Species Accounts for the Sierra Nevada Bird Conservation Plan

Prepared by David F. DeSante
Posted 10.3.99
Contact: CPIFPlans at prbo dot org

See the introduction to Appendix 1 for explanations of codes and abbreviations.

(Page 1.  Page 2.  Page 3.)



CALIFORNIA TOWHEE - Pipilo crissalis

Stat: R West: fR,xT. East:

Dist: T West: N:F-4; T:F-8; W:F-4. East:

Sign: CAL-10 (although occurs extensively in Baja California as well). Ssp. carolae west slope except for extreme southern portion - PCAL-11; kernensis extreme southern part of west slope and southern end of the Sierra (up-slope from South Fork of Kern River) - PCAL11. California Towhees are much less common in the Sierra than in other parts of California so the Sierra is less important to their overall range than expected from their importance classifications. However, both subspecies, but especially kernensis, have very limited ranges so all populations, even the small ones in the Sierra, are of considerable importance.

Hab: R: 3-RSP; 2-MCP.

F: 3-RSP; 2-MCP.

Sp: Requires open woodland, broken chaparral, or brushy riparianhabitats where shrubland edges on grassland or meadows. Very muchattracted to the neighborhood of human habitations.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: Faces very few risks other than complete urbanization. Aggregate numbers have probably increased somewhat historically and, I suspect, an increasing population trend would still be evident if data were available. In addition, they have probably extended their breeding range higher into the mountains in recent years, following the advance of human settlement.

 

RUFOUS-CROWNED SPARROW - Aimophila ruficeps

Stat: R West: luR,xT. East:

Dist: T West: N:F-3; T:F-4; W:F-3. East:

Sign: SW-9. Ssp. ruficeps - PCAL-11. This species occurs only marginally on the lower foothills of the west slope of the Sierra. Thus the Sierra is unimportant to the overall range of the species. However, it may be of great importance to the subspecies ruficeps, which is confinedto central California.

Hab: R: 2-MCP.

F: 2-MCP.

Sp: Confined year-round to dry, sunny, predominately grassy slopes withscattered small shrubs and rocky outcrops. Generally avoids densechaparral and woodlands of all types.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: This species seems to have expanded its range northward in recent years to include the foothills of the northern west slope of the Sierra (as well as the northern east slope of the inner coast ranges bordering the Sacramento Valley). It is possible, however, that this species was previously overlooked in this part of its range. Population trends for this species in the Sierra are unknown. However, the subspecies deserves careful monitoring as a great deal of its range occurs in the Sierra. Increased residential development of its habitat represents a potentially serious risk, as does increased grazing pressures on its very specialized habitat and associated cowbird parasitism. The southern California race of this species, canescens, is a federal Candidate 2 species.

 

CHIPPING SPARROW - Spizella passerina

Stat: SD-NTMWest: fS,fT. East: fS,fT.

Dist: T West: N:3-10; T:F-10. East: N:6-10; T:B-10.

Sign: CONT-1. Ssp. arizonae - PAC-7 (but also extends into central western and southeastern Arizona). This species is (or at least was) quite common in the Sierra which, therefore, represents an important part of the subspecies' range.

Hab: R: 3-MHW,MHC,PPN,MCN; 2-DFR,JPN,RFR,LPN,EPN,PJN,JUN,MRI.

F: 3-MHW,MHC,PPN,MCN,WTM; 2-DFR,JPN,RFR,LPN,EPN,PJN,JUN,MRI,MCP.

Sp: Prefers the edges of relatively dry montane meadows and open woodland and forest with little or no shrub cover. Perhaps most common on the west slope between 5,000' and 9,000' where, in contrast to the above WHR, they may prefer the edges and openings in mixed coniferous, jeffrey pine, and lodgepole pine forests. On the east slope, they associate with jeffrey pines, mountain mahoganies, and, perhaps to a lesser extent, pinyon pines and junipers. Up-

slope dispersal brings birds into montane riparian and montane meadow habitats but even there they generally choose the drier partof such habitats.

