Canaries should be housed in cages with no greater than 5/8 inch bar spacing; ½ inch is standard. Any wider bar spacing can allow a bird to stick his head through the bars and injure itself.
Despite the fact that pet bird cage manufacturers produce great numbers of tall, round, highly ornamented cages, what a canary really needs is a simple rectangular cage which is longer than it is tall to provide room to fly back and forth. Some height is beneficial since a bird that has to fly from a high perch down to the floor of its cage and back up is exercising some of the same muscles it uses to sing.
Locating a good cage in a pet store is often difficult- the majority of cages sold there are simply inappropriate and more hassle than they are worth. Most of my customers who have purchased cages in pet stores tell me that they have had to buy a more suitable cage within a few months, so it is best to simply buy a good cage in the beginning and save the money.
The only cage I recommend for canaries is a flight cage- this is a rectangular cage that provides plenty of space for flying back and forth as well as allowing for up and down flight. It has room for placing perches at different heights, is easy to clean, and allows for full viewing of the bird. Wooden cages or highly decorative cages are hard to clean and provide mites and other parasites space to hide and breed. Metal or plastic coated metal is fine- it’s easy to clean and sterilize. Floor grills are not necessary and add to clean up work. Many flight cages are made with an irremovable floor grill- removing it makes the entire cage unstable. Irremovable grills can be covered with newspaper. As for cage size, the general rule of thumb is the larger the better unless birds will be let out of the cage daily for exercise.
The best- and most inexpensive- material to use for covering the cage floor is newspaper. Other items such as ground corncob, wood shavings, etc. harbor parasites, bacteria, and can grow moldy if they become wet. It is difficult to clean fresh food out of the cage if one uses materials such as wood shavings- canaries often scatter or carry food to other parts of the cage and may become ill from eating spoiled tidbits they locate in the bedding. Besides the tendency of the material to scatter in the breeze created by birds in flight, some birds develop a habit of gathering this material up and soaking it in their water dish creating an unsanitary situation. Newspaper can be laid down in a single layer and rolled up, thrown out and replaced in a few seconds on a daily or every other day basis.
Sunlight is important to a bird’s health. Place the cage in a bright location with a portion of the cage out of direct sunlight so the bird can take shelter and avoid overheating. If natural sunshine is not available, a full-spectrum light should be used to ensure that your bird receives an adequate amount of light.
Fresh air is wonderful, but keep your pet out of hot or cold drafts including those created by fans, heat and air conditioning vents. Sometimes a bird can get a draft from an unexpected source- such as when air from a fan directed away from his cage bounces off of a wall or other object and is redirected back at the cage. The common wisdom is that if the flame of a candle flickers near his cage, it is probably too drafty for your bird. This said, I believe that a certain amount of airflow is needed and that the gentle breeze from a window will not harm a canary as long as he is able to move out of it if he desires (a cloth can be placed over one end of the cage to block the breeze) and the breeze is neither extremely cooler or hotter than the overall temperature of the room. Certainly, a breeze from an air conditioning or furnace vent would not be good.
Generally, a canary will be comfortable at the same room temperature people are- 65 to 70 degrees. Be careful if the temperature becomes too high as this can stimulate your bird into an unseasonable molt.
It depends. Canaries, although friendly, are not particularly sociable. In fact, they have a distinctly territorial attitude.
Male canaries should be housed separately. Two males caged together WILL fight- sometimes until one is killed or both are injured badly. Once in a while two males seem to work out an arrangement and do manage to live together in relative peace but in almost all of these cases, one of the males stops singing. Males caged separately seem to enjoy the presence of each other and encourage each other to sing more often, though, so having another bird for companionship is beneficial.
Female canaries can be caged together throughout the year, though once again they do have their own personalities and some get along better than others.
Males and females should NOT be kept together at any time except during the breeding season and during the molting period (BOTH must be in full molt, however). Males can chase a hen to death trying to mate with her and hens can be pushed into laying eggs when they are not in condition to do so, which can lead to egg binding and death.
The social dynamics of a large walk-in flight are different than that of a small flight cage - if the space provided is sufficient, often a number of canaries may be housed together throughout the year if the personalities of the individual canaries is amiable. Occasionally, a particularly territorial bird (and it can be either a male OR a hen) will cause problems so an alternate housing arrangement should always be available should the need arise.
I have resolved these issues in the past by removing the offending individual to separate quarters for a week or two and then reintroducing him to the flight, which alters the social dynamic of the flock enough that most "bully birds" do not become repeat offenders.
You may also encounter a rare bird that seems to be the "omega flock member" and is bullied incessantly by other birds. These birds can become seriously injured and severely stressed by being ruthlessly chased, pecked, plucked, and just generally mistreated. The kindest thing to do for these unfortunate birds is to house them separately- perhaps with other birds of a similarly meek temperament.