Bawean Deer is found in primary and secondary forest, reaching higher densities in the latter (Blouch and Atmosoedirdjo 1978, G. Semiadi and S. Pudyatmoko pers. comm. 2006). The species occurs up to 500 m (G. Semiadi and S. Pudyatmoko pers. comm. 2006), typically in hill forests rather than the marshy grasslands where Hog Deer is most numerous (Blouch and Atmosoedirdjo 1987), despite the close taxonomic relationship of these two species. Bawean Deer uses forests with dense undergrowth for refuge while they rest during the day (Blouch and Atmosoedirdjo 1978). It enters croplands, feeding on corn and cassava leaves, as well as grasses among the crops (Blouch and Atmosoedirdjo 1987, G. Semiadi and Boeadi pers. comm. 2006). The species is found mainly in secondary forest, but enters burned grassy openings during the dry season (Blouch and Sumaryoto 1987). The most recent assessments are in Semiadi (2004).

Bawean Deer primarily grazes on herbs and grasses, but also browses young leaves and twigs (Blouch and Atmosoedirdjo 1987). An individual deer produces 13 faecal pellet groups per day, a number which has been used to estimate population numbers (Blouch and Atmosoedirdjo 1978). The seasonal rut is in September and October, although males may be found in breeding condition (i.e. with hard antlers) throughout the year (Blouch and Atmosoedirdjo 1987, Whitehead 1993). The gestation period is 225–230 days, after which a single fawn is born, very rarely twins (Blouch and Atmosoedirdjo 1987, Whitehead 1993). Most births occur from February to June; they occasionally occur in other months (Blouch and Atmosoedirdjo 1987). In captivity, breeding occurs year round with females maintaining an interbirth interval of 9 months (Blouch and Atmosoedirdjo 1978).

Bawean Deer are primarily nocturnal, active intermittently through the night. They are very wary, and appear to avoid contact with people; where human activity is heavy, the deer spend the day in forests on steep slopes that are inaccessible to teak loggers. Individuals are occasionally seen on the beach in the southwest of the island, but otherwise are rarely seen directly (Blouch and Atmosoedirdjo 1978, 1987). It is typically solitary, although duos made up of a doe and fawn or a buck following a doe sometimes occur (Blouch and Atmosoedirdjo 1978).

This species is endemic to Bawean Island (= Pulau Bawean), in the Javan Sea off the northern coast of Java, Indonesia (Lachenmeier and Melisch 1996, Grubb 2005). Two main parts of the island are used, the central mountain range, and Mount Bulu in the south-west (Blouch and Atmosoedirdjo 1978, 1987). Tanjung Cina (= Cina Cape), an area of 950 m x 300 m, which has hilly topography in its centre and no resident human population, lies at the north-west of Bawean Island and is often cut off from the main island by a sea level of 20–150 m; it has been much used by Bawean Deer since at least the 1990s (Semiadi 2004).

Today’s restriction to Bawean is a relict from occurrence on Java, probably into the Holocene (van den Brink 1982), its disappearance from Java perhaps being caused by competition with Javan Rusa Rusa timorensis and Southern Red Muntjac Muntiacus muntjak (Meijaard and Groves 2004).

A specimen in the Institute of Zoology, Beijing, is labelled from Bangka Island, which lies off Sumatra (Indonesia); this is presumably in error (Grubb 2005). The species was supposedly discovered by Salomon Müller in 1836 in Tuban, a small town on the northern coast of Java, where the local governor kept a small herd in his garden, and the native range was discovered only after the name was proposed (Sitwell 1970). The species presumably evolved from a Pleistocene Javan Axis species (perhaps Axis lydekkeri) at a time when Bawean was connected to Java via a land bridge (Blouch and Atmosoedirdjo 1987, Meijaard and Groves 2004). Suggestions that the genus was introduced to Bawean by early European settlers seem unlikely (Sitwell 1970) because of the wealth of fossil material (reviewed in Meijaard and Groves 2004), and were not ever referred to by Grubb (2005).

This species is listed on CITES Appendix I (CITES 2000). It is protected from hunting not just on paper, but effectively in practice (G. Semiadi pers. comm. 2008). It inhabits Bawean Island Nature Reserve (5,000 ha; the island is 200 km² in size), established in 1979 for which a management plan prepared in 1979 (WWF 1979; Blouch and Sumaryoto 1987) warrants revision. Management activities have included termination of hunting, controlled burning of grassy areas within forests, and thinning of teak plantations to encourage understorey development (Blouch and Sumaryoto 1987). Since 2000 a captive breeding programme has been operative on Bawean; in 2006 it involved a founder population of two stags and five hinds, and by 2014 numbered 35 animals (Meijaard et al. 2014). About 300–350 animals are held in zoos and private captive breeding facilities off the island (G. Semiadi pers. comm. 2006).

Recommended conservation actions, which should proceed through appropriate revisions to the management plan, include:

1) Increase the populations and if possible expand the area used by the deer. While the population seems to be stable, its small size and insular nature leave it susceptible to chance events (e.g. weather-related disasters or earthquakes or disease), to any resumption of hunting and probably to inbreeding. Increasing Chromolaena will result in time in population decrease. There is thus a major role for active management of habitat through control of Chromolaena, so as to increase population density within the protected area, and thus total population. This species, a problem plant throughout much of South and South-east Asia, is very difficult to control and review of international successes and failures is needed to inform management of the weed on Bawean. Full security would come only through an increase of the range on the island, requiring some deer-centred management for areas outside the protected area.

2) Assess the impact of deer on crops as this may have become a problem if effective protection has allowed the population to increase substantially, or the invasion of Chromolaena is pushing deer to eat more crops. If so, community-based mediation with local conservation officials may be required to find solutions and mitigate conflict.

3) Initiate a co-ordinated breeding programme to evaluate and if necessary address possible inbreeding deficiencies in the captive population.