The effect of rope color, size and fray on environmental enrichment device interaction in male and female Orange-winged Amazon parrots (Amazona amazonica)

Environmental enrichment devices (EDs; a.k.a. cage “toys”) are often provided to captive parrots to mitigate the austerity of their environments, but the basis of attraction to EDs by parrots is poorly understood and many EDs go un-used. Preferences of Orange-winged Amazon parrots (Amazona amazonica) for various properties of sisal rope were tested by suspending rope EDs from computer-monitored switches attached to cage ceilings, two ED-switches per cage. Separate experiments examined preference for rope fray, length, diameter, and color, as operationalized by switch closures elicited by each ED when EDs of varying parameter quality were offered on either side of the cage. Bradley–Terry analysis contrasting woven vs. frayed rope found that both female and male parrots preferred wound (i.e., non-frayed) over frayed rope, though the extent of the difference was substantially greater for females than males (Cohen's d = 0.86 vs. 0.10, respectively). In contrasts of different rope lengths (6, 16, 26 and 36 cm), females preferred longer over shorter rope in four of six contrasts (d = 0.45–0.90), while males preferred shorter over longer rope in four of six contrasts (d = 0.25–0.72). Similarly, in contrasts of three rope diameters (12, 26 and 38 mm), female parrots preferred 38 mm over 26 mm diameter rope (d = 0.20; other diameter contrasts were not significant), while in all contrasts males consistently preferred smaller over larger rope diameters (d = 0.20–0.44). Both male and female parrots preferred red rope over green (d = 0.92, 1.21, respectively) or yellow (d = 1.23, 1.04, respectively); females additionally favored red rope over brown (d = 1.34); males additionally preferred brown over both green (d = 0.87) and yellow ropes (d = 1.78). Overall, male parrots interacted much more extensively with rope EDs than did female parrots (t = −3.431, P = 0.006; Cohen's d = −2.11). These results show that Orange-winged Amazon parrots have sex-specific preferences for rope length, diameter and color and that males interact more with EDs more than do females. These results provide the basis for developing EDs that are more likely to engage bird behavior and therefore be more effective in mitigating the austerity of cage environments.