birdhouse; nest box; bird box
A box placed for birds to nest in, often in gardens or parks.
When I put up a birdhouse in the garden, a great tit moved in.
Specifically a man-made box for keeping bees; see also 養蜂箱.
See also: 養蜂箱
There are many honeybees in this beehive.
Compound of 巣 (su, 'nest') and 箱 (hako, 'box'). The reading すばこ is a straightforward combination.