Impact of Broad-Spectrum Lighting on Recall Behaviour in a Pair of Captive Blue-Throated Macaws (Ara glaucogularis)

Many birds, including macaws, are highly visual animals able to detect a wide band of light wavelengths ranging into ultraviolet A, but in captivity, full-spectrum lighting is not universally employed. Where purpose-made bird lighting is used, this is typically made with the provision of ultraviolet B radiation and vitamin D3 synthesis in mind. Limited research in this field suggests behavioural and physiological benefits of broad-spectrum lighting provision, but more work is needed to broaden the taxonomic scope and to investigate its impacts on understudied areas of husbandry, including behavioural management. We compared the duration of time a bonded pair of blue-throated macaws at ZSL London Zoo opted to remain in an inside den after being recalled from an outdoors flight aviary, with and without the presence of artificial lighting in the form of High Output T5 Fluorescent lamps, which are rich in UVA and UVB wavelengths as well as those visible to humans. We hypothesized that the birds would remain inside for longer when T5 lighting was on, as they would be more visually comfortable. Using randomization analyses, we show that, over 54 trials split between winter and spring, the mean duration spent inside after recall increased from 81.04 to 515.13 s with the presence of the lighting unit, which was highly statistically significant. Our results are likely to be explained by much higher visibility of indoor surroundings creating a more hospitable indoor environment for the birds and will have implications for captive macaw management.