Passerella iliaca zaboria, P. i. iliaca
Status: Fairly common regular spring and fall migrant east, uncommon east-central, rare casual west-central and west. Uncommon regular winter visitor southeast, rare casual elsewhere.
Documentation: Specimens: iliaca?, UNSM ZM17887, 21 Oct 2000 Lincoln, Lancaster Co; zaboria? UNSM ZM18334, 7 Nov 2005 Dodge Co (see Taxonomy). Regarding schistacea, see Comments, below.
Taxonomy: Some 15-24 subspecies are recognized by various authorities (Pyle 1997, Gill et al 2020, Clements 2016, Weckstein et al 2020). These are generally divided into four subspecies groups (Pyle 1997): Sooty Fox Sparrow (P. unalaschcensis), Thick-billed Fox Sparrow (P. megarhyncha), Slate-colored Fox Sparrow (P. schistacea), and Red Fox Sparrow (P. iliaca). Recent genetic studies (Zink 1994, Zink and Weckstein 2003) confirm the status of these four groups as full species, and we follow Gill et al (2020) and Wright (2019) in adopting this approach.
Of these groups, the first two are restricted to the coastal and western montane Pacific region, and interior montane Slate-colored Fox Sparrow is unlikely to occur in Nebraska (see Comments below). According to Pyle (1997), Red Fox Sparrow subspecies are zaboria, breeding from interior Alaska to central Alberta south to Northwest Territories and Manitoba, wintering from southern California to south Texas, north and east to Iowa and Georgia, and iliaca, breeding from northeast Manitoba and Ontario to Newfoundland, wintering from Michigan to Mississippi east to New Hampshire and Florida. Pyle’s proposed placement of altivagans interior British Columbia and southwestern Alberta, wintering California to Arizona, was either with the Red group or the Slate-colored group; recent genetic studies (Zink 1994, Zink and Weckstein 2003) confirm inclusion of altivagans in Slate-colored Fox Sparrow. There are no Nebraska records of altivagans and it is unlikely to occur in Nebraska based on its currently accepted range.
All Nebraska observations are of Red Fox Sparrow (see Comments regarding occurrence of P. schistacea); it has been assumed that subspecies P. p. iliaca and P. p. zaboria migrate through Nebraska (Bent 1968; Pyle 1997). Both iliaca and zaboria Red Fox Sparrows winter in the southeastern US. Since zaboria breeds westward into Alaska, its migration route is southeastward on the northern Great Plains including Nebraska; it is only a rare migrant in northeastern Colorado (Andrews and Righter 1992). All Oklahoma specimens (>35) are zaboria (Joe Grzybowski, pers. comm.). Subspecies iliaca breeds west in Canada to the longitude of Minnesota, and winters with zaboria in the southeastern US. Thus, iliaca migrates southward and southeastward and could be expected to be less numerous in Nebraska than zaboria. In addition, intergrades might be expected to occur in at least eastern Nebraska. Field identification of these two subspecies in Nebraska is very difficult, with only extremes of rufous (iliaca) and gray (zaboria) plumages possibly identifiable, as suggested by Beadle and Rising (2003). Probable examples from Nebraska of such extremes are a grayish bird photographed in Dawes Co 13 Oct 2018 (Jorgensen 2018), a bird suggestive of zaboria picked up in Dodge Co 7 Nov 2005 and sent to UNSM, now ZM18334 (cited above), and reddish birds that are good candidates for iliaca, the specimen cited above (Documentation) which is a fresh, very reddish bird from Fontenelle Forest, Sarpy Co 5 Mar 2017 (Peterson 2017), and 25 Mar 2017 Dodge Co (Croshaw 2017).
Changes since 2000: Even though numbers observed in winter are variable, reports have increased in recent years including numbers recorded on CBCs (Figure 1); prior to winter 2009-2010 there had been only about 25 reports for Feb, but since then such reports have been numerous. During the winter of 2014-2015 at least 16 individuals were at 11 locations in the southeast.
Figure 1: Number of Fox Sparrows detected per party hour on Nebraska Christmas Bird Counts during the period 1970-2016. Points represent reported values and trend line created using locally weighted scatterplot (LOESS) smoothing. Data collected by volunteers and provided by National Audubon Society and the Nebraska Ornithologists Union.
Spring: winter <<<>>> Apr 26, 27, 28 (south and east); Mar 20, 20, 21 <<<>>> Apr 4, 7, 9 (north and west)
A later date east is 5 May 2018 Saunders Co.
Earlier dates north and west are 15 Mar 2016 Garfield Co, and 16 Mar 2015 Brown Co.
Later dates north and west are 16 Apr 2018 Knox Co, and 19 Apr 2018 Antelope Co.
Migration is from late Mar through Apr; peak movement is in early Apr in the southeast, mid-Apr elsewhere.
There is one documented Panhandle report, a single grayish Red Fox Sparrow photographed in Morrill Co 18 Apr 2014. On the eastern Colorado plains, Fox Sparrow was listed as a rare migrant by Andrews and Righter (1992) and in eastern Wyoming it is a rare migrant, “presumably iliaca/zaboria” (Faulkner 2010).
- High counts: 62 at Fontenelle Forest 1 Apr 2017, 25 there 5 Apr 2009, 23 there 29 Mar 2005, and 22 at Wood Duck WMA, Stanton Co 1 Apr 1998.
