Animal behaviour is an integral part of any assessment of animal welfare– including the impacts of pest control. However, there are specific challenges. For instance, animal welfare assessments of pest control often must use captive, wild-caught animals to allow the necessary close observation. Practical challenges arise from the lack of background data and the need to observe rare behaviours and to allow for extreme peaks in frequency. All of these make it difficult to know how to design a sampling regime and what behaviours to expect. Rare behaviours may be significant for animal welfare (eg seizures) but may not be seen in normal situations– they occur irregularly and infrequently, may not be recognised or expected, and may not be identified as significant (eg postural adjustments, twitching).

Interpretation can be difficult: often, there is not much known about the species– can it suffer in particular ways? Does it normally express pain-related behaviour? Their previous and current environments can have unexpected effects (eg reactions to chronic stress) and time needs to be taken ensure they acclimate. How does the behaviour of a wild-caught, captive animal relate to its free-living counterparts?

Ethical realities also make the research a challenge. Some behaviours are not pleasant to observe, but the ‘look’ must separated from the ‘real effect’. Also, how do we abide by the ‘Three Rs’ when we must document extremes of suffering and observe sufficient animals to get robust data from infrequent and irregular behaviours? Researchers often struggle to get ethical approval, despite the fact that millions of animals are subjected to the same treatment outside of the laboratory in our forests and fields.

Based on our own work, we review these and other challenges in the application of animal behaviour to assessing the animal welfare impacts of pest control methods.