Although it is known that many birds possess ultraviolet (UV)-sensitive vision, most commercially housed poultry species, as well as species held in zoos, laboratories, or bred for show, are maintained under lighting that is deficient in UV wavelengths compared with normal daylight. UV-sensitive vision has been shown to be important in both foraging and mate-choice decisions. UV-poor conditions, in which information in this waveband is eliminated, could, therefore, present an important welfare issue. Eight European starlings were given a series of preference tests (eight hours per trial, for six days), in which they could choose to feed in one of four channels. Four experimental trials were carried out, during which the channels were covered in either UV-transmitting (UV+) or UV-blocking (UV-) filters, to determine whether birds had an initial preference for feeding in UV-rich environments and whether there was any change in their preference over time. There was an initial preference for the UV+ environment, but this preference declined very rapidly with familiarity, and was absent by the final trial. These results imply that starlings can rapidly adjust their feeding behaviour if faced with unfamiliar light environments and that any initial behavioural changes attributable to UV-deficient environments may be short-lived. However, further work is necessary to establish whether these adjustments occur across a range of species and contexts before any welfare concerns can be ruled out.

This study examined the impact of rearing environment on the behavioural responses of wild European starlings (Sturnus vulgaris) to standard laboratory husbandry procedures. We compared birds that had been caught from the wild as independent juveniles with birds taken from the nest and hand-reared in the laboratory from approximately ten days post-hatch. Although hand-rearing can increase habituation to humans and hence reduce fearfulness in laboratory birds, in other species maternal deprivation is also associated with increased stress-sensitivity in later life. Thus, the welfare benefits of hand-rearing are unclear. We investigated the interaction between rearing environment (12 hand-reared versus 12 wild-caught birds) and current laboratory housing conditions (enriched versus non-enriched cages and top-level cages versus bottom-level cages) on measures of behaviour before, during and after husbandry. Both wild-caught and hand-reared birds reacted to focal husbandry by moving to the periphery of their cages, indicative of high escape motivation during a stressful procedure. Wild-caught birds were overall less active than hand-reared birds. We found no difference in the response of the wild-caught and hand-reared birds to focal husbandry, but hand-reared birds were faster to resume normal behaviour following husbandry than wild-caught birds when housed in the top cages. We interpret our results as showing evidence for chronic depressive apathy (lower overall activity) coupled with greater fear (longer latencies to resume normal behaviour following husbandry) in the wild-caught birds in some environments. Our data support the conclusion that hand-rearing is associated with some welfare benefits for birds involved in laboratory research.