Blog: Look and Listen - Events Monitoring at Chester Zoo

With the winter events season coming into full swing, Chester Zoo's Conservation Science team are keeping a keen eye on any potential changes to welfare:  

Out-of-hours events have become increasingly popular in the zoo industry, attracting gatherings of families and friends and providing much needed income during times when visitation would otherwise be low. This unique combination of extended visitor hours, artificial lighting, and music creates a sensory landscape that’s exciting for visitors but also changes the daily routine for zoo animals which may impact animal welfare. While we want to create a unique experience for visitors, it is important we closely monitor animals in our care and mitigate risks to animal welfare to ensure that events are successful.

Welfare status can fluctuate day-to-day based on several impacts, both from intrinsic factors such as health condition to external factors such as environment. The COVID-19 pandemic unexpectedly provided zoo researchers with a rare opportunity to study animal behaviour in zoos in the absence of visitors with responses varying between positive, negative or neutral, changing between species and individuals. The addition of artificial light to the zoo landscape outside of normal daylight hours can disrupt an animal’s circadian rhythm, or sleep-wake cycle, impacting physiological and behavioural processes key to survival.

Unpredictable and continuous music along with visitor noise can also affect animals, especially those sensitive to changes in their acoustic environment. Over time, repeated exposure to unpredictable noise may affect mood and stress levels and even influence physiological processes such as immune function or hormone balance. The prevalence of infrasound from machinery, funfair rides or light structures, adds a level of complexity to the zoo soundscape. These very low-frequency sounds are outside of the human hearing range, but some zoo animals can not only detect them but communicate at that frequency and therefore may not be able to perceive social calls from group members.

All of this highlights an important takeaway: animal welfare should and does remain the main priority for zoos and aquariums, but this doesn’t mean commercial incentives such as evening events should be avoided.

Advances in zoo research have made zoo welfare monitoring more accessible and effective across organisations, and at Chester Zoo, we have put those tools to use during our events period. A major challenge we find ourselves faced with year after year is the scale of a zoo-wide event. Spanning a large area of the zoo, dozens of species may be exposed to event-specific stimuli. Working closely with the animal teams allows us to gain on-the-ground understanding of which species are most vulnerable. Welfare may be particularly impacted if an individual is undergoing veterinary treatment, if they are a recent addition to the zoo, or simply near event infrastructure. As it would be too time consuming to monitor every individual intensively, selecting priority animals ensures efforts are concentrated in the priority areas.

Using remote monitoring from a combination of camera traps, CCTV systems and sound recorders, we build a picture of how these species are reacting to changes in the environment during events. Data collected on consecutive Friday and Saturday nights for a minimum of two weeks prior to the event are compared to data collected during the event using species-specific behavioural indicators such as:

• REM sleep duration, which can inform us on disruptions to sleep cycles
• Habitat use, which can highlight preferred or areas they avoid during events
• Activity budgets, which can identify changes in key behaviours
• Changes in social interactions, which can track social cohesion within groups

Tailoring these methods to the individual level relies on us having a baseline knowledge of individual patterns and status. For example, if a female is pregnant, her needs and behaviours will differ from her normal baseline, resulting in an adaptation of data collection methods to focus on indicators like resting and feeding behaviours. Individuals may react differently to an event due to age, gender, life history, but also their temperament and personality. This is why it is important to collect baseline data as close to the event as possible, ideally avoiding any periods where equipment may be installed in the area.

The use of autonomous recording units (ARUs), or sound recorders, allow us to record sound in a range of frequencies, even outside of human hearing range. Positioned as near to the animal habitats as safely possible, to best represent the target animal’s sound perception (e.g. installing it at the same height as the animal’s ears) allows us to understand how much sound from the event reaches the animals once it has travelled through infrastructures, habitat walls and substrate.

At Chester Zoo, we combine keepers’ knowledge, accessible technology and collaboration with event planners to ensure welfare is considered throughout the event, from planning, to implementation, to review of findings in preparation for the next event. We have used these results to re-position speakers, move installation features at a suitable distance from sensitive species and alter visitor routes through the zoo. To apply this approach in your own organisation we’d recommend reading the Welfare Toolkit resources produced by the BIAZA Animal Welfare Working Group, particularly the guide to monitoring welfare during events.

- Laura Naidenov (she/her), Conservation Scientist: Behaviour and Welfare, Chester Zoo

- Lisa Holmes (she/her), Lead Conservation Scientist: Behaviour and Welfare, Chester Zoo; Vice-Chair BIAZA Animal Welfare Working Group

All blogs reflect the views of their author and are not necessarily a reflection of BIAZA's position