Status: Uncommon regular spring migrant east, rare elsewhere. Uncommon regular breeder east, locally uncommon central and west. Rare regular fall migrant east.
Documentation: Specimen: UNSM ZM7658, 18 May 1901 Nebraska City, Otoe Co.
Taxonomy: There are six subspecies in all, five occurring from Mexico southward (Gill and Donsker 2017) and only one, exilis, in North America. Nebraska birds are exilis.
Spring: Apr 22,24, May 1 <<<>>> summer
There are earlier reports 8 Apr 1978 Douglas-Sarpy Cos, 14 Apr 2010 North Platte, Lincoln Co, 15 Apr 1981 Lancaster Co, and an undated report Apr 1898 at Neligh, Antelope Co (Cary 1900). Peak migration is mid- to late May.
Westernmost reports, some of which are at known breeding locations but may indicate arrival dates, are 14 Apr 2010 North Platte, Lincoln Co, 13 May 1961 near Lakeside, Sheridan Co (Tremaine 1962), 14 May 2003 Clear Creek WMA, Keith and Garden Cos, 1-2 calling at Crescent Lake NWR, Garden Co 18-19 May 2016, a specimen, HMM 7655, taken 19 May 1914 near Oshkosh, Garden Co (Rosche 1994), 21 May 2010 Crescent Lake NWR, 24 May 2009 Valentine NWR, Cherry Co and 26 May 1983 at Ash Hollow SHP, Garden Co (Rosche 1994).
Summer: This species is associated with marshes with dense stands of emergent vegetation; many of these are dynamic with variable conditions except for certain large, Sandhills marshes with relatively stable water levels. Away from the Sandhills, wetter springs and summers usually yield increased sightings of this species as the extent and quality of habitat increases. Such a year was 2010, when 15 Least Bitterns were reported.
Around 1900 it was a common summer resident in the east (Bruner et al 1904, Ducey 1988), and it was a “very common summer resident and common breeder at Inland Lagoon [Harvard WPA, Clay Co] 1915-16 (Swenk, Notes Before 1925; Jorgensen 2012). The only additional reports since then until 1973 were single reports from each of Dakota and Webster Cos (Ducey 1988), Clay Co in 1971 (Jorgensen 2012), and York Co Jun 1973 (Morris 1973, Jorgensen 2012), but since 1973, there have been numerous breeding season reports in the southeast. In the period 1992 through 2015 there were 35 reports in 16 of those 24 years, with concentrations in 1997-99, 2009-2010, 2014, and 2016, presumably wet years. Many of these reports probably involved breeding birds.
Despite the number of summer reports, there are few confirmed breeding records in the east. In Lancaster Co, Cink (1971) found a nest in 1970, 4-5 nests were found in 1984 (Williams 1984, Bennett 1985) one in 1986 (Bennett 1987), one in 2003 (Carey Grell, pers. comm.), and 1-3, “a family”, were at Jack Sinn WMA, Lancaster Co 2-16 Jul 2014. In Sarpy Co, one was seen carrying nesting material in 1984 (Williams 1984). A small colony with 4-5 nests was at Massie WPA, Clay Co, 21 Jun 1981 (Jorgensen 2012), and nesting occurred at Weis WPA (now part of Mallard Haven WPA), Fillmore Co, 23 Jun 1985 (Garthright 1985).
There are several reports west of those cited above. It is probably more widespread and numerous in Sandhills marshes than the small number of records indicate due to limited coverage by observers. There are only two confirmed Sandhills breeding records: 1938 in Garden Co (Tout 1947) and a nest in Wheeler Co 17 Jun during 1984-89 (Mollhoff 2001). It was “common in the Garden Co lakes” prior to 1925 (Swenk, Notes Before 1925). Most reports are from Crescent Lake NWR; a juvenile was found 18 Jul 2009, and during Jun-Jul 2016 and 2017, Least Bitterns were observed in numbers at both Crescent Lake and Valentine NWRs during call-playback surveys in which this species was one of several focal species (McGregor et al; in press). Tout (1947) considered it a “common summer resident and breeder in swamps” in Lincoln Co.
