Ring-necked ducks are small to medium in size. Males are slightly larger than females. Total length of males falls between 40 and 46 cm, and between 39 and 43 cm for females. The mass of males falls between 542 and 910 g and in females is usually between 490 and 894 g. Ring-necked ducks have a wingspan of 63.5 cm.
Defining characteristics of adult males include a black head, neck, breast, and upper portions, with a whitish gray belly and flanks. On the folded wing is a distinct white wedge on the shoulder that extends upwards. Adult females are grayish brown, with the darkest coloration on top of the head. They are pale on the front of their heads, chins, and throats. Eyes are bordered by a white ring, and females appear overall duller than males. The species is similar in profile to other diving ducks, but with a tail that is somewhat longer and a head that contains a short crest, which gives it its distinct peaked or angular appearance. Immature ring-necked ducks appear similar to adults, but are more dull in coloration. (Hohman and Eberhardt, 1998; Hohman and Weller, 1994)
Ring-necked ducks are mainly a migratory species that lives in North America from Canada to Mexico. During the breeding season, it can be found as far north as southern and central Alaska. Other populated portions of North America include the central Canadian regions as well as Minnesota, Maine, and some smaller portions of the northern United States. A few areas, including parts of Washington, Idaho, and other central western states of the United States are home to ring-necked ducks year-round. The species nests most often in the northern regions of Alberta, Saskatchewan, Minnesota, Wisconsin, Michigan, the central regions of Manitoba, and the southern regions of Ontario and Quebec.
These ducks prefer to spend their winters in the southern regions of New England and the Great Plains in the United States, the southern regions of British Columbia in Canada, and areas farther south including Mexico, Costa Rica, Jamaica, and Puerto Rico. During the winter, small numbers have been found in Venezuela and Trinidad. Small numbers have also been recorded in Panama, Bermuda, the Bahamas, Cuba, and the Dominican Republic. ("Aythya collaris", 2009; Hohman and Eberhardt, 1998)
Ring-necked ducks' habitat varies seasonally. During the breeding and post-breeding season the species prefers shallow freshwater wetlands, usually fens, bogs, and marshes. There is usually abundant vegetation, both floating and submerged, with open water found throughout as well.
During the winter, the species utilizes a huge array of wetlands but is rarely found in areas with high salt levels or depths greater than 1.5 meters. Floodplains of rivers, fresh and brackish parts of estuaries, and shallow inland lakes and marshes are common habitats.
When nesting, ring-necked ducks prefer to live in smaller, shallower wetlands. Because these areas are relatively more abundant than the large open waters preferred by several other duck species, ring-necked ducks have abundant nesting areas high nesting success. (Bendell and McNicol, 1995; Hohman and Eberhardt, 1998; Maxson and Riggs, 1996)
Ring-necked ducks are monogamous, which means that one male and one female pair together to breed and raise their young. These pairs form during spring migration, from March until April.
Reproductive behaviors are similar to that of other species of diving birds and include courtship displays. An example of this includes a neck stretch, in which the head is raised with the bill pointed forward and slightly elevated. This behavior can occur both in or out of the water. Pairs may also dip their bills into the water together, or swim side by side with heads held high.
