A worldwide community photographing and learning about wildlife
Setophaga coronata
It had yellow spots on it chest and where it's tail met it's body on top.
I live in California and I agree, no way a Kingbird though we have had Tropical Kingbirds recently, Kingbirds don't have streaks ever, they are also too big and posture is more upright. This is definitely a Yellow-rump Warbler.
Definitely not a kingbird. Not only are kingbirds thousands of miles away in central America right now, but they also do not have streaks on the body at any age. Not to mention you can clearly see the yellow rump in the second photo, which is where the yellow-rumped warbler gets its name from.