🏠 Housing & Husbandry · 8 min
Designing a cage
Why this matters
There is no such thing as one cage that works for any animal. Cage design is where species knowledge turns into a physical object, and where most preventable injuries originate.
By the end of this lesson you will be able to
- Apply minimum standards and choose materials by species
- Design for safety from predators, weather and escape
- Provide for an animal's psychological well-being
The NWRA Minimum Standards for Wildlife Rehabilitation lists minimum cage sizes for juveniles, recovering adults, and pre-release conditioning. They are minimums, and larger is often better. You will need to meet them if you apply for a USFWS permit for federally regulated birds.
Materials
- Wire caging is not appropriate for most migratory birds, especially raptors. Birds housed that way damage their feathers to the point of being non-releasable. Chicken wire will not do for a raptor.
- Waterfowl and many mammals can be housed in wire, as long as you watch their foot health.
- Uprights can be wood, metal or fiberglass. Use nontoxic, untreated lumber for dens and platforms if the occupants chew: rabbits, squirrels, other rodents.
- Flooring must be cleanable. Concrete cleans easily but is cold in winter and hard on feet. Soil or sand can be excellent, but the top few inches become contaminated with feces and parasites and must be dug out regularly.
- An aquarium is a poor long-term choice: poor ventilation, and it acts as a heat trap.
The raccoon rule
Because of Baylisascaris, the raccoon roundworm, no other species should ever be housed in a cage that raccoons have occupied. The only exception is stainless steel caging sterilized with a blowtorch. Roundworm eggs survive on surfaces for up to ten years and resist ordinary disinfectants.
Safety features
- Double-door entry prevents escapes and is a genuine safety feature, not a luxury.
- Double wiring and solid or wire cage bases keep free-ranging predators out. Raccoons, foxes, opossums and owls will patrol your cages at night, and raccoons are adept at reaching in and pulling animals to the wire to kill them.
- For digging species (foxes, woodchucks), extend the walls three feet below ground, or at minimum wire the bottom. Walls angled inward below ground eliminate digging out entirely.
- Outdoor cages must shelter animals from the elements and provide shade in summer. A cage that works in July may fail under heavy snow or an ice storm. Fresh, ice-free drinking water must be available at all times: bird bath heaters or heated outdoor dog bowls with wire-wrapped cords are invaluable in winter.
Psychological well-being
Cages must isolate animals from sights and sounds that frighten or stress them. Exposure to people must be minimized. Never house a prey species where it can hear, see or smell a predator. Domestic pets read as predators to wildlife, so limit all physical and visual contact between pets and patients.
Furnishings depend on the species. Provide dens and hiding places, without making it impossible for you to see the animal when you need to check it. Supply opportunities for perching, climbing, foraging and exploring, while remembering that you may need to go in and catch the animal. Provide water for drinking and swimming in a way that prevents accidental drowning.
Light
Simulate the proper photoperiod, the natural ratio of daylight to darkness, for animals housed indoors. Animals on the wrong light cycle molt, migrate and breed at the wrong times.
This lesson is part of the NY Wildlife Rehabilitator Exam course. Open it in the course to answer the retrieval checks that go with it, track what you have read, and quiz the whole unit. Lessons, quizzes and the glossary are free.