Just when you’ve figured out purple and house finches, an orange finch shows up. Is it a new species?
No. It’s a house finch whose diet shows in his feathers.
Many birds acquire their intense red color from carotenoids in their diet. Flamingoes are pink because their favored food, brine shrimp, is rich in carotene. Northern cardinals are brighter red when they eat red fruits. This is true of house finches too.
The key is what they eat and when they eat it. A house finch can eat red carotenoid food all year, but if he skips it during his molt his new feathers won’t be as red. House finches molt in July and August. Back then the orange-colored finch was eating food containing beta carotene, which makes yellow or orange feathers, but not enough red.
Here’s a side view of Mr. Orange and Mr. Red.
Pretty as he is, Mr. Orange will have a poorer selection of ladies this spring. Female house finches prefer the brightest red males as mates so he’ll end up with a less favored female.
Fortunately he doesn’t have to be orange the rest of his life. If he eats red carotenoids next summer he’ll be much redder next winter. It will surely improve his love life.
(photos by Marcy Cunkelman)