4. Jarrah Forest with Orchids

This area has impressively large jarrahs transitioning to banksia-dominated woodland over a low understorey of herbs, sedges, irises, etc.

Common Wildflowers (see Points of Interest 2, 3 and 5)

Focus Topic 9. Common Orchids on the Jarrah Trail

Hare orchids (Leporella fimbria) are the first to flower in autumn and early winter but are very inconspicuous. Banded Greenhoods (Pterostylis orbiculata) and Bluebeards (Pheladenia deformis) flower in winter. Red Beak (Pyrorchis nigricans) leaves are very common, but flowers are only seen after fire (POI 9). Pansy Orchids (Diuris magnifica) and Cowslip Orchids (Caladenia flava) are most common on this trail in early spring, but you can also see Blue Sun Orchids (Thelymitra macrophylla) in mid spring. The last two orchids have very small green flowers in dense spikes and flower in late spring. These are the Mignonette Orchid (Microtis media) and the South African Orchid (Disa bracteata), which is a weed. These orchids are are illustrated below along with videos explaining complexities of orchid pollination.

In total, 34 species or subspecies of orchids have been recorded in Warwick Bushland and 30 of these are still present. These include 7 common and widespread, 10 common is some areas, 2 only seen after fire and 11 locally rare species (see full list).

Hare Orchid Pollination

Carousel Spider Orchid Pollination

Focus Topic 10. Black Cockatoos

Carnaby’s Black Cockatoos (Calyptorhynchus latirostris) and Red-tailed Black Cockatoos (Calyptorhynchus banksii naso) are often seen in Warwick Bushland and feed on trees. These impressively large birds, live for about 25 to 50 years, begin breeding at four years of age, mate for life and tend to nest in the same hollow each breeding season. Unfortunately, suitable nesting hollows are in short supply because feral honeybees and other birds that are new to urban bushland have occupied most of them. These two cockatoo species are closely related and primarily distinguished by red or white coloured bars under their tail feathers that are most visible when flying. Both species are endemic to Southwest Western Australia and are specially protected as they are considered at risk of extinction. Numbers of both species have declined overall due to the destruction of their habitat and competition for nesting hollows, but Red-tailed Black Cockatoos have recently become much more common in Perth.

Red-tailed Black Cockatoos feed primarily on the seed of native trees, such as Marri, Jarrah and Sheoak, as well as some urban landscaping trees. They use their powerful beaks to extract seeds from the fruits and nuts. Examples of chewed gumnuts are shown below. In Warwick Bushland they are primarily feeding on jarrah fruit leaving a carpet of chewed gumnuts and pruned branches under trees. Unfortunately, they prune off many branches that get in their way so that trees can look defoliated.

Carnaby’s Black Cockatoos feed on the seeds of species of Banksia, Hakea, Eucalyptus, Grevillea and Marri (Corymbia calophylla). They have also adapted to feeding on exotic species such as pines and cape lilac. In Warwick Bushland they feed primarily on banksia seeds and grubs. They rip open woody seed cones with their very sharp and strong beaks. It is common to see partly shredded cones lying on the ground after flocks of these birds have passed through. See Focus Topic 38 for more information about birds.