I was watching a DVD on parrot care (I hope to post a review in the next few days) when one of the presenters mentioned how important it is to weigh your bird once a week. Parrots are really good about hiding their illnesses, and weight gain/loss might be one of the first signs something is amiss.
With many things, the earlier you catch a problem, the easier it may be to correct. This vet said that a weight loss/gain of 5% of the parrot's body weight indicates a vet visit is in order (my vet has told me 10% in the past). I try to always weigh my parrots first thing in the morning, after they've eliminated everything from their system, and before they put any more in.
Although I know this, I don't always do it. I'll get in the groove and do weekly weigh-ins for several months, but then I just stop doing them and months go by again.
I pulled out the scale and weighed everyone this weekend. I don't have a fancy parrot scale with a perch; my parrots just perch on the flat surface.
Looking over the trends, it's interesting to see the weight gain the greys have made over the years. When Max was a baby, she was consistently around 300 grams. As she's matured, and especially since she started building muscles through flight, she now hovers around the 350 gram mark. That's near the upper limit for timnehs!
When Stella came to us, she weighed around 400 grams; pretty small for a congo. She's now in the 420 gram range. But she's still tiny compared to many of the greys I see at the rescue where I volunteer.
I really enjoy looking back over their log and seeing the changes; I need to remember to do this more frequently for all of the parrots (I need Thomas's help to get Rocky on the scale!)