Mimus polyglottos polyglottos
Status: Uncommon regular spring and fall migrant west, south, east, rare north. Fairly common regular breeder south, southern Panhandle, and southeast, rare elsewhere. Rare casual winter visitor statewide.
Documentation: Specimen: UNSM ZM11667, 31 May 1895 Lincoln, Lancaster Co.
Taxonomy: Three subspecies are currently recognized (Farnsworth et al 2011); polyglottos breeds over much of North America, from southern Canada south to central Mexico and the northern Bahamas, with northern breeders migratory; orpheus and dominicus are restricted to islands in the Caribbean. Previously-recognized western leucopterus has been synonymized with polyglottos (Phillips 1986).
Prior to their synonymy, most Nebraska breeders were thought to be intergrades of leucopterus and polyglottos; (AOU 1957) stated that leucopterus “intergrades with polyglottos in the eastern plains area of Nebraska”. Rapp et al (1958) suggested that leucopterus occurs in the Panhandle and east in the Platte Valley as far as Lincoln and Logan Cos, while polyglottos was resident in the eastern third of the state “most numerous in the southeastern region”.
Spring: Mar 2,3,4 <<<>>> summer
Arrival is in mid- to late Mar. Late Jan and Feb reports are discussed below (Winter).
This species is generally sedentary, but populations at the northern edge of the range, as in Nebraska, are migratory and depart in winter. Migration is most noticeable in spring when birds return and establish territories.
- High counts: 5 at Spring Creek Prairie, Lancaster Co 9 Apr 2016.
Summer: This species’ range has remained relatively stable for more than a century. Bruner et al (1904) wrote: “This bird is found throughout the entire state; south of the Platte a common summer resident and breeder; rare north of middle of state.” This distribution resembles closely that found by Mollhoff (2016). Numbers may have been reduced in the 1950s, however, as Rapp et al (1958) considered it an “uncommon summer resident” both in the Panhandle and the eastern third of the state. The distribution described by Rapp et al (1958) is reflected by the current BBS-determined distribution for 2011-2015, with highest densities in the southeast and southern Panhandle (Sauer et al 2017). Mollhoff (2016) showed that although total reports of mockingbirds increased moderately between the first (1984-1989) and second (2006-2011) breeding bird atlas periods (detected in 16% of blocks compared with 14%), the percentage of total reports north of the North Platte and Platte River Valleys doubled (27% compared with 14%). However, overall blocks and observer effort also increased markedly during the second atlas compared to the first (Mollhoff 2016). BBS trend analysis shows an annual change in abundance of – 0.61 (95% C.I.; -2.52, 1.33) during the period 1966-2015 (Sauer et al 2017). These figures suggest that mockingbirds are maintaining overall numbers in southern Nebraska. Reports farther north may suggest the species is continuing to expand northward. However, Jorgensen (2012) considered it still a rare migrant and casual breeder in the Rainwater Basin.
The BBS routes with highest numbers of Northern Mockingbirds are located in the extreme southeast (Johnson, Nemaha, Gage and Pawnee Cos), and along or south of the Platte River Valley (Gosper, Furnas, Keith and Lincoln Cos). A route in Nemaha and Pawnee Cos had 16 on 20 Jun 2015, a BBA block in Johnson Co had 12 on 8 Jul 2010, and five singing birds were on an 80-acre site in Pawnee Co 30 Jun 2007. Ludlow (1935) considered this species a “common summer resident” in Webster Co.
Breeding reports are fewest in the north; Mollhoff (2001) reported a nest in Arthur Co, one was found on a BBS route in northern Garden Co 17 Jun 2003, and one was carrying food in Wayne Co 14 Jun 2011. Of 16 total records in the north, including the three breeding records, 14 have occurred since 2005.
