White-crowned Sparrow Zonotrichia leucophrys

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Geographic Variation

Five subspecies, four illustrated in the Sibley Guide:

• Eastern Taiga (Eastern) Z. l. leucophrys ((Nomenclature: It has been argued that the type specimen of Z. l. leucophrys (now lost) came from a population on Hudson Bay that is mostly pale-lored, therefore the name leucophrys should be applied to the western pale-lored populations currently known as gambelii, and the eastern dark-lored populations would then be named nigrilora. Most authors prefer the stability of maintaining the existing names, and I agree, but be aware that some authors have used the name leucophrys to refer to what is commonly known as gambelii.))
• Western Taiga (Gambel’s) Z. l. gambelii ((Intergrades with Eastern Taiga all around the shores of Hudson Bay, and with Interior West birds in Montana and Alberta.))
• Interior West (Mountain) Z. l. oriantha ((Interior West intergrades with Western Taiga birds in Montana and Alberta.
  Taxonomy: The Interior West (Mountain) subspecies oriantha has been lumped with Eastern leucophrys by some authors (e.g. Banks 1964, Chilton et al. 1995), but this makes no sense biogeographically. Several other authorities argue for recognition as a valid subspecies (e.g. Godfrey 1965) as does recent mtDNA data (Weckstein et al, 2001). Interior West birds are extremely similar to Eastern in general appearance, and very difficult to distinguish, but slight differences exist in color, loral pattern, bill size and color, song, and call, as described above.))
• Pacific group (Nuttall’s) Z. l. nuttalli group ((These two subspecies together form the most distinctive group, readily distinguishable from the others in all plumages, and with mtDNA clustering separately from all leucophrys and gambelii, and some oriantha (Weckstein et al, 2001). Their breeding range does not overlap with any other subspecies. These two Pacific subspecies differ from all other subspecies in having shorter wing, shorter primary projection, yellower bill, drabber upperparts, yellow bend of wing (vs white), different song, etc.)) (includes Nuttall’s Z. l. nuttalli and Puget Sound Z. l. pugetensis subspecies ((Nuttall’s and Puget Sound are barely distinguishable from each other, and intergrade from northern California to southern Oregon, but likely identity can be determined by song and inferred from range and migratory behavior. Nuttall’s averages slightly larger and heavier, slightly more richly-colored overall, and often retains brown feathers in the crown in 1st spring or even as adults. Its song differs from pugetensis, and it is entirely nonmigratory. The contact zone between them is one of the best-studied of any bird and, interestingly, different features show different zones of intergradation.))

Taxonomy

Studies have traditionally focused on loral pattern as the most obvious difference between subspecies – dark in Eastern Taiga and Interior West birds, pale in all others. But this emphasis on loral pattern is misleading, and tends to obscure other subtle differences between subspecies. Voice (both songs and calls) is also very helpful, and suggests the close relationship of all Taiga birds.

The Pacific birds form a distinctive group and are definitely separate. The other three subspecies are very similar to each other and any permutation of one, two, or three groups is defensible. Based on the observed features, and biogeographically, my preferred arrangement is to group Western and Eastern Taiga populations together, with Interior West as a separate group, thus forming a total of three groups:

• a Pacific form with pale lores but distinctive in many other ways
• an Interior West form (oriantha) with dark lores
• a continent-wide Taiga form nesting from Newfoundland to Alaska (including Eastern and Western Taiga), dark-lored in the east and pale-lored in the west.

Subspecies Identification – Western Taiga vs. Eastern Taiga

Overview

Distinguishing these two subspecies is the challenge facing observers in most of eastern North America. Adults nesting west of Hudson Bay and wintering mainly from California to Texas have pale lores and more orange bills, while those nesting in eastern Canada and wintering from the Atlantic coast to Texas generally have dark lores and more pinkish bills. Details of song also differ, but a large intermediate population around Hudson Bay greatly complicates identification. Immatures are much less distinctive, as the face pattern of immature Eastern Taiga birds is very similar to that of Western Taiga, and along with intergrades this renders immatures effectively indistinguishable.

Intergrades

Both of these subspecies nest in the far north, and mix across a wide area around southern Hudson and James Bays. At Churchill, Manitoba, the breeding White-crowned Sparrows are variable. Most are intermediate and tending towards Western Taiga-like, but they can show a full range of variation from pale-lored and orange-billed Western-like birds to dark-lored and pink-billed Eastern-like birds. Birds showing pale lores have been reported breeding as far east as the Hudson Bay coast of Quebec, and it’s possible that occasional individuals showing these features nest even farther east in northern Quebec or Labrador. Intermediate birds are numerous enough that they are frequently encountered on migration and in winter ((An apparent Eastern x Western Taiga intergrade photographed on the wintering grounds in Wise County, Texas is here http://www.flickr.com/photos/pk_capt_sun/3282318543/ )).

