Why wouldn't a bird want an RV? They spend their whole lives flying around using the power of their own wings. Give them a break, they deserve it!
Sometimes birds just yearn for the open road without spreading their little wings, you know?
Luckily birds don't need a trailer to take a trip, they can just sleep in it when they get home.
A feast for finches! A roast for robins! A cornucopia for crows!