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Why Cardinals Are Red

12-12-14 cardinal DA8A9669The diet of a Northern Cardinal consists mainly of seeds, fruits and insects (average annual consumption is 29% animal and 71% vegetable matter). As fall progresses, the proportion of vegetable matter in its diet increases until it reaches a high of 88% during winter. The red plumage color of both males and females (females have some red feathers in wings and tail) results from the ingestion of carotenoid pigments obtained from their diet during the fall molt (September/October). Fruits and insects are high in carotenoids, while most seeds are poor sources. According to Cornell Lab of Ornithology, new research has shown that brighter males have higher reproductive success and territories with greater vegetation density, and that plumage brightness in both the male (breast color) and female (color of underwing-coverts) is positively correlated with parental care (feeding nestlings).

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10 responses

  1. Karen Burns

    I like to think it’s because they’re trying to brighten up the world.

    Sent from my iPad

    December 8, 2014 at 1:35 pm

  2. Marilyn

    Beautiful photo. It’s always exciting to see bright birds at the feeder!

    December 8, 2014 at 2:05 pm

  3. Beautiful capture, Mary. So the color relates to them eating things like rose hips, sumac, etc?

    December 8, 2014 at 3:37 pm

  4. Libby

    Interesting about diet….why aren’t more birds a brilliant red – wouldn’t the Cardinal diet be similar to other birds? Or is the amount that different….?

    December 8, 2014 at 4:54 pm

    • Excellent question, Libby, and one to which I don’t know the answer, but will try to find out!

      December 9, 2014 at 1:45 am

      • Libby

        Thanks, Mary! I’ll be so interested to hear…..perhaps the red feather color gene is in place and diet plus health enhance the tone? And I wonder if there is a relationship, as with Blue Jays, to light for our perception of their blue or grey.

        December 9, 2014 at 5:19 pm

  5. I’ve watched cardinals feast on the bright red fruit of euonymus, that pesky super invasive landscaping shrub. Can’t fault such a gorgeous bird for aiding and abetting!

    December 8, 2014 at 5:42 pm

  6. Similar to pink flamingoes, but I am not sure if it is carotenoids or pink crustaceans, such as shrimp, that affect their pink color.

    December 8, 2014 at 6:28 pm

  7. Gaylee Amend

    Hello Mary. What about the other birds who eat the same diet of mini apples, viburnum and other red plants, and would I turn red on a diet of red foods? hmmmmmm. My daughter was once mightily embarrassed by accepting the yarn sales woman’s explanation that the dark wools were determined by the sheeps’ diets…un uh. The woman was joking and pulled a “gotcha”; our child told her father who had raised sheep and had quite a laugh. Let us know about the feedback on this. Thanks, Gay Amend

    December 9, 2014 at 12:23 am

    • Very astute comment, Gay. I, too, wondered why it would affect one species and not another, but the fact that it does is indisputable…now I just have to find out why!

      December 9, 2014 at 1:45 am

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