Aythya collaris is a primarily monogamous species that forms pair bonds. This occurs during spring migration, from March until April.
Reproductive behaviors are similar to that of other species of diving birds and include mutual displays. An example of this includes a neck stretch, in which the head is raised to full neck extension with the bill pointed forward and slightly elevated. This behavior can occur both in or out of the water. Drinking or bill-dipping, in which the bill is lowered into the water without raising the head, and post-copulatory swimming, where the male and female swim side by side with heads held high, are two other examples of mutual mating displays.
Male only displays include a head throw (the head is brought back until the throat is part vertical), nod swimming (a rapid swim while the head nods back and forth with the crest fully extended) and preening behind the wing (the preening of the scapular region with the wing partially extended).
Extra-pair copulations are very uncommon but have been seen in northwestern Minnesota during a drought year. This happened at a time when the body masses of returning birds, food availability, and breeding participation of the females were much lower than they had been in previous years.
Mating System: monogamous
The breeding season of ring-necked ducks occurs between the months of May and early August, with peak activity from mid-May until mid-July. Pair bonds are formed during spring migration and remain until late June or early July.
In selecting a site for nesting, pairs swim along the open waters of wetlands. The females swim into flooded vegetation looking for suitable sites, while the male keeps lookout nearby. They search for a dry or semidry site situated near water, often with clumps of vegetation. The female constructs the nest. After 3 to 4 days of nest building, the nest resembles a bowl, and by day 6 the nest is strong with a clear shape to it. Occasionally nest construction doesn't begin until the 3rd or 4th egg is laid. Nests are lined with bent grasses and downy feathers.
Female ring-necked ducks lay between 6 and 14 eggs per season, with an average between 8 and 10. The eggs are ovular in shape and range in color from olive-gray to olive-brown, possessing a smooth surface texture. Incubation starts after the clutch is completed, and the beginning of incubation is the first day the female remains at the nest overnight. Incubation generally lasts 26 or 27 days. The precocial chicks hatch weighing between 28 and 31 g. Chicks are covered in downy feathers and are capable of following parents and feeding themselves soon after hatching. Young fledge after 49 to 56 days and reach independence 21 to 56 days after fledging. Reproductive maturity is achieved quite quickly in both sexes, with both breeding in their first year, although young ducks may shy away from breeding some years due to lower availability of nesting areas.
Breeding interval: Ring-necked ducks produce one brood per season, but may produce another clutch if initial nest is destroyed.
Breeding season: Ring-necked ducks breed from May to early August (peak activity from mid-May until mid-July).
Range eggs per season: 6 to 14.
Average eggs per season: 8 to 10.
Range time to hatching: 25 to 29 days.
Average time to hatching: 26 to 27 days.
Range birth mass: 28.4 to 31.0 g.
Range fledging age: 49 to 56 days.
Range time to independence: 21 to 56 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization
Average eggs per season: 9.
Parental care of offspring is exhibited by females only, but males aid indirectly in the production of offspring by attending to the nutritional needs of their mates while they are in the laying stage of reproduction. The young emerge from the egg without their mother's aid, after which she crushes the shells and proceeds to bury them, carrying them away from the nest, or ingesting them. Aythya collaris young gain the ability to dive about 48 hours post hatching, but count on surface foods mostly for the first week of life, and do not count on their mothers to feed them.
The mother generally remains with the young until fledging, but sometimes leaves earlier if the young have begun to develop the contour feathers necessary for flight. Maternal care is mostly protective. After the mother leaves, broods have been shown to spend more time feeding and less time resting, probably due to the loss of the mother's vigilant eye.
Parental Investment: precocial ; female parental care ; pre-fertilization (Provisioning, Protecting: Male, Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Protecting: Female); pre-independence (Protecting: Female)