The most common problem you will have with your birds will be aggression. This will be more of a problem in smaller cages with more birds. If you notice that one bird is starting to bully the others, it is a good idea to seperate the bully by placing them into another cage. Bear in mind that some species are incompatible, and many others will become aggressive during the mating season.
Canaries are usually placid, but aggression is possible
As with most other animals, tensions will be high during the mating season. Canaries will sometimes enter bouts of competitive singing, even if they are being kept in separate cages. Whilst this can often be pleasant to the human ear, a constant song-based showdown between two birds will soon stress the involved parties out. If you have this problem, the best solution is to separate the two cages so that they are not within earshot. If the competitors are in the same cage, there is little you can do. The confrontation may even end in a scuffle, or one of the birds may become so tired that they’ll retreat to a corner. Keep an eye on any such development to make sure the user doesn’t succumb to any illness due to the fatigue.
Hens may sometimes lay eggs even when no mating has taken place. It is mating and nesting that require the specific stimulation of courtship and bonding, not so much egg-laying per se. If a hen does lay an egg without a cock bird, it will of course be infertile.
Hot or Cold
Your birds will have several tell-tale signs which will let you know if they are feeling overheated or cold. A bird that is too hot will have drooping wings and an open beak. Make sure that your birds have some shade that they are able to retreat to, or even install a cooler if things are really too hot. A hot bird is not usually in any danger and will just spend more time sitting and panting.Keep in mind that these symptoms can also be symptoms of a more serious illness.
The feet of a Canary can be a clue to its health
A fluffed-up bird could, again, indicate illness; though it could also simply mean that your bird is cold. If there is anything you can do to safely heat up the environment, do so. A cover over the cage during the night is a good move.
Owners whose pet canaries or Zebra finches perch on their finger will come to recognise the normal temperature of their pets’ feet. If the bird is hotter or colder than usual, you will be able to tell by their feet.
Sometimes a cock bird will enter the mating season earlier than then hen. In cases such as these, the hen will not be receptive of the cock’s courtship, and the frustrated male may begin chasing, or even attacking her. If this does happen the pair will need to be temporarily separated.
A tired bird doesn’t necessarily have to be ill, they might just not be getting a good night's sleep. If there are lights on in the house during the night, your finches will not be happy and will lose sleep over it. Make sure that your birds are in a dark room during the night, and if it’s not possible to turn off all the lights try covering their cage with a sheet overnight.
Some cock finches will take great pride in their nests whilst the hen is incubating the eggs. During this time it is not uncommon for them to become aggressive towards other birds that get slightly too close. If given enough space, the other finches will simply learn to stay away until things calm down. In a smaller cage, this is a more serious problem with no real solution other than separating all the other birds. This is one of the reasons why Canaries are usually kept either alone or in breeding pairs.