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It was a great pleasure to share this idea with the staff from the Cornell Lab of Ornithology and Compost Facility, and the director of Cornell Waste Management Institute at the Cornell University, Ithaca NY last month. Also for the tour to see all possibilities to exchange the experience,

My first visit at the large compost facility abroad was at the waste management company at VAM (Vuil Avfoer Maatchappij) in the Netherlands in Summer at the end of the last millennium. I was impressed with the waste transportation by train operated by the company from the towns directly to the facility, control system for monitoring the processes of composting, and thousands seagull birds at the compost facility. Seagulls can be used as a bioindicator during the early stage of the decay of the organic material can still be used as food to create the energy for them before doing a long migration facing the Winter. As far as the composting facility is not nearby the airport, the high density of the bird traffic may not disturb the human air traffic.

One of the largest birds of prey in North America is the bald eagle. It is very beautiful with the plumage of an adult with dark brown, white head and tail, and bright yellow beak and claws. Most of the bird watchers will enjoy much to watch the bald eagle, unfortunately in nature they always fly high and stay at the highest tree. It was found that the bald eagles stay nearby the compost facility during the winter and become tame. They enjoy the warm climate and abundance food at the compost facility. It was reported recently by CBC (Canadian Broadcasting Corporation), during the Winter almost 800 bald eagles were counted on a single day at the composting facility in Delta, British Columbia. They keep warming and feasting on organic scraps and seagulls instead of salmon.

The most amazing story is about the bird that make a compost pile. In Australia, there is a bird called the brush-turkey (Alectura lathami) that builds large nests made of leaves, other composting material, and dirt. They build compost pile to incubate their eggs so that they will not have to sit on them. The heat produced by the microbial decay maintains the eggs at about 33 – 35°C or about 15°C warmer than the ambient air temperature. Because each nest generates more than 20 times the heat production of a resting adult brush-turkey, many more eggs can be incubated this way than if they relied on warmth from the parent birds. Male brush-turkey builds the compost pile on shady areas beneath trees (about 80% shade) to attract the female to lay eggs that can be up to 24 eggs per mating season.

Each nest can be 1 to 1.5 meters high and up to 4 across meters. The largest brush-turkey’s nests were on Kangaroo Island in South Australia, where the average mound measures about 12.7 cubic meters and weighs about 6,800 kg. Scientists have constructed a computer model using data on mound size, ambient temperature, and the nest’s rate of heat production, water content, dry density, and thermal conductivity. The model predicts that as little as 1 cm of litter added to the mound will raise the core temperature about 1.5°C. Experiments indicate that the composting nests require (1) a critical mass of fresh litter (about 3,000 kg), (2) sufficient water content (more than 0.2 ml/g dry material), and (3) occasional mixing of the litter. This bird is clever by instinct and doing.

Nature gives a chance and everything. The Australian brush-turkey checks the temperature by sticking its beak into the compost pile. The temperature of the pile is regulated by adding or removing material to maintain the temperature in optimum. Like in some reptiles, incubation temperature will affect the sex ratio of chicks. It was reported that the sex ratio in brush turkeys is equal at the incubation temperature of 34°C, but results in more males when cooler and more females when warmer. Whether the parents use this phenomenon to manipulate the sex of their offspring by selecting the nesting site accordingly is still unclear.

The photo is courtesy of Esther Beaton, Australian Geographic. A pair of brush-turkey female (left) and male (right) on the compost pile.

It seems that we can use the warm climate and leftover resource specially during the Winter time to create the rest energy at the compost facility for other purposes. It is not only for the organic waste management and producing the compost, but also for producing beneficial soil microbes and protein such as single cell protein, bird protein, and worm protein in the near future.

-Bintoro Gunadi