Wildlife Photographer of the Year: the turkey that builds its own ‘oven’
Australia is home to many well-known creatures, but one you may not have heard of is the Australian brush turkey. Photographer Gerry Pearce spent every morning for four months observing a male and documenting his captivating behaviour.
The Australian brush turkey, Alectura lathami, is from the megapode family - birds that incubate their eggs by building oven-like nest-mounds of decaying vegetation, which are then tended by the males.
Gerry's image, The incubator bird, shows his subject piling insulation onto his nest. The shot won the Behaviour: Birds category in this year's Wildlife Photographer of the Year competition.
Turning up the heat
Gerry's project focussed on a local brush turkey that started constructing a nest-mound near the photographer's Sydney home.
At the start of the breeding season male brush turkeys spend weeks building their nests out of leaves, soil and other debris.
Gerry says, 'In July, mound building was in full swing. Each morning he would descend from his roost, perhaps 30 metres up in a nearby gum tree, and make his way to the mound.
'He used his large feet and strong legs to clear an area, and for a while there was a trail of leaves and branches stretching across the road.'
Brush turkeys build their mounds up to 1.5 metres in height and 4 metres across, and they sometimes steal materials from neighbouring nests. Upon completion, the male is visited by a succession of local females.
'When a female approached the mound, he would always hear her long before I did. I knew this because he would become quite excited.
'She would not be allowed to inspect the mound until after they had mated.
'Once on the mound she would dig a suitable chamber and lay an egg. All this time he would be paying close attention, often getting an eyeful of dirt as a reward.'
The heat produced by the decaying organic matter in the mound is what incubates the eggs. This forms a natural 'oven'. Male brush turkeys regularly monitor their mound's temperature using sensors in their upper bill to ensure it stays in the optimum temperature range.
If the nest is too hot, they must remove leaf litter - too cool and more insulation must be added to the pile.
A protective father
The role of temperature regulator is not the only responsibility of the male brush turkey when it comes to tending to the nest. He also acts as bodyguard to the unborn chicks.
Introduced predators such as domestic cats and red foxes are known to steal eggs from brush turkeys, but Gerry observed native Australian lizards giving this particular brush turkey the most trouble.
'When summer arrived, lace monitors started to raid the mound every day.
'I saw three lace monitors approach the mound. Two juveniles were easily chased away but the adult was more determined.
'The turkey was desperate to protect the eggs, grabbing at the lizard's tail and yanking, more than once receiving a violent lashing in return.
'However, the monitor was never deterred and regularly left with at least one egg, which it ate nearby.'
The great eggscape
The eggs that survived the lace monitor's attack hatched at various times throughout the season.
Brush turkeys are precocial, meaning the young are already quite physically mature when they hatch, compared to many other birds.
After emerging from the egg with their eyes open, the chicks use their large feet and impressive bodily coordination and strength to tunnel their way to the surface of the mound.
The chicks are completely independent once they leave the nest.
'Brush turkey chicks hatch after 49 days and emerge from the mound,' says Gerry.
'During the season I saw several chicks either leaving the mound or hiding in the undergrowth nearby.
'A single mound may contain 50 or more eggs.'
Friends in the field
When photographers focus for a long period of time on a single specific subject they often develop a sense of camaraderie with the animal.
'Mornings were cold and dark and there were sometimes long periods of inactivity, times when it was difficult to just sit and wait when you are acutely aware of just how cold you were getting.'
Both photographer and bird worked hard at their craft every chilly morning and the brush turkey grew to trust that Gerry meant him no harm. They became so familiar that the turkey would approach Gerry, taking a great interest in his cup of tea.
'I read that brush turkeys rarely seek out water but it seemed my morning cup of tea was a different matter.'
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