Materials & Methods

Animals

Cage 4 pair: The C4 birds arrived at Begawan Giri in June of 1999, along with one other pair. They came from Nick Wileman, a breeder in England, and formed the foundation of Begawan Giri's breeding program (Figures 6, 8). Their ages and how long they have been paired are unknown. The pair was nesting during the time of the study (Wirayudha, June 2002).

Cage 16 pair: The C16 pair is the oldest pair hatched from the offspring of the birds from England. The female was hatched in January, and the male in April of 2000. At six months old, the birds were placed into a large flight cage with several other birds where they spent four months before being selected as a pair. In the six months that they had been paired, they bred twice, but not successfully raised the offspring (Wirayudha, June 2002).

Cage D27 pair: The Bali Bird Park acquired the male, whose origins were somewhere in the Netherlands, in August 1998, and his age remains unknown (Figure 5). The female was hatched at the Bali Bird Park in November 1998 from the offspring of birds imported from America in 1995. The D27 birds were paired in February of 2002 and moved to their current enclosure in April 2002. They laid one clutch of eggs since being paired, but the eggs were not fertile. Previously, both birds had been paired with one or more other partners (Wawan, June 2002).

Flight cage: The 21 birds occupying the flight cage were all hatched and reared at Begawan Giri beginning in 1999 (Figure 7). All are the offspring of the two pairs Begawan Giri acquired from England. They were generally around 6 months old when they were placed in the flight cage.

Released birds: The 5 released the Bali mynahs observed were originally raised at the TNBB Bali mynah breeding facility at Tegal Bunder. The birds then spent a year in the release cage at Teluk Brumbun, which also contained Great Tits (Parus major) and Common Ioras (Aegithina tiphia), prior to their release in December 2001, which coincided with Bali's rainy season, when food and water were most readily available to the newly released birds (Figure 3). They still receive food and water from park rangers on a daily basis (Ngurah, June 2002).

Data Collection

The three pairs of Bali mynahs were observed for 19 to 20 hours each. Scans and bouts were recorded simultaneously every minute for each bird in each cage based on an ethogram of the birds' behaviors (Figure 9). Scans were also recorded for the 21 birds in Begawan Giri's flight cage and for 5 birds that had recently been released at the Bali Barat National Park, for 3 hours and 2.63 hours, respectively. Birds in the flight cage were chosen randomly and observed for 10 minutes each, at which point a new focal bird was chosen and observed. Released birds were observed 2 at a time as they were visible. General observations of the birds and facilities were also made and recorded, and all available information was gathered at each of the three locations visited.

Figure 3. Photograph of the three year-old release cage at Teluk Brumbun, measuring 30m in diameter and 17 m high in the center, with two released Bali mynahs perched on top of it (Ngurah, June 2002).

Figure 5. The D27 male performing a head-bobbing behavior.

Figure 6. The C4 male at the Begawan Giri Estate

Figure 7. This photograph taken inside the flight cage shows 11, or over half, of the flight cage's 21 birds. Several of the birds in the back are clearly proximate to more than one other bird

Figure 8. The C4 female, originally from England, exhibiting extensive feather loss in the neck area, a common problem for birds raised in captivity in many places

Figure 9. Sketches of several behaviors included in the ethorgam. From left to right, they are allogrooming, head-bobbing, exploring/foraging, self-maintenance, and stationary.