3 Things You Need to Know about Yellow Cardinals
The recent yellow cardinal sighting from a backyard in Alabama has taken the internet by storm, appearing in social media news feeds, email inboxes, and on YouTube. But this isn't the first, and most certainly won't be the last. Here's a few factoids you should know and share with your bird-loving friends who are all enamored with photos of this bird.
1.) This isn't the first yellow cardinal.
From what I could find with a little bit of internet digging, the first yellow cardinal was spotted in 1989 in Baton Rouge, Louisiana. It was collected (that's museum terminology for humanely killed) by scientists from Louisiana State University (LSU) and added to their museum collection. At that time, the research potential of having that specimen was untapped, but in 2001 feathers were taken from this specimen, and analyzed to better understand what caused the aberrent plumage.
In 2009, and again in 2012, an Ohio birder had a yellow cardinal visit his feeders. You can learn more about it and see photos here.
On January 21, 2011, a yellow cardinal was seen at a bird feeder in Kentucky (Lexington Herald Leader, 2011) Even more strange, the following weekend a second identical bird appeared- possibly related to the first?
Several years ago, another male had been visiting a feeder in Wynne, Arkansas for multiple years, according to Cyndi Morgan via Facebook.
2.) What made this cardinal yellow?
The simple answer: A rare genetic mutation
A more complex explanation: Animals and plants exhibit a variety of colors, resulting from chemical pigments. Pigments absorb and reflect different wavelengths of light which allow a variety of biological processes to happen, including photosynthesis in plants. Plants use a variety of pigments including chlorophyll, xanthophyll, and carotenes to absorb light energy to covert carbon dioxide and water into useable energy. Carotenes or carotenoids are a pigment which gives carrots their orange color, absorbing UV, violet, and blue light and reflecting red and orange wavelengths.
Since carotenoids occur in plants, they are passed on to birds after plant material (seeds and berries) have been eaten and digested. It's not very well understood how these pigments are metabolized and exhibited in feathers, but according to the 2001 study mentioned above, McGraw and his colleagues discovered that the mutation in yellow cardinals disrupts the expression of red pigments normally found in male cardinals (McGraw et al, 2005) This condition of abnormal yellow pigmentation is referred to as xanthochromism. Examples of this condition in the wild exist in multiple species of songbird, including Evening Grosbeak, Red-bellied woodpecker, and Scarlet tanagers, among others.
It gets much more complex, and you super sciency-folks can read the full paper here.
3.) This isn't a Yellow Cardinal (Gubernatrix cristata)
Please don't confuse this yellow cardinal with the endangered Yellow Cardinal (Gubernatrix cristata) of South America. Found in Brazil, Paraguay, Argentina, and Uruguay, the Yellow Cardinal has undergone significant population decline due to illegal trapping for the cage bird market. Combined with habitat loss, this species has undergone a rapid decline- as few as 1,000 might remain in the wild (BirdLife International, 2018).
Overall, it's a real treat to see this gorgeous bird, and understanding a little of the history and science behind this rare expression of genetics makes enjoying the sightings all the more sweet.
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Please note- this post is intended to pull together information, photos, and facts in a different way than recent news articles. Although these articles have been used as a reference, all material is cited and referenced and presented in a unique way for others to learn and enjoy. If I missed anything- please let me know!
BirdLife International Species factsheet: Gubernatrix cristata. Available from: from http://datazone.birdlife.org/species/factsheet/22721578. Accessed 27 Feb 2018.
"Rare Yellow Cardinals Spotted in Boyle" Lexington Herald Leader. Available from: http://www.kentucky.com/living/home-garden/article44078892.html. Accessed 27 Feb 2018.