SEDGE WREN

Cistothorus platensis stellaris

Status:    Uncommon regular spring and fall migrant east and east-central, rare casual west-central and Panhandle. Rare regular breeder east and east-central (May-Jun). Uncommon regular breeder east and east-central (Jul-Aug).

Documentation:  Specimen: UNSM ZM6605, 28 Aug 1902 Lancaster Co.

Taxonomy: Of 19 subspecies recognized, only one, stellaris, occurs north of Mexico (Robbins and Nyari 2014, Herkert et al 2001). Nebraska birds are stellaris.

Since stellaris differs from all other taxa within C. platensis in being polygynous, migratory, non-site specific, and improvises song, it may deserve specific status as C. stellaris Sedge Wren (Robbins and Nyari 2014, Gill and Donsker 2017).

Changes Since 2000:  Nesting in May-Jun in Nebraska was essentially nonexistent until about 2000, when such reports started to increase dramatically. Previously, breeding Sedge Wrens were not present until mid-Jul (see Summer).

Spring:   Apr 18,20,20 <<<>>> Jun 7,7,9

There is a well-defined movement in Apr and May, with apparently very small numbers remaining to breed, then a return migration beginning in mid-Jul and continuing into Oct. Early fall migrants are potential intra-seasonal double breeders (see Summer). Reports into early Jun may be late migrants or birds attempting to breed.

Reports away from the east are few; there are seven reports for northeast Cherry Co 11 May-5 Jun, and these additional reports: 20 April 1957 Thomas Co, 9 May 1997 Ackley Valley Marsh, Keith Co (Brown and Brown 2001), 19 May 2012 Blaine Co, and 7 Jun 2016 Sheridan Co. It was listed as an “uncommon migrant/summer resident” in Thomas Co (Bray 1994).

  • High counts: 19 on 22 May 2000 at Boyer Chute NWR, Washington Co, 12 at DeSoto NWR, Washington Co 1 May 2016, and 8 at Spring Creek Prairie, Denton, Lancaster Co 2 May 2003.

Summer:  The Sedge Wren has one of the more complex and difficult to define breeding strategies amongst Nebraska’s birds.  Its occurrence, understanding of which is based largely on the presence of singing males, has definable patterns from spring through early fall, but is variable and apparently evolving.  There are two apparent peaks in numbers per breeding season in Nebraska, possibly comprised of different individuals and representing different populations. Both are restricted mostly to the eastern half of the state (Mollhoff 2016) but separated by breeding phenology; the first peak in numbers is typical of most migratory passerines breeding in the state, involving nesting in spring and early summer. The second peak in numbers occurs in mid-summer and involves birds arriving and apparently nesting during late summer.  Regarding the latter influx, Robbins and Nyari (2014) stated “Unique [to the North American subspecies, stellaris] is the intra-breeding seasonal movement, presumed to be from north to south that results in double breeding” (see below).

Sedge Wren has rather exacting breeding habitat requirements, best-described as damp grassy or sedge meadows; Bedell (1996) described a preferred habitat type as “sub-irrigated native meadow”, although this habitat type is restricted essentially to the central Platte River Valley. In Nebraska, territorial birds are most often found in lush mid- and tall-grass prairie during summers with above-normal precipitation. Nests are well-hidden and low in dense vegetation over damp ground or mud or at most a little standing water. Such habitat is extremely sensitive to weather conditions, and it appears that this species has the ability to search out suitable habitat and breed as late as Aug if necessary.

Breeding during spring and early summer (the early peak) has been rare in Nebraska, with few confirmed records; the Jun range of Sedge Wren in Nebraska is east of a line from the Valentine, Cherry Co area southeast to Lancaster and Richardson Cos. Jun records include a nest with five young in Thurston Co 24 Jun 1971 which was the first in Nebraska for at least 70 years (Cink 1973) since Wolcott (1902) noted nests at West Point and Lincoln prior to 1902. Beginning around 2000, reports of Sedge Wrens in Jun have increased markedly. Sedge Wrens had been seen Jun-Aug each year since 1999 but without evidence of nesting at Boyer Chute NWR (Jerry Toll, personal communication). Grasslands in Hall Co had nesting birds late May through Jul 2005 (Mollhoff 2005b), and one was reported on River Road, Phelps Co 12 Jun 2017. In 2018 there were three reports of possible breeding birds, all in Lancaster Co at three different locations 11-16 Jun.

