Kookaburras are ingrained in the Australian psyche – oh and they love eating snakes.
Kookaburras are ingrained in the Australian psyche – oh and they love eating snakes.

For kookaburras, it’s about family

IT is one of those quiet, still winter days and a raucous laugh rings over our small patch of forest, for a moment drowning out the persistent rumble of a distant cane harvester.

I must admit it's a cackling racket which always brings a smile to my face.

It is such a mad sound, yet the bird making it boasts some of the best survival strategies of any species.

It is, of course, the kookaburra, and our resident family is calling to each other to re-establish their territory and warn neighbours in the next territory that they are doing so.

These are the birds which tell us to wake up at dawn and also signal the end of their day as dusk falls.

In the meantime, they keep in touch with each other and keep an eye on the youngsters from subsequent hatches.

For kookaburras, family is foremost. This enables many to enjoy a long life, perhaps up to 20 years in really good conditions, and it is all based on help and co-operation between the generations.

Kookaburras form permanent pairs - the belief is they mate for life - and maintain a continuing family structure in which the young from one hatching stay in the family and help with raising the next generation.

Many birds do not leave the family until they are at least four years old, meaning they have helped with several broods. They are sexually mature at one year old.

The breeding pair meanwhile, are the only birds which produce young, laying at most three eggs in a clutch, produced at about three-day intervals.

The eggs take some 24 days to hatch, with the siblings from earlier broods helping to incubate them, and then helping to feed the young over the more than about five weeks it takes for them to fledge.

A study of one kookaburra family showed that the siblings provided up to 60 per cent of the food for the nestlings, taking huge pressure off the parents.

After this, the fledglings, which are now flying, are fed for up to another 13 weeks.

So breeding in the kookaburra world is a slow process, but an efficient one, making for a low birthrate but strong, well-reared young, although from the start the young are fierce. For example, the third chick seldom survives having been attacked in the nest by the two older, stronger chicks.

Kookaburras will eat almost anything they can catch, from insects to rodents.
Kookaburras will eat almost anything they can catch, from insects to rodents.

All that assistance for the breeding pair means that stress is much reduced for them. It also means that the sibling helpers have the chance to learn the art of raising a successful family once their turn comes around, which it may when one of a breeding pair dies.

However, although kookaburras are rightfully regarded as an extremely successful species, they do not have it entirely their own way.

Along with natural hazards such as being eaten by goannas, hawks, owls, eagles and snakes - kookaburras themselves eat small snakes - there are what one might call "unnatural" hazards facing them such as car strikes. Kookaburras are naturally slow flyers so often cannot get out of the way of an approaching vehicle. As well, they also often eat road kill, again a habit which can get them run over.

Feral cats are now a common menace and so is habitat loss as land is cleared for development or agriculture.

Fire destroys both the birds and the old trees with the tree holes that they need to breed.

It is estimated most tree holes have taken at least 100 years to form, so each loss is major, especially considering the competition there is for tree holes as homes. So many creatures rely on them. I have heard many a beautiful old tree sporting holes large and small described as a natural boarding house.

Snakes are a favoured delicacy for kookaburras.
Snakes are a favoured delicacy for kookaburras.

The kookaburra's is a carnivorous lifestyle. This extends from large insects such as dragonflies and grasshoppers which, surprisingly, make up a major part of their diet, to small reptiles and mammals such as mice, to baby birds.

Snake is a favourite delicacy and it is not unusual to hear hard tapping noises and look up and see a kookaburra bashing a snake it has caught to divide it into small pieces. These fearless birds will also turn up at barbecues and expect handouts of meat.

Interestingly, during plagues of large insects such as locusts, kookaburras have been observed to eat nothing else.

A trio of 4-week-old kookaburra chicks.
A trio of 4-week-old kookaburra chicks.

Like so many other wild creatures, they are opportunistic, and this stands them in great stead.

Do kookaburras have to learn to laugh?

We felt sure this is what we were hearing recently when a young bird among a group was making the funniest of noises. Apparently, each family has its own subtle vocal sequence and this bird was joining in with the others but not quite managing all the notes.

However, supervised practice during adult tutoring soon had the student advancing the repetitious "hoos" and "haas" in the correct cadence.

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