Over-sized pellets naturalize foraging time of captive Orange-winged Amazon parrots (Amazona amazonica)

摘要

Parrots held in captivity experience distinctly different environmental demands, as compared to their wild conspecifics, particularly in regard to feeding. Cages equipped with computer-monitored infra-red beams (placed across a primary perch, in front of the feeder, in front of the drinking fount, and at the peak of the cage; interruption of a beam indicated a parrot's location) were used to supplement direct observation in characterizing activity budgets of adult male and female captive Orange-winged Amazon parrots (Arnazona amazonica) fed pelleted diets. Parrots spent nearly all of their time perching, moving off the perch only a few times daily to drink and a few dozen times daily for pellet meals (each meal consisting of pellet retrieval and manipulation of the pellet(s) before swallowing). Such meals were temporally clumped, usually into 3-5 meal clusters per day, and clusters tended to be concentrated in morning and afternoon periods of a 12:12 LD light cycle, with a midday respite. Over-sized pellets formulated to be approximately 20-30 times larger than regular pellets (approximately 3-5g each vs. 0.16g each, respectively) exerted no detectable effect on the frequency distribution of off-perch bout lengths, but over-sized pellets dramatically increased post-pellet retrieval manipulation time approximately five-fold. In choice preference trials, parrots strongly preferred over-sized pellets to regular pellets, retrieving over-sized pellets approximately seven-times more often. Likewise, parrots offered only regular pellets removed 47.6 +/- 6.4g (mean +/- SE) pellets from their feeder per day, but removed only 6.5 +/- 2.0 of regular pellets, if over-sized pellets were offered concurrently. Finally, the option of manipulating/consuming over-sized pellets strongly affected use of wooden cube enrichment devices. During a 3-day period, parrots offered both regular and over-sized pellets reduced the mass of wooden cubes (through biting/chewing) by approximately 0.13 g; removal of the over-sized pellet option increased this amount 50-fold. These results suggest that parrots offered only regular-size pelleted diets are deprived of an opportunity to engage in foraging behavior. Offering parrots over-sized pellets or enrichment devices that provide foraging-like opportunities can dramatically reduce periods of inactivity and encourage a more naturalistic activity budget, thereby enhancing welfare.