Given this extensive intergradation it seems misleading to assign subspecies names to these two populations. Birds showing characteristics of one subspecies nest alongside (or pair with) birds showing characteristics of the other subspecies, and this situation exists across hundreds of miles of central Canada. The reality is better-described by referring to, for example, “birds showing characteristics of the eastern breeding populations” or “showing intermediate features”, rather than the implied clarity of subspecies names.

Range

In fall Eastern Taiga birds migrate southwest at least as far as the hill country of central Texas, while some Western Taiga-like birds can rarely be seen as far north and east as New Jersey and Massachusetts ((see my post here https://www.sibleyguides.com/2010/11/white-crowned-sparrow-subspecies-where/ on migration directions and winter range)). Both subspecies should be expected in winter from the Atlantic coast to central Texas, but the proportions of each subspecies regionally still need to be worked out.

Eastern birds with dark lores are the majority of wintering White-crowned Sparrows west to Austin and Dallas, Texas, and regularly winter as far west as Uvalde County, Texas ((see photo here http://www.flickr.com/photos/tdavenport/4223692295/ )). They probably occur in small numbers in far west Texas and southern New Mexico, where most dark-lored birds are the Interior West subspecies; and presumably Eastern birds sometimes stray even farther west. Observers in New Mexico, Arizona and California should not assume that dark-lored White-crowneds are all Interior West birds. Similarly, dark-lored birds in central Texas are mostly Eastern Taiga birds but could also include Interior West White-crowneds (which are known to winter in west Texas).

Identification

• Adult – Lores all pale gray on Western Taiga (vs black of crown stripe extends farther down onto lores and connects narrowly to front of eye)

Color of the lores is variable in the wide zone of intergradation around Hudson Bay, where many adults show a pattern in between that of the classic Western (pale) and Eastern (dark). This is expressed as a larger or smaller extent of black, not as a dark gray color, so intermediates show pale gray lores with a narrow black line from the balck forehead to the eye.

• Bill more yellow-orange on Western Taiga (vs. darker pink without yellow or orange tones on Eastern)

More obvious on adults but immatures also show a subtle difference. It seems that bill color varies more or less along with loral pattern – birds with pale lores usually look a bit more yellow-billed – but birds with intermediate loral pattern do not always have intermediate bill color, and can have either distinctly pinkish or yellowish bills.

Unreliable or untested differences

• Song may differ (see Voice below); and immatures, at least by late winter, are singing more or less full songs

• Immature – Lores more extensively pale on Western Taiga, especially just in front of eye (vs. some dark on lores)

Immature Eastern birds usually have mostly pale lores with just a narrow and broken dusky stripe in front of the eye, unlike adults and very similar to Western Taiga. Caution: The apparent color of the short bristly loral feathers is highly dependent on lighting and angle of view, making this difficult to judge. Differences between the subspecies are subtle and many intergrades create a continuum of variation. ((Compare photos of October immatures from Massachusetts – typical Eastern here http://www.flickr.com/photos/rstymeist/5084326966/in/photostream/lightbox/
and a paler bird approaching Western Taiga here http://www.flickr.com/photos/rstymeist/5118531822/in/photostream/lightbox/))

• dark lateral crown stripes slightly narrower, especially on forehead

This creates a slightly larger pale area on the lores, and combined with the paleness of the lores helps to create a different appearance.

• Auriculars slightly cleaner and paler gray (vs. gray washed with brownish)
• Flanks may be paler and grayer (vs. more washed with buff and brown)
• Overall size and bill size averages very slightly smaller on Western Taiga (vs slightly larger on Eastern birds)

Subspecies Identification – Interior West vs. Eastern Taiga

Overview

These two dark-lored subspecies are very similar in appearance, but have widely separated breeding ranges. They have never been recorded in each others’ breeding range. Wintering birds probably do overlap in Texas and New Mexico, although this is unconfirmed. Several Arizona records of specimens identified as Eastern ((Monsen and Phillips)) suggest the potential for overlap on the wintering grounds. Adults may be distinguishable by the slightly more extensive black lores and slightly heavier and darker bill of Interior West, as well as by different song and call. Immatures seem to be reliably distinguished by the much more extensively dark lores of Interior West birds, and also by voice.

