Come with me into the weird world of bird spit and avian stomach oils! To study it or even as a home business supplying restaurants there is considerable interest in the stuff.
I've seen snow petrels and despite all the fuss made about penguins they were my absolute favourite bird on my Antarctic trip. Along with a few other birds snow petrels produce strong stomach oils that can be used to:
1. Feed their young
2. Feed themselves on long journeys, but also...
3. Sprayed out to deter predators
Mumijo is the term used for accumulations of these regurgitated stomach oils – these get mixed up with poo, dirt and grit and harden into thick layers in some parts of Antarctica. Mumijo needs to be collected using a hammer and chisel. Studying it will help scientists look at 'the movement and changes in snow petrel populations over geological time scales'. In Antarctica where it is being collected by field biologists Marcus Salton and Dr Anna Lashko, it is then wrapped in kitchen foil, kept frozen before coming back to Australia for radiocarbon dating.
"Previous work has shown that some mumijo layers go back thousands of years" said Dr Louise Emmerson an Australian Antarctic Division Seabird ecologist.
"Because snow petrels only nest in ice-free areas, we can date these layers to work out how long it took for the snow petrels to occupy the landscape after it had been deglaciated."
"As the birds usually nest within about one day's flight from feeding grounds, the mumijo also provides information on changes in the coastal food web and sea-ice conditions over geological time."
So from Antarctic snow petrels on to little swiftlets in Vietnam where bird saliva is farmed as a delicacy. There is a huge market for edible birds nests especially in China. The edible-nest swiftlet (Aerodramus fuciphagus) is a small bird that uses solidified saliva to make its nest. Several other swiftlets also use saliva that can be harvested for human consumption. One species is even endemic to northern Queensland.
You can even buy the farmed nests in Australia. I found "Dried Golden Orange Bird Nest" for $499.97 per 100gms online. It is expensive stuff with many purported medical benefits from the minerals and proteins found within – such as amino acids like lysine, histidine, cysteine, arginine, humin and amide.
In Vietnam's Mekong Delta this demand has encouraged some family businesses to farm the nests – encouraging swiftlets to come to their specially built cavernous outbuildings where incessant swiftlet bird calls are played to reassure and lure in the birds. Once their nest has been built and the young reared then the nests are harvested, the birds are not harmed in any way. If you are successful in farming, each year it is hoped more swiftlets will return to breed at the same location. I can but hope this type of farming is sustainable and benefits the species or at the very least ensures the survival of the species, as once seen as an asset we are more likely to preserve than persecute. The swiftlets may well keep a farm's neighbourhood pest free and healthy for humans as well, amongst the many insects the swiftlets consume are mosquitoes!