Does artificial feeding impact neonate growth rates in a large free-ranging mammal?

Abstract

Variation and disparity in resource access between individuals in an animal population within human-dominated landscapes require attention as artificial selection processes may be at work. Independent, recreational human–wildlife feeding interactions constitute an increasingly prevalent, yet understudied, food resource for birds and mammals living in our cities. However, only a limited number of risk-taking individuals may access it. Using urban fallow deer as our model species, we hypothesized that if these interactions result in positive effects for the engaging individual, e.g. increased milk quality and yield, then this would result in the increased growth rates of their offspring. Alternatively, if these individuals were prioritizing investing time in engagement with humans, resulting in decreased maternal care, then this would result in slower growth rates in their offspring. We found that the offspring of those females that regularly interacted with humans displayed significantly faster growth rates than their risk-adverse counterparts. This advantage for fearless mothers in terms of boosted neonatal growth rates could be mirrored in birds accessing garden feeders, seagulls or pigeons utilizing urban resources, or seals approaching city harbours. Here, we add a new piece to the complex puzzle of how humans are impacting wildlife living within human-dominated landscapes.

Do human–wildlife interactions predict offspring hiding strategies in peri-urban fallow deer?

“…where hunting pressure would be greater and more likely to target approachable individuals). Also the link between the increased likelihood of offspring survival due to multiple factors, like increased birth weight, growth rates [7,32,48] and superior bedsite, as shown here, and food acceptance may be context dependent and artificial food could not be necessarily be linked to benefits for the acceptors. It has been argued that feeding activities should only be deemed acceptable, 'if it could be controlled, has a beneficial conservation effect and does not compromise an animal's long-term welfare' [18].…”

“…Concurrent research in the park collected observational data on human−deer interactions and ranked deer along a continuum ranging from deer avoiding any interaction with humans to deer consistently begging (i.e. approaching humans) for food [7,32]. The majority of adults in the population were tagged as fawns so are individually recognizable.…”

“…Based on the context provided, we investigated anti-predator strategies adopted by fallow deer (Dama dama) females during weaning in a population living in this peri-urban area where human-wildlife feeding interactions occur. Despite being strongly discouraged by management, feeding the deer has become commonplace in the park [7,32]. This popular activity has led researchers to identify a spectrum of distinct behavioural types in the population to date, consisting of acceptors who show reduced fear responses to humans and avoiders [7].…”

“…Despite our understanding of the impacts on individuals who engage with humans [7,32,33], it remains unclear how these associations affect future generations. Examining the effects of humanwildlife interactions on parental care and offspring fitness can provide insight into future impacts on offspring if these activities continue and help to inform management and mitigation strategies.…”

Should we feed wildlife? A call for further research into this recreational activity

“…If engagement with feeding interactions is not random, and instead is driven by behavioral type, then they may also only be occurring in a subset of the population. Recent studies have indicated that independent feeding of wildlife can impact the weight and growth rates of offspring (Griffin, Haigh, et al, 2023; Griffin, Haigh, Amin, et al, 2022) (Figure 2) and that the resultingly larger neonates have increased survival rates (Amin et al, 2022). This highlights the potential that artificial selection may be at work and we may involuntarily be manipulating wild populations.…”