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. (Hohman and Eberhardt, 1998)
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 pairs remain together 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 semi-dry 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 smooth ovals that range in color from olive-gray to olive-brown. 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. When they hatch, the chicks are "precocial" which means they have downy feathers and are capable of following their parents and feeding themselves soon after hatching. Young fledge (leave the nest) after 49 to 56 days but will remain close to their parents for 21 to 56 more days. Ring-necked ducks are able to reproduce at 1 year old. (Hohman and Eberhardt, 1998; Hohman, 1986)
Female ring-necked ducks are the primary caretakers of the young. Males help by bringing food to females who spend nearly all of their time on the nest, incubating the young. 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. Young ring-necked ducks can dive about 48 hours after hatching, but mostly eat food on the surface for the first week of life and do not count on their mothers to feed them. The mother generally remains with the young until they fledge (leave the nest) and can take care of themselves. (Hohman and Eberhardt, 1998; Hohman, 1986)
In captivity, ring-necked ducks are known to live just over 20 years. The oldest ring-necked duck was banded young and was recovered twenty years later. Researchers estimated that this duck was just over 20 years old. Research has shown that females have lower survival rates than males, likely because females are vulnerable while incubating the nest and will remain near their young to defend them from predators. (Hohman and Eberhardt, 1998)
Ring-necked ducks are a highly motile species that moves by walking, hopping, flying, swimming, and diving. It leaves the water to stand on floating objects for rest or comfort, and during nesting. The flight of this species is swift and flocks of twenty or less fly together in dense wedges. These ducks can dive to depths of up to ten meters using foot propulsion. Ring-necked ducks also perform self-maintenance in the form of preening, head-scratching, stretching, and bathing. While resting or sunbathing, ducks are usually found in calm, open water sheltered from the wind. They spend most of their time foraging during daylight hours.
The hierarchy present within ring-necked ducks is as follows: Male adult dominant to female adult and adult dominant to immature duckling. There is no evidence of territoriality, but in open water a paired male defends a radius of 2 to 3 meters around his mate. During migratory periods and winter, if food and resources are plentiful, flocks may reach greater than 10,000 individuals.
Ring-necked ducks can exhibit molting throughout the majority of the year. The highest levels of molting have been found to be during April-May, July-September, and December-January, while the lowest levels have been observed in March. Molting is related to seasonal change, and is in preparation of the spring and fall migrations. Spring migration occurs from February to May, with peak levels during March and April. Fall migration occurs from September to December, with peak levels during October and November. (Crook, et al., 2009; Hohman and Crawford, 1995; Hohman and Eberhardt, 1998)
There is no evidence of territoriality, but in open water a paired male defends a radius of 2 to 3 meters around his mate.
Ring-necked ducks are vocal, but these vocalizations have not been studied in depth. The male "kink-neck" call is emitted during the courtship displays of neck stretching and head throwing. During courtship displays or when curious, the female makes a soft purring growl. When alarmed or during flight in the nesting season, the female may make a high pitched growl. Alarm calls given to a brood by the mother are short and soft 'cut-cut-cut' noises.
Ring-necked ducks rely heavily on visual communication during courtship displays. Males attract mates through various displays including neck stretching, head throwing, and nod swimming. Females respond to these displays using head bobbing. Successfully paired mates swim side by side with heads held high. Like all birds, ring-necked ducks perceive their environments through the senses of sight, smell, taste, sound, and touch. (Hohman and Eberhardt, 1998)
In winter, shallow bodies of water such as flood plains and the margins of lakes and bogs are filled and aquatic plants are abundant. Spring migrants locate food in these flooded areas. Members of this species eat mainly plant seeds and tubers from the moist soil and feed on aquatic invertebrates as well. Occasionally they prey on insects. Nesting adults and offspring forage on aquatic plant species like pondweed, coontail, cow lily, and water milfoil. Fall migrants obtain food from shallow lakes and rivers that have wild rice, American wild celery, or arrowheads.
Ring-necked ducks feed mainly by shallow diving, but also collecting items on or near the surface of the water. Its preference for obtaining food from shallow waters, even though it can dive, can be attributed to the high level of biomass closer to the surface. This species is more of an opportunistic and generalized feeder than others in the same genus. The species usually consumes food during dives, but some food is brought back to the surface to be processed, such as removing food from the shell of snails and removing protective layers from insects.
Prey ranges in size from less than 0.1 mm to 5 cm. Invertebrate consumption is the greatest in young, and makes up 98% of the total diet. Females tend to eat more invertebrates than usual during the breeding season, a time when more protein is necessary. The males sometimes exhibit slight increases in invertebrate consumption, but the change is not as significant as in females. Some common prey of ring-necked ducks includes aquatic earthworms, snails, clams, dragonflies, and caddis flies. (Alisauskas, et al., 1990; Eberhardt and Riggs, 1995; Hohman and Eberhardt, 1998; Olsen and Perry, 1997; Torrence and Butler, 2006)
In Maine, examples of predators on adult ring-necked ducks include red fox, raccoons, Northern harriers, great horned owls, American mink, bald eagles, peregrine falcons, and common snapping turtles. There are also many organisms which prey on the eggs of ring-necked ducks. Major predators of eggs include American mink, crows, ravens, raccoons, red fox, muskrat, skunks, and domestic dogs. Ducklings may fall prey to large, predatory fish such as pike and bass.
