Gadwall (Anas Strepera) Mike Sefton

Gadwall (Anas strepera) Mike Sefton

Toronto, ON © Greg Schneider

he elegantly understated Gadwall is a T (Click to view comparison of Atlas I & II) medium sized dabbler that lacks the bright colors of many of the Anas species. The and the northern shore of Lake Ontario male is grayish brown with a black rump (LeShack et al. 1997). and undertail coverts, a lighter colored head and neck, a white belly, a conspicuous white Distribution speculum seen when the bird is in flight and Barrows (1912) described the Gadwall as sometimes seen when the bird is on the one of Michigan’s rarer ducks, and believed water, and a dark bill. The female is a buffy that it probably nested in the state, but had tan with a smaller white speculum than the no evidence of breeding. An increase in male, and a grayish bill with yellow-orange observations in Michigan, at the same time along the opening of the bill. Gadwalls are the bird was increasing in the central U.S., monogamous, with more than 90% of the resulted in Payne (1983) revising the status females paired by November. Gadwalls as a transient from uncommon to common. prefer islands for nesting (LeSchack et al. The Gadwall is now considered a common 1997). migrant and rare breeder.

The Gadwall is widespread over much of the During the MBBA I period there were seven Northern Hemisphere. In North America, Confirmed breeding records at scattered the Gadwall breeds in the Great Plains and sites around the state, mostly coastal, such prairies, from southern Canada to California, as Drummond and Beaver Islands, the and to Iowa in the east. It also breeds Muskegon Wastewater Treatment System, at occasionally east and south of this area, and Nayanquing and Fish Point in Saginaw Bay, is well-established along the Eastern and at Pte. Mouillee State Game Area. The Seaboard from North Carolina to Quebec. Gadwall’s status as a rare breeder in Gadwalls winter in southern North America Michigan was validated in MBBA II, with south to Central Mexico, Jamaica, and Cuba only three Confirmed breeding records, in in the New World (Madge and Burn 1988). Luce, Chippewa, and Saginaw Counties. In the Great Lakes area, Gadwall breeds MBBA I noted three townships with regularly in parts of northwest and eastern Probable breeders, and ten with Possible Wisconsin, at scattered locations in breeders (Eastman 1991), whereas MBBA II Michigan, the western shore of Lake Erie in had eight Probable and nine Possible Ohio, and the eastern shore of Lake Huron breeders.

Breeding Biology September to mid-October, and rare from Most Gadwalls begin to form male/female mid-October through December, falling off pairs before leaving their wintering areas, to casual in January and February. The and 90% are paired by November, four to Gadwall is absent in the UP for most of five months before breeding takes place. March, becoming casual during the last Males keep watch while the female looks for week of the month, rare through mid-April, a suitable location for the nest. Nests are and uncommon from mid-April through usually located in dense brush, forbs, or tall May, then casual for June and July, rare grasses in dry areas. Nests are usually less until mid-August, and uncommon from mid- than 150 meters from water, but may be as August through September. Numbers drop far as 2.4 kilometers from water. Island off to rare through mid-October, and nests may be within a few meters of water. accidental from mid-October through early The nest is lined with vegetation and down January, and the birds are absent for the rest from the female’s breast. Gadwalls usually of the winter period (Chartier and Ziarno nest later than other Anas species, with the 2004). average time between spring arrival and the laying of the first egg being 28 days, though The first confirmed breeding record for Ohio nest site availability and weather can affect was in 1979, where the Gadwall is a rare the timing. The late start in nesting may breeder with seven confirmed sites during explain the unusually high success rate of their atlas period, primarily in the western 68% documented elsewhere in their range Lake Erie marshes (Peterjohn and Rice (Granlund 1994). Gadwalls are single 1991). Ontario showed a slight increase in brooded, though the hen often renests if the breeding records from their first atlas (1987) first eggs are destroyed. Nests are to their second (2007) with the largest sometimes parasitized by Lesser Scaup, concentration of breeders on the northern Redheads, Ring-necked Pheasants, and other shore of Lake Ontario and further east along Gadwalls (LeSchack et al. 1997). the St. Lawrence River (Curry 2007). Wisconsin had confirmed nesters in 13 In Michigan, egg laying occurs from 30 May blocks, and another 15 blocks had probable to 25 July, with an incubation period of 25 or possible breeders (Cutright et al. 2006). to 28 days. Unfledged juveniles are found from 16 June to 25 August, and fledglings Conservation Needs from 29 June to 19 September (MI-DNR. While the Gadwall is increasing overall in 2005a). the United States, there are too few breeding records for Michigan to predict whether Abundance and Population Trends Gadwall will increase or decline in the state. (Click to view trends from the BBS) It is possible that the Gadwall may increase In the SLP, Gadwalls are fairly common in in the state due to its general increase and migration during March through May, rare range expansion in other areas of the in June through August, then increase to country, and the efforts of the Michigan fairly common again with fall migration DNRE to increase restoration, retention, and from September to late November, dropping regulation of wetlands on public lands, and off to uncommon from late November to encourage similar efforts by private through February. In the NLP, they are rare landowners (MI-DNR 2005b.). in March, uncommon in April and May, and rare from June through August, becoming fairly common in fall migration from

Literature Cited . Barrows, W.B. 1912. Michigan Bird Life. Accessed 12 Feb 2010. Special Bulletin. Michigan Agricultural Michigan Department of Natural Resources College. Lansing, MI. (MI-DNR). 2005b. Michigan’s Wildlife Chartier, A.T., and J. Ziarno. 2004. A Action Plan, Executive Summary. Birder’s Guide to Michigan. American Michigan Department of Natural Birding Association. Colorado Springs, Resources. Lansing, MI. CO. . Accessed Beck, D. Lepage, and A.R. Couturier 12 Feb 2010. (eds.). 2007. Atlas of the Breeding Payne, R.B. 1983. A Distributional Birds of Ontario, 2001-2005. Bird Studies Canada, Environment Canada, Checklist of the Birds of Michigan. MP Ontario Field Ornithologists, Ontario 164. University of Michigan Museum of Ministry of Natural Resources, and Zoology. Ann Arbor, MI. Ontario Nature. Toronto, Ontario. Peterjohn, B.G., and D.L. Rice. 1991. The Cutright, N.J., B.R. Harriman, and R.W. Ohio Breeding Bird Atlas. Ohio Howe. 2006. Atlas of the Breeding Department of Natural Resources . Birds of Wisconsin. Wisconsin Society Columbus, OH. for Ornithology. Waukesha, WI. Eastman, J. 1991. Gadwall (Anas strepera). In Brewer, R., G.A. McPeek, and R.J.

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University Press. East Lansing, MI. Granlund, J. 1994. Gadwall (Anas strepera). In McPeek, G.A., and R.J. Adams (eds.). 1994. The Birds of Michigan. Indiana University Press. Indianapolis, IN. LeSchack, C.R., S.K. McKnight, and G.R. Hepp. 1997. Gadwall (Anas strepera). In The Birds of North America, No. 163 (A. Poole and F. Gill, eds.). The Birds of North America, Inc. Philadelphia, PA. Madge, S. and H. Burn. 1988. Waterfowl: A Guide to the Ducks, Geese, and Swans of the World. Houghton Mifflin. New York, NY. Michigan Department of Natural Resources (MI-DNR). 2005a. Michigan breeding bird atlas: species breeding season dates. Michigan Department of Natural Resources. Lansing, MI.