In the open forests For many mammals, there's not much food to be found in the open forests that spread across the plateaus and ridges of the mountains. If you go on a daytime bushwalk in these places, you could run into an echidna. However, you're unlikely to see any fur among the foliage - particularly since most of the open forest mammals are nocturnal.
Come back at night, and you might see brushtailed possums, or various species of glider. Koalas, which used to be abundant around the turn of the 20th century, are also believed to live in the park's forests in small numbers. They are fussy eaters, feeding on the leaves of only a few eucalypt species - particularly the forest red gum and the grey gum. You could look for these marsupials around Bilpin or Mount Tomah - but don't expect any great success. They're well camouflaged by their grey fur and slow movements.
The closed forests, down in the sheltered gullies, offer much better pickings for mammals. On the forest floor there are insects, frogs, spiders, beetles and grubs to be hunted out. Meanwhile, the leaves of trees like the ribbon gum are covered with manna, a sugary deposit left by feeding insects.
Possums, gliders, bandicoots, brown antechinuses and swamp wallabies all inhabit the closed forest. The largest of the gliders, the greater glider, measures almost one metre from head to tail. It uses the flap of skin between its front and back legs to leap up to 40 m as it feeds among the trees. The smaller sugar glider is more common. It feeds on the sap of wattle trees and on blossoms, insects and insect larvae. Sugar gliders live in communal nests, with up to seven adults and their offspring sharing a single tree hollow.
There are also small numbers of spotted-tailed quolls in the park's closed forests. The largest marsupial carnivores on the Australian mainland, these 75 cm animals are listed as a vulnerable species. They eat insects, lizards, birds and mammals. They will also attack animals much larger than themselves - including echidnas, wombats and even kangaroos. Quolls mainly hunt at night, running along the forest floor and climbing among the trees.
Woodland habitats have large, spreading trees with plenty of nesting hollows. This attracts mammals like bats, possums and gliders - look out for scratch marks on the trees, left by gliders harvesting sap. In the undergrowth, you might find evidence of echidnas, bandicoots and antechinuses.
Woodlands have plenty of grassy clearings, which suits the larger marsupials that prefer these environments. Common wombats, red-necked wallabies, wallaroos and swamp wallabies are all found in the park, and eastern grey kangaroos can be found in quite large numbers.
Like most kangaroos, eastern greys are easiest to find around dawn and dusk, when they do most of their feeding. Try looking for them in places like Kedumba Valley and around Lake Burragorang (south of Wentworth Falls and Katoomba), or head to towns like Hartley and Lithgow. One of the best places to find these kangaroos is at Euroka, a popular camping and picnicking spot near Glenbrook.
On the heath You're unlikely to find too many large mammals among the exposed, low-growing heathlands (although wallabies occasionally graze here). However, smaller native mammals are drawn to the nectar and pollen of the many wildflowers. The tiny eastern pygmy possum is one such animal - it's as small as a mouse, lives in old birds' nests and tree hollows, and is particularly fond of banksia nectar.
Many rainforest plants produce soft berries and sticky seeds that attract birds and mammals. There are also plenty of invertebrates to eat on the forest floor - spiders, snails, leeches, beetles, butterflies and other insects. However, the diversity of fauna in the rainforests is not as rich as in the closed forests.
The park's main rainforest mammals are brushtailed and ring-tail possums, bandicoots, spotted-tailed quolls, grey-headed flying foxes, brown and dusky antechinuses, marsupial mice and bush rats.
Not surprisingly, the mountain swamps provide habitat for swamp wallabies. They also support populations of antechinuses, tiny marsupials which forage for beetles, spiders, cockroaches and other invertebrates in the trees and on the ground. The mating season is hard on male antechinuses - the stress of finding a mate, and then the exhaustion of a six-hour copulation session, weakens their immune systems. All males die soon after mating.
In the open forests Banksias and grevilleas line the understorey of the Blue Mountains' open forests. Their flowers attract the brilliantly coloured rainbow lorikeet - along with other nectar-feeding birds such as honeyeaters, silvereyes and eastern spinebills. Other birds of the open forest include laughing kookaburras, gang gangs, crimson rosellas, grey and pied currawongs, scarlet robins, scrub wrens, tree creepers, pardalotes, spotted quail-thrushes and striated thornbills. Listen out for the distinctive 'ringing' call of the bellbird.
The open forest provides habitat for birds of prey, which hunt lizards, mice and insects on the park's heathlands. When you're out walking on the plateaus and ridges, look up - you may see eagles, hawks, falcons and kestrels gliding and hovering in the updrafts.
