Diet of the Yellow-tailed Black-Cockatoo

Yellow-tailed Black-Cockatoos have a diverse diet.

They feed mainly on the seeds of native plants particularly in the Proteaceae family (Banksia, Hakea), while larvae of wood-boring insects (in Acacia, Casuarina) can make up a significant portion of the diet; making the Yellow-tailed Black Cockatoo unique amongst parrot species in south-eastern Australia as they can be thought of as an omnivorous cockatoo.

Proteaceae (Banksia, Hakea)

Lambertia formosa (Mountain Devil)

Wood-boring Larvae

Nectar and/or flowers are commonly eaten and seeds of introduced pine like Pinus radiata have become an important food source even if many plantations have replaced native habitat.

Male YTBC with banksia

Yellow-tailed Black-Cockatoos consume the rich nectar of Lambertia formosa by either squeezing the base of the flower, or tipping the flower up into the beak with their head back, in what could only be described as a drinking action.

YTBC feeding on Lambertia formosa nectar by tipping the flower upside down to pour the nectar out

An observation and lab study in the late 1980s confirmed the species extracted fungi and slime mould from under the bark of dead trees (1). These exceptionally intelligent birds know exactly where, when and how to find the food they want, and there is still a lot to learn about them.

YTBC digging into wood

Juvenile Yellow-tailed Black Cockatoos in their first year (dependent on parents) will alternate between staying still and begging – often for long periods of time – and experimenting with self feeding such as with Banksia to (often clumsily) try and extract seed. Often the Banksia infructescence (in the case of B.integrifolia) will not be removed from the tree; rather the bird will attempt to extract seeds without holding it, or pull seeds out if there are open follicles.

Juvenile YTBC with Banksia

YTBC has a long, slender bill unlike that of any other black-cockatoos, besides the Baudin’s which is longer but for different reasons. The slenderness of the YTBC bill can only be appreciated when viewed front on.

The evolution of the YTBC beak is clearly heavily adapted to their common behaviour of digging deep into wood to pull out grubs/larvae deep within branches and trunks of hardwood species like Acacia and Casuarina.

Female extracting larvae

YTBC are adept at locating standalone individual Banksia trees planted in suburban gardens, to which they will often return annually.

Most Banksia species in the south east provide a year-round food source for Yellow-tailed Black-Cockatoos, as their seed-containing follicles mostly remain closed for long periods of time, until fire or death of part of all of the plant stimulates the opening of the follicles and release of the seeds.

YTBC flying with banksia

An exception to this is Banksia integrifolia (coast banksia) which does not hold on to its seed. When the seed is mature the follicles soon open for seed release, with no seed being held on this plant at the end of each season. This usually occurs in the late spring into early to mid-summer. Yellow-tailed Black-Cockatoos have an obvious instinctive pattern of behaviour to descend on coastal areas during this time specifically to access the seeds of B.integrifolia, although they will also consume some other foods while in the area (e.g. larvae).

Some years I have noted some arriving earlier in the season and consuming the flowers of B.integrifolia before any infructescences have formed.

YTBC eating Banksia integrifolia flower

YTBC flying with Banksia integrifolia flower

Once the concentration of B.integrifolia seed pods have diminished to the point where there’s not enough to sustain the flock or warrant their effort, the number of birds reduces and flocks eventually move on.

This is a widespread species in eastern Australia occuring in many different habitat types from the mountains to the coastal fringe and importantly, they are capable of travelling vast distances. Little to nothing is known about their nesting and movement habits in NSW. Regardless of where they are, the Yellow-tailed Black Cockatoo seeks out specific types of inverterbrates in the form of wood-boring larvae. At times it’s possible that these larvae are not just a supplement to the diet, but could be a dominant part of the diet. This species has a powerful beak that has evolved to carry out this very task in a methodical and expert manner.(2)


References
1. Fungal feeding by Yellow-tailed Black-Cockatoo
2. Cockatoos, Matt Cameron CSIRO Publishing 2007