Conservationists said that the black-faced spoonbills death toll rose from 11 to 37 as of noon yesterday but the cause may have been bad fish, not the weather.
The advent of a severe cold front over the weekend coincided with the dramatic discovery of dozens of ill spoonbills in the estuary of the Tsengwen Creek Sunday night.
Plummeting temperatures were originally blamed for the birds' illnesses as well as for the deaths of fish in some defunct fish pounds near the creek.
The critically-ill birds were rounded up on Sunday and given emergency medical care. Officials say 55 birds have been saved.
Autopsies were conducted on nine of the dead birds and extracts of their stomach samples were then injected into six white mice, which later died. Fish and water samples have also been tested.
One specialist found a botulinus in the dead fish eaten by the spoonbills which may have killed the birds.
Some conservationists suspect the fish ponds were deliberately poisoned, while others have speculated that the fish died as the result of hazardous wastewater from a nearby industrial zone.
However, the exact cause of death for both the endangered birds and the fish remains to be determined.
By the end of Saturday, 705 of the black-faced spoonbills are estimated to have arrived in Chiku.
At the beginning of the year, international estimates put the number of birds at around 950.
RSS