Data from: Culling-induced perturbation of social networks of wild geese reinforces rather than disrupts associations among survivors

Wildlife populations may be the subject of management interventions for
disease control that can have unintended, counterproductive effects.
Social structure exerts a strong influence over infectious disease
transmission in addition to other characteristics of populations such as
size and density that are the primary target for disease control. Social
network approaches have been widely used to understand disease
transmission in wildlife but rarely in the context of perturbations, such
as culling, despite the likely impacts of such disturbance on social
structure and disease dynamics. Here we present a ‘removal’ study of a
free-living population of resident Canada geese Branta canadensis, a
highly social species that is frequently managed by culling and can carry
pathogens relevant to human and domestic animal health. We quantified
social network structure and spatial behaviour before and after controlled
culling of individuals during the summer moult. Culling did not
substantially increase individual social connectivity. Individuals that
moulted at cull sites or were formerly strongly associated with removed
birds were more likely to strengthen and maintain any surviving existing
associations while also forming new associations. However, the
establishment of new associations was largely compensatory (with only
small increases in the number and strength of connections) and occurred
locally. Synthesis & applications: geese that survived the cull
responded by strengthening existing social relationships and forming new,
compensatory relationships with birds local to them in the network. In the
short-term such compensatory adjustments to patterns of association in
response to culling could facilitate pathogen transmission. But in the
longer term, controlled culling of geese is unlikely to strongly influence
pathogen spread and may even slow transmission into new social clusters by
reducing wider mixing. When managing wildlife for disease control, in
addition to changes in social network structure the prevalence of
infection at the time of the cull and the mode of transmission (e.g.,
direct versus environmental) will also be critical determinants of disease
transmission risk in perturbed populations of geese and other wild
animals.