Intergrades

Interior West populations intergrade with Western Taiga across a fairly wide region of the Rocky Mountains from northern Montana to southern Alberta. Intermediate birds from this region may be indistinguishable from Eastern Taiga birds and from Eastern/Western Taiga intergrades from the Hudson Bay region. Birds from the two intergrade populations (Hudson Bay and Rocky Mountains) are likely to occur together on the wintering grounds in and around Texas, which makes identification of subspecies there extremely complex. ((A photo here http://www.flickr.com/photos/fortphoto/2169658443/ taken at Bosque del Apache NWR in New Mexico shows an intergrade like Western Taiga but with partly dark lores. Whether this bird is from the Hudson Bay intergrade zone (Eastern x Western Taiga) or from the Northern Rocky Mountains intergrade zone (Interior West x Western Taiga) is impossible to determine.))

Identification

• immature has very extensive dark brown forehead and lores with pattern similar to adult (vs. lores mostly pale, paler than adult)

The difference in loral pattern seems more obvious and more reliable in immatures than adults, but more testing is needed.

Unreliable and untested differences

• Bill of Interior West averages very slightly larger and heavier and may look more “swollen” with curved culmen

This difference will be most obvious when comparing Interior West birds to the relatively small-billed Western Taiga populations. Many Eastern Taiga birds have fairly large bills, so bill size and shape may not be helpful in distinguishing these populations.

• Bill may average darker pink with dark culmen

Many Eastern birds have the bill pale and even slightly yellowish like Western Taiga, but others have bills that are quite dark and dusky, similar to Interior West.

• call note differs (see Voice below)
• song differs (see Voice below)

• adult always has solid dark lores and very little white in front of eye (vs. many adults have partly gray lores and a small point of white eyebrow extending in front of eye)

This may be useful as a one-way field mark (birds with the most black are Interior West, those with less black could be either), but some Eastern Taiga birds appear to have just as much black as typical Interior West. ((For example, an Eastern Taiga bird from Boston, MA, with extensive black lores is shown here http://www.flickr.com/photos/ryser915/4581430249/ ))

• immature has darker brown forehead and crown stripes (vs. paler reddish brown)

This difference may be too subtle and/or variable to be useful in the field, but it deserves more study.

• Paler overall, with breast and upper back paler gray, rump paler gray-brown, and flanks and undertail coverts paler buff

Subtle differences in plumage color reported by Godfrey and others, these may be useful when comparing a series of specimens, but are unlikely to be useful under field conditions.

may be more likely to raise crown feathers?

A possible behavioral difference along with possibly broader and brighter white crown stripes make white crown more obvious (Dunn et al), but males have whiter stripes and are more likely to raise crown feathers than females (see Sexual variation) and even if this is true it is no more than a tendency and unlikely to be useful for identification.

• Auriculars may be more brownish and more contrasting with nape? (reported by Pyle 1997)

Extreme Challenge – identifying an Interior West White-crowned in the east

This identification may be possible based on loral pattern. Immatures seem more distinctive than adults, since all immature Eastern White-crowneds have mostly pale lores close to Western Taiga (less extensively dark than adult Eastern), and immature Interior West apparently have extensively dark lores in a pattern similar to the adult. Adults are more difficult to identify, and the darkest extreme of adult Eastern apparently overlaps with Interior West. Most Easterns have less black on the lores as illustrated, but the darkest Eastern birds can apparently match Interior West (( for example, an Eastern Taiga bird from Boston, MA, with extensive black lores is shown here http://www.flickr.com/photos/ryser915/4581430249/ , more typical Eastern birds are shown here http://www.migrationresearch.org/mbo/id/wcsp.html#asymb )).

