So you've found a Doberman? Now what? Certainly - call the nearest rescue
for advice but they are not Animal Control, do not expect them
to immediately come and take the dog off your hands. A dog without ID is still somebody's property -
if you are not prepared to provide shelter and look for the owner yourself then the correct thing to do is to take it to an
official animal control facility. Rescue is not the local Lost and Found
drop-off/pick-up department.
There is no simple answer to that question - except that it is loose knit, independant, groups of volunteers who are united by their love the breed and who each give what they can in their own way for the welfare of homeless Dobermans.
Rescues have the ability to advertise - through their website and other contacts. Rescues have the ability to screen potential adopters - to help find the appropriate home for the Doberman. They may be able to help you with food, medication and other supplies. They may give advice on behavior and temperament.
Have reasonable expectations, they cannot take every dog offered, nor magically place every dog at the drop of a hat. Listen to their advice - it has usually been learnt from years of experience.