I am so sorry about Ginger, but sometimes we have to do "what we have to do"...it is never easy. I've told my DH that if I ever don't cry, then that's the end of animals for me.
When I did wildlife rehab, (and MOST of what wildlife rehabbers get in, don't make it), it was the hardest thing to do. I rehabbed only "backyard birds",(for almost 10 yrs), not the larger and "have-to-have-a-permit" raptors or the larger mammals. Some birds were so "broken" when brought to me and still alive, that the only merciful thing to do was "cervical dislocation"(recommended by our wildlife vet)...a firm quick pull and twist at the neck... I could not do it at first, DH did, but when he wasn't home I could not stand the suffering, and did it.
The other Vet recommendation, for small birds, was a large jar filled with cotton, saturated with ether (carb starter is ether, or at least WAS back then/ I have not looked recently), put the bird in for 10-15 mins (if I remember correctly), then put in freezer. The bird will be asleep and not feel any pain.
Ok...enough rambling...I'm getting teary.
Blessings and hugs to you.