The park is rich in native wildlife.
If you're exploring Ku-ring-gai Chase National Park, you might be lucky enough to see the occasional swamp wallaby or echidna, but you're unlikely to see any other mammals. Most of the park's 28 recorded mammals are largely nocturnal and generally shy of humans.
Nearly all are marsupials. They include species of possums, gliders, flying foxes, marsupial mice and the platypus. Among its 13 threatened species, the park protects the southern brown bandicoot, koala, tiger quoll and bent-wing bat.
A good place to see native mammals, though not quite in the wild, is the Kalkari Visitor Centre. The centre's wildlife enclosure contains grey kangaroos, possums, gliders and echidna.
The most conspicuous creatures in the park are the birds. Over 160 species have been recorded, some of which are seen all over the park. They include the whistling kite, Australian raven, laughing kookaburra and black-backed magpie.
The wedge-tailed eagle, Australia's largest bird of prey, lives throughout the park. At the other end of the scale, smaller birds include the welcome swallow, grey-breasted silvereye, red-browed firetail finch, yellow-faced honeyeater and willy wagtail.
Wherever seed is in abundance, you'll find parrots. Crimson rosellas, galahs, sulphur-crested cockatoos and yellow-tailed black cockatoos are most common. These all distinguish themselves by their appearance, while other birds are more easily identified by their voice.
You're unlikely to see the elusive eastern whipbird, but you'll probably hear its call, which sounds like a whip-crack - or something out of a sci-fi movie gunfight. Superb lyrebirds, which can imitate whipbirds and just about any other animal's call, are common in the park's forest areas.
Down near the water, you might see the tiny blue and orange azure kingfisher, or even the sacred kingfisher, in the mangroves. On the mudflats there will be the white ibis, eastern curlew, white-faced heron and probably spoonbills and egrets. Pelicans are common and little penguins are known to fish in the waters of the park - but they rarely come into shore.
Amphibians and reptiles
There are a number of snakes and lizards in Ku-ring-gai Chase National Park. Venomous snakes include the death adder, red-bellied black snake and brown snake. The harmless brown tree snake also lives in the park. Among the lizards, you might spot geckoes, skinks, goannas and blue-tongued lizards - or even the eastern water dragon, which grows to about a metre in length.
The threatened giant burrowing frog and red-crowned toadlet both live in the park.
Around 100 species of butterfly and moth have been found in the park, which protects a rich diversity of invertebrate life. The Sydney funnelweb spider - Australia's deadliest - is also an inhabitant. So is the rare freshwater crayfish Euastacus australasiensis.