Overview

This study focuses on investigating the diet composition of red foxes (Vulpes vulpes) living in urban areas in northern Japan. Red foxes rely on varying food sources, including several types of small mammals and fruits. This study suggests that the home range of urban foxes can be around 30 hectares, so they have a large area to forage for food in. This paper looked at the types of small mammals that the urban foxes were consuming by analyzing scat samples. The species of animals being consumed by urban foxes was determined by extracting DNA from the scat samples that were collected. The advantages of fecal DNA analysis include non-invasiveness, ease of collection, and high accuracy. The goal of this analysis is to understand the diet of urban red foxes in northern Japan, specifically what animals they are consuming.

Methods:

The ‘urban areas’ that were included in this study had to be considered densely inhabited districts by the Statistics Bureau of Japan. The ‘suburban areas’ in this study were areas that were in the city but outside of densely inhabited districts. One challenge for sample collection was distinguishing the scat of urban foxes from that of other species such as dogs. This was solved by using polymerase chain reaction (PCR) to test for primers that were specific to red foxes. This allowed the researchers to ensure that their samples were actually coming from urban foxes. The researchers also had to develop PCR primers for the species they were testing for in the red fox scat. The wild species that had PCR primers developed for them were gray red-backed vole, Hokkaido red-backed vole, northern red-backed vole, large Japanese field mouse, small Japanese field mouse, brown rat, house mouse, Eurasian red squirrel, Siberian chipmunk, mountain hare, and sika deer. Additionally, the researchers also used PCR primers to test for the presence of livestock species in the urban fox scat (cattle, pig, and chicken). The development of the PCR primers for prey species was essential for allowing the researchers to analyze the scat samples from the urban foxes.

Results:

In total there were 110 scat samples collected, and 78 of them were determined to come from red foxes (these 78 were used for the analysis). The wild mammals that were tested for were found in 47.4% of the samples. The gray red-backed vole was the most commonly detected wild mammal species, and it was found in both urban and suburban samples. Other commonly detected species were the brown rat and the large Japanese field mouse. Interestingly, the mountain hare, house mouse, Hokkaido red-backed vole, northern red-backed vole, and small Japanese field mouse were not found in any of the samples that were collected. When looking at the dietary composition of livestock, chicken was most commonly found in the scat samples (56% of samples contained chicken). Pig was also commonly found in the samples (29% of samples contained pig). Although cattle were not found as commonly, the total frequency of livestock in the urban fox scat samples was 61.5%. Additionally, multiple prey species were found in 38% of the samples.

Reflection/Critiques:

Wild mammals play an important role in the diet of urban red foxes in the study area. The primary wild mammal prey species for urban foxes in this area was determined to be the gray red-backed vole. This was supported through wild mammals being found in 47.4% of samples and the gray red-backed vole being found in 30.2% of samples. Although it is possible that the urban foxes were feeding in different areas than where they were dropping feces, the researchers concluded that this was unlikely due to the home range size of the red foxes. The brown rat was also found to be an important dietary component for the urban foxes. This was likely due to the high abundance of this species in cities (brown rats can take advantage of the urban environment). Sitka deer was only found in one scat sample. This was likely from a scavenged carcass since sitka deer are a much larger mammal species. Overall, wild mammal species are an integral part of the diets of urban red foxes in the study area.

Livestock species were found in a larger percentage of the fecal samples for urban red foxes when compared to wild mammal species. According to this study, livestock species were found in 61.5% of the collected scat samples. This suggests that livestock species play a crucial role in supporting the diet of urban foxes. It is likely that this dietary component was primarily sourced from human garbage due to the urban location. The livestock species that was most commonly found in urban fox diets was chicken. This is likely due to it being frequently discarded in garbage. This area of Japan has higher average pork consumption when compared to cattle. This explains why pork was found more frequently in urban fox scat when compared to cattle. Overall, anthropogenic food sources are very important to the diets of urban red foxes in the study area.