Extreme Challenge – identifying an Eastern Taiga White-crowned in the west

This will be extremely difficult, if it is possible at all. The differences listed above for distinguishing Interior West from Eastern should all apply, but the biggest differences between the two populations are the slightly less extensive dark color on the lores and slightly smaller and paler bill of Eastern. Many intergrades between Interior West and Western Taiga birds will show the same features listed as characteristic of Eastern White-crowneds. So distinguishing a potential Eastern White-crowned from an Interior West x Western Taiga intergrade may not be possible on current knowledge. It’s possible that songs and calls could distinguish the two subspecies, but the potential exists for an Interior West X Western Taiga intergrade to match Eastern Taiga in voice as well. ((A dark-lored adult White-crowned Sparrow photographed in September at Southeast Farallon Island off San Francisco CA (photo at http://www.flickr.com/photos/podoces/3978530929/ ) is probably an Interior West bird rather than Eastern, based on the expanded black crown stripe in front of the eye, and the relatively dark and dusky pink bill. I’m not sure whether the extent of black on the lores is beyond the range of variation of Eastern birds, but this bird certainly shows more black than most Easterns. Compare an apparent Eastern from Junction Texas here adult Eastern-type from Junction TX http://www.flickr.com/photos/23736263@N04/3040625222/in/photostream/ ))

Subspecies Identification – Pacific vs. Western Taiga

Overview

These two groups share pale lores and yellowish bills, but they differ in many other subtle features that combine to give Pacific a fundamentally different appearance – overall drabber and browner. Songs and calls also differ slightly. Pacific birds are common within their limited range, mostly along the immediate coast. The two groups can form mixed flocks and choose similar habitats in winter, but Western Taiga are uncommon along the coast (where Pacific predominates) and Pacific rarely venture far inland (where winter flocks are almost exclusively Western Taiga birds) (Roberson). Pacific birds might occur as vagrants a short distance east or south of their normal winter range, and should be watched for especially in Nevada and Arizona in winter.

Intergrades

Pacific birds do not interbreed with any other subspecies, and intergrades of Western Taiga with Interior West or Eastern Taiga will show more extensive dark lores and pinker bills, obviously different from Pacific.

• bill dirty yellowish with small dark tip (vs. more orange-pink with less well-defined dusky tip)
• back dull brown with black streaks (vs. tricolored gray with reddish brown centers and black streaks)
• wing coverts and tertials edged drab brown (vs. rich reddish brown)
• Underparts strongly washed brownish (vs. clean gray on breast, buff flanks)
• bend of wing and underwing coverts yellowish (vs whitish)
• Adult has pale crown stripes drabber, less clean, less broad and do not flare as broadly when crown feathers are raised (vs. crown stripes bright white and sometimes obviously flared)
• thin dark lateral throat stripes often present, usually obvious on immatures (vs. occasionally present and less distinct on immatures of other subspecies)
• primary projection shorter
• legs more yellowish (vs pinkish)
• auriculars browner (vs gray)
• voice differs

Sexual variation

Males, at least in breeding season, average brighter overall with cleaner white median crown stripe and supercilium all the way to the back of the head (vs. female washed with gray and sometimes speckled on rear end of white crown stripes); male shows more obvious whitish border below black eyeline and above gray cheek (vs. little or no pale border); pale crown stripes appear broader and more conspicuous, perhaps because of the male’s habit of raising crown feathers more (vs. female keeps crown feathers down and stripes appear narrow). These differences are subtle and probably overlapping, but in a known pair it can be relatively easy to tell which bird is the male and which the female.

Males average slightly larger than females, but there is much overlap and the size difference is not detectable in the field.

Voice:

Call – Dunn et al. (1995) describe the call of Western Taiga and Eastern subspecies as a sharp pink; the call of Pacific subspecies as a flatter pink, and the call of Interior West birds as a metallic penk. They report that with practice it is possible to pick out each of these three types by call.

Song – Dunn et al (1995) describe Western Taiga/Eastern song as “lazier, wheezier, and more wavering than Pacific” and note that the songs of northern birds “generally lack clear trills, paired whistles, and sprightly patterning”. Pacific birds “tend to have a more sprightly and patterned song that usually incorporates one or more rather clear introductory whistles and a pair or more of rapidly-delivered slurred whistles or short trills at or near the end”. Interior West birds sing clear songs more suggestive of Pacific, although some (e.g. in OR) sound more like Western Taiga.

Hybrids:

White-crowned x Golden-crowned Sparrow – several records include Alaska (photos here: http://www.valdosta.edu/~bergstrm/zono.html) and California (photos here: http://www.calpoly.edu/~mstiles/gldwht.html)

White-crowned x Harris’s Sparrow

References

Austen and Handford 1991 http://elibrary.unm.edu/sora/Condor/files/issues/v093n01/p0147-p0152.pdf

Baker, M. C. 1987. Intergradation of song between two subspecies of White-crowned Sparrows on the west coast of North America. Ornis Scand. 18:265-268.

