The Golden-crowned Sparrow is the mystery cousin of the White-crowned. Much is known about the latter, but the Golden-crowned has had very little scientific effort devoted to it, by comparison. The Cornell Bird Lab website comments:
This sparrow is one of the least known of our songbirds, particularly on its northern breeding grounds. It has been the subject of only a few laboratory and field studies, so most of what we know about it comes from scattered notes in scientific journals.
Miners in the Yukon at the turn of the twentieth century woefully referred to the Golden-crowned Sparrow as the “no gold here” bird, because its song resembled that depressing phrase. They also interpreted its song to say “I’m so tired,” prompting them to dub the bird “Weary Willie.”
The Golden-crowned Sparrow arrives earlier and stays longer on its California wintering grounds than almost any other bird species.
When day length increases in the spring, the Golden-crowned Sparrow detects the change through photoreceptors (light-sensitive cells). Its body responds by putting on fat and getting an urge to migrate.
The oldest Golden-crowned Sparrow on record was at least 10 years, 6 months old. It was caught by a bird bander in California and released.https://www.allaboutbirds.org/guide/Golden-crowned_Sparrow
Here in the park, I see the Golden-crowned mostly on and around the perimeter trail on the north side. I rarely see them elsewhere in the park. The White-crowned, by contrast, can be seen feeding on the ground almost anywhere in the park in season.