Birds

Thermometer birds

September 1, 2012 by Redgannet 10 Comments

The Australian Brush-turkey is far enough removed from the American Turkey’s Phasianidae family to not even get considered for wedding and funeral invitations. It belongs instead to the Megapodiidae branch of the Galliformes family tree. They are thought to keep in touch with the furthest reaches of their kin by sending Christmas cards, but are consistently disappointed and confused when their greetings are not returned.

Megapodes are mound-builders, scraping fallen twigs and leaves into large piles for their nests. The male builds the mound and will seek to entice multiple females to lay their eggs into it. Once they have laid, the females take no further part in the process and the male is left to tend the nest. This individual was seen at Mount Coot-Tha near Brisbane. Maintenance workers were resurfacing a track with bark chippings, but had left their task unfinished on the Friday afternoon, intending to complete the job after the weekend. When they returned to work on the Monday morning, they found that this male had taken vacant possession of their un-spread pile of chippings and had embellished it with a few touches of his own.

He had scraped up leaves from around the heap, but for the most part it was ready to move straight in and the workers watched three females laying eggs into the mound. With nothing to spread, the workers were taking it easy until some more chippings could be delivered and they came over for a chat while they waited. One, with charming Australian candour, described the yellow collar of the male as looking like “a saggy scrotum.” He also claimed that he could tell the temperature by how saggy the scr collar appeared. There may be something in what he says as the breeding season and hence the saggy collar season, coincide with the approach of the southern summer.

The scrub-turkey male must also be able to accurately gauge the temperature as he needs to adjust the nest to maintain it at the perfect incubating range between 33 and 35C. He uses his bald head as a thermometer, thrusting it into the decaying heap and manages the temperature by opening up the mound to allow a little heat to escape, or by adding more composting material to raise the temperature. Incubation at the higher end of the range produces a greater percentage of female offspring.

It would seem that Australian Brush-turkeys have adapted well to life in the suburbs where a constant battle is being fought as the householders lovingly tend their gardens, spreading moisture retaining mulch over their flowerbeds only to wake the next morning to find that it has all been scraped back up into a large nest mound.

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Written by Redgannet
Redgannet worked for more than 35 years as a flight attendant for an international airline. He came to birding late in his career but, considering the distractions, doesn't regret the missed opportunities. He was paid to visit six continents and took full advantage of the chance to bird the world. He adopted the nom de blog, Redgannet, to avoid remonstrations from his overbearing employer, but secretly hoped that the air of mystery would make him more attractive to women. Now grounded, he is looking forward to seeing the seasons turn from a fixed point.