Effects of Environmental Enrichment on Macaw Behavior and Cortisol Levels


Researchers in Brazil found that providing enrichment significantly decreases certain abnormal behaviors in macaws, such as pacing and excessive preening.

Chronic stress and boredom can lead to negative behavior in captive parrots, such as feather picking, aggression, and stereotypies. Therefore, most avian behaviorists recommend various forms of environmental enrichment (EE) to improve physical and mental well-being.

Researchers recently examined the effect of providing EE on blue-and-gold macaw behavior and fecal corticosteroid metabolite (CM) levels.

Study Design

The study included 22 healthy, adult macaws housed in 8 enclosures at 2 zoological facilities in Brazil. Pre-enrichment, enrichment, and post-enrichment phases were consecutively performed in 2-month durations. Each bird’s behavior was examined at 30-second intervals over 5-minute periods, for a total of 30 minutes during a single day. Behavioral observation occurred only during daytime visitor hours.

Total observation time for each bird was:

  • Pre-enrichment phase: 8 hours
  • Enrichment phase: 9 hours
  • Post-enrichment phase: 9 hours

The enrichment phase incorporated various structural, occupational, and food items to each enclosure 3 times per week. Structural items (eg, climbing ropes) remained for the entire phase, while 1 type of food or occupational enrichment item was provided each day. The pre- and post-enrichment phases provided no EE items.


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Voided fecal samples from each bird were collected from 4 of the enclosures 3 times per week. Separately, an ACTH challenge was performed in 4 of the female macaws via intramuscular injection of 0.5 mg/kg synthetic ACTH. Fecal samples were collected at 72, 48, 24, and 2 hours pre-injection and at 2, 4, 6, 8, 22, 24, 48, and 72 hours post-injection. CM values were measured using an 11-oxo etiocholanolone enzyme immunoassay (EIA).


Baseline CM levels in the ACTH challenge study averaged 40 ng/g feces. ACTH administration significantly increased CM levels, which peaked at a median of 12-fold (range 9 to 18) above baseline levels between 8 and 24 hours after ACTH injection.

The addition of EE significantly increased certain positive behaviors, including walking and flight throughout the enclosure. Some “abnormal” behaviors, including preening, pacing, self-biting, and vocalization, significantly decreased with EE, although preening and pacing levels rose again in the post-enrichment phase. Many birds showed a preference for food EE over occupational EE.

Overall CM levels were similar during the 3 experiment phases, although there was a significant effect with regard to the individual, sex, enclosure, and zoo facility on CM level. Interestingly, there was no correlation between abnormal behaviors and CM levels during the enrichment phase. The authors hypothesized that the duration of enrichment may have been too short to significantly lower CM, as many parrots are initially phobic of even minor habitat changes; thus, the addition and removal of EE may have been stressful. Additional stressors, such as high visitor volume at the zoos, may have also influenced CM levels.

The Bottom Line

Fecal samples are appropriate for non-invasive measurement of blue-and-gold macaw CM levels. While enrichment increased activity levels and decreased certain abnormal behaviors, such as pacing and excessive preening, abnormal behavior often returned after removal of EE.

Dr. Stilwell received her DVM from Auburn University, followed by a MS in Fisheries and Aquatic Sciences and a PhD in Veterinary Medical Sciences from the University of Florida. She provides freelance medical writing and aquatic veterinary consulting services through her business, Seastar Communications and Consulting.

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