The primary critique I have for this study is the relatively small sample size of urban red fox scat. The researchers only analyzed 78 scat samples. If the number of samples were increased, then the conclusions that the study found would be more reliable. The researchers could have greater confidence in the new discoveries regarding the dietary composition of urban red foxes in the study area. Although this would have required more input, the researchers had a reliable method to distinguish the red fox scat from other species.

Another critique for this study is the choice to collect samples without any way of identifying which individual fox they came from. This could have an impact on the data if multiple samples were collected from the same individual fox. It would be beneficial to have a method of quantifying the number of different individual foxes that contributed samples to the study. It would also be beneficial to know the number of samples that came from each individual fox. This would improve the analysis since the diet of each individual is variable and unique. Although this would improve the study, it is likely not practical. Monitoring individual foxes would be difficult, time consuming, and costly. It would also be difficult to attribute particular scat samples to individual foxes.

Reference:

Waga, D., Amaike, Y., Nonaka, N., & Masuda, R. (2025). Identification of mammal species preyed upon by urban foxes (Vulpes vulpes) in Sapporo, Japan, determined by fecal DNA analysis. The Journal of veterinary medical science, 87(8), 960–965. https://doi.org/10.1292/jvms.25-0199

Overview:

The title of the article I will be reviewing is “Greater consumption of protein-poor anthropogenic food by urban relative to rural coyotes increases diet breadth and potential for human–wildlife conflict”. This study focuses on the diet of an urban-adapted generalist species called Canis latrans, more commonly known as coyotes. This species has been increasingly present in urban environments, and this has led to dietary changes for urban coyotes. This study examines how these urban coyotes have adapted to consuming more anthropogenic food sources in their diet (bird seed, compost, pet food, trash, etc.). Although having a broad number of dietary sources can benefit coyotes, consuming these anthropogenic sources may lead to increased amounts of human-wildlife conflict in urban areas. Coyotes are very flexible when it comes to their dietary and environmental needs, so this explains why urban coyote populations have been increasing in recent years. In order to better understand the role of anthropogenic food sources in urban coyote diets and how these impact human-wildlife conflicts, this study compared the diets of urban and rural coyotes. It aimed to determine what kinds/amounts of anthropogenic food were part of urban coyote diets and how this impacted the prevalence of conflicts between urban coyotes and humans. 

Methods:

The diets of coyotes from several urban and rural areas of Canada were compared for this study. The researchers collected samples of coyote scat and hair to conduct the necessary analysis for this experiment. The scat samples were collected in a variety of areas that had either received reports of coyote sightings, had coyote tracks, or where radio-collared coyotes had been located. Several characteristics were utilized to distinguish the coyote scat from other similar species such as domestic dogs, wolves, or foxes. The items found in the scat were categorized to separate natural and anthropogenic food sources. The prevalence and relative abundance of each diet component were calculated for both the urban and rural coyotes. These comparisons were able to give an in-depth understanding of the differences between urban and rural coyote diets. 

The hair samples were collected for the purpose of performing stable isotope analysis. These samples were taken from coyotes that had known histories of having conflicts with people. This type of analysis was able to give an accurate and longer-term view of anthropogenic food consumption by the coyotes of interest. The hair samples were taken from coyotes that had been live-trapped as well as ones that had been killed for various reasons. In order for a coyote to be categorized as conflict-prone, it had to have received complaints from the public regarding its behavior. The bodily conditions of each coyote were observed at the time that the hair sample was retrieved, and each coyote was analyzed for disease (sarcoptic mange infestation). Once the hair samples were obtained, they were used to perform the stable isotope analysis. 

Results:

The analysis of scat samples found that urban coyotes had more diverse diets when compared to rural coyotes. This was true at both the population level and the individual level. It also showed that urban coyotes consumed anthropogenic food sources much more often than rural coyotes (26% of all urban coyote scat samples and <1% of all rural coyote scat samples). Additionally, urban coyotes consumed far less animals when compared to rural coyotes. However, urban coyotes did consume small mammals more frequently than rural coyotes. 

Figure 2 Diet diversity of urban coyote scats from two urban (black bars) and two rural sites (white bars). We measured population diet diversity by calculating Shannon’s H′ index from pooled scats (a) and measured individual diet breadth using the number of species per scat (b). Bars show mean values and error bars indicate standard error.