Abundance: BBS: 16 routes;7. 44 birds/route. MAPS: 2. 49 ad/600 nh

Trends: BBS: DD;-6. 3% per year***

Demographics: MAPS: Prod. index: 24. 8% yg.

Potential risks and suggested causes of population trends: This is one of ten species that are definitely declining in the Sierra. The highly significant decline is 6. 3% per year. I cannot confidently suggest a likely cause for this decline, but suspect that it is connected with the deterioration of grassland habitat on its southwestern winter range. Logging in the Sierra may present a serious risk if the logging produces an accelerated growth of montane chaparral or brush which the species usually avoids. Loss and degradation of montane riparian habitat and montane meadows due to grazing and other causes would seem to be less of a risk to this species than to other species that are not declining. The species, however, is very susceptible to cowbird parasitism and this may be the most important risk to the species in the Sierra. It may also suffer from high rates of nest predation, perhaps from Steller's Jays. The low MAPS productivity index suggests that these latter causes may offer a partial explanation for the pronounced decline. This species warrants intensive monitoring as it may be able to shed considerable light on the causes of declines in Sierran birds in general. Moreover, the species seems to be declining rapidly over most of the western U. S. (DeSante and George 1994).

 

BREWER'S SPARROW - Spizella breweri

Stat: SDM West: rT. East: fS,uT.

Dist: T West: T:4-10. East: N:B-9; T:B-10.

Sign: WEST-4. Ssp. breweri - RM/GB-8. This species is of marginal distribution in the Sierra; thus, the Sierra does not constitute an important part of this species overall range.

Hab: R: 3-[MCP].

F: 3-[MCP]; 2-[WTM],PAS.

Sp: This is a sagebrush species par excellance that prefers extensive, unbroken stands of sagebrush and bitterbrush. On east slope ridgesit also occurs in stunted mountain mahogany, but otherwise generally avoids arborescent mahoganies. In up-mountain drift, it also occurs in wet meadows and alpine grasslands.

Abundance: BBS: 2 routes;0. 20 birds/route. MAPS: 0. 13 ad/600 nh

Trends: BBS: UN; 10. 9% per year

Demographics: MAPS:

Potential risks and suggested causes of population trends: Although the species is declining over most of western U. S. (DeSante and George 1994), the species appears to be increasing in the Sierra at a high rate, although it was only detected on two routes. I can offer no explanation for this phenomenon, if it is not just a local aberration. I suspect that declines are caused by degradation of winter grassland habitat in the Southwest. Increased cowbird parasitism may also be a risk that the species faces on its breeding grounds.

 

BLACK-CHINNED SPARROW - Spizella atrogularis

Stat: NTM West: ilrS. East: iluS,rT.

Dist: CSW,SEWest: N:1-4. East: N:B-8; T:B-8.

Sign: SW-9. Ssp. cana central and southern portions of the west slope and extreme southern end of the Sierra above South Fork of the Kern River - PCAL-11; evura southern portion of the east slope - SW-8. This species generally is rare in the Sierra which does not constitute a major portion of the overall range; thus the Sierra is of minor importance to the species as a whole. It is, however, much more important to the subspecies cana which is endemic to a relatively small portion of California.

Hab: R: 3-PJN,[MCP].

F: 3-PJN,[MCP].

Sp: On the west slope of the Sierra, this species is generally associated with arid slopes clothed with moderately dense and diverse chaparral. Often reaches maximum densities on old burned over tracts that are well along toward recovery. Habitat

preferences are similar on the east slope, but there they are often associated with rocky outcrops and scattered pinyons or junipers.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: Nothing is known regarding Sierran population trends for this rare species, except that it is notably irregular in occurrence and may be subject to substantial population fluctuations that may be dependent upon the burning regime of the chaparral. Years of rigid fire suppression may have substantially decreased populations of this species, and fire suppression followed by catastrophic fires may be serious threat to its existence. Development of west slope foothill chaparral habitat may be another threat, as might cowbird parasitism in foothill areas subjected to nearby grazing. Populations of this species need to be monitored closely in the Sierra.

 

VESPER SPARROW - Pooecetes gramineus

Stat: SDM West: rT. East: uS,rT.

Dist: T West: T:F-10. East: N:6-9; T:B-10.

