The Great Central Valley supports an impressive array of little brown sparrows, but there is hope for the birder! Pick up a good field guide, and start narrowing your options down by season and by habitat. For example, determine which species are likely to be in the Central Valley in the fall. You'll be left with a shorter list of potential species after a process of elimination.
Another good tip is to learn the most common species backwards and forwards. I suggest getting to know the English Sparrow (Passer domesticus) first - although they're not sparrows in the true sense, but rather a type of Old World sparrow introduced from Europe in the 1800's. (Some ornithologists classify them as weaver finches, some argue otherwise.) Turns out they like it here; they are everywhere, the ubiquitous little brown birds of cities, suburbia, and fast food parking lots. Once you are acquainted with English Sparrows (also called House Sparrows), you will be better equipped to distinguish between the imposters and our true native sparrows.
|English Sparrow (Passer domesticus)|
The first native sparrow you ought to learn is the White-crowned Sparrow (Zonotrichia leucophrys), distinct with its prominent black-and-white striped head, and common enough to frequent bird feeders during the winter months. (This one at Merced NWR proved difficult to photograph!)
|White-crowned Sparrow (Zonotrichia leucophrys)|
|White-crowned Sparrow feeding on weed seeds|
|Song Sparrow (Melospiza melodia)|
So there's your assignment: make the acquaintance of our invasive imposter sparrow, then learn to recognize two of our most familiar and beautiful native sparrows, and you'll be well on your way to identifying more of the little brown birds you see in the field!