Figure 3 Differences in prey use in urban (black bars) and rural (white bars) coyote scats from two urban and two rural studies in Alberta, Canada. (a) The frequency of occurrence (displayed as proportion of scats that contained item) for the diet items that differed significantly between urban and rural coyotes. (b) The proportion of analyzed scats from urban or rural coyotes that contained prey remains such as hair, bones, or teeth (animals) and all other items including anthropogenic food. Error bars show standard deviation.

The analysis of the hair samples was able to support several conclusions. Urban coyotes were more likely to experience poor bodily conditions and disease presence. This was also true for urban coyotes that had behaved in conflict-prone ways. The coyotes that had not caused human-wildlife conflict were less likely to have poor bodily conditions and disease. The urban coyotes did consume more anthropogenic food, but they did consume similar amounts of protein as rural coyotes. Interestingly, this study found that the conflict-prone urban coyotes did not consume significantly more anthropogenic food sources. However, it did find that the conflict-prone urban coyotes did consume significantly less protein when compared to all other sampled coyotes. 

Reflection/Critiques:

Overall, this study was able to confirm that urban coyotes had more diverse diets when compared to rural coyotes. This is largely due to the consumption of additional anthropogenic food sources by urban coyotes. Additionally, conflict-prone urban coyotes consumed similar amounts of anthropogenic food sources. However, these coyotes consumed less protein when compared to the rest of the samples. 

The use of anthropogenic food sources has likely contributed to the increased prevalence of coyotes in urban areas. These additional food sources allow coyotes to be less reliant on any one particular source of food, which increases their likelihood for survival. Anthropogenic food sources are often consistently available, which may cause coyotes to favor them over natural food sources in some scenarios. 

This study aimed to determine if the use of anthropogenic food sources increased the prevalence of human-coyote conflicts in urban areas. According to its findings, the consumption of anthropogenic food sources does not drive these conflicts. Instead, the amount of protein consumption by coyotes was correlated with the likelihood of them exhibiting conflict-prone behavior. The coyotes that were reported as being conflict-prone had significantly less protein in their diets and were more likely to be in poor health. These coyotes likely exhibited conflict-prone behaviors due to their lack of health and bodily vigor. They would likely be more reliant on anthropogenic food sources since they can be easily obtained and are consistently available. 

One critique for this paper is that the scat samples were collected across multiple different years in each location. This is problematic because many influential variables can change over these long time periods. Things such as weather, prey populations, predator populations, human presence, urbanization, and anthropogenic food sources can change significantly across multiple years. This decreases the reliability of the conclusions that were drawn from the analysis of the scat samples. Although it is not completely clear how much this would impact the findings, it certainly has some meaningful impact and should be acknowledged. 

Another critique is that there was a small and unevenly distributed sample size for the coyote hair analysis. According to the paper, only 72 hair samples were analyzed across urban and rural coyotes. Of these samples, 49 were urban and 23 were rural. This is problematic because the overall sample size is small, which decreases the statistical soundness of any conclusions that were drawn from it. Additionally, far more urban samples were analyzed when compared with rural samples. This increases the likelihood of random variation causing inaccurate results for the rural samples since there were so few. This issue could be fixed by increasing the total number of samples and by ensuring that they were evenly distributed between urban and rural coyotes.  

Reference:

Murray, M., Cembrowski, A., Latham, A.D.M., Lukasik, V.M., Pruss, S. and St Clair, C.C. (2015), Greater consumption of protein-poor anthropogenic food by urban relative to rural coyotes increases diet breadth and potential for human–wildlife conflict. Ecography, 38: 1235-1242. https://doi-org.prox.lib.ncsu.edu/10.1111/ecog.01128

