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The estimation of abundance of wildlife populations is an essential part of ecological research and monitoring. Spatially explicit capture–recapture (SCR) models are widely used for abundance and density estimation, frequently through individual identification of target species using camera‐trap sampling. Generalized spatial mark–resight (Gen‐SMR) is a recently developed SCR extension that allows for abundance estimation when only a subset of the population is recognizable by artificial or natural marks. However, in many cases, it is not possible to read the marks in camera‐trap pictures, even though individuals can be recognized as marked. We present a new extension of Gen‐SMR that allows for this type of incomplete identification. We used simulation to assess how the number of marked individuals and the individual identification rate influenced bias and precision. We demonstrate the model's performance in estimating red fox ( Vulpes vulpes ) density with two empirical datasets characterized by contrasting densities and rates of identification of marked individuals. According to the simulations, accuracy increases with the number of marked individuals ( m ), but is less sensitive to changes in individual identification rate (δ). In our case studies of red fox density estimation, we obtained a posterior mean of 1.60 (standard deviation SD: 0.32) and 0.28 ( SD : 0.06) individuals/km 2 , in high and low density, with an identification rate of 0.21 and 0.91, respectively. This extension of Gen‐SMR is broadly applicable as it addresses the common problem of incomplete identification of marked individuals during resighting surveys.

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The use of conditioned food aversion (CFA) can reduce the predation conflict and therefore the incidence of illegal poisoning, which is one of the most important conservation threats for predators and scavengers around the world. CFA is a robust learning paradigm that occurs when animals associate a food with a discomfort induced by a chemical, thereby avoiding that food in subsequent encounters. We reviewed the potential of 167 chemical compounds to be used in CFA, considering effects, margin of safety, accessibility, and detectability. After the review, 15 compounds fulfilled the required characteristics, but only five were finally selected to be tested in CFA assays with dogs. Of the tested compounds, thiabendazole, thiram and levamisole caused target food rejection by dogs and reduced the time spent eating during post-conditioning. However, despite being microencapsulated, levamisole appeared to be detectable by dogs, whereas thiram and thiabendazole were not. Fluconazole and fluralaner did not produce any CFA effect. Thiabendazole, thiram and levamisole can therefore induce CFA, and thus are potential candidates as aversive compounds for wildlife management. Thiram is a new undetectable, safe and accessible compound that can induce CFA in canids, and opens new possibilities to develop methods of non-lethal predation control.

Worldwide, predators and humans are in conflict for resources such as game species or livestock, especially in the case of medium-large wild canids. One non-lethal method to reduce predation is conditioned food aversion (CFA), in which animals learn to avoid a food due to the illness after its ingestion, caused by the addition of an undetected chemical compound. Food aversion can be enhanced by adding an artificial odour cue, in a process known as taste-potentiated odour aversion (TPOA). We carried out an experiment on penned dogs with three experimental groups to test CFA and TPOA. We offered the food mixed with a combination of microencapsulated levamisole + vanilla odour (ODO), microencapsulated levamisole (LEV), and plain food as a control. The aims were: a) to test whether dogs are able to detect the microencapsulated levamisole; b) to analyse the strength and extinction of CFA induced by microencapsulated levamisole; c) to analyse the strength and extinction of TPOA. Two-choice tests were carried out during 11 months in the post-conditioning phase, and two reinforcements with microencapsulated levamisole were done during the first month. In the first post-conditioning test, ODO and LEV groups ate significantly less untreated food than control group. After the reinforcement, suddenly the dogs in LEV group started to eat the food. Three of four dogs in ODO group showed longlasting CFA until the 11 th month. These results show that TPOA could be used to induce odour aversion on canids and that the odour cue overshadows the slight bitter taste of microencapsulated levamisole.These results open new possibilities to develop TPOA as tool to reduce predation by wild canids.