MONTEREY BIRDS
 
White-crowned Sparrow Zonotrichia leucophrys
 
a web page by Don Roberson

The White-crowned Sparrow has an amazing diversity in its status and distribution in Monterey County. Three populations, members of three named subspecies, are present every year. Birders should aim to learn them all, starting with our locally breeding race Z. l. nuttalli, the Nuttall's White-crowned Sparrow (left, singing on territory in Pacific Grove 7 Apr 2010 © D. Roberson).

The underlying map (below) is from Grinnell & Miller's classic (1944) The Distribution of the Birds of California. It shows the breeding range of the three subspecies that breed in California:
  • Z. l. pugetensis, the "Puget Sound White-crowned," nests in extreme northwestern California [area outlined in orange on map]
  • Z. l. nuttalli, the "Nuttall's White-crowned," nests in a very narrow strip along the California coast from southern Humbolt County to Santa Barbara County [dense gray stippling along coast]
  • Z. l. oriantha, the "Mountain White-crowned," nests at high elevation in the Sierra Nevada and some mountain ranges in northeast California. In winter it moves south into the deserts of Arizona & n. Mexico. There are no MTY records, so I will not discuss it further, except at the very end of the project.

What is most interesting here in MTY is what happens in winter:

  • Z. l. pugetensis, the "Puget Sound White-crowned," arrives from its breeding grounds (s. British Columbia to nw. Calif.) to winter near the coast from Humboldt Co. all the way south to San Diego Co. [area shown in yellow on map]. It spreads a bit more inland around the Bay Area delta, and may winter in small numbers in the Central Valley (orange question marks on map). The orange dots along the edge of the yellow approximate the eastern edge of its regular wintering zone, and other orange dots what could be the complete winter range. There is more to learn about what happens in winter.
  • Z. l. nuttalli, the "Nuttall's White-crowned," remains entirely within its very narrow strip along the California coast from southern Humbolt County to Santa Barbara County. These birds don't wander more than a block or two from the nesting habitat. Thus Nuttall's stays within a couple miles of the coast all year; here in MTY the vast majority stay within a few hundred yards of the coast.
  • Z. l. gambelii, the "Gambel's White-crowned," nests in Alaska and Canada. Huge numbers come to winter throughout the California lowlands, and mostly away from the coast (below). Gambel's is the abundant White-crowned throughout the interior of California in winter (range not shown on map: it is everywhere except the snowy mountains). A small percentage of Gambel's winter along the coast with flocks of pugetensis or nuttalli, but more often these races segregate into more or less 'pure' flocks.
 
 

Recognizing these important differences in distribution goes a long way towards learning how to identify the subspecies in the field. In spring and fall migration, though, there is more mixing among the groups. Nuttall's don't migrate so they are always right on the coast, but Puget Sound or Gambel's White-crowneds can be anywhere in MTY in migration.

The geographic variation in White-crowned Sparrow has long been of substantial interest to ornithologists (e.g., Banks 1964). Comparative biology and migration of Pacific coastal White-crowneds were studied by Blanchard (1941), Blanchard (1942), and Mewaldt, Kibby & Morton (1968). Research on the biology of the species was summarized in Chilton et al. (1995). Local status and distribution is summarized in Roberson & Tenney (1993), Roberson (2002).

This web project deals with adults. Fortunately, both sexes look more or less alike (right; mated pair of nuttalli 7 Apr 2010 Pacific Grove). The major paper on identification of subspecies of White-crowned Sparrow, aimed at birders, is Dunn, Garrett & Alderfer (1995). They dealt not only with the three subspecies that reach coastal California, but also the two additional 'black-lored' subspecies from back East and in the western mountains. As to our three races in coastal California, they proposed differences for adult White-crowneds in:

  • general bill color,
  • back pattern,
  • color of inner greater secondary coverts and tertial edges,
  • color at bend of the wing,
  • color of sides and flanks in adults,
  • median crown stripe and supercilium of adults,
  • primary extension, and
  • song

They also mentioned variation in the extent of dark on the bill (usually on the culmen) and in malar stripe, plus discussed a few other characters for first-year immatures or black-lored populations. Pyle (1997) added to identification criteria of birds in the hand.

Geographic variation in the song of White-crowned Sparrows has been the subject of much focused research, including important papers by Austen & Handford (1991), Baptista (1975, 1977), Baptista et al. (1997), and DeWolfe & Baptista (1995).

