Or a birthday gift for a good friend? Since most of us have more worldly goods than we actually need, why not give a wildlife adoption.
What is a wildlife adoption and how does it work?
There are many wildlife support groups out there that offer wildlife adoptions. Most of the organizations have different packages, some starting as low as $ 10. You choose the amount of money you want to spend and for this amount a donation will be made in the name of the person you want to give the gift to. The recipient then gets, depending on the organization and the package you chose, a certificate of adoption and other information regarding the chosen animal. The money they raise with the adoption will be used to protect the specified animal and it's environment. Some offer the adoption of one specific animal, like the WDCS (Whale and Dolphin Conservation Society), others put it use for the whole selected species, where ever it's needed most.
A few of the organizations I have used in the past are: Defenders of Wildlife, Polar Bears International and WWF
But this is by far not a complete list, just suggestions to start with. Also check with your local organizations.
Not into wildlife? Check out Heifer to support families and farmers in third world countries.
Feel free to add your favorite organization in the comments as an idea pool for others!