Additional early peak breeding season reports include singing birds occupying meadows at Wehrspann Lake, Sarpy Co, for two months prior to 25 Aug 2006; no evidence for breeding was observed other than territorial behavior.  There is a breeding record of an adult feeding young in Sarpy Co 6 Jul 2003 (Mollhoff 2005a), but between 2009 and 2016 there have been at least 34 reports of Sedge Wrens 23 May-11 Jul, including the discovery of two nests near Hastings, Adams Co 23 May 2009, possibly dummy nests as no eggs were present and no female was sighted with the 2-3 males (Paul Dunbar, personal communication). Westernmost of these early breeding season reports are from Keya Paha and Garfield Cos 15-24 Jun 2011, and eight calling birds were in Holt Co 18 Jun 2016. There are two mid-Jun records from Valentine NWR, Cherry Co: 18 Jun 2005 and 25 Jun 2009. The only Jun-early Jul records for the eastern Rainwater Basin are of two singing males 18 Jun 2003 at County Line WPA (Jorgensen 2004), a single bird at Flatsedge WMA 24 Jun 2005, one at Troester WPA, Hamilton Co, 3 Jul, and three singing males in Thayer Co 3 Jul 2015. Until recently, Sedge Wrens would arrive in mid- to late summer after being absent during early summer; earliest arrival dates are 8-10 Jul (see Fall).

At one time, Sedge Wrens arriving in Jul were thought to be early fall migrants, but it is now understood that they represent a second breeding peak (late peak) following an intra-seasonal movement or migration, known as “intra-seasonal double breeding” (Robbins and Nyari 2014).  Herkert et al (2001) remarked broadly about the species summer distribution in the Interior and stated that breeding occurs May-Sep, but that “breeding is concentrated in different portions of the range at different times of the season”.  Nesting in May–Jun is mostly concentrated in north-central areas including Wisconsin, Minnesota, North Dakota, and Saskatchewan, but in the south and east, including Arkansas, Kansas, southern Illinois, Nebraska, and Missouri, nesting is frequently not initiated until Jul or Aug, or even Sep (Herkert et al 2001).

The phenomenon of intra-seasonal double breeding in Sedge Wrens has been well-studied in Nebraska (Lingle and Bedell 1989, Bedell 1996, Herkert et al 2001; see above). Bedell (1996) suggested that late summer breeding in Nebraska may involve bachelor males moving south from northern breeding areas in hopes that if conditions are unsuitable to the north then returning females may arrive and allow breeding with these bachelor males. It has been suggested (Joe Roller, personal communication) that migrants which pass through Nebraska northward in spring and are unsuccessful in locating suitable breeding habitat, or indeed successfully raise a first brood but mowing or other intrusions cause failure of a second brood, apparently return to Nebraska and breed in Jul and Aug (and even Sep in Kansas). According to Herkert et al (2001), these Jul-Aug nestings may represent re-nesting attempts by individuals arriving from elsewhere within their range, as suggested by Bedell (1996),  or could be an adaptive response of local birds to delayed availability of moist but un-flooded grassland habitat, as suggested by Gibbs and Melvin 1992. Bedell’s (1996) hypothesis is possibly correct; coinciding with late midsummer arrival dates at many southerly breeding locations are (1) the late Jun-early Jul cessation of breeding at northern breeding areas such as Quebec; (2) beginning of departures from northern breeding areas such as northern Wisconsin (Temple and Carey 1987),  and (3) a general shifting about in and out of nesting territories as reported in both Minnesota and Illinois (Herkert et al 2001).

Sedge Wrens are often numerous in suitable grasslands beginning in mid-Jul in the eastern half of Nebraska, but westerly reports are few: 1-2 singing in wet meadow northwest of North Platte, Lincoln Co 6 Aug 2008, five at Valentine NWR 10 Aug 2012, and singles at Oliver Reservoir, Kimball Co 7 Sep 2015 and 5 Sep 2016.  There are several records of nesting during the late peak period, including a nest with eggs in Hall Co 26 Jul 1988 at a location where 123 wrens were present (Lingle and Bedell 1989, Grzybowski 1988, 1989), seven nests with eggs in early Aug 1989 in Hall Co (Grzybowski 1990), nests with eggs 24 Aug and 1 Sep in Hall Co in the period 1984-89 (Mollhoff 2001), and a nest with young in Boone Co 28 Aug in the period 1984-89 (Mollhoff 2001). Territorial males and adults carrying food were found in a grass and sedge meadow near Clay Center, Clay Co 17 Jul 1971 (Cink 1973). Nest building by Sedge Wrens may not indicate breeding; dummy nests are common, such as those found north of Lincoln in Lancaster Co 8 Jul 1972 (Cink 1973), a bird carrying nest material in Otoe Co 22 Jul 2007, and reports during 1996 and 1997 of territorial males in lush mid- and tall-grass prairie habitat at Nine-mile Prairie, Lancaster Co; a nest was under construction there 14 Aug 2000.

