Dozens of birds found dead in eastern Romania had drunk themselves to death, the local sanitary and veterinary authority (DSVSA) said.

The starlings died after they ate grape marc left over from the wine-making process, Romeu Lazar, head of the local DSVSA, told Agerpres new agency.

The cause of death was determined after the contents of the birds' gizzards were analyzed, he added.

On Saturday, several residents of Constanta, 260 kilometers (156 miles) east of Bucharest, alerted the authorities after they discovered dozens of dead starlings on the outskirts of the city.

They said they feared the birds had been killed by avian flu, but the DSVSA immediately ruled out that possibility.

The incident came after unexplained mass bird and fish deaths were reported in several countries, including the United States, Sweden and Britain.