Social behaviour Javan mynas are gregarious birds that are typically found in pairs or small groups. They associate in larger flocks at favoured feeding sites and communal roosts. The species is notably bold and shows little fear of humans; individuals often remain in place even when approached to within two metres. When foraging, Javan mynas typically scavenge in groups of two to four or more individuals. Usually, one bird acts as a sentinel, keeping watch from a vantage point while the others feed. If the sentinel detects a potential threat, it alerts the group with a high-pitched alarm call, prompting all members to flee the area swiftly. The species is territorial and frequently engages in noisy confrontations. Fights typically involve two pairs of birds and occur over territory, mates, or food resources. During combat, an aggressor will attempt to pin its opponent to the ground, gaining a positional advantage from which to deliver strikes. These encounters usually last between one and ten minutes, and the objective appears to be establishing dominance rather than causing serious injury. Fights typically end with the losing party retreating.
Intelligence and problem-solving Javan mynas demonstrate considerable adaptability and learning ability. In one documented case, a myna learned to activate an
automatic door by flying up to its
motion sensor, enabling it and its mate to exit a building.
Roosting Javan mynas form large communal roosts, often gathering in trees in urban areas. Two sleeping postures have been documented: • The bird supports itself on its
tarsi and
rump, with its head tucked to one side of its shoulder and eyes closed by raising the lower eyelids. • The bird rests its entire body on the ground or perch, including its head.
Diet The Javan myna is
omnivorous and highly opportunistic in its feeding habits. Its diet includes: •
Invertebrates, particularly
insects •
Seeds and
grains •
Fruits •
Nectar • Human food waste and scraps The
incubation period is 13–14 days. After hatching, the adults remove the eggshells from the nest and dispose of them some distance away, a behaviour thought to reduce the risk of attracting predators to the nest.
Fledging and parental care The
fledgling period lasts approximately 25 days. Juvenile birds beg for food with incessant high-pitched, scratchy calls (described
onomatopoeically as
"kaeeu kaeeu kaeeu"), accompanied by characteristic "half-flaps" and wing quivering. Adults feed the young with food items such as small seeds, fruits, and insects, which are delivered directly rather than
regurgitated.
Vocalisations The Javan myna has a varied vocal repertoire similar to that of the
common myna. Calls include loud whistles, chattering, and harsh, grating notes. The species is often vocal, particularly at communal roosts where large numbers gather in the evening and produce a considerable cacophony. ==Conservation status==