I VENTURED into the secret world of the forty-spotted pardalote one fine morning, a harsh environment that confirms the tiny bird’s status as a Tasmanian battler.
I had sponsored a nestbox as part of a pardalote conservation program but my trip to NorthBrunyIsland to monitor the pardalote “shack” did not prepare me for the uncompromising existence of these beautiful but endangered birds.
Battles for nesting sites, plagued by parasites, a constant life and death struggle against predators, the life of a pardalote does not appear to be a happy one. On top of this the tiny pardalotes – at nine centimetres, Australia’s second smallest bird – are seeing their exclusive habitat of white gums shrinking, either because of drought or land-clearance operations that leave eucalypt forests fragmented and scattered.
The researcher leading the project, Amanda Edworthy, had told me that the pardalotes occupying my box had four eggs and I had timed my arrival to see the chicks soon after they were due to hatch.
With Amanda, I had gone to the site of Box 10 at Waterview Hill with high expectation but I was in for a crushing disappointment. When Amanda climbed up to the nestbox, she found it empty. What had happened to the eggs, or young, remained a mystery but Amanda speculated that the chicks had died and their bodies had been consumed by ants.
There was more disappointment to come as we inspected more of the 240 nest boxes Amanda and her team had erected across the main breeding range of the forty-spot, North and South Bruny island, and a few remaining breeding locations further afield, at Tinderbox, Kingston, and on Maria Island to the east.
An initial assessment showed that only 10 per cent had been occupied but Amanda was hopeful this would improve in coming years as the 40-spots discovered the boxes.
Numbers of forty-spotted pardalotes – a bird endemic to Tasmania – have crashed by 60 per cent in recent years, leaving a population of less than 1500.
The research conducted by Amanda, a PhD candidate from Australian National University, is designed to uncover the reason for this staggering decline, and to see how it can be halted.
A day spent with Amanda, roaming across Waterview and Dennes Hills near the hamlet of Dennes Point, reveals the daily struggle of the birds just to survive. Even before the introduction of man-made pressures, it appears the life and times of the pardalote would always have been an arduous, tortuous one.
The state of the white gum woodlands were at first thought to be the main cause of population decline but Amanda has since found another, vital factor – insect parasites.
The pardalote nests are prone to infestation by flies which lay their eggs on the young, where blood is a food source.
In the 30 or so nest boxes Amanda opened when I was with her, a fair proportion had young infested with parasites. Amanda removed these from the nests momentarily so she could weigh and measure them, and give them a health check. Those exposed to parasites either had maggots still in their bodies or scar tissue from where maggots had done damage before emerging as flies.
Amanda has also been studying the battles that occur every spring for ever-diminishing nesting sites. The chief rival for sites is another family member, the striated pardalote, which arrives each year from the mainland.
As part of her research into this aspect of the pardalote battle for survival, Amanda placed a model striated pardalote on top of a box that had already been chosen as a potential home by a pair of forty-spots. The aggression of the pardalotes was remarkable – if a little sad – to observe, as the male pardalote chirped loudly at the bigger striated pardalote and swooped at it an attempt to drive it off.
It was just another day in the life of a battling pardalote.