Art by Christopher Maida
The avian homeplanet has an usually large amount of elemental cobalt. It compromises over 5% of the planet's crust, comparable to iron on Earth. Cobalt compounds generally have a much higher solubility in water than iron compounds, though, and the avian oceans are stained a purplish red from huge amounts of dissolved cobalt nitrate, cobalt chloride, and cobalt carbonate. Mineral veins of cobalt can be found commonly in the planet's rocks, forming streaks of red, blue, black, green, and sometimes yellow depending on rock composition. Sand and soil are sometimes stained purple and blue by the mineral as well, much like iron-heavy red soil on Earth.
Uninterrupted by large landmasses and driven by the heat of a higher energy star than our sun, huge hurricanes and storm systems often sweep through the planet's atmosphere. Classic architecture often dealt with these frequent heavy winds by being relatively low to the ground, tapering from the ground up, having a rounded shape, or having part or all of the structure underground.
As their population grew on planet, space-saving in cities became a major issue for avians. Modern architecture deals with the population density issue with advanced and dynamic shapes that flex in the winds, often reinforced with metal mined from undersea and off-world sources. Cities often grow outwards, into the ocean as well-- either on stilts and pontoons like those found on oil rigs, or on fill dredged up from elsewhere on the ocean floor.
Above is a traditional-style pygmy avian dwelling, which is about 3.3 meters tall.
They’re constructed from woody and fibrous plant materials, a plaster of crushed worm tree shells, and as little rare metal as possible. The surface of the avian homeplanet is over 90% ocean and most settlements are on scattered islands, so extensive mining for metal ore or even stone is tricky. The round shape protects against strong typhoon winds, and the upper balcony is left open for ease of takeoff and landing. Flight is not required to access any part of the building, though.