Large grayish bird, golden under wings. What is it ?

by margaret
(genesee, pa)

I live in northern PA. We have been seeing a large grayish/tan bird (larger wingspan than a robin but smaller than a hawk) when it takes to flight it has orangish or golden color under its wings, it has kind of a slim body and has white on its tail. We have lived here our entire lives but have never seen a bird like this. Help identify this please!!