With help (and the loan of traps) from the Feral Cat Coaltion, my husband and I trapped a mother cat and her two kittens. We had them neutered and inoculated by another animal welfare group, then brought them home. They'll join a few other community cats in our neighborhood, where several crazy cat ladies (and my husband) care for them.
The scope of the feral cat problem is sobering: this female was already in heat again and the rapidly-growing kittens would have started reproducing soon. Sad that people abandon animals to such uncertain lives.
@joysabin Thanks! I was amazed by the people who helped us: three different nonprofits, volunteers who trap cats and the vets who spay and neuter about 30 cats every Sunday.
Heart warming to know there are still so many people who care enough.