Sign: CONT-1. Ssp. confinus - WEST-4. This species is of very marginal occurrence in the Sierra which is not important to its overall range. The Sierra, however, is of somewhat greater importance to the species' breeding range in California.

Hab: R: 2-PJN,JUN,[MCP].

F: 2-PJN,JUN,[MCP],PAS.

Sp: Generally restricted to low, sparse sagebrush scrub interspersed with grassy cover or margined by dry grassy meadows. Generally avoids continuous expanses of sagebrush scrub and moist meadows but will occur occasionally in dry pastureland.

Abundance: BBS: MAPS: 0. 23 ad/600 nh

Trends: BBS:

Demographics: MAPS: Prod. index: 22. 9% yg.

Potential risks and suggested causes of population trends: The species has declined seriously over the past 70 years both on the east slope and east of the Sierran escarpment. Overgrazing of the grasses and forbs, primarily by sheep, was apparently responsible for this decline (Gaines 1988). Continued grazing of its rather unique habitat is still a serious risk for this species. Degradation of its wintering habitat in the southwest, also through grazing, is an additional risk. Cowbird parasitism could be another more minor risk. Careful monitoring of this species is warranted.

 

LARK SPARROW - Chondestes grammacus

Stat: SDM West: fS,rT,rW. East: rT.

Dist: T West: N:F-2; T:F-9; W:F-2. East: T:B-10.

Sign: US-2 (although generally absent from the eastern seaboard). Ssp. strigatus - WEST-4. This species occurs only marginally in the Sierra which is of little importance to its overall populations.

Hab: R: 2-MHW,(MHC),(PJN),(JUN),PAS.

F: 2-MHW,MHC,PJN,JUN,PAS.

Sp: Prefers open grassland habitat interspersed with widely scatteredt rees (telephone lines may sometimes suffice) and open oak savannah on the lower foothills of the west slope. Occurs less frequently in open brushland.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: Agricultural and residential development of foothill grasslands and oak savannah is a serious risk. Increased grazing of such habitat might also pose a risk; cowbird parasitism associated with such grazing certainly poses a risk. Degradation of winter grassland habitat is also a likely risk.

 

BLACK-THROATED SPARROW - Amphispiza bilineata

Stat: SDM West: lrS,rT. East: uS?,rT.

Dist: SW,SE West: N:8?; T:F-7. East: N:B-5?; T:B-10.

Sign: RM/GB-8 or SW-9. Ssp. deserticola - RM/GB-8 or SW-9. This species is extremely rare in the Sierra; the only verified breeding record is apparently on the Kern Plateau on the southern west slope (Beedy and Granholm 1985). May breed along the southern eastern base of the Sierran escarpment in the Owens Valley. Thus, the Sierra is extremely unimportant as regards the total population of the species. Transient records appear to exist for the length of the Sierra on both slopes.

Hab: R: 3-[MCP]; 2-EPN,PJN,JUN.

F: 3-[MCP]; 2-EPN,PJN,JUN.

Sp: Prefers sparsely vegetated, strongly insolated desert terrain.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: Nothing is known of population trends in the Sierra. I can identify no important risks during the breeding season, but degradation of winter desert shrubland and grassland habitat could be a risk.

 

SAGE SPARROW - Amphispiza belli

Stat: R-SDM West: luR,rT. East: liuS,rT

Dist: CW,TE West: N:1-3; T:1-6; W:1-3. East: N:B-8; T:B-10.

Sign: WUS-5 (although absent from Pacific Northwest, so classification very nearly RM/GB-8). Ssp. belli central portion of west slope - PCAL-11; nevadensis northern and central portions of the east slope, but may not nest in the Sierra proper as all nesting records to my knowledge lie east of the eastern base of the Sierran escarpment - RM/GB-8; canescens southern portion of east slope and extreme southern end of the Sierra north of the South Fork of the Walker River; apparently nests along the eastern base of the Sierran escarpment bordering the Owens Valley - PCAL-11 (although occurs into western Nevada). East slope races are of very limited distribution in the Sierra proper so of little importance to the species or subspecies despite even the limited range of canescens. However, even the limited range of belli on the central west slope of the Sierra is of great importance to this subspecies which is a federal Category 2 Candidate species.

