The most common bird in California is the House Finch (Haemorhous mexicanus). Known for its bright red head and chest (in males) and streaked brown plumage (in females), this small songbird is widely spotted throughout California’s diverse habitats, including urban areas, parks, and gardens. Originally a native of the southwestern U.S. and Mexico, the House Finch has adapted extremely well to human-populated areas, making it one of the most frequently observed birds across the state. What Is The Most Common Bird In California?