Caviana, the Ilha Caviana, is an island lying off the north coast of Ilha de Marajó

Marajó

Marajó is an island located at the mouth of the Amazon River in Brazil. It is part of the state of Pará.- Geography :With a land area of 40,100 km² , which compares to the size of Switzerland, it is the largest island to be completely surrounded by freshwater in the world...

 in the delta lowlands at the mouth of the Amazon

Amazon River

The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

 in the state of Pará

Pará

Pará is a state in the north of Brazil. It borders the Brazilian states of Amapá, Maranhão, Tocantins, Mato Grosso, Amazonas and Roraima. To the northwest it also borders Guyana and Suriname, and to the northeast it borders the Atlantic Ocean. The capital is Belém.Pará is the most populous state...

, Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. The island forms part of the low-lying marajó várzea, the inundated land in and around the mouth of the Amazon River. The island is an excellent place to observe the tidal bore

Tidal bore

A tidal bore is a tidal phenomenon in which the leading edge of the incoming tide forms a wave of water that travel up a river or narrow bay against the direction of the river or bay's current...

 called the pororoca

Pororoca

The pororoca is a tidal bore, with waves up to 4 metres high that travel as much as 13 km inland upstream on the Amazon River and adjacent rivers. Its name comes from the indigenous Tupi language, where it translates into "great destructive noise". It occurs at the mouth of the river where river...

, where the Amazon river waters meet the incoming Atlantic tides and form a standing wave

Standing wave

In physics, a standing wave – also known as a stationary wave – is a wave that remains in a constant position.This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling...

, and is a birdwatchers'

Birdwatching

Birdwatching or birding is the observation of birds as a recreational activity. It can be done with the naked eye, through a visual enhancement device like binoculars and telescopes, or by listening for bird sounds. Birding often involves a significant auditory component, as many bird species are...

haven.

External links

• Worldwildlife.org Terrestrial Ecoregions: marajó várzea