Bird blind

A bird hide (or hide, British usage; known as a blind or bird blind in North America,) is a shelter, often camouflaged, that is used to observe wildlife, especially birds, at close quarters. Although hides or hunting blinds were once built chiefly as hunting aids, they are now commonly found in parks and wetlands for the use of bird watchers, ornithologists and other observers who do not want to disturb wildlife as it is being observed.

A typical bird hide resembles a garden shed, with small openings, shutters, or windows built into at least one side to enable observation. However, because birds do not recognize humans as predatory threats unless the human is standing in the open, a bird blind can be little more than a large shed open on one side in which birders stand, and motor vehicles are effective blinds even with the windows open.

Variant types of bird hide include:

...
Wikipedia