Lowland evergreen and semi-evergreen forest
Characterised by a high diversity of broadleaf tree species and rich, diverse bird communities, lowland evergreen forest is the natural forest type over much of lowland Vietnam below c.900 m. This habitat type, one of the most threatened forest types in Asia, now covers just a fraction of what it once did, primarily due to its clearance for agricultural use. Semi evergreen, or mixed deciduous, forest is very similar in composition to lowland evergreen forest but with the addition of deciduous trees such as dipterocarps. Buttressed trees, bamboos, palms and vines are prevalent in this forest type. Typical birds species found in Vietnam’s lowland evergreen and semi-evergreen forest include cuckoos, trogons, hornbills, barbets, woodpeckers, pittas, broadbills, bulbuls, ground babblers, flowerpeckers and sunbirds.
Montane evergreen forest
Above c.900 m montane evergreen forest takes over from lowland evergreen with oaks, chestnuts, beeches, laurels and conifers dominating. Two distinct types of montane evergreen forest in Vietnam can be recognized, lower montane and upper montane evergreen forest. Above 1700 m there is a clearly defined transition to upper montane evergreen forest with tree species such as rhododendrons starting to dominate. Vietnam’s montane evergreen forests harbour a high density of bird species including skrike-babblers, tits, warblers, babblers, nuthatches, thrushes and flycatchers. Montane evergreen forest is of particular interest in Vietnam as it is in this habitat that many of the endemic and near-endemic babblers and laughingthrushes occur.
Deciduous forest is found in the drier low-lying areas of west-central and southern Vietnam, particularly those areas bordering eastern Cambodia. Deciduous forest in Vietnam can be subdivided into two types, dry dipterocarp forest and mixed deciduous forest. Dry dipterocarp forest grows in drier areas on poor soil and is characterised by a canopy of dipterocarp trees and an open grassy understorey. As there is no midstorey in this forest type it is not as rich in bird species as lowland evergreen or semi-evergreen forest. Woodpeckers and parakeets are among those species typical of this forest type.
Mixed deciduous forest occurs in areas with more nutrient-rich soil leading to more diverse vegetation with varied tree species, often some bamboo, and a middle storey making this forest type richer in bird species than dry dipterocarp. Bird communities are similar to those found in lowland evergreen forest.
Vietnam’s native coniferous forest on the Dalat Plateau, at the southern extremity of the Annamites, is dominated by Benguet pine, Pinus kesiya, also known as three-needled pine. Bird diversity in this forest type is low compared to most others, but some key species such as Slender-billed Oriole, Red Crossbill and the endemic Langbian Tit and Vietnamese Greenfinch are almost entirely restricted to this habitat. At higher elevations on the Dalat Plateau, conifer species including two endemic pines, Krempf’s pine Pinus krempfi and Dalat pine Pinus dalatensis, are mixed with montane evergreen forest, and bird communities here are very similar to those in montane evergreen forest. Conifer species such as the cypress Taiwania and the highly-prized Fokienia grow in montane forests of the Hoang Lien range in the far north-west of Vietnam.
This forest type is an evergreen forest that grows in areas of limestone and on limestone outcrops, often sculpted into striking karst formations with sharp jagged peaks. It is found in parts of northern and central Vietnam, and is an important habitat for several limestone specialists such as Limestone Leaf-warbler, Greyish Limestone-babbler and the near endemics Sooty Babbler and Nonggang Babbler.
Freshwater wetlands in Vietnam include rivers, lakes and marshes. The bird communities of all these habitats have suffered as a result of human exploitation and encroachment. Typical riverine birds such as River Lapwing, Masked Finfoot, White-winged Duck and Blyth’s Kingfisher are rare, and some are on the verge of extinction in the country.
Many artificial lakes and reservoirs have been created throughout the country in recent years, but perhaps due to pressure from hunting or simply being unsuitable, they attract few birds. Several protected areas incorporating fresh water wetlands throughout Vietnam provide an important refuge for waterbirds such as crakes, rails, storks, ibises, bitterns, herons, egrets, cormorants and Oriental Darter, as well as small numbers of wintering ducks.
Seasonally inundated grasslands
One of the most threatened habitats in Vietnam, seasonally inundated grasslands, once covered large areas of southern Vietnam, particularly the Mekong Delta region bordering Cambodia. Much of the original grassland has been converted to agriculture and only a few fragments now remain. Bird species restricted to this habitat in Vietnam include dwindling numbers of wintering Sarus Cranes.
Coastal wetlands and other coastal habitats
Vietnam’s coastal wetlands include intertidal mudflats, and man-made habitats such as salt pans and shrimp ponds. In northern Vietnam, the Red River’s intertidal mudflats represent important habitat for migratory and wintering birds including globally threatened such as Black-faced Spoonbill, Spoon-billed Sandpiper, Spotted Greenshank and Saunders’ Gull. In the south of the country parts of the Mekong Delta offer similar habitats, while saltpans and shrimp ponds along Vietnam’s central and southern coastline provide important feeding areas for migrant waders.
Much of Vietnam’s native mangrove forest has disappeared, but what remains or has been replanted in recent years provides habitat for bitterns, herons, egrets, cormorants and kingfishers as well as Golden-bellied Gerygone, Mangrove Whistler, Mangrove Blue-flycatcher and Copper-throated Sunbird.
Undisturbed beaches and coastal scrub along Vietnam’s long coastline provide suitable breeding habitat for a variety of species including plovers, terns, bee-eaters and kingfishers, while stands of beachside Casuarina trees are favoured by Plain-backed Sparrow and Oriental Greenfinch.
The rocky offshore islands and islets that comprise the Con Dao archipelago off Vietnam’s south-east coast offer important breeding sites for seabirds, several of which occur nowhere else in Vietnam. These include Red-billed Tropicbird, Brown Noddy, two species of booby and several species of tern. In addition to seabirds, Con Dao is also home to two pigeons adapted to island life, Nicobar Pigeon and Pied Imperial Pigeon.