In order to prevent predation at the nest, some females will defecate on eggs to cover their scent. Some ducks fake injury when disturbed. When broods are attacked from below the water, the mother uses her wings and feet to attack while the ducklings scatter away. Adults and young use their diving ability to try and escape aerial predation. (Hohman and Eberhardt, 1998)
Ring-necked ducks serve as a host to parasites Clostridium botulinum and Pasteurella multocida, which cause avian botulism and avian cholera, respectively. The parasites are most prevalent in California, but have been found to cause botulism and cholera throughout the Pacific, central, and Mississippi waterways. Bacterial diseases which cause mortality in these ducks include coccidiosis, aspergillosis, and avian tuberculosis. Ring-necked ducks can be infected by a wide array of parasites.
Ring-necked ducks are both herbivores and predators on aquatic invertebrates and have a significant impact on those populations where they forage. Eggs, young, and adult ring-necked ducks are a source of food for many predators. (Hohman and Eberhardt, 1998)
There is no direct negative effect of ring-necked ducks on humans. (Hohman and Eberhardt, 1998)
Ring-necked ducks are economically important in the hunting and game industry. They are widely hunted across Canada and the United States. (Hohman and Eberhardt, 1998)
This species has an extremely large range and is not declining or fluctuating in population size. Ring-necked duck habitats are currently healthy and abundant. The species is considered by the IUCN Red List to be of least concern. As migratory birds, ring-necked ducks are protected under the United States Migratory Bird Act.
However, lead poisoning is common in some areas due to the ingestion of lead pellets used by hunters. In 1991 the United States called for a mandatory switch to non-toxic shot made of steel or bismuth and tin. Lead levels continue to be a problem years after the switch. Also, these ducks are hunted in other countries that still permit the use of lead shot.
Shahina Patel (author), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor, Rachelle Sterling (editor), Special Projects.
2009. "Aythya collaris" (On-line). Red List. Accessed March 20, 2010 at http://www.iucnredlist.org/apps/redlist/details/141543/0.
Alisauskas, R., R. Eberhardt, C. Ankney. 1990. Nutrient reserves of breeding Ring-necked Ducks (Aythya collaris). Canadian Journal of Zoology, 68(12): 2524-2530. Accessed April 13, 2010 at http://rparticle.web-p.cisti.nrc.ca/rparticle/AbstractTemplateServlet?journal=cjz&volume=68&year=1990&issue=68&msno=z90-353&calyLang=eng.
Anderson, W., S. Havera, B. Zercher. 2000. Ingestion of Lead and Nontoxic Shotgun Pellets by Ducks in the Mississippi Flyway. The Journal of Wildlife Management, 64(3): 848-857. Accessed April 16, 2010 at http://www.jstor.org/sici?sici=0022-541X%28200007%2964%3A3%3C848%3AIOLANS%3E2.0.CO%3B2-C&origin=ISI&cookieSet=1.
Bendell, B., D. McNicol. 1995. The diet of insectivorous ducklings and the acidification of small Ontario lakes. Canadian Journal of Zoology, 73(11): 2044–2051. Accessed March 20, 2010 at http://rparticle.web-p.cisti.nrc.ca.proxy.lib.umich.edu/rparticle/AbstractTemplateServlet?journal=cjz&volume=73&year=1995&issue=73&msno=z95-240&calyLang=eng.
Crook, S., W. Conway, C. Mason, K. Kraai. 2009. Winter Time-Activity Budgets of Diving Ducks on Eastern Texas Reservoirs. Waterbirds, 32(4): 548-558. Accessed April 13, 2010 at http://www.bioone.org/doi/full/10.1675/063.032.0408.