There's more food for birds in the closed forests of the mountains. Amphibians and invertebrates thrive on the forest floor, and the trees provide a plentiful supply of seeds. Pilot birds, which can't fly very well, hop around catching insects and spiders. Lyrebirds can also be found scratching for food in the leaf litter - if you're lucky, you'll hear their rapid-fire mimicry of other bird calls.
You'd have to be very lucky to see an eastern whip bird, which is elusive and well camouflaged. However, you're likely to hear its whistle - a long, clear note suddenly cut short.
Other distinctive birds of the closed forest include the king parrot, yellow-tailed black cockatoo, white-naped honeyeater, wonga pigeon, brown and striated thornbill, satin flycatcher, eastern yellow robin, rose robin, grey fantail, white-browed scrub wren and golden whistler.
Many birds rely on the forests and woodlands of the Blue Mountains not just for food, but also for shelter. Eastern rosellas, crimson rosellas, galahs and cockatoos all need tree hollows to nest in. You're likely to see them in woodland areas - along with smaller birds like thornbills, scrub wrens, pigeons, doves, rufous whistlers, eastern spinebills, spotted pardalotes and grey fantails.
Given the wide variety of flowering plants on the heathlands, you might expect to find insect- and nectar-eating birds here - and you'd be right. Nectar-feeders include the chestnut-tailed heath wren, New Holland honeyeater, yellow-faced honeyeater, white-eared honeyeater and eastern spinebill. You might also see chestnut-tailed heath wrens and scrub wrens, which forage for both insects and nectar.
Other birds prefer the seeds of heathland plants. Gang gangs feed on conesticks, red-browed finches eat the grass seeds, and black cockatoos are fond of banksia seeds.
Rainforests If you come across a scattered collection of blue objects when you're in the rainforest, you've probably wandered into the domain of a male satin bowerbird. These glossy black birds line their intricate display areas - or bowers - with blue flowers, clothes pegs and other objects to attract a mate.
Other rainforest birds of the Blue Mountains include the eastern whip bird, superb lyrebird, pilot bird, king parrot, crimson rosella, wonga pigeon, yellow-throated scrub wren, golden whistler, Lewin's honeyeater, brown thornbill, rose robin and rufous fantail.
The mountain swamps are visited by many small birds in search of insects, seeds and nectar. Honeyeaters are attracted to the nectar of grevillea, hakea and melaleuca blossoms, while finches and wrens hunt for insects in the thick grass and bushes. Look out for the yellow-faced honeyeater, southern emu wren, buff-banded rail, Lewin's rail and beautiful firetail.
Amphibians and reptiles
Blue Mountains National Park is home to a variety of snake species. In the open forests, you may come across eastern brown snakes, yellow-faced whip snakes and eastern blind snakes - particularly in the Lower Mountains (east of Wentworth Falls). Death adders also live in the dense forests of Lower Mountains, but their numbers appear to be declining.
In the closed forests and rainforests, you might come across a green tree snake, golden-crown snake, diamond python or brown tree snake in a sheltered gully or beside a stream. Or if you're around a valley swamp you might disturb a red-bellied black snake or a copperhead in the moist grassy vegetation. Remember that some snakes are venomous. If you disturb a snake, don't try to kill it - you're more likely to scare it into attacking you. Just walk slowly and calmly away.
The lizards of the Blue Mountains range from tiny skinks and geckos to enormous lace monitors (better known as goannas), which can measure more than 2 m from head to tail. In between, you might see bearded dragons, mountain dragons, eastern water dragons, jacky lizards and blue-tongued lizards. Long-necked tortoises are also found in the park.
The Blue Mountains are not short of frogs either. One species gets its name from the region: the Blue Mountains tree frog, which is green with red thighs. Its soft, chuckling call can be hard to hear against the sound of running water. Other amphibians include the giant burrowing frog, bleating tree frog, tusked frog, brown toadlet, great barred frog and red-crowned toadlet.
Little is known about distribution of insects, spiders, molluscs, crustaceans and other invertebrates in Blue Mountains National Park. However, given its great variety of vegetation communities, the park probably protects a high diversity of invertebrates.
If you go canyoning (or take the Grand Canyon walk), there are two invertebrate treats in store. First, you're likely to see various species of yabby - small, often brightly-coloured freshwater crustaceans that live in the mountain streams. Second, you might come across glow worms in a particularly gloomy spot. These fungus gnat larvae produce light through a chemical reaction in their bodies. They spin sticky threads that hang down below them, catching small insects that are attracted to the light.