Habituation, den defence, and predatory opportunism appear to have contributed to coyote aggression in an urban park
Description
Context Between December 2020 and August 2021, there were an unprecedented 45 coyote attacks and 63 additional aggressive encounters involving humans in Stanley Park, Vancouver, BC, Canada. Study Objectives The objectives of this study were to (1) determine the spatial and temporal factors that distinguished aggressive human-coyote encounters from non-aggressive coyote sightings in Stanley Park and (2) identify the individual and group characteristics of human attack victims. Based on the complementary hypotheses that aggression typically stems from one or more of (1) habituation, (2) food conditioning, (3) defence of dens or resources, and (4) opportunistic predation, we predicted that coyote aggression would increase when there were more park users (causing habituation), closer to potential sources of human-associated food (causing food conditioning or as resource defence), in contexts with opportunities for predatory behaviour (e.g., times of the day or week when individuals were more likely to be alone), closer to den sites (den defence), and during the pup-rearing season (den or pup defence). We further predicted that attack victims would more often be exhibiting flight behaviour (e.g., running), vulnerability (e.g., alone, nighttime activity, or children), or threats (e.g., presence of dogs) at the time of the attack. Description of Data The file "sp_coyote_project_dataset" contains all variables used for objective 1. In the absence of daily human visitation data, we used COVID-19 pandemic-induced restrictions on indoor social gatherings as a proxy for long-term human park use, with the lockdown phase representing the phase of greatest human activity. Time of day was converted to radians and then cosine-transformed with a phase shift of -7π/6 to make 2pm the high and 2am the low, emulating hours of peak human activity in the park. Land cover variables are presented in pixels and in proportion of total area within a fixed radius corresponding to the distance included in the variable name. All distance measurements (i.e., land cover radii and variables starting with "d2") are in metres and all variables used for analyses were scaled to standard deviation=1 and mean=0, denoted as [variable]_scaled in the data. Both human activity datasets contain data collected in 2024, which we used as the reference period for expected human activity and proportion of park users within each demographic and activity category in the park at various times of day. The .lyrx file is an ArcGIS file that depicts the edited land cover classifications we used for this study. Key Findings We found that aggression increased with greater long-term human activity, times of day and week with lower human activity, proximity to dens, and areas of greater human activity in the park. We also found that human victims were more likely than expected by chance to be alone and running at the time of the attack, but that age, gender and dog presence had no significant effect.
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Steps to reproduce
Reports We received coyote attack reports from the British Columbia Conservation Officer Service via a Freedom of Information Act request and all other reports from the Stanley Park Ecology Society's public website. For attack reports that did not include latitude and longitude coordinates, we created a polygon of the area described in the report and extracted the coordinates for the centre point. For analysis, attacks and other aggressive encounters were combined into a single group. Spatial Predictors We collected location data for anthropogenic food resources on foot using the Gaia mobile application and Google Maps. Den locations were approximations provided by the Vancouver Parks Board. Distances between reported encounters and water bodies, dens, and food resources were calculated using the distm function from the geosphere package in R. Land cover LIDAR data were collected for 2020 from the Metro Vancouver Open Data Portal and edited in ArcGIS Pro 3.2 to remove shadows and improve accuracy. We condensed the resulting 14 land cover categories into natural, developed, open (i.e., mowed grass, sand, etc.), and water and tidal. To determine the effect of land cover on coyote aggression, we created 100, 150, 200, and 250 m radius buffers around each encounter in ArcGIS Pro and identified the most explanatory radius length using Bayesian Information Criterion. Temporal Predictors We classified pandemic lockdown phases as (1) pre-lockdown, meaning preliminary restrictions in place without a ban on indoor gatherings, (2) lockdown, meaning the time during which indoor gatherings were banned, and (3) post-lockdown, meaning the loosened restrictions in place after the complete ban on indoor gatherings was lifted. We categorized coyote phenological seasons as breeding (January to April), pup-rearing (May to August), and dispersal (September to December). We determined 1400 hours (2pm) to be the time of peak human activity by monitoring the number of people moving on trails through the park at 8 sites representing areas of high and low human activity at 6 different times of day, spanning from 0700-2200 hours. Human Characteristics While monitoring human activity in the park (see Temporal Predictors), we recorded the age (adult or child under 10 years), gender (male, female, or unknown, based solely on physical appearance), group size, dog presence, activity (walking, running, or wheels, e.g. cycling), and weather conditions (sunny, overcast, or rain) for each passerby. People were considered to be traveling in a group if they were traveling via the same form of transportation/activity in the same direction and within 3 seconds of each other. Statistics Our statistical approach is explained in the R script's comments. For more detailed information, please read the methods of the associated article.
Institutions
- University of British ColumbiaBritish Columbia, Vancouver
- University of AlbertaAlberta, Edmonton
Categories
Funders
- Habitat Conservation Trust Foundation