Pigeon nests are messy piles of sticks and other debris carelessly woven together. In the city they like sitting them high up on flat ledges of apartments. If there isn't a place like that, they are highly adaptable and position their nest in any sheltered place from rain gutters to window boxes.
Sugar ant nests can be found between rocks and in holes in the woods. Their nests usually look like raised hills with a hole in the middle.
No, not quite sun conures are a little larger than green cheek conures.
Owls do make their own nests.In fact they look alot like birds nest's but bigger.
Flies do not make nests, they lay their eggs directly on a food source.
Zebra's behave pretty much like horses and don't have "nests". They lay down when and where it suits them.
Conures are not one specific breed of bird. Conures is used to describe either large parakeets or small parrots. There are over forty different species that are described as conures. Conure is not a scientific name, therefore it does not have a specific definition.
Some Conures when you buy them do come in pairs but others they come individually.
Scientists refer to aquatic-snails nests appearing bubble-shaped or similar to a cocoon where pairs of snails reproduce every 6 days or few weeks.
Squirrels build nests kind of like birds do. They pretty much look like bird's nests, and if they build them inside a tree, it looks like a nest inside a birdhouse does.
Finch nests look like a normal bird nest with a top encompassing most of the nest. Sortta like an igloo. There's a tunnel that leads to the main nesting area. Pretty complex design compared to most bird nests. I have one on my front porch in a hanging plant basket. It has about 4 eggs in it last time I looked.
They sound like anthills the way you describe it. Ants will build little nests that look like that.
Hawk nests are just mats of sticks, placed on an elevated cliff, or in the fork of a tree.