Hab: R: 3-[MCP]; 2-EPN,PJN,JUN.

F: 3-[MCP]; 2-EPN,PJN,JUN.

Sp: On the west slope, belli, the "Bell's Sparrow" is restricted torelatively dense unbroken chaparral and has a marked preference for chamise. On the east slope, the two races of typical "Sage Sparrow" prefer fairly dense to moderately open sagebrush and bitterbrush scrub with a gravel "pavement" or alkali "hardpan" between and underneath the bushes.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: No population trend data exist for this species in the Sierra. Populations on (or east of) the east slope are often notably irregular in numbers from year-to-year. They face relatively few risks, however, other than possible degradation of their winter habitat on southwest deserts and grasslands. Populations of belli face serious risks from development of their foothill range and from catastrophic fires caused by years of fire suppression. Both populations may be susceptible to cowbird parasitism if grazing is allowed to penetrate their domain. Populations of belli require intensive monitoring as it is a federal Candidate 2 species.

 

SAVANNAH SPARROW - Passerculus sandwichensis

Stat: SDM West: lrS,rT. East: fS,rT.

Dist: CW,TE West: N:8-9; T:F-10. East: N:B-7; T:B-10.

Sign: CONT-1. Ssp. nevadensis - WEST-4 (although absent from the Pacific slope and southwest). This species occurs only marginally in the Sierra proper which is, therefore, unimportant to its total range, even within California.

Hab: R: 3-WTM; 2-PAS.

F: 3-WTM; 2-PAS.

Sp: Prefers relatively dense, moist or wet, short grassland, meadowland, pastureland, and marshland along the lower reaches of mountain streams or about alkali sinks. Avoid both dense shrub cover and very sparse dry grassland, but often forages in the open on sparsely vegetated muddy shores.

Abundance: BBS: MAPS: 0. 09 ad/600 nh

Trends: BBS:

Demographics: MAPS: Prod. index: 68. 7% yg.

Potential risks and suggested causes of population trends: The species has recently colonized Tuolumne Meadows, the only certain nesting location on the west slope. Population trends are otherwise unknown but, unlike Vesper Sparrow, the species seems to be holding its own along the east slope and east of the Sierran escarpment. Possible risks include habitat degradation due to overgrazing and associated cowbird parasitism.

 

GRASSHOPPER SPARROW - Ammodramus savannarum

Stat: SD-NTMWest: lirS. East:

Dist: T West: N:F-5. East:

Sign: US-2. Ssp. perpallidus WUS-5. The species is very rare in the Sierra which does not constitute an important portion of the overall or California range of the species.

Hab: R: 2-[PAS].

F: 2-[PAS].

Sp: Restricted to dry grassland, meadows, or pastures where the herbaceous vegetation is dense, diverse, and relatively tall.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: No data exist for population trends of the species in the Sierra. However, the species is notably irregular in occurrence from year to year and probably occurs well up onto the west slope only in drought years. Has seemingly become very scarce in central California during the recent drought years. Population of this species need to be monitored but, because of the irregular nature of their occurrences, this will be a difficult task. Risks include habitat destruction and degradation due to agricultural and residential development and grazing; possible cowbird parasitism; prolonged drought conditions resulting from climate change; and loss and degradation of grasslands for wintering in the Southwest.

 

FOX SPARROW - Passerella iliaca

Stat: SDM West: cS,uT,uW. East: cS,rT.

Dist: T West: N:5-9; T:F-10; W:F-3. East: N:6-9; T:B-10.

Sign: CAN/WMT-3. Ssp. megarhynchus west slope, except southernmost portion, and northern and central-southern portions of east slope - PCAL-11 (although this race also extends into southwestern Oregon); monoensis central east slope from northern Alpine County to the southern rim of the Mono Basin - PCAL-11 (but, except for birds breeding in the higher portions of the Mono Basin and Glass Mountain, could be considered to be SIE-12); stephensi southernmost portion of the west slope (apparently Fox Sparrows are absent from the southernmost portion of the east slope; this needs to be verified) - PCAL-11 (but, except for isolated populations in the higher Transverse Ranges of southern California, could be considered SIE-12). Fox Sparrows are very common and characteristic inhabitants of the Sierra which is of extremely great importance to the species' range in California and, of course, to the ranges of these California-endemic races.

