by Wolf » Thu Jul 17, 2014 1:35 pm
Good question, and at the risk of sounding condescending, the correct answer is when it is ready to.
Now, I will try to explain my answer. I don't have a cockatiel but some things are the same regardless of the species and this is one of them. First one never knows what type of vocalizations that their bird will choose to bless them with. some will sing up a storm as long as they are not aware that you can hear them, some will only sing for the right person, and only they know who that will be. Some of them will not indulge in it at all, some of them will only sing a tune that catches their attention and that they like and again, only they know which ones they like.
My best example of this is my African Grey Parrot. She is now 14 yrs. old and when she came to me she spoke a little and sometimes she said enough for me to know that she knew how to say a lot more and in context. Then she stopped talking and only whistled, about a month ago, she started talking again out of the blue. Interestingly enough, the only thing that she says now that she did when she arrived is her name. She still speaks in context, but it is totally different words and phrases then before. And while she talks to me, she rarely says anything when my Lady is present.
One just never knows.