I think you mean a hide. It's to allow good views of birds without disturbing them.
You are probably thinking of a hide.
BirdWatchers was created in 2008.
The duration of BirdWatchers is 1.73 hours.
Newsletter for Birdwatchers was created in 1960.
Birds go tweet. And twitters is shorter and catchier than birdwatcher.
The cast of Birdwatchers - 2011 includes: Humberto Castello as Conquistador 2
A "Twitcher" or more properly an "Ornithologist".
They are called lairs, dens, burrows or earths.
So that they have somewhere to live and to raise their kits.
An otter's den is called a holt or a couch.
den
It is called a lair, a den, a burrow or an earth.
A bird-watcher's den is called a HIDE.