This "chubby" angle reminds me of the pic of the mammoth looking Junco I posted a few days ago .... a skinny little bird captured at an odd angle and looking so huge.
Here's an excerpt from the Cornell Lab of Ornithology about Goldfinches and their strict vegetarian diet: "When Brown-headed Cowbirds lay eggs in an American Goldfinch nest, the cowbird egg may hatch but the nestling seldom survives longer than three days. The cowbird chick simply can’t survive on the all-seed diet that goldfinches feed their young."
[ps. "The Brown-headed Cowbird is North America’s most common “brood parasite.” A female cowbird makes no nest of her own, but instead lays her eggs in the nests of other bird species, who then raise the young cowbirds. Brown-headed Cowbird lay eggs in the nests of more than 220 species of birds."]