Hab: R: 3-MHW,MHC,MCN,JPN,EPN,MRI,MCP; 2-PPN,(DFR),RFR,LPN,ASP,PJN,JUN.

F: 3-MHW,MHC,MCN,JPN,EPN,MRI,MCP; 2-PPN,(DFR),RFR,LPN,ASP,PJN,JUN,RSP.

Sp: Requires dense growths of montane chaparral, either as pure stands in shrub-covered hillsides or as dense clumps in the understory of open forest. To a lesser extent, and primarily on the east slope, other dense shrubby growth such as aspen thickets and willow tangles near seeps and streams. Typical forest types inhabited when occurring in the understory of open forest on the west slope are mixed conifers and jeffrey pines and, to a lesser extent, black oaks, ponderosa pines, and red firs. On the east slope, such tree species are most often mountain mahoganies and jeffrey pines.

Abundance: BBS: 16 routes; 16. 51 birds/route. MAPS: 0. 82 ad/600 nh

Trends: BBS: LS; 0. 9% per year

Demographics: MAPS: Prod. index: 17. 9% yg.

Potential risks and suggested causes of population trends: Forestry practices that convert closed forest to open forest with a shrubby understory, and clearcutting that coverts large forested areas to brush-covered hillsides undoubtedly favor this species. Loss of winter brushland habitat to development in southern California is an important risk.

 

SONG SPARROW - Melospiza melodia

Stat: SDM West: cS,rT,uW. East: cS,rT,uW.

Dist: T West: N:F-7; T:F-10; W:F-4. East: N:B-9; T:B-10; W:B-7.

Sign: CONT-1. Ssp. fisherella entire east slope and nothernmost part of the west slope - RM/GB-8 (but essentially limited to eastern Oregon and northeastern California); mailliardi northern half of west slope except for northernmost portion - PCAL-11; heermanni southern half of west slope from Yosemite region south -PCAL-11. The Sierra is becoming an increasingly important part of the ranges of these latter two subspecies which, apparently, were formerly nearly limited to the Central Valley and have recently expanded up the west slope of the Sierra.

Hab: R: 3-WTM,MRI; 2-MHW,MHC,PPN,DFR,[MCN],ASP,RSP.

F: 3-WTM,MRI; 2-MHW,MHC,PPN,DFR,[MCN],ASP,RSP.

Sp: Prefers dense shrubby vegetation in wet meadows and along the margins of ponds, streams, and lakes, including, especially at higher elevations and on the east side, willow thickets in montane meadows and montane riparian situations. May prefer more woody, rather than herbaceous, vegetation than Lincoln's Sparrow, but the two species now often nest side-by-side in many west-slope Sierran meadows.

Abundance: BBS: 12 routes;1. 99 birds/route. MAPS: 4. 39 ad/600 nh

Trends: BBS: IT; 2. 2% per year

Demographics: MAPS: Prod. index: 57. 2% yg. Ann. surv. rate: 0. 410 (0. 092);

Cap. prob. : 0. 709 (0. 119).

Potential risks and suggested causes of population trends: Song Sparrows have apparently expanded their breeding range dramatically up the west slope of the Sierra over the past 50 years, and probably on the east slope as well. They were first found nesting in Yosemite Valley, where they are now prominent breeders, in 1939 (Gaines 1988). Moreover, they have recently (1992) begun nesting successfully along Slate and Lee Vining Creeks near the Hall Natural Area in the Inyo National Forest; there were only two records of transient birds here during the previous 20 years (DeSante unpub. data). The causes of this range expansion are unclear, but could be related to a general warming and drying climatic trend in the Sierra that may have favored this species over the Lincoln's Sparrow. Song Sparrows now occupy many meadows (such as Yosemite Valley) that were formerly occupied by Lincoln's Sparrows. If Lincoln's Sparrows tend to prefer more herbaceous growth than