University of Central Florida Undergraduate Research Journal - A Courting Behavioral Study on a Hyacinth Macaw (<i>Anodorhynchus hyacinthinus</i>) Pair
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This study consists of careful observations of the A. hyacinthinus pair at the Central Florida Zoo and Botanical Gardens in Sanford, Florida. Zookeepers had seen the pair increase their destructive behaviors, especially Zack, who has been observed to break and gnaw at bark from the posts in their “Display Enclosure.” However, the frequency, duration and force observed during those destructive sessions, and the pair’s focus on more than one post, are not definitive enough to identify as nesting behaviors. Additionally, neither enclosure contained a confined area with thin branches or bark ripped from the posts, confirming that the pair has not attempted to build a nest.  This destructive behavior of the A. hyacinthinus pair is normal for their species, since they instinctually use bark to clean and sharpen their beaks and break open palm fruit (Lafeber Pet Trade). Conversely, wild A. hyacinthinus have been recorded using nest boxes provided by farmers due to the massive deforestation of the manduvis trees (Wildlife Conservation Society). If the zoo provided a nest box and additional palm leaves, it might entice the pair to begin nesting.

As previously detailed, A. hyacinthinus reproductive behaviors occur in four distinct steps: Allopreening, Cloacal allopreening, Back to Back Copulation Position, and finally, Copulation (Schneider 2006). From the observations collected during this study, we can conclude that the pair only fully completed step 1 (Allopreening) of the mating process. Although mutual preening behaviors (grooming each other’s face and neck) were observed, the pair spent most of their time participating in non-reproductive behaviors, as seen above in Figure 1. Typically, allopreening for this species lasts 10 minutes or less, while the pair in this study  was observed engaging in this behavior for 30 minutes. This figure is most likely a direct effect of the low temperatures and humidity levels recorded on that day, similar to the climates at dawn and dusk, which is when A. hyacinthinus is most likely to preen (Schneider 2006). Conversely, from observations collected during the afternoon in Week 9, Zack and Stich spent the majority of the session exhibiting heat loss behaviors (perched with their wings away from their body and panting) due to the high temperatures (Schneider 2006). During the last three weeks of observations (Weeks 8, 9, 10), little to no movement was recorded until the zookeepers turned on sprinklers designed explicitly to aid the birds in cooling down.

Moreover, the pair was observed performing back to back preening of the tail near the cloaca. However, the species is known to produce specialized vocalizations when Cloacal Allopreening is reached (Schneider 2006). These vocalizations were absent during the above described behaviors, indicating that the pair only reached the beginning stages of step 2 (Cloacal Allopreening). Stitch was observed positioning herself so her rear body was over Zack’s, possibly signifying that she was attempting the Back-to-Back Copulation Position. This behavior was only observed twice, and Zack did not reciprocate, indicating that step 3 (Back-to-Back Copulation Position) was not completed. Step 4 (Copulation) was not observed and overall, “Destruction,” “Allopreening,” and “Vocalization” all declined in duration and frequency throughout the last three weeks of the study. From the above analysis, it is clear that the A. hyacinthinus pair is not performing any copulating behaviors.

There is a significant factor that could have impacted the lack of copulating or mating behaviors in this A. hyacinthinus pair:  Zack and Stitch both had long-term mates prior to being paired together. Stitch and her previous mate, Henry, produced one egg while they resided at Disney’s Animal Kingdom. Unfortunately, it was unknown which of the pair produced the egg, and the egg turned out to be infertile. A. hyacinthinus is a socially and sexually monogamous species (Caparroz 2011). In fact, A. hyacinthinus is one of the two known species of macaw that are unable to recognize hatchlings from extra-pair copulations, suggesting that extra-pair copulations are rare or nonexistent (Caparroz 2011). If such is the case, Zack and Stitch would not be inclined to mate since they have each had their own mates for many years. Not recognizing extra-pair copulations or attempting to mate again after the loss of a mate can affect current and future conservation efforts to improve the A. hyacinthinus natural population since this species of macaw has limited options to widen the gene pool and increase genetic success of multiple fledglings. Additionally, A. hyacinthinus is a phylopatric species, meaning that individuals keep to their own feeding and reproductive sites (Caparroz 2011). If the A. hyacinthinus pair were to begin copulating behaviors, they should be transferred to their “Night Enclosure” to allow them privacy from the visitors.  Although the A. hyacinthinus pair is not performing any reproductive behaviors, this study indicates that they are very well bonded. Like Blue-and-Yellow Macaws (Ara ararauna), A. hyacinthinus need social interactions to live a healthy lifestyle. A study conducted by Plair et al (2008), established that reintroduced A. ararauna populations had a higher success rates when there was an established pioneer group with sufficient social interactions and feeding. This finding suggests that Zack and Stitch bonded together after the loss of their mates for social contact.

While the observations of this study led to the conclusion that the A. hyacinthinus pair at the Central Florida Zoo and Botanical Gardens are not currently mating, there were significant limitations that could have affected the results. Being constricted by the Zoo’s hours of operation, observations were not conducted during the A. hyacinthinus hours of high activity, dawn and dusk (Schneider 2006). Additionally, having the pair out in the “Main Display Enclosure” could have affected the behavior of the A. hyacinthinus pair in regard to their willingness to mate. Future studies could be conducted to observe A. hyacinthinus during dawn and dusk in an isolated enclosure with a variety of proper nesting materials and privacy to expand on the behavior of this macaw species with minimal impediments. An expansion of this study could be focused on A. hyacinthinus that have had long-term mates previously and look at how mating behavior (or social behavior) changes when paired a second time in one lifetime. Looking at if the Hyacinth Macaw is able to have multiple pairings can aid in conservation efforts such as SSPs (species survival plans) that can help potentially increase the population number in this endangered species.

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