WARSAW, Poland (AP) — White storks that have nested in Poland are heading south for the winter earlier than usual after an especially hot, dry summer, a development experts are linking to climate change.

Poland has a large population of white storks that arrive from Africa every spring and nest all summer before returning south by the end of August.

Gabriela Kulakowska, an ornithologist with the Polish Society for Bird Protection, said storks in many cases have departed about two weeks earlier than usual this year.

Kulakowska said Tuesday that "ornithologists say they have never seen anything like this."

She said that if the weather this summer is a result of climate change, "then this early year's journey is also an effect of climate change."