Monarch butterflies wintering in Mexico rebound this year

FABIOLA SÁNCHEZ

MEXICO CITY — The number of monarch butterflies wintering in the mountains west of Mexico City rebounded this year, doubling the area they covered in 2024 despite the stresses of climate change and habitat loss, experts said Thursday.

The annual butterfly count doesn’t calculate the individual number of butterflies, but rather the number of acres they cover as they gather on tree branches in the mountain pine and fir forests. Monarchs from east of the Rocky Mountains in the United States and Canada overwinter there.

Mexico’s Commission for National Protected Areas (CONANP) said that this year, butterflies covered 4.4 acres (1.79 hectares) compared to only 2.2 acres (0.9 hectares) the year before. Last year’s figure represented a 59 per cent drop from 2023, the second lowest level since record keeping began.

After wintering in Mexico, the iconic butterflies with black and orange wings fly north, breeding multiple generations along the way for thousands of miles. The offspring that reach southern Canada begin the trip back to Mexico at the end of summer.

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