You can spot very old ducks in city ponds. And they are very easy to tell apart
While strolling by the ponds, pay closer attention to the ducks. Perhaps you'll meet a true bird-grandma who saw this park when it was completely different, writes the Telegram channel "Wild nature nearby".
Photo by Aliaksandr Vinchėŭski, taken in Minsk
Look closely at these two pictures. The duck below looks somewhat unusual; it has elements of male coloration. Pay attention to the coloration of its beak, head, chest and flanks, back, and wing coverts.
Before us is an experienced, respected lady. Mallards are capable of living up to 30 years. In cities, where there is no need for risky migrations and the food base is stable, they have every chance to reach such a respectable age. Scientists call such old birds 'senex' — aged.
Older female ducks develop male plumage mainly due to a significant decrease in estrogen levels, caused by aging or ovarian damage. When their only functioning ovary ceases to work, it stops the production of the hormone that normally suppresses male plumage genes.
Unlike humans and other animals, in birds, males have two identical sex chromosomes (ZZ), while females have one female and one male chromosome (ZW).