (0.95). However, in 2018, ground monitoring resulted in 19 nests being abandoned by females, compared to only one monitored with the UAV. Our results demonstrate that UAVs equipped with thermal cameras can be used to find nests of ducks located over water, with greater success for species that nest earlier and those whose nests are not buried under matted vegetation. Furthermore, monitoring nests with the UAV resulted in lower rates of nest abandonment, and survival of nests monitored with the UAV was similar to that of nests monitored using traditional methods. Additional species- and habitat-specific studies are needed to fully understand the utility and challenges associated with using UAVs equipped with thermal imaging to survey species of wetland wildlife.     

Evolution at the Crossroads: Modern Human Emergence in Western Asia

There is long-standing disagreement regarding Upper Pleistocene human evolution in Western Asia, particularly the Levant. Some argue that there were two dilierent populations, perhaps different species, of Upper Pleistocene Levantine hominids. The first, from the Israeli silcs of Qafzeh and Skhul. is anatomically modern. The second, from sites such as Amud. Kcbara. and Tabun, is archaic, or "Neandertal" in morphology. Others argue that ihis is a false dichotomy and that all of lliese hominids belong to a single, highly variable population. In this paper I attempt to resolve this issue by examining posteranial measures reflective of body shape. Results indicate that the Qafzeh-Skhul hominids have African-like, or tropically adapted, proportions, while tliosc from Amud, Kebara. Tabun. and Shanidar (Iraq) have more European-like, or cold-adapled. proportions. This suggests that iherc were in fact two distinct Western Asian populations and that the Qaf/ch-Skhul hominids were likely African in origin—i result consistent with the "Replacement"' model of modern human origins, [modern human origins, NeunJertals, Qafzeh-Skhul hominids, body shape]     

New model for estimating the relationship between surface area and volume in the human body using skeletal remains

A new model for estimating human body surface area and body volume/mass from standard skeletal metrics is presented. This model is then tested against both 1) “independently estimated” body surface areas and “independently estimated” body volume/mass (both derived from anthropometric data) and 2) the cylindrical model of Ruff. The model is found to be more accurate in estimating both body surface area and body volume/mass than the cylindrical model, but it is more accurate in estimating body surface area than it is for estimating body volume/mass (as reflected by the standard error of the estimate when “independently estimated” surface area or volume/mass is regressed on estimates derived from the present model). Two practical applications of the model are tested. In the first test, the relative contribution of the limbs versus the trunk to the body's volume and surface area is compared between “heat-adapted” and “cold-adapted” populations. As expected, the “cold-adapted” group has significantly more of its body surface area and volume in its trunk than does the “heat-adapted” group. In the second test, we evaluate the effect of variation in bi-iliac breadth, elongated or foreshortened limbs, and differences in crural index on the body's surface area to volume ratio (SA:V). Results indicate that the effects of bi-iliac breadth on SA:V are substantial, while those of limb lengths and (especially) the crural index are minor, which suggests that factors other than surface area relative to volume are driving morphological variation and ecogeographical patterning in limb prorportions. Am J Phys Anthropol 156:614–624, 2015. © 2014 Wiley Periodicals, Inc.