There are additional western breeding season reports at Willy Lake, Sheridan Co 23 Jun 2002, in west-central Cherry Co 13 Jun, at “several sites” in Cherry Co in early Jun 2011, at Valentine NWR, Cherry Co 20 Jun 2006 and 25 Jun 2009, at Avocet WMA, Grant Co 8 Aug 2014, in Arthur Co 15 Jun 1990 (Grzybowski 1993), and in Lincoln Co along the North Platte River 20 Jul 2009. Some of the reports listed under Spring are likely summer residents also.
- Breeding Phenology:
Eggs 4 Jun-13 Jul.
- High counts: 8 in eastern Otoe Co 5-16 Aug 1997.
Fall: summer <<<>>> Sep 23,23,23
Departure from breeding locations is in Aug. There are late reports 26 Sep 1998 at Black Island WMA, Cuming Co, 2 Oct 1986 Lancaster Co (Williams 1987), 4 Oct 1999 Walnut Creek Lake, Sarpy Co, 11 Oct 2018 Knox Co, 12 Oct 2005 Hitchcock Park, Omaha, 17 Oct 1983 Lancaster Co, and 3 Nov 2017 Stanton Co. Westernmost reports are 14 and 30 Aug 1986 at Keystone Lake (Rosche 1994, Williams 1987). There is a specimen, WSC 914, collected in Boone Co 13 Sep 1982 (Bray et al 1986).
HMM: Hastings Municipal Museum
NWR: National Wildlife Refuge
SHP: State Historical Park
UNSM: University of Nebraska State Museum
WMA: Wildlife Management Area (State)
WPA: Waterfowl Production Area (Federal)
WSC: Wayne State College
Photograph (top) of a Least Bittern at La Platte Bottoms, Sarpy Co 6 Aug 2010 by Phil Swanson.
Bennett, E.V. 1985. 1984 Nebraska nesting survey. NBR 53: 46-49.
Bennett, E.V. 1987. 1986 Nebraska nesting survey. NBR 55: 31-35.
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.
Bruner, L., R.H. Wolcott, and M.H. Swenk. 1904. A preliminary review of the birds of Nebraska, with synopses. Klopp and Bartlett, Omaha, Nebraska, USA.
Cary, M. 1900. Some bird notes From the Upper Elkhorn. Proceedings of Nebraska Ornithologists’ Union 1: 21-29.
Cink, C.L. 1971. Some interesting summer bird records for Lancaster County in 1970. NBR 39: 58-59.
Ducey, J.E. 1988. Nebraska birds, breeding status and distribution. Simmons-Boardman Books, Omaha, Nebraska, USA.
Garthright, W.C. 1985. Fillmore County. NBR 53: 76-77.
Gill, F., and D. Donsker (Eds). 2017. IOC World Bird List (v 7.3), accessed 30 January 2018.
Grzybowski, J.A. 1993. Southern Great Plains Region. American Birds 47: 1122-1124.
Jorgensen, J.G. 2012. Birds of the Rainwater Basin, Nebraska. Nebraska Game and Parks Commission, Lincoln, Nebraska, USA.
Mollhoff, W.J. 2001. 1999-2000 Nebraska nesting report. NBR 69: 92-101.
Morris, L. 1973. Wetland birds in York County. NBR 41: 66.
Rosche, R.C. 1994. Birds of the Lake McConaughy area and the North Platte River valley, Nebraska. Chadron, Nebraska, USA.
Swenk, M.H. Notes after 1925. Critical notes on specimens in Brooking, Black, and Olson collections made subsequent to January 1, 1925. Handwritten manuscript in the Nebraska Ornithologists’ Union Archives, University of Nebraska State Museum, Lincoln, Nebraska, USA.
Tout, W. 1947. Lincoln County birds. Published by the author, North Platte, Nebraska, USA.
Tremaine, M. 1962. Excerpts from letters. NBR 30: 14.
Williams, F. 1984. Southern Great Plains Region. American Birds 38: 1035-1037.
Williams, F. 1987. Southern Great Plains Region. American Birds 41: 454-458.
Silcock, W.R., and J.G. Jorgensen. 2017. Least Bittern (Ixobrychus exilis), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org
Birds of Nebraska – Online