There are three main way to tell how old your Parakeet is;
1. HEAD BARS: In most mutations, Sexually Immature parakeets will have bars on their head all the way down to the cere. Immature parakeets will go through their first molt at around 3-4 months of age, and then lose the bars up to the top of the forehead.
*So... a parakeet with stripes down to the cere is less than 3-4 months old.
*Therefore, a parakeet with lines that stop at the top of the forehead, has gone through its first molt, so it is older than 3-4 months.
A Parakeet that is 3-4 months old or less will have bars going all the way to its cere (above)
A Parakeet that is older than 4 months will have bars that stop at the top of the forehead, after it's first molt.
2. ID/LEG BAND: Most Parakeets have a leg band on their leg (Usually left) that tells information about the bird, like It's ID number, the state it was born in, and the breeders initials. Learn more about leg bands on "Breeding Parakeets" page.
*The Band should also have the year, state and the bird's ID number. Most breeders color the leg bands depending on what year is was born in.
Leg Bands can tell the year that your bird was born in
Parakeets with eyes that are completly black are likely under 4-5 months old (See Chiko,below)
Birds with light or dark grey ireses are 5 months and older (see, Kito, Left)
3. PUPILS: In most Mutations, young parakeets' eyes will be all black, with no iris. As they get older, the iris gradually lightens to very light grey/brown.
* A parakeet with a completely black eye is most likely under 4-5 months old.
*A parakeet with a dark grey iris is probably 5-8 months old.
* As a parakeet gets older, it's iris will lighten, to a lighter grey, (or brown in some varieties).
So, budgie with a light grey, iris is probably older than 9 months.