Monarch Butterfly Reserve

Every autumn, monarch butterflies from across eastern North America - some having flown thousands of kilometres - funnel into a handful of high oyamel fir groves on the Michoacan-Mexico State border, and the result is one of the planet's great wildlife spectacles. Through the winter they cluster in their millions at around 3,000 metres, coating trunks and bending branches under sheer insect weight; on warm, sunny middays they lift into the air in drifting orange clouds that fill the forest with the sound of wings. The reserve was inscribed by UNESCO in 2008, and the sanctuaries of El Rosario and Sierra Chincua receive visitors from late November to March, always with local guides, on trails that climb through the firs to the roped-off colony edges. Silence is asked and rewarded - the spectacle is close, wild and strangely solemn.

What you actually see

• The clustered firs - branches bowed under millions of wings.
• The midday lift-off - orange clouds when the sun warms the colony.
• El Rosario's trail - the classic climb to the largest colony.
• Sierra Chincua - the quieter sanctuary over the ridge.

When to go

Late November to March, with January and February the dense heart of the season. Choose a sunny day if you can - the butterflies fly in warm midday light and sit tight in cold cloud.

Honest expectations

The trails climb steeply at 3,000-plus metres, so the altitude bites - horses are available for hire at the main sanctuaries. Colony locations shift and viewing is at a respectful rope's distance in enforced quiet. Cold mornings show still clusters, not flight; patience and midday timing make the visit.

Nearby

The town of Angangueo, colonial Morelia and the lakeside villages of Patzcuaro.