Forty Spotted Pardalote

SPECIES Forty Spotted Pardalote
TAXONOMY Pardalotus (Pardalotus) quadragintus
STATUS Endangered (Redlist.org); Endangered (ala.org.au)

Tiny and elusive, the Forty Spotted Pardalote lives high in the canopy of the White Gum (Eucalyptus viminalis) forests and is exclusive to eastern Tasmania and some of the surrounding islands. Fragmented colonies appear on Maria Island, Tinderbox, Kingston, Bruny Island, Coningham, and two locations on Flinders Island. The largest colonies are at Bruny and Maria Island. They occur along with two other pardalote species; the Spotted Pardalote and Striated Pardalote, however the Forty Spotted is significantly more rare. With habitat loss an ongoing threat, this highly specialised species is listed as endangered with resources being channeled to protect their habitat.

Feeding
Pardalotes feed on a variety of insects, the protective coating of insect larvae (called ‘lerp’), and the sap of eucalyptus trees. Specific to habitat, the Forty Spotted Pardalote has survived through the adaptation of harvesting a sugary substance that is secreted by white gums. Eucalyptus viminalis (a.k.a. White Gum, Ribbon Gum, or Manna Gum) are a native tree often 40 metres tall, and widely distributed in the cooler regions of Australia. They have rough bark on the trunk and base of larger branches, with the upper bark peeling away in long ribbons which can collect on the branches and surrounding ground. They are the favoured food source of koalas. The sap they exude has a high sugar content and is vital to the energy diet of the Forty Spotted Pardalote.

Considered as eco-engineers, this tiny creature is the only known Australian bird to conduct farming operations for food sources. Farming behaviour has been detected in many species throughout the world, including ants and other insects. However in Australia, only pardalotes ‘mine’ trees. The bird will deliberately clip the leaf stalks on the tree, and the tree will react by releasing manna from the incisions. Over time, they return to widen the same incision and harvest this nutritious food source. They actually stimulate production of manna through this behaviour. Pardalotes feed their offspring almost exclusively on manna.

Behaviour
Generally found in pairs or small groups, Forty Spotted Pardalotes are found high in the canopy of dry eucalyptus forests. 

Appearance
Belonging to a group known as ‘diamond birds’ because of their tiny and jewel-like appearance, they measure between 9 to 10 centimetres. Their body is olive green with grey and yellow plumage, and pale yellow around the eye and rump. The wings are black with distinctive white dots, generally around forty - hence the name.

Reproduction
Relying on mature White Gum for nesting in tree hollows, a pair will build their nest as a dome shape using grass, tree bark, and feathers. Both sexes take responsibility in feeding the young.

Threats
As Forty Spotted Pardalotes serve as eco-engineers, they contribute to other manna feeding species by stimulating food production. Mature White Gum forests are continually challenged by land clearing, die back, atrophy, and poor sapling recruitment during drought. Landcare groups have emerged to protect old growth trees and regenerate clearings. 

There is also a species specific parasite threatening this tiny bird. The screw worm fly (Passeromyia longicornis) lays its eggs in the nests of Forty Spotted Pardalotes. The maggots burrow into the skin and consume the blood of the nestlings. Unfortunately this results in high death rates among this species. In some areas, nine out of ten pardalote chicks will die from these parasites, further decreasing their numbers and the time we have to save this rare species.

Thanks to the creative efforts of scientists and conservationists in Tasmania they have come up with an ingenious solution! In their thorough and detailed research of the pardalote, conservationists have fully understood how the pardalote lives and particularly how they build their nests.

The birds scout the forest floors to find the softest feathers to make a warm cosy nest for their young. As time consuming as this takes, scientists decided to ease the workload, with something extra special.

Using sterilised chicken feathers (readily available at pet stores), they laced the feathers with bird-safe insecticide to deter the parasites. Hanging a self serve dispenser of nest building materials around known pardalote colonies, it wasn’t long before these treated feathers were put to good use! Now the average survival rate of the Forty Spotted Pardalote chicks is 95% successful - compared to the 8% survival rate of chicks without insecticide-treated feathers in the nest.

It is a monumental improvement for the future generations of this species.

Updated 5 May 2021