Maximum longevity records for banded birds range from 16 to 20 years.
Average lifespan a bit harder but here's a bit of biologist speak ... of all the birds hatched the year Trey was hatched and assuming 80% of all adult birds survive each year, only 11% of the birds hatched in 1996 are still alive at 11 years of age and 1% at 20 years. So assuming that Trey is average (and we know he's NOT ) out of say 1,000 chicks hatched in 1996 including Trey, he is one of between 10 and 110 birds still alive today.
Very interesting information, TPC. Trey is anything but average -- he is an exceptional peregrine, and extremely handsome. I think about tiercels such as Sir James (20 years old), Kinney (17 years old), Zeus (16 years old), and Bandit (15 years old), who are still successfully raising chicks. And Mercury, who at 17 years old raised three chicks successfully on his own after the loss of Snowball.
Trey is one of a kind. Talons crossed for him to return very, very soon.