Overview

The title of the paper I will be reviewing is “Urban and Suburban Deer Management by State Wildlife-Conservation Agencies.” The primary reason this study was conducted is because of increasing populations of white-tailed deer in urban and suburban areas throughout the United States. Human-wildlife conflicts have increased as a result of this population growth, which has led to the implementation of various deer management strategies in urban areas. These strategies can either be lethal or nonlethal. Some examples of urban management strategies are bow hunting, firearm hunting, contraception, sharpshooting, trap-and-relocate, and trap-and-kill. There are significant amounts of data available regarding public opinion of various deer management methods in urban areas. However, there has been little effort to understand the management techniques that are preferred by wildlife biologists at state agencies. This study focused on two primary goals. The first of these was to determine what deer management techniques are currently being used by state conservation agencies, their perceived efficacy, and their legality. The second goal was to identify possible drivers for differences in opinions between deer biologists and the general public. 

Methods

The primary method of data collection used in this study was an online survey that was provided to deer biologists who worked at state wildlife agencies. The survey was sent to 41 different state agencies, and 34 of these agencies provided a response. The survey included 10 questions to be answered by deer biologists. These questions mainly focused on the management techniques currently being used in each state, their level of effectiveness, reasons for managing deer populations, and the legality of management techniques. 

Results

The results from this survey were informative for providing answers to the questions being answered by this study. The majority of states indicated that their urban/suburban deer populations were increasing, and the majority of deer biologists believed that urban/suburban deer populations were an issue in their state. One interesting finding was that 64.7% of deer biologists have not done any surveys of local communities regarding their opinions on urban/suburban deer management. The most popular and effective management techniques according to deer biologists were archery hunts, sharpshooting, and firearm hunts. The least popular methods according to deer biologists were trap-and-kill, contraception, sterilization, and trap-and-relocate. The legality of the previously mentioned methods is an influential factor for determining how much they are used in certain states. The vast majority of deer biologists indicated that the primary reasons for management of urban/suburban deer populations were deer-vehicle collisions and damage to gardens. Other popular reasons for management were native vegetation damage and agricultural damage due to deer populations. Additionally, 88.2% of states concluded that the current management of urban/suburban deer populations in their state was effective. 

Critiques/Reflection

This study was able to collect valuable information regarding the opinions of deer biologists on managing urban/suburban deer populations. Although deer biologists and the public commonly agree on the reasons for managing these deer populations (car collisions and garden damage), they have not been able to reach a consensus on the methods that should be implemented. The public is typically not heavily involved with decision making regarding urban deer management policies. This was shown in the survey results since 64.7% of state deer biologists have not made the effort to survey communities about their opinions on deer management. This study could be improved by asking an additional question relating to public opinions. Instead of simply asking if public opinion surveys had been conducted in each state, the questionnaire should have also asked for the reasoning behind this decision. If the state agencies chose not to involve public opinion when making decisions on urban/suburban deer management, then it would be valuable to know why this was the case. There could be a variety of reasons (lack of funds, lack of public interest, inability to reflect public opinion in policies, etc.) for not surveying public opinions, but this study does not provide data to answer this question.

Another suggestion to improve this study could be to modify the methods used for data collection. Overall, there was a high response rate to the survey that was sent to the state wildlife agencies. Although many of the agencies responded to the survey, increasing the amount of data collected would increase the reliability of the study’s findings. This study chose to send the survey in an email and then send a reminder email two weeks after the first email was delivered. I believe that choosing to send the reminder email was a beneficial idea, however, I think that this could be improved. Instead of solely communicating with the wildlife agencies through email, I think that the researchers should have made phone calls to the state wildlife agencies that had not responded to the survey. The agencies could have overlooked the email, or they may not have been certain about the legitimacy of the survey. By making a phone call to the agency, the researchers could have made a more personal connection to the deer biologists who work there. This could have led to higher response rates to the survey, which would have led to larger amounts of data being available to analyze for the study. 

Reference

Rachael E. Urbanek, et al. “Urban and Suburban Deer Management by State Wildlife-Conservation Agencies.” Wildlife Society Bulletin (2011-), vol. 35, no. 3, 2011, pp. 310–15. JSTOR, http://www.jstor.org/stable/wildsocibull2011.35.3.310. Accessed 11 Sept. 2025.