  • Breeding phenology:
    Nest building: 23 May-14 Aug
    Eggs: 30 May-1 Sep
    Nestlings: 24 Jun-28 Aug
    Fledglings: 6 Jul

Fall: Jul 8,9,10 <<<>>> Oct 29,30, 1 Nov

Earlier dates are of one in Douglas Co 5 Jul 2018 and 2-3 there at a different location 6-7 Jul 2018.

Migration apparently begins in mid-Jul where breeding did not occur; Jul arrivals are birds that often if not usually attempt nesting (see Summer). True fall migration (after nesting) in this species probably takes place in Sep-Oct, although there are later documented records: 9 Nov 2002 Dwight, Butler Co, 15 Nov 2011 Lancaster Co, 29 Oct-17 Nov 2015 Sarpy Co, a specimen, WSC 196, 20 Nov 1976 Boone Co.

There are seven reports from northeast Cherry Co 12 Jul-9 Oct. Westerly was one in Keith Co 16 Sep 2017.

  • High counts:  123 on 26 Jul 1988 in Hall Co (Lingle and Bedell 1989), 60 in the eastern Rainwater Basin 7 Aug 1999, and 60 there 7 Aug 1999.

Abbreviations

NWR: National Wildlife Refuge
UNSM: University of Nebraska State Museum
WMA: Wildlife Management Area (State)
WPA: Waterfowl Production Area (Federal)
WSC: Wayne State College

Literature Cited

Bedell, P.A. 1996. Evidence of dual breeding ranges for the Sedge Wren in the central Great Plains.  Wilson Bulletin 108: 115-122.

Bray, T.E., B.K. Padelford, and W.R. Silcock. 1986. The birds of Nebraska: A critically evaluated list. Published by the authors, Bellevue, Nebraska, USA.

Brown, C.R., and M.B. Brown. 2001. Birds of the Cedar Point Biological Station. Occasional Papers of the Cedar Point Biological Station, No. 1.

Cink, C.L. 1973. Summer records of the Short-billed Marsh Wren in Nebraska. NBR 41: 17-19.

Gibbs, J.P., and S.M. Melvin. 1992. “Sedge Wren, Cistothorus platensis.” In Migratory nongame birds of management concern in the Northeast., edited by K. J. Schneider and D. M. Pence, 191-209.  Newton Corner, MA: U.S. Department of Interior, Fish and Wildlife Service.

Gill, F., and D. Donsker (Eds). 2017. IOC World Bird List (v 7.3), accessed 30 January 2018.

Grzybowski, J.A. 1988. Southern Great Plains Region. American Birds 42: 1308-1310.

Grzybowski, J.A. 1989. Southern Great Plains Region. American Birds 43: 124-126.

Grzybowski, J.A. 1990. Southern Great Plains Region. American Birds 44: 114-117.

Herkert, J.R., D.E. Kroodsma, and J.P. Gibbs. 2001. Sedge Wren (Cistothorus platensis), version 2.0. In The Birds of North America (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, New York, USA. https://doi.org/10.2173/bna.582

Jorgensen, J.G. 2004. A preliminary assessment of eastern Rainwater Basin birdlife.  Published by the author, Blair, Nebraska, USA.

Lingle, G.R., and P.A. Bedell. 1989. Nesting ecology of Sedge Wrens in Hall County, Nebraska. NBR 57: 47-49.

Mollhoff, W.J. 2001. The Nebraska Breeding Bird Atlas 1984-1989. Nebraska Ornithologists’ Union Occasional Papers No. 7. Nebraska Game and Parks Commission, Lincoln, Nebraska, USA.

Mollhoff, W.J. 2005a. The 2003-2004 Nebraska nest report. NBR 73: 15-19.

Mollhoff, W.J. 2005b. The 2005 Nebraska nest report. NBR 73: 119-123.

Mollhoff, W.J. 2016. The Second Nebraska Breeding Bird Atlas. Bull. Univ. Nebraska State Museum Vol 29. University of Nebraska State Museum, Lincoln, Nebraska, USA.

Robbins, M.B., and A.S. Nyari. 2014. Canada to Tierra del Fuego: species limits and historical biogeography of the Sedge Wren (Cistothorus platensis). Wilson Journal of Ornithology 126: 649-662.

Temple, S.A. and J.R. Carey. 1987. Wisconsin birds: a seasonal and geographic guide. University of Wisconsin Press, Madison, Wisconsin, USA.

Wolcott, R.H. 1902. Short-billed Marsh Wren and Carolina Wren at Lincoln. Proceedings Nebraska Ornithologists’ Union 3: 108.

Recommended Citation

Silcock, W.R., and J.G. Jorgensen. 2018.  Sedge Wren (Cistothorus platensis), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org


Birds of Nebraska – Online