Blue-headed Mallard

As one of the most common ducks in North America, most everyone is familiar with the iridescent green head of the male mallard (Anas platyrhynchos). Feather color, as I mentioned in an earlier post, is determined by pigments, the structure of the feather or a combination of both.

While watching the ducks on a pond at Crystal Lake Fish Hatchery (Shasta County CA) one mallard caught my attention. The head of this mallard was blue. Because the iridescence and color of birds is affected by the angle of observation, I watched this particular mallard for nearly fifteen minutes, yet the blue color never varied. This was not a blue-green color nor was the mallard’s head simply “dark”  due to shadows – the head was a constant, beautiful, rich blue. On occasion I hear about a blue-headed mallard and have even seen mallards whose heads seem blue in certain light. But the blue head color proves in reality to be brilliant green when the duck moves. No matter how this duck moved or how the light changed, its head was blue. I wondered why?

I certainly have not done a comprehensive review of the literature, but I could find no explanation for this blue-headed mallard although as I thought about the little information I had, I came up with several theories, one of which I will mention. Please remember, what follows are simply my musings, not, to my knowledge,  scientific fact.

According to Nina G. Joblonski  in her book “Living Color”, the intensity of the mallard’s  iridescent green head feathers is related to the level of testosterone, higher levels of this hormone resulting in brighter green color. But since a non-breeding or eclipse male has a nondescript brown head similar to the female, where does a blue head enter the picture?

Eberhard Haase et. al. (reported in “Pigment Cell Research”) studied the pheomelanin and eumelanin levels in mallard duck feathers. Melanin is a pigment in feathers. Pheomelanin is a more yellow form and eumelanin is more brown. Without going into the entire content of their research, let me note, in a very superficial manner, that Haase and his colleagues found that males, as their testosterone levels rose in the spring, developed significantly more of the yellowish pheomelanin in their feathers while the brown eumelanin declined. Females displayed more of the brown eumelanin in their feathers. Following so far?

Remember from high school physics that green is a combination of the primary colors blue and yellow. Is the blue color (structural or pigmented?) of mallard head feathers disguised by the brown eumelanin in females and in males whose testosterone is low outside of the breeding season? Then as the male’s testosterone level begins to increase in the spring, the blue shows through as the eumelanin decreases. After the amount of yellowish pheomelanin gets high enough, the head feathers appear green since blue and yellow make green.

A mallard with a blue head could, repeat could, simply not have a high enough testosterone level to produce enough yellow pheomelanin in the head feathers to make the feathers appear green. This lack of testosterone could result from a genetic inadequacy or perhaps the mallard was a young male that still was not making enough of the hormone. Or. . . ?

I certainly do not know the correct answer. Yet speculating is an interesting mental exercise.

I would love to know why this mallard’s head appeared to be truly blue and not simply an optical trick.

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56 Responses to Blue-headed Mallard

  1. Elise Fleming says:

    Got a photo of a purple-y blue-headed drake swimming just ahead of a green-headed mallard. No trick of the light. Like an earlier poster, this was on a private lake in NE Ohio. Thanks for the hypothesis of the testosterone levels!

  2. Iris Peterson says:

    Three blue-headed ducks in N. San Diego County by Ponto Beach.

  3. Melissa Cates says:

    Very interesting! I live on a lake in TN. Of course there is a plethora of wild life! I love watching all the different kinds of ducks. The most familiar being the mallard. Today I saw one with a completely blue head! Like you, I watched for a good while to see if it was just “the light”! It never changed…it stayed a gorgeous blue! I tried to take a pic, but you can’t see the brilliant blue! Thanks for sharing your hypothesis!

  4. Nickie Drysdale says:

    This is great information, thank you for sharing! I experienced the same thing – I was watching a blue headed mallard, waiting for the sun to hit it differently and appear green as usual. But that never happened. I watched for several minutes as it swam around on the river, ever blue. Hence my online search for blue headed mallards. Looking forward to reading more from you!
    Cadillac, MI

    • gingkochris says:

      I did the same thing. I got a picture of a blue-headed mallard and thought it was the light. So I went back and again saw the blue head. It was only after watching and taking photographs with the light at various angles that I finally decided the mallard had a blue head.