Fall: Oct 2, 3, 4 <<<>>> winter
Earlier dates are 11 Sep 2010 Wind Springs Ranch, Sioux Co, 26 Sep 2012 Douglas Co, 27 Sep 2016 Dawes Co, 29 Sep 2012 Scotts Bluff Co, and 30 Sep 2011 Cass Co.
Later dates include a number of CBC reports, with high counts of 19 on the DeSoto NWR CBC 29 Dec 2012, 17 on the Branched Oak Lake-Seward CBC 17 Dec 2009, and 13 there 15 Dec 2007. In 2015, a total of 21 were reported on CBCs, all in the southeast, including nine on the Branched Oak Lake-Seward CBC 20 Dec 2015. There are several Jan reports.
Migration is from Oct through late Nov, with peak numbers in late Oct-early Nov, although fall departure is protracted, especially in the southeast, where a few overwinter.
Fox Sparrow is rare in the Panhandle, with reports 11 Sep 2010 Wind Springs Ranch, 27 Sep 2016 Dawes Co, 29 Sep 2012 Scotts Bluff Co, 4 Oct 2020 Scotts Bluff Co, 8 Oct 2015 Kimball Co, 10 Oct 2020, Scotts Bluff Co, 13 Oct 2018 Dawes Co, and 8 Nov 2015 Kimball Co.
Reports from the west-central, where the species is less than annual, are 9 Oct 2019 Red Willow Co, 9 Oct 2020 Dundy Co, 16 Oct 2012 Lincoln Co (reported as “Red”), and 29 Oct 2015 two at Wood Lake, Cherry Co.
- High counts: 32 at Boyer Chute NWR, Washington Co 18 Oct 1998, 18 at Wood Duck WMA 28 Oct 1997, and 15 at Fontenelle Forest 2 Nov 2016.
Winter: Prior to the winter of 2009-2010, there had been only about 25 reports in Feb, indicating that overwintering was less than annual. Since then, however, this species has wintered in the southeast in good numbers. In 2013-2014 there were 12-13 birds reported at five locations through 22 Feb, and in 2014-2015 at least 16 individuals were at 11 locations in the southeast. Continuing the trend, in winter 2017-2018 there were an amazing 34 individuals reported Jan-Feb.
Away from the southeast, there are few reports of overwintering or birds seen in Feb. Westerly was one 29 Dec 1964-1 Feb 1965 in Scotts Bluff Co, one was at a feeder in southeast Lincoln Co 9-14 Feb 2014, one was at Pressey WMA, Custer Co 14 Feb 2015, and one was in Custer Co 27 Feb 2013, while northerly was one wintering 2010-2011 in Winside, Wayne Co and still present 7 Mar 2011. Perhaps defining the expected limits for most winters were one that wintered at feeders in Hooper, Dodge Co 2009-2010, three that wintered at a Platte Co feeder 2012-2013, one in Kearney, Buffalo Co 20 Jan 2019, apparently the same bird in the same place 23 Dec and 11 Jan 2020, and three in Franklin Co 15 Feb 2015,
Comments: The occurrence of schistacea in Nebraska is based on the purported collection of a specimen (USNM A 5718) in southwest Nebraska 19 July 1856 (Deignan 1961), generally considered to be “Head of the Platte = south fork of the Platte River, about 25 miles east of the northeastern corner of Colorado, in Nebraska” (AOU 1957, Deignan 1961). The accuracy of this location is questionable for several reasons, as outlined in Silcock (2021). As suggested by Wright (2019), “it seems most plausible that the bird was mis-labeled or the date was misread”. Silcock (2021) presented a case that indeed the collecting locality of the specimen was within its breeding range in the northern Medicine Bow Mountains in Wyoming between 7 and 25 August 1856 rather than in Nebraska on 19 July 1856.
AOS: American Ornithological Society (formerly American Ornithologists’ Union)
CBC: Christmas Bird Count
UNSM: University of Nebraska State Museum
WMA: Wildlife Management Area (State)
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Croshaw, C. 2017. eBird checklist S35425193: Dodge Co, Nebraska.
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Peterson, B. 2017. eBird checklist S34987164: Sarpy Co, Nebraska.
Pyle, P. 1997. Identification Guide to North American Birds. Part I, Columbidae to Ploceidae. Slate Creek Press, Bolinas, California, USA.
Silcock, W.R. 2021. Locality and date of collection of the type specimen of the Slate-colored Fox Sparrow. Western Birds 52: 165–167. doi 10.21199/WB52.2.6.
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Zink, R.M. 1994. The geography of mitochondrial DNA variation, population structure, hybridization, and species limits in the Fox Sparrow (Passerella iliaca). Evolution 48: 96-111.
Zink, R.M., and J.D. Weckstein. 2003. Recent Evolutionary History of the Fox Sparrows (Genus: Passerella). Auk 120: 522-527. https://doi.org/10.1093/auk/120.2.522.
Silcock, W.R., and J.G. Jorgensen. 2021. Fox Sparrow (Passerella iliaca). In Birds of Nebraska — Online. www.BirdsofNebraska.org
Birds of Nebraska – Online
Updated 6 May 2021