Bird cage safety comes down mostly to one detail that varies by species: bar spacing tight enough to prevent a real, common escape and injury risk.
Bar spacing must match the bird, not just the cage size
A large, spacious cage with bar spacing too wide for a small bird is genuinely more dangerous than a smaller cage with correctly spaced bars — a bird can squeeze its head partway through gaps that are too wide, then become stuck or injured trying to pull back, or escape entirely into a room with other hazards. Smaller birds (like budgies and finches) need noticeably tighter bar spacing than larger birds (like macaws), whose heads and bodies are too large to fit through the same gap that would be dangerous for a small bird. Checking bar spacing recommendations for the specific species, not just picking the largest or most attractive cage available, is the right starting point.
Horizontal bars matter for climbing species
Many parrot species are natural climbers and use their beaks and feet to move around a cage's bars — horizontal bars, at least on some sides of the cage, give these species a way to climb and exercise that vertical-only bar orientations don't provide. For species known to be active climbers, checking that a cage includes horizontal bar sections, not just decorative vertical styling, supports natural behavior better than a cage chosen for appearance alone.
Cage material affects both safety and durability
Powder-coated or stainless steel cages resist corrosion and are generally considered safe long-term options. Some cheaper cages use coatings or metals that can degrade over time, particularly with exposure to moisture from food, water, and normal cage cleaning — a bird chewing on a degrading coating is a real health concern, not just a cosmetic issue with the cage's appearance. Stainless steel, while more expensive, avoids this degradation concern entirely and holds up well to the acidic droppings and regular cleaning bird cages need.
Cage size should account for wingspan, not just the bird's resting size
A cage needs to be large enough for a bird to fully spread its wings and flap without hitting the sides — a genuine welfare consideration, not just a matter of the bird "having more room." Sizing a cage to a species' wingspan and typical activity level, rather than just its body size at rest, gives a more accurate sense of the minimum reasonable cage size for that species.
The one thing people forget
Check the cage tray and grate design for how easily it can actually be cleaned regularly — a cage that's technically appropriately sized and spaced but difficult to clean thoroughly tends to get cleaned less often in practice, which affects bird health over time regardless of how well-chosen the cage was on paper.