  5. Janine Rewers says:

    Saw a larger than usual mallard – body colour like that of a femaile – but definitely purple on the wings and the head North Thompson River in Kamloops, British COlumbia.

  6. Marilyn says:

    Checking in with a blue-headed mallard siting on a private lake in NE Ohio!

  7. Frank Cotty says:

    Wow, glad I found your site. Denise and I saw at least 5 purple (not blue) head “mallards”. In a pond in Merrick, south shore community of Long Island NY. The beak was a light yellow, no ring around the eye. Prominent white neck ring only visible when they stretched up. There were regular green head mallards there also, but those were significantly smaller than the purple heads. unlike other crossesall the individuals we saw showed the same striking black & white pattern of back and wings. Did not see them flying. Green head mallards were apart from the purples. We suspect these could be mallard X ring neck duck cross. But have no way to prove it. This is a common migration pond for a variety of ducks, geese and, on one occasion, one whistling duck.

    • gingkochris says:

      This is not a scientific observation, but personally it seems to me that over time I am seeing more “blue” or “purple” mallards. I never read anything about a mallard/ring neck duck cross.

  8. Dana says:

    We live in Boise, on the canal behind our house, we have a purple headed drake. He is an adolescent, and have been watching him in all angles of light. In the shade it looks just about black.

  9. Amanda says:

    I’m in southern Indiana–two purple-headed males hung out for a couple of weeks in our pond this spring. There appeared to be only one female with them. Dark, royal purple! I believe at least one nest had been built, based on the one location near the shore where they seemed to always be when not swimming. They disappeared after an enormous all-night downpour. Perhaps the nest was swamped when the water level rose?

    • gingkochris says:

      I keep hearing about blue-headed mallard sightings from all parts of the United States.

      • bruce Montgomery says:

        Hi, In my pond the we have pair of Mallards that fly in every year , Same ones as they are tame and come up to the house to visit when they arrive every fall. The males head turns from dark green to blue and purple. Very strange but i guess its common. I used to think it was different ducks before they became tame. We have watched his head turn colors and cant figure out if its the light of day or his mood

      • gingkochris says:

        The blue-headed mallards in my post did not change color. They remained blue no matter what the light conditions were – or how they moved about. I watched them for several days.

      • J. Rose says:

        As with many things this topic has proven to be quite a merry chase. When painting a pull toy – you guessed it – duck, I started to just looking at ducks in a different light. Someone sent me a fill in the spaces with flat paint without feathers, etc. Then I decided to look up some photos and noticed the bluish color, and my search lead me to this site. Thank you for this info which has proven to be more interesting than I imagined. I had notice the blue stripe on the wing feathers. God did an amazing paint job on the beautiful birds!

      • gingkochris says:

        Glad to be of help with your creative project.

  10. I have my sailboat at a marina in Sandusky, Ohio and saw green mallards last year, and one this year, but I have seen a blue-headed mallard with a female this year. I love watching them and I needed a few days to believe this male had a blue head.

  11. Sasha Takis says:

    Saw blue-headed mallard drakes in Northern Utah. Did a double take. These were VERY aggressive. We watched one jump on the back of a non-mallard duck, bite its head, and push it under the water, holding it down. Then it chased it out of the pond.

  12. Toni Dalman says:

    We saw a blue mallard today in Tucson AZ. I wanted to post my photo. It looks like one of yours. But I can’t figure out how to do it.

  13. Gretchen Kozinski says:

    I have two blue headed mallards in my pond…the one has a blue striped tail ! Thier bills are almost black….very beautiful ! I also have four hooded mergansers that come everyday. .the male is absolutely beautiful ! We live in wheatfield N.Y. .

    • gingkochris says:

      My blue-headed mallard post probably has had more interest than any of my posts.

    • Bruce Montgomery says:

      It seems our blue headed mallards head turns from purple/blue to green depending on either the light or his mood…And here I thought we had two different ducks visiting our pond.

  14. Bob says:

    I love in Massachusetts and saw 2 mallard couples floating around offshore in Plymouth… both males had a dark blue/indigo head. It’s early spring, which supports your breeding theory. However there was also a flock of seagulls nearby so it could’ve been a protection situation just as easily… either way, beautiful bird!

  15. Bd Montgomery says:

    I have a farm pond and a pair of mallards have returned every for years year to breed .
    The male has a purple head. The offspring males all had green heads..Still havnt found an answer.

  16. I live in central Oklahoma and have had the opportunity to photograph all three,blue, purple and green headed Mallards. I was wondering if the blue and purple were mallards! Thanks everyone for clearing that up for me.

  17. Samantha says:

    I live in northeast Iowa. This weekend while camping I noticed a pair of ducks had built a nest near the creek at the edge of the campground. I watched them come and go and finally was able to get within about 20 feet of them and took a ton of pictures. They had beautiful deep blue heads. My husband still won’t believe me..even after seeing pictures!

    • gingkochris says:

      It took several photographs and some research before I realized there are blue-headed mallards. At first I thought it was only the angle of the light making the head seem blue.

  18. Christine Corcoran says:

    I also have just seen a blue headed male mallard along with a flock of a dozen or so other mallards, mottled ducks and mallard mottled hybrids. The blue headed one comes to eat cracked corn on his own, apart from the group and is a bit timid, otherwise I haven’t noticed any other unusual behavior, he is new to this group.

  19. Sarah SSM says:

    I have just seen a bunch of purple-headed mallards in Jamaica Pond in Boston. Can’t figure out what’s going on! More than one. I have (not very good) pictures I took with my phone.

    • gingkochris says:

      I also have seen some mallards that appear to have purple heads.

      • Carole says:

        April 2018. Golden, Colorado. Have a purple headed mallard coming and going in my yard- for bird seed last month. With female. Also, see the green headed with female. We have a little creek behind our yard where they have nests I am quite sure. I couldn’t belioeve it when I saw that beautiful irredescent purple head! I have noted it for many days- in different lights.

      • gingkochris says:

        The purple/blue headed mallards appear to be more common than I originally believed.

  20. Jen says:

    I just saw one this morning hanging out in my pool!

    The fact that it was blue is what caught my eye and made me watch. We’ve had a green headed one hanging out there for a few days. Blue was a new one.

    I’m in Joliet, IL 🙂

  21. Nora says:

    I heard a duck fight next to our neighbour’s dock on Orr Lake this morning, which caught my attention. Two drakes appeared to be fighting over a female. After the battle was won, the pair came to our dock to dry off. She definitely is a mallard. He definitely has a blue head, and appears in other ways to be a mallard. I checked our bird book, which says that mallards have a blue violet spectrum, which this one did, and the head was the same colour. This drake certainly seemed to have plenty of testerone, based on the way he was attacking the other drake!
    This is in southern Ontario, Canada, just north of Barrie.

  22. Ruth Halligan says:

    I have a blue-headed mallard in my pond right now. I’ve been trying to find out what the heck kind of duck this thing is. Just found your site with pictures. That’s my duck! I’m located in Bethel, NY. I am so happy to have an answer. (Sibley was no help.)

    • Jenny says:

      I too am looking at this beautiful duck, I thought that it was black but with binoculars in the beautiful sun it appears to be deep purple or as you say blue. He was cleaning his wings on top of a rock on my lake that also had that beautiful purple/blue color on it. This is the second time in 2 years since I have had the privilege to witness such unusual beauty.

  23. Bill says:

    I came across your post looking for answers as well. I keep seeing these in the lake behind my house in Orlando Fl. I had the same thought as you, maybe just a weird angle. Today though, I got a lot of close up pictures of a group of green head and blue head mallards and they definitely have bluish purple heads. another thing i noticed was the bills on the blue heads were a slightly lighter yellow than on the green heads. Upon further observation, the blue heads actually seemed to be more aggressive and dominating than the green as well. Maybe slightly larger too, unless that was just illusion. But they definitely seemed to be the leaders of the group. Maybe another weird hybrid?

    • gingkochris says:

      I did not notice the bill color nor did I note more aggressiveness in the blue-heads. If I ever come across blue-headed mallards again I will be certain to look more closely at their bills and observe their behavior. Nice to know you did see blue-heads. More confirmation I was not imagining.

  24. Pingback: Mallard and Her Ducklings | The Nature Niche

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