26 October 2021

In October male mallards challenge each other and pair with females. This seems odd since it isn’t the breeding season … but it is! Mallards pick their springtime mates in the fall.

The majority of pairs form on wintering grounds, far in advance of breeding. Mallard pairs form earlier (September–November) than do most Northern Hemisphere Anas species. At Ithaca, New York, courtship begins in September; 90% of females are paired by November. In coastal Louisiana, approximately 55% of migratory females arrived in November already paired; 95% paired by late December. 

— Mallard Pair Formation: Cornell Lab’s Birds of the World

Courtship is easy to observe because the males show off in groups.

Social courtship [among mallards] occurs on open water. Several males gather around one female and perform displays directed at her. … Especially characteristic of Mallards are synchronized bursts of male displays (Grunt-Whistle, Head-Up-Tail-Up, or Down-Up) involving up to 5 males performing one of these displays each per bout.

— Mallard behavior: Cornell Lab’s Birds Of The World

The male at top is performing the Head-Up-Tail-Up display. There are more courtship moves in this All About Birds video.

Listen for the high whistle of the males that are arching their backs and necks in the Grunt-Whistle display.

Competition is fierce and the ladies can afford to be choosy. In North America there are always more male mallards than females, averaging 1.33 to 1. When desperate a male may choose a female of another species. No wonder these ducks hybridize!

p.s. Maybe we’ll see courtship behavior at Duck Hollow next Sunday.

(photo from Wikimedia Commons; click on the caption to see the original)