KEY POINTS:
To swoop or not to swoop, or even to sing, the decisions of the humble magpie are not as black and white as they seem.
There is the wrath of an angry, nesting female who threatens divorce if her orders are not carried out.
There is the secretive sneaking off for an occasional illicit affair.
And there's the commando-like planning that goes into one of those fear-inspiring springtime dive-bombings.
In fact, there is so much going on in this bird's brain that Professor Gisela Kaplan of the University of New England's Centre for Neuroscience and Animal Behaviour argues the magpie shows high cognitive development of the kind normally associated with apes and dogs.
She says magpies put a lot of thought into whether to deliver that sharp clip to the back of your head that says you're in their nesting zone. Before your entrance, they've already built a body of knowledge - by mimicking sounds and watching - of who and what belongs in the area.
Like humans, young magpies take some years to grow up. They need four to five years to learn the skills they will need in life before they can breed. And although they are sexually mature after one year, they often don't leave their parents for about three.
"There is a huge gap between fledging and reproducing," Dr Kaplan says. "That time is needed for learning in a complex world. To get a territory is not easy ... to hold a territory requires enormous skill."
Part of that skill is the mimicry magpies develop and use to map their area.
"Mimicry is part of learning," Dr Kaplan says. "It shouldn't be dismissed as mindless. On the contrary, it can be seen as a high degree of learning."
Magpies only ever mimic permanent residents in their territory.
"They create in their minds a memory, a vocal map of their own territory - this is what is in it, this is what I should know, this is what I should remember. Sounds are picked up and then practised at a high rate."
Territories range in size from just under one hectare to 120ha and boundaries are guarded vigilantly. Dr Kaplan says one magpie family she observed stayed in a territory for 18 years - almost a lifetime for birds who live for 25-30 years.
For that reason, backyard swoopings are rare, and friendships with human neighbours are common.
"As a bird, they are extremely generous in the way they allow us to come close to them ... There is a family now introducing their young to us and that's very touching because that's a very generous act."
Of course, some humans need to learn when to stop loving, or feeding, their local magpies. Food with preservatives and complex compounds harms kidneys and liver and overfeeding can create dependency.
"The harm starts when you start feeding them on a regular basis," Dr Kaplan says. "They adjust their family size to the size of the food source and when you go on holidays those birds will starve."
Socially, much can be learned from a magpie family, she says.
"Magpie parents are extremely good and conscientious parents, they will only breed when conditions are right, when they have a proper home."
Magpies are hard workers with strict rules and quiet offspring, but occasionally those rules are broken. They may sneak away for a hidden romance but - like chimps - they are secretive and will look around before they leave.
"There are sometimes illicit affairs. It would make a very interesting study of whether there is moral development."
Oodle ardle wardle
* Magpies sing over four octaves and have been known to neigh like a horse, bark, meow and even greet a neighbour.
* Magpies usually are not aggressive, but during nesting they defend their territory vigorously.
* Denis Glover wrote a poem about magpies, with the memorable line:
"Quardle ardle oodle ardle wardle doodle
The magpies said."
- AAP