Other summer reports in the north-central are 1 Jun 2016 Thomas Creek WMA, Keya Paha Co, 11 Jun 2016 Dakota Co, a pair in Brown Co Jun 2008, 30 Jun 2007 southern Cherry Co, one at Fort Niobrara NWR, Cherry Co 6 Jul 2014, singles at Valentine NWR, Cherry Co 13 Jul 2017 and 14 Jul 2015, one at Fort Niobrara NWR 14 Jul 2017, and one in Hooker Co 1 Aug 2006.
- Breeding phenology:
Nest-building: 29 May-25 Jul
Eggs: 11 Jun
Nestlings: 5-23 Jun
Fledglings: 9 May-6 Sep
- High counts: 15 in southeast Thayer Co 8 Jul, 13 in southwest Kimball Co 6 Aug 2000, and 12 in Gage Co 27 Jun 2006.
Fall: summer <<<>>> Jan 4,5,7
Departure times are difficult to determine, as there is a gradual movement southward in late fall (see Winter). A group of eight in cedars near Arthur, Arthur Co 21 Sep was indicative of peak migration timing.
Later Jan and Feb reports are discussed below under winter.
Winter: In fall and early winter, numbers decline as birds gradually leave the state. The few winter reports are scattered statewide, although the only records of over-wintering are of one at Pawnee Lake, Lancaster Co seen through the winter 2010-2011, and another that was present through winter 2013-2014 until 14 Mar 2014 in the North Platte, Lincoln Co area.
There are 13 reports in Jan after 7 Jan (see late fall dates above), but only these eight for Feb: 7 Feb 1987 Lincoln Co, 9 Feb 1981 Douglas Co, 11 Feb 2004 Lancaster Co, 13 Feb 2010 Brady, Lincoln Co, 16 Feb 2017 Webster Co, 20 Feb 1990 Lincoln Co, 26 Feb 2000 Clear Creek WMA, Keith Co, and 28 Feb 1954 Boyd Co.
BBA: Breeding Bird Atlas
BBS: Breeding Bird Survey
NWR: National Wildlife Refuge
UNSM: University of Nebraska State Museum
WMA: Wildlife Management Area (State)
Photograph (top) of a Northern Mockingbird at Papillion, Sarpy Co 16 Apr 2016 by Phil Swanson.
American Ornithologists’ Union [AOU]. 1957. The AOU Check-list of North American birds, 5th ed. Port City Press, Baltimore, Maryland, 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.
Farnsworth, G., G.A. Londono, J.U. Martin, K.C. Derrickson, and R. Breitwisch. 2011. Northern Mockingbird (Mimus polyglottos), version 2.0. In The Birds of North America (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bna.7
Jorgensen, J.G. 2012. Birds of the Rainwater Basin, Nebraska. Nebraska Game and Parks Commission, Lincoln, Nebraska, USA.
Ludlow, C.S. 1935. A quarter-century of bird migration records at Red Cloud, Nebraska. NBR 3: 3-25.
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.
Phillips, A.R. 1986. The known birds of North and Middle America. Part 1. Published by the author, Denver Colorado, USA.
Pyle, P. 1997. Identification Guide to North American Birds. Part I, Columbidae to Ploceidae. Slate Creek Press, Bolinas, California, USA.
Rapp, W.F. Jr., J.L.C. Rapp, H.E. Baumgarten, and R.A. Moser. 1958. Revised checklist of Nebraska birds. Occasional Papers 5, Nebraska Ornithologists’ Union, Crete, Nebraska, USA.
Rosche, R.C. 1982. Birds of northwestern Nebraska and southwestern South Dakota, an annotated checklist. Cottonwood Press, Crawford, Nebraska, USA.
Sauer, J.R., D.K. Niven, J.E. Hines, D.J. Ziolkowski, Jr, K.L. Pardieck, J.E. Fallon, and W.A. Link. 2017. The North American Breeding Bird Survey, Results and Analysis 1966 – 2015 (Nebraska). Version 2.07. USGS Patuxent Wildlife Research Center, Laurel, Maryland, USA.
Silcock, W.R., and J.G. Jorgensen. 2018. Northern Mockingbird (Mimus polyglottos), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org