See, the thing is, I like trees, too. And those guys not only send me at least one mailing a week — they've also obviously sold/given my name to other animal organizations, who also now send me mail spam.
I wrote them and said I wasn't going to donate to them anymore if they kept spamming me. They kept spamming me. So lately, I've resorted to becoming my own manual spam filter by writing "return to sender" on the envelopes, and blacking out the address. I used to not black out the address, but about half the mail just ended up back in my mailbox. The Postal Service...not the most observant crew out there.
So, donater beware — if you donate to the ASPCA, only do it if you love animals but hate trees. And if anyone out there knows of an organization that helps animals but doesn't mail you a crap ton of stuff, let me know.