Migratory species

Costa Rica is a bridge for migratory species

Costa Rica is an important stopover and breeding ground for some of the largest and most iconic migratory animals in the Americas. The most popular and largest migratory species you can encounter here are: The broad-winged hawk (Buteo platypterus) and the swainson’s hawk (Buteo swainsoni). Another is the Urania Swallowtail Moth (Urania fulgens). Other species that migrate to or pass through Costa Rica include: humpback whales (Megaptera novaeangliae) from North and South America. The green sea turtle (Chelonia mydas) comes from the Florida, Caribbean and South American regions. The olive ridley sea turtle (Lepidochelys olivacea) comes from the Pacific Ocean. Leatherback turtles (Dermochelys coriacea) migrate from the Gulf of Mexico and the east coast of the United States and Canada.

The broad-winged hawk (Buteo platypterus) and the swainson’s hawk (Buteo swainsoni) are two of the most iconic and awe-inspiring migratory raptors in the Americas, and are a particular highlight for birdwatchers in Costa Rica.

🧭 Migration marvel

It is among the world’s longest-distance migrating raptors
It breeds in North America (the USA and Canada)
It winters in Argentina and southern South America
It migrates through Central America, with Costa Rica being a vital corridor

🗓️ Migration timing in Costa Rica

Southbound (to South America): September-October
Northbound (return to breeding grounds): April

They travel in large flocks, known as ‘kettles’, using thermals to conserve energy.

📍 Best places to watch them in Costa Rica

Cerro de la Muerte
Caribbean lowlands (e.g., Kéköldi, Sarapiquí region). Migrants are most visible at midday when the thermals are at their strongest
Pacific coastal areas near open fields

🦅 Estimated numbers over Costa Rica (per migration season)

Broad-winged Hawk (Buteo platypterus)

🔢 1 to 2 million individuals
Seen primarily from late September to early November (southbound migration)
Some also winter in Costa Rica, especially in the forests

Swainson’s Hawk (Buteo swainsoni)

🔢 Hundreds of thousands, sometimes exceeding 1 million
Most pass through Costa Rica in October (southbound) and March–April (northbound)

🦋 Urania fulgens Moth

Visually stunning, day-flying moth
🗓️ Peaks in April–May and September–October
📍 Best seen in Caribbean foothills and lowlands and by the Pacific Coast (Alto de San Juan)

The urania swallowtail moth, one of Central America’s most spectacular migratory insects, is a day-flying, iridescent green-and-black moth that is often mistaken for a butterfly. Here’s an overview of its origin, life cycle, reproduction and migration patterns.

🦋 Where does the Urania swallowtail come from?

They are native to Central and northern South America, particularly southern Mexico, Costa Rica, Ecuador and Colombia
Costa Rican populations are particularly prevalent in the humid tropical forests of the Caribbean lowlands

🌱 Life cycle and reproduction

Egg stage: females lay their eggs exclusively on Omphalea plants, which are toxic vines or shrubs and are the only known hosts
Caterpillar stage: the caterpillars feed on Omphalea leaves. Over time, the plant becomes more toxic as a defence mechanism
Pupation: the caterpillar forms a pupa (chrysalis) and later emerges as an adult moth
The adult moth lives for only a few weeks. During this short time, it must reproduce and/or migrate

🧭 Why and when do they migrate?

Unlike many insects, the Urania fulgens moth does not migrate due to the changing seasons, but rather due to the cycles of plant toxicity
When the Omphalea plants become too toxic due to caterpillar feeding, the moths migrate en masse to find new plants
Two main migration waves are often observed: April–May and September–October
However, these timings may vary depending on rainfall and food availability

🔁 Do they return?

Urania fulgens does not typically return as individuals; it’s more like a wave migration
After laying their eggs in a new location, the next generation continues the cycle
Therefore, while the species cycles through regions, individual moths do not migrate back like birds or whales