There are many organizations that help wildlife and need your support. Here are three to which I am personally connected; I encourage you to donate to one or more, if you have found this blog useful.
The Cornell Lab of Ornithology conducts research on every area of ornithology, from behavior through evolution to conservation. They run a number of citizen science projects that you might enjoy participating in too, such as NestWatch. I got my start in ornithology as an undergraduate at Cornell, and it changed my life.
The San Francisco Bay Bird Observatory runs a number of programs aimed at understanding and conserving birds in the San Francisco Bay Area. They run a banding station (at which I volunteer), monitor local breeding birds, protect local plovers, survey for sick or injured waterbirds, and engage in lots of outreach and public education for all ages.
The Lindsay Wildlife Rehabilitation Hospital provides medical care for injured and in-need wildlife in the East Bay. They see everything from Red-shouldered Hawks to squirrels to gopher snakes, from new-hatched (or newborn) babies to injured adults. They take great care to keep the animals wild and to give babies the chance to learn critical wild behaviors before releasing them. I volunteer here, and I am very proud of the high level of care each animal receives. Since none of the animals pay their own medical bills, this place survives on donations.
If you want to help wildlife in a non-financial way, here are some easy suggestions: spay/neuter your pets; keep cats indoors, and encourage others to do the same; keep an eye out for nests (bird or squirrel) when trimming trees or mowing the lawn; grow local species of plants in your yard, including species that provide food (such as berries) and species that provide shelter from predators and places to nest; learn how to tell if an animal needs your help, and don’t touch or pick up wildlife (even/especially babies!) unless they meet those criteria.