Police in Ukraine on Monday launched a probe into the deaths of at least 185 cranes in a large nature reserve in the south of the country.
Staff at the Askania-Nova sanctuary said they initially suspected that the cranes, some of which were coughing up blood, had bird flu. But this was not confirmed.
The regional police department cited the director of the reserve as saying that "around 185 endangered grey cranes died within a week".
Investigators suspect the Grus grus cranes, also known as the Eurasian crane and declared endangered in Ukraine, ate poisoned seeds planted at nearby farms to fight rodents, the police statement added.
The police probe is looking into "pollution or damage to the land" and establishing the exact cause of death.
Located near the Black Sea, Askania-Nova occupies some 33,300 hectares (81,500 acres) and is the oldest steppe reserve in the world.
It was founded in the late 19th century by a German colonist, Friedrich Faltz-Fein. It is home to more than 500 plant and more than 3,000 animal species of animals, some of which are endangered.
