Thousands of dead turtle doves rained down on roofs and cars in an Italian town on Friday in the latest in a growing spate of mass animal deaths across the globe.
Residents in Faenza described the birds falling to the ground like 'little Christmas balls' with strange blue stains on their beaks.
Initial tests on up to 8,000 of the doves indicated that the blue stain could have been caused by poisoning or hypoxia.
A witness told www.examiner.com: 'We have no idea why this happened all of a sudden.
'The doves just started falling one-by-one then in groups of 10s and 20s.'
Hypoxia, a lack of oxygen, is known to cause confusion and illness in animals. It is also a common precursor to altitude sickness.
Experts said results from tests on the doves will not be available for at least a week.
They said that cold weather could have caused the birds' deaths as the flock was swept into a high-altitude wind storm before falling to the earth.
It comes after two million dead fish were found to have washed up on shores in Chesapeake Bay, Maryland.
The alarming find is being blamed by authorities in Maryland on the stress caused by unusually cold water and overbreeding among spot fish.
That investigation comes just days after the deaths of an estimated 100,000 fish in northwest Arkansas, which is being blamed on disease.
A statement by the Maryland Department of the Environment said: 'Natural causes appear to be the reason.
'Cold water stress exacerbated by a large population of the affected species (juvenile spot fish) appears to be the cause of the kill.'
Mass winter deaths among spot fish have occurred twice before in the Maryland area -- in 1976 and 1980.
The incident is the latest mass animal death to hit the headlines in the last two weeks.
- 450 red-winged blackbirds, brown-headed cowbirds, grackles and starlings found littering a highway in Baton Rouge, Louisiana
- 3,000 blackbirds on roofs and roads in the small town of Beebe, Arkansas
- Thousands of 'devil crabs' washed up along the Kent coast near Thanet
- Thousands of drum fish washed along a 20-mile stretch of the Arkansas River
- Two million small fish in Chesapeake Bay, Maryland
- Thousands of dead fish found floating in warm Florida creek
- Hundreds of snapper fish found dead in New Zealand
- Scores of American Coots found dead on Texas highway bridge
Experts have speculated that New Year fireworks, thunderstorms, cold weather, parasites and even poisoning may be behind the deaths.
But conspiracy theorists have also speculated on the internet that secret government experiments could be behind them, with some even claiming it was a sign of a looming Armageddon at the end of the Mayan calendar next year.
Tests are being carried out on the dead birds and fish, but results are not expected for several weeks.
Scientists have been baffled by the sudden deaths of hundreds of birds which have plummeted to the ground seemingly simultaneously in several locations.
Two hundred American Coots were found dead on a highway bridge crossing Lake O' the Pines in Big Cypress Creek, Texas.
They are believed to have been hit by passing vehicles while walking or apparently trying to roost on the bridge.
The largest incident took place in Beebe, Arkansas, were horrified revellers witnessed around 3,000 blackbirds crashing to their deaths into homes, cars and each other as they celebrated New Year.
The deaths of tons of fish across the globe are being attributed to unusually cold water.
Thousands of Brazilian fishermen have been left struggling to make ends meet after the sale of seafood was temporarily suspended when masses of fish were discovered in Paranaguá, Antonina and Guaraqueçaba Pontal do Paraná.
Fish were also discovered rotting and floating in Spruce Creek, Florida, after another period of cold weather.
Courtesy the Daily Mail, UK