Back in January, I wrote briefly about mysterious bird deaths - sudden and unexplained dieoffs of birds en masse - and not related to bird flu.

The Australian occurrence I mentioned wound up being traced to lead carbonate transport and shipping activities in the port and surrounding environment. That led on to a health scare in the local community and a revision of lead carbonate transport practices.

These birds were true "canaries in the coal mine"; alerting authorities to the problem.

Recently, around 1,000 Greater Shearwaters have been found dead in an area stretching from the Bahamas to Florida to the Carolinas; with 160 found along the South Carolina coast. Wildlife biologists aren't sure what's causing the dieoff, but have observed that the birds are very malnourished.

They hypothesise that wind may be blowing them off course from feeding areas, or that fish in feeding areas are scarce as has been reported by people familiar with the waters.

There's quite a few different species of shearwaters, all seasoned travellers - the Greater Shearwater follow a migration route up to a distance of around 8,000 miles. The common species in Australia is the Sooty Shearwater, aka Muttonbird or Mother Carey's Chicken. They were common companions during my fishing years and we did see mass dieoffs annually; but it seems this is not a regular phenomenon in regards the Greater Shearwater.

As with our local species, the Greater Shearwaters number in the millions, so the concern isn't so much about the loss of the birds in this isolated incident as such, but more as to why. We need to take heed of our feathered friends as they are so much more sensitive to changes in the environment than we are. Are these deaths, like the incident in Esperance, Australia, a harbinger of something much bigger happening off the coast?

Read more on the Shearwater deaths