 

This collage (right) attempts to compare the 3 subspecies that occur in Monterey County, using both birds of 'known' identity or identified on presumptive grounds. The birds are:

  1. Known nuttalli — 1 Feb 2009 Asilomar SB, male on territory
  2. Known gambelii — 11 Apr 2009 Pixley NWR, Tulare Co. (no other race recorded in Tulare Co.)
  3. Presumed pugetensis — 13 Mar 2010 Carmel Valley Village (singing a pugetensis-like song)
  4. Presumed gambelii — 2 Apr 2010 Pacific Grove (my yard, where it is a vagrant; sang a gambelii song)
  5. Presumed pugetensis — 17 Oct 2009 Pacific Grove (bottlebrush Acropolis & Shell, where a wintering flock had just arrived).

All but # 3 were taken in good full sunlight of well-lit birds; # 3 was in overcast conditions and brightened in a standard automatic way in PhotoShop. All birds essentially the same size — in creating the collage the front row birds were intentionally made slightly larger for perspective.

Using my proposed identifications, the front row (#2 & #4) are Gambel's White-crowned: they have orange or orange-pink bills (to my eye in the field, I tend to call them pink but the photos do look rather rich orange); the back is striped with feathers having rich dark red centers and pale gray edges; the breast tone is decidedly darker gray than the others; and the eye looks disproportionately large in comparison with the others.

The upper left bird is a known Nuttall's on breeding territory. The bill is yellow — but it is a rich yellow. The nape is washed with brown and the sides of the neck behind the auriculars are streaked with brown; the breast has a slight brownish cast to the gray; the black-and-white head stripes are perhaps less contrasty than all the others (the crest is slightly raised on this agitated bird).

The upper right two birds are presumed to be Puget Sound White-crowns. To me the bill color is yellow — albeit a rich yellow with an overtone of orange. One could call it pale orange, but to my eye it is decidedly paler and yellower than the two Gambel's in the front so, on the yellow to orange continuum, I call it 'yellow'. The back is a less rich brown than Gambel's, and has some gray overtones to it. The breast is quite pale gray (not as dark as Gambel's) but is a pure gray (not mixed with brown) and the gray continues through the neck & nape.

To my eye, the front row has orange bills (or orange-pink) while the back row is of birds with yellow bills. If we can agree on that terminology, the following pages delve into the identification questions in more depth.

Literature cited:

Austen, M.J.W., and P.T. Handford. 1991. Variation in the songs of breeding Gambel's White-crowned Sparrows near Churchill, Manitoba. Condor 93: 147–152.

Banks, R.C. 1964. Geographic variation in the White-crowned Sparrow. Univ. Calif. Publ. Zool. 70: 1–123.

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, L.F. 1977. Geographic variation in song and dialects of the Puget Sound White-crowned Sparrow. Condor 79: 356-370.

Baptista, L.F., A. Jess, D.A. Bell, and C. Cebrian. 1997. Acquisition and recall of Gambel's Sparrow dialects by Nuttal's White-crowned Sparrow in the wild. Wilson Bull. 109: 516–521.

Blanchard, B.D. 1941. The White-crowned Sparrow (Zonotrichia leucophrys) of the Pacific seaboard: environment and annual cycle. Univ. Calif. Publ. Zool. 46: 1–178.

Blanchard, B.D. 1942. Migration in Pacific Coast White-crowned Sparrows. Auk 59: 47–63.

Chilton, G., M.C. Baker, C.D. Barrentine, and M.A. Cunningham. 1995. White-crowned Sparrow (Zonotrichia leucophrys) in Birds of North America (A. Poole, ed.), No. 1983. Cornell Lab. Ornithol., Ithaca, N.Y.

DeWolfe, B.B., and L.F. Baptista. 1995. Singing behavior, song types on their wintering grounds, and the question of leap-frog migration in Puget Sound White-crowned Sparrows. Condor 97: 376–389.

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

Grinnell, J., and A.H. Miller. 1944. The distribution of the birds of California. Pac. Coast Avifauna 27.

Mewaldt, L.R., S.S. Kibby, and M.L. Morton. 1968. Comparative biology of Pacific coastal White-crowned Sparrows. Condor 70: 14–30.

Pyle, P. 1997. Identification guide to North American Birds. Vol. 1. Slate Creek Press, Bolinas, CA.

Roberson, D. 2002. Monterey Birds, 2d ed. Monterey Pen. Audubon Soc., Carmel, CA.

Roberson, D., and C. Tenney. 1993. Atlas of the Breeding Birds of Monterey County, California. Monterey Pen. Audubon Soc., Carmel, CA.

Shuford, W.D. 1993. The Marin County Breeding Bird Atlas. Bushtit Books, Bolinas, CA.

 
 

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