My sketch:

Thinking something like 12 small schooling fish, most likely tropical (neons?), some insects, and two parakeets.
I originally thought 36x36x18 tank with 36x36x36 cage top, for total dimensions of 36x36x54h but now I'm thinking 24x24x16h tank with 24x24x24 cage top for 24x24x40 for both size and cost considerations. This would make the entire tank about 40 gallons, and with what is shown in the sketch it'd actually be about 7.7* US Gallons of useable water. I'm thinking expand the water to 1/2 the tank (12") then add a 4" radius semi circle for 10.8** US Gallons.
Have any of you done, or seen anything like this?
My main concerns are waste from the bird landing all over, could be hard to clean and cause problems.
Basically thinking to attempt to squeeze as much of a small ecosystem into a 24x24x40 area as I can.
*
(((8*3) + (.5*10*8))24) + ((pi(4)^2)5) = 1787.32741 in^3
1787.32741 in^3 = 7.73734806 US gallons
**
(12*8*24)+((pi(4)^2)*.5*8) = 2505.06193 in^3
2505.06193 in^3 = 10.8444239 US gallons

Thinking something like 12 small schooling fish, most likely tropical (neons?), some insects, and two parakeets.
I originally thought 36x36x18 tank with 36x36x36 cage top, for total dimensions of 36x36x54h but now I'm thinking 24x24x16h tank with 24x24x24 cage top for 24x24x40 for both size and cost considerations. This would make the entire tank about 40 gallons, and with what is shown in the sketch it'd actually be about 7.7* US Gallons of useable water. I'm thinking expand the water to 1/2 the tank (12") then add a 4" radius semi circle for 10.8** US Gallons.
Have any of you done, or seen anything like this?
My main concerns are waste from the bird landing all over, could be hard to clean and cause problems.
Basically thinking to attempt to squeeze as much of a small ecosystem into a 24x24x40 area as I can.
*
(((8*3) + (.5*10*8))24) + ((pi(4)^2)5) = 1787.32741 in^3
1787.32741 in^3 = 7.73734806 US gallons
**
(12*8*24)+((pi(4)^2)*.5*8) = 2505.06193 in^3
2505.06193 in^3 = 10.8444239 US gallons