Baker, M. C. and D. B. Thompson. 1985. Song dialects of sparrows: historical processes inferred from patterns of geographic variation. Condor 87:127-141. http://elibrary.unm.edu/sora/Condor/files/issues/v087n01/p0127-p0141.pdf

Baker, M. C., M. A. Cunningham, and A. D. Thompson, Jr. 1984. Cultural and genetic differentiation of two subspecies of White-crowned Sparrow. Condor 86:359-367. http://elibrary.unm.edu/sora/Condor/files/issues/v086n04/p0359-p0367.pdf

Banks, R. C. 1963. Geographic variation in the White-crowned Sparrow Zonotrichia leucophrys Univ. Calif. Publ. Zool. 70:1-123.

Baptista – 1997 Acquisition and recall of Gambel’s Sparrow dialects by Nuttall’s White-crowned
Sparrows in the wild. http://elibrary.unm.edu/sora/Wilson/v109n03/p0516-p0521.pdf

Baptista, L. F. 1975. Song dialects and demes in sedentary populations of the White-crowned Sparrow (Zonotrichia leucophrys nuttalli) Univ. Calif. Publ. Zool. 105:1-52.

Baptista 1977 http://elibrary.unm.edu/sora/Condor/files/issues/v079n03/p0356-p0370.pdf

Baptista and King 1980 http://elibrary.unm.edu/sora/Condor/files/issues/v082n03/p0267-p0284.pdf

Baptista and Morton 1982 http://elibrary.unm.edu/sora/Auk/v099n03/p0537-p0547.pdf

Chilton, G., M. C. Baker, C. D. Barrentine and M. A. Cunningham. 1995. White-crowned Sparrow (Zonotrichia leucophrys), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/183

Chilton and Lein 1996 http://elibrary.unm.edu/sora/Condor/files/issues/v098n03/p0567-p0580.pdf

Cortopassi, A. J. and L. R. Mewaldt. 1965. The Circumannual distribution of White-crowned Sparrows. Bird-Banding 36:141-169. pdf here: http://elibrary.unm.edu/sora/JFO/v036n03/p0141-p0169.pdf

Cunningham, M. A., M. C. Baker, and T. Boardman. 1987. Microgeographic song variation in the Nuttall’s White-crowned Sparrow. Condor 89:261-275.

Dewolfe, B. B., D. D. Kaska, and L. Peyton. 1974. Prominent variations in the songs of Gambel’s White-crowned Sparrows. Bird-Banding 45:224-252.

DeWolfe http://elibrary.unm.edu/sora/Condor/files/issues/v097n02/p0376-p0389.pdf

Dunn, J.L., K.L. Garrett, and J.K. Alderfer. 1995. White-crowned Sparrow Subspecies: Identification and Distribution. Birding 27:182-200.

Fugle and Rothstein – plumage brightness by sex http://elibrary.unm.edu/sora/JFO/v056n04/p0356-p0368.pdf

Godfrey 1965 http://elibrary.unm.edu/sora/Auk/v082n03/p0510-p0518.pdf

Harbison et al 1999. http://elibrary.unm.edu/sora/Condor/files/issues/v101n01/p0133-p0148.pdf

Hill, B. G. and M. R. Lein. 1985. The non-song vocal repertoire of the White-crowned Sparrow. Condor 87:327-335.
http://elibrary.unm.edu/sora/Condor/files/issues/v087n03/p0327-p0335.pdf

Kern 1984 http://elibrary.unm.edu/sora/Condor/files/issues/v086n04/p0455-p0466.pdf

Lampe, H. M. and M. C. Baker. 1994. Behavioral response to song playback by male and female White-crowned Sparrows of two subspecies. Bioacoustics 5:171-185.

Miller, Alden H. 1940. A hybrid between Zonotrichia coronata and Zonotrichia leucophrys Condor 42(1):45-48.

Morton, M. L. and L. R. Mewaldt. 1960. Further evidence of hybridization between Zonotrichia atricapilla and Zonotrichia leucophrys Condor 62:485-486.

Orejuela, J. E. and M. L. Morton. 1975. Song dialects in several populations of Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha) in the Sierra Nevada. Condor 77:145-153.

Patten, Michael A., Guy McCaskie, and Philip Unitt. 2003. Birds of the Salton Sea: status, biogeography, and ecology. Univ. Calif. Press, Berkeley.

Pyle, P. 1997. Identification Guide to North American Birds: Part I. Slate Creek Press.

Roberson, D. White-crowned Sparrow. web page http://www.creagrus.home.montereybay.com/MTYbirdsWCSP.
html

Notes: