Unless you plan to breed your small pet birds for the show bench then successfully breeding budgies, cockatiels, zebra and society (Bengalese) finches is hardly challenging. All these four species of small pet birds will breed quite happily if given some simple basic necessities.

Sexing your small pet birds can sometimes be a bit hit and miss as not all have obvious differences between the two sexes. Adult male (cock) budgies will have a blue cere (the small flesh-like part above their beak (looks like nostrils) whereas the adult female (hen) budgie has a brown or tan-like cere, all juvenile budgies will have a pale blue cere until fully fledged. Bengalese (society) finches are very difficult to sex and best left to an avian professional (or you could just take your chances with a few and hope some pair up); the only really obvious trait is that a male will sing whereas a female will not (again not strictly true as hen birds can sometimes turn out a few pleasant notes, but the cock bird is much more efficient with his vocal chords). Normal zebra finches are generally easier to sex as the cock bird will have red or orange cheeks whereas the hen bird will not. As for cockatiels; well to be honest with you, I haven't got a clue and just have to take my chances, an avian professional will be more able to help. With many other breeds, especially the many types of parakeets (small parrots) the male is often more brightly coloured than the female, but not in every case.

Firstly any pet birds you wish to breed should be in good health as raising chicks can be an exhaustive task and unfit birds would be unable to achieve it successfully.
Secondly your small pet birds are going to require some sort of nest box, loads are available at very reasonable prices (or you could make your own), more info below.
Also you will have to ensure that there will be sufficient heat for your birds to breed and raise chicks, not excessive heat but enough for them to be comfortable.
Plus your small pet birds will need a good regular supply of various foods to help them keep up their strength and feed their offspring.
Finally, certain nesting materials will be required for your birds to use.

So lets start at the beginning shall we; keep an eye on your birds to make sure that they display no signs of ill health or weakness. Of course the birds you hope to breed will have to be fully fledged and adult, this should go without saying. If you only have an opposite sex pair in a cage or small aviary don't assume that they will want to breed, some just don't fancy each other or are not ready. If however you have a large communal (or mixed) aviary your chances of breeding success will be much improved. Unless you plan to breed for the show bench (this requires much more attention) then you should allow your birds to choose their own mates. Most of the commonest birds kept as pets are monogamous by nature, that means they will pair for life and the same pair will mate year after year, there are exceptions of course but as a general rule monogamy is in where your pet birds are concerned. You will notice a paired couple in your mixed aviary as they will follow each other around and stick together, and an act known as 'billing' will occur often between the pair. Billing can be described as kissing, your birds will effectively 'kiss' each other with their bills (beaks), imitating the act of feeding each other (which of course they will actually do once nesting takes place).

This subject and others are covered more extensively in my new ebook out now. So for more information or to get your copy please email me.