Sandhill cranes are seen at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year. (Photos: Xinhua)

Birdwatchers watch sandhill cranes at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year.

Sandhill cranes are seen at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year.

Sandhill cranes are seen at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year.

A wildlife photographer watches sandhill cranes at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year.

Sandhill cranes are seen at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year.

A sandhill crane is seen at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year.

Sandhill cranes are seen at the Jasper-Pulaski Fish & Wildlife Area in Medaryville, Indiana, the United States, on Nov. 19, 2020. The Jasper-Pulaski Fish & Wildlife Area is one of the roosting spots for sandhill cranes when they move from breeding grounds in the north to wintering grounds in the south from October through early December every year.