Games like Avian Colony
Games like Avian Colony include Frostpunk, Oxygen Not Included, RimWorld, Prison Architect, and Kingdoms and Castles. We matched them by the tags players give Avian Colony on Steam (Colony Sim, Simulation, Base Building, Survival, and Management): closest matches first, and among equally close ones the better-known games.

Frostpunk
Shared: Survival · Colony Sim · City Builder

Oxygen Not Included
Shared: Colony Sim · Base Building · Survival

RimWorld
Shared: Colony Sim · Base Building · Survival

Prison Architect
Shared: Simulation · Colony Sim · Base Building

Kingdoms and Castles
Shared: Colony Sim · Simulation · City Builder

Manor Lords
Shared: Simulation · Base Building · City Builder

Dwarf Fortress
Shared: Colony Sim · Base Building · Simulation

Against the Storm
Shared: Simulation · Base Building · City Builder

Timberborn
Shared: Colony Sim · City Builder · Base Building

Banished
Shared: Colony Sim · Simulation · City Builder

IXION
Shared: Colony Sim · Survival · City Builder

Space Haven
Shared: Colony Sim · Base Building · Survival

Empires of the Undergrowth
Shared: Simulation · Base Building · Colony Sim

Frostpunk 2
Shared: Survival · City Builder · Simulation

Settlement Survival
Shared: Colony Sim · City Builder · Survival

Ostriv
Shared: Simulation · Colony Sim · City Builder

Endzone - A World Apart
Shared: Survival · Simulation · City Builder

Workers & Resources: Soviet Republic
Shared: Simulation · Base Building · City Builder

Foundation
Shared: Simulation · City Builder · Management

Norland
Shared: Simulation · Colony Sim · Base Building

Infection Free Zone
Shared: Base Building · City Builder · Simulation

Planetbase
Shared: Colony Sim · Base Building · City Builder

Captain of Industry
Shared: Base Building · Simulation · Resource Management

Factorio
Shared: Base Building · Resource Management · Survival