Effective wildlife management and conservation require reliable assessments of animal abundance. However, no ungulate monitoring methods is entirely satisfying in terms of cost-effectiveness and accuracy. A new method combining unmanned aerial vehicles (drones) and thermal infrared (TIR) imaging may have great potential as a tool for ungulate surveys. Drones enable safe operations at low flying altitudes, and at night – a time that often offers the optimal conditions for wildlife monitoring. To assess the feasibility of the proposed method we used fixed-wing drones with TIR cameras to conduct test surveys in Drawieński National Park, Poland. We demonstrated that ungulate thermal signatures are visible both in leafless deciduous and in pine-dominated coniferous forests. Survey timing highly influenced the results – the best quality thermal images were obtained at sunrise, late evening, and at night. Our preliminary results indicated that thermal surveys from drones are a promising method for ungulate enumeration. We demonstrated that with ground resolution of ~10 cm it is possible to visibly distinguish large species (i.e. red deer) and achieve a good level of area coverage. The main challenges of the method are difficulties in species identification due to relatively low resolution of TIR cameras, regulations limiting drone operations to visual line of sight, and high dependence on weather.

The 20th century extensive range expansion of coyote Canis latrans throughout North America may impose negative effects on native carnivores. We investigated the interspecific niche relationships to assess potential for competition between sympatric coyote and a similar‐sized felid – bobcat Lynx rufus – throughout the highland zones (elevation >1000 m) of Olympic National Park, Olympic Peninsula, Washington. Through systematic collection and analyses of scats for both carnivores (May–September 2005–2006), we determined food habits (composition, diversity, overlap of diets) and habitat use patterns. To ensure correct determination of carnivore species, we used mtDNA analysis of scats. Scat analysis indicated extensive dietary overlap between coyote and bobcat (Pianka's overlap index = 0.97). For both carnivores medium‐sized mammals comprised the predominant prey: mountain beaver Aplodontia rufa and snowshoe hare Lepus americanus; each occurring in about 50% of the scats. High dietary similarity indicated the potential for interspecific exploitative competition for mammalian prey, especially in harsh climatic conditions of high mountains. However, observed patterns of habitat selection inferred from scat distribution showed differences between coyotes and bobcats, implying some degree of habitat partitioning. Bobcats preferred relatively dense montane forests (canopy cover >40%) at lower elevations, and avoided the alpine zone, while coyotes inhabited mainly alpine and subalpine zones and mostly avoided forest. We conclude that observed habitat separation may alleviate foraging competition between coyote and bobcat. Whether this habitat separation will decrease potential negative effects of coyote colonization on bobcat abundance, or whether it indicates ongoing displacement of bobcats by coyotes, remains an open question.

Resource pulses can generate cross-habitat dispersal of consumers, and therefore affect organisms even in areas where the resource pulses do not occur. We investigated this phenomenon at the elevational treeline in the Carpathian Mountains, where beech (Fagus sylvatica) masting caused an increase in abundance of forest rodents and intensified their use of alpine meadows. We tested 3 hypotheses concerning the impact of forest rodent spillover on the abundance of meadow-dwelling pine voles (Microtus subterraneus): 1) the competition hypothesis: if the spillover affects pine voles mostly through intensified competitive interactions, then pine voles should decline when forest rodents reach their peak abundance, i.e., 1 year after masting; 2) the apparent competition hypothesis: if predators switch to alternative prey when populations of forest rodents collapse, then pine voles should decline 2 years after masting; and 3) the apparent mutualism hypothesis: if the increase of forest rodents temporarily releases pine voles from predatory pressure, pine voles should increase in synchrony with forest rodents—1 year after masting. Our results, while correlative in nature, supported the apparent mutualism hypothesis: 1 year after masting, both forest rodents and pine voles strongly increased their abundance. Two years after masting, when populations of forest rodents crashed, abundance of pine voles returned to pre-masting levels rather than collapse. These findings suggest that pulsed spillover, known mostly from negative effects on organisms in recipient habitats, can also create indirect positive interactions. Furthermore, they illustrate how density-dependent spillover of animals might increase the spatial scale of masting effects beyond the habitats where seeds are released.

We investigated predation by normative coyotes (Canis latrans) on endemic Olympic marmots (Marmota olympus) in Olympic National Park, Washington, in

The rapidly developing technology of unmanned aerial vehicles (drones) extends to the availability of aerial surveys for wildlife research and management. However, regulations limiting drone operations to visual line of sight (VLOS) seriously affect the design of surveys, as flight paths must be concentrated within small sampling blocks. Such a design is inferior to spatially unrestricted randomized designs available if operations beyond visual line of sight (BVLOS) are allowed. We used computer simulations to assess whether the VLOS rule affects the accuracy and precision of wildlife density estimates derived from drone collected data. We tested two alternative flight plans (VLOS vs. BVLOS) in simulated surveys of low-, medium- and high-density populations of a hypothetical ungulate species with three levels of effort (one to three repetitions). The population density was estimated using the ratio estimate and distance sampling method. The observed differences in the accuracy and precision of estimates from the VLOS and BVLOS surveys were relatively small and negligible. Only in the case of the low-density population (2 ind./100 ha) surveyed once was the VLOS design inferior to BVLOS, delivering biased and less precise estimates. These results show that while the VLOS regulations complicate survey logistics and interfere with random survey design, the quality of derived estimates does not have to be compromised. We advise testing alternative survey variants with the aid of computer simulations to achieve reliable estimates while minimizing survey costs.