In addition to the 5,200 dead, another 10,000 are believed to be infected, according to Ohad Hatsofe, a specialist at the Israel Nature and Parks Authority.
A bird flu outbreak has killed thousands of wild cranes on a reserve in northern Israel, an unusually high toll for the seasonal flu, the parks authority said Sunday.
Israeli officials say the bird flu outbreak is the deadliest wildlife disaster in the country's history, with at least 5,200 cranes of the half-million which travel through Israel on their way to Africa laying dead in the Hula Valley.
A spokesperson for the Jewish National Fund's Hula Lake park said workers were removing the carcasses as quickly as possible, fearing they could infect other wildlife, including vultures that feast on dead animals.
In addition to the 5,200 dead, another 10,000 are believed to be infected, according to Ohad Hatsofe, a specialist at the Israel Nature and Parks Authority.
Environmental Protection Minister Tamar Zandberg tweeted the crisis was "the most serious damage to wildlife in the history of the country".
An Agriculture Ministry spokesperson announced that half a million chickens in the area were to be slaughtered to prevent the disease from spreading.
About 500,000 cranes pass through Israel each year on the way to Africa, most stopping in the Hula Valley, an important point on their migratory path.
"This year's outbreak is much larger than previous years," said Uri Naveh, a senior scientist at the authority. He described the number of dead cranes as "exceptional".
An estimated 30,000 cranes are believed to have remained in the area for the winter.
"The avian flu ravaging the population, H5N1, has been detected in some chicken populations in northern Israel," Israel's Agriculture Ministry spokesperson added.
The ministry has suspended egg sales from affected farms.
"It is rare for H5N1 to spread among humans, but there have been past outbreaks," he went on.
According to the World Health Organization, H5N1 has killed more than 450 people -- mainly in Indonesia, Egypt, and Vietnam -- since 2003.