Despite the drake curl and hints of green emerging on this Mallard’s head, this bird is 100% a female Mallard. She’s what biologists refer to as having intersex plumage.
In Mallards, the bill rarely lies — and the orange bill, dark saddle, and overall body patterning all point clearly to a hen. So why the male traits? Typically, only drakes show the green head and curled tail feathers.
Here’s what’s happening:
This hen is experiencing a hormonal imbalance, most likely caused by damage to her ovaries and a resulting drop in estrogen. This can occur in older birds, or in birds that are no longer reproductively viable due to age, injury, or disease. When estrogen levels fall, dormant male traits can begin to express themselves in the plumage.
The good news? She appears otherwise healthy — she just won’t be hatching eggs. The flecking along her sides, her bill color, and even her vocalizations all confirmed she is female.
What does this tell us?
1️⃣ It pays to slow down and really observe even the most “common” birds.
2️⃣ Nature doesn’t always color within the lines when it comes to sex and appearance.
3️⃣ First impressions can be misleading — especially in the natural world.