Eberhardt, R., M. Riggs. 1995. Effects of sex and reproductive status on the diets of breeding Ring-necked Ducks (Aythya collaris) in north-central Minnesota. Canadian Journal of Zoology, 73(2): 392–399. Accessed March 20, 2010 at http://rparticle.web-p.cisti.nrc.ca.proxy.lib.umich.edu/rparticle/AbstractTemplateServlet?journal=cjz&volume=73&year=1995&issue=73&msno=z95-043&calyLang=eng.
Hohman, W. 1986. Changes in Body Weight and Body Composition of Breeding Ring-Necked Ducks (Aythya collaris). The Auk, 103(1): 181-188. Accessed April 13, 2010 at http://www.jstor.org/stable/pdfplus/4086978.pdf.
Hohman, W., R. Crawford. 1995. Molt in the Annual Cycle of Ring-Necked Ducks. The Condor, 97(2): 473-483. Accessed March 20, 2010 at http://www.jstor.org.proxy.lib.umich.edu/sici?origin=sfx%3Asfx&sici=0010-5422(199505)97%3A2%3C473%3AMITACO%3E2.0.CO%3B2-L.
Hohman, W., R. Eberhardt. 1998. "The Birds of North America Online" (On-line). The Birds of North America Online. Accessed March 09, 2010 at http://bna.birds.cornell.edu.proxy.lib.umich.edu/bna/species/329/articles/introduction.
Hohman, W., M. Weller. 1994. Body Mass and Composition of Ring-Necked Ducks Wintering in Southern Florida. The Wilson Bulletin, 106(3): 494-507. Accessed March 20, 2010 at http://www.jstor.org.proxy.lib.umich.edu/sici?origin=sfx%3Asfx&sici=0043-5643(199409)106%3A3%3C494%3ABMACOR%3E2.0.CO%3B2-P.
Maxson, S., M. Riggs. 1996. Habitat Use and Nest Success of Overwater Nesting Ducks in Westcentral Minnesota. The Journal of Wildlife Management, 60(1): 108-119. Accessed April 13, 2010 at http://www.jstor.org/sici?sici=0022-541X%28199601%2960%3A1%3C108%3AHUANSO%3E2.0.CO%3B2-1&origin=ISI.
McCracken, K., A. Afton, M. Peters. 2000. Condition bias of hunter-shot ring-necked ducks exposed to lead. Journal of Wildlife Management, 64(2): 584-590. Accessed April 13, 2010 at http://www.jstor.org/stable/3803256?seq=1.
Noseworthy, S., W. Threlfall. 1978. Some Metazoan Parasites of Ring-Necked Ducks, Aythya collaris (Donovan), from Canada. The Journal of Parasitology, 64(2): 365-367. Accessed March 20, 2010 at http://www.jstor.org.proxy.lib.umich.edu/sici?origin=sfx%3Asfx&sici=0022-3395(1978)64%3A2%3C365%3ASMPORD%3E2.0.CO%3B2-I.
Olsen, J., M. Perry. 1997. Watershield Use by Ring-Necked Ducks. Northeastern Naturalist, 4(3): 197-204. Accessed March 20, 2010 at http://www.jstor.org.proxy.lib.umich.edu/sici?origin=sfx%3Asfx&sici=1092-6194(1997)4%3A3%3C197%3AWUBRD%3E2.0.CO%3B2-R.
Torrence, S., M. Butler. 2006. Spatial structure of a diving duck (Aythya, Oxyura) guild: hwo does habitat structure and competition influence diving duck habitat use within northern prairie wetlands. Canadian Journal of Zoology, 84(9): 1358-1367. Accessed April 13, 2010 at http://proquest.umi.com/pqdlink?vinst=PROD&fmt=6&startpage=-1&ver=1&clientid=17822&vname=PQD&RQT=309&did=1189227701&exp=04-14-2015&scaling=FULL&vtype=PQD&rqt=309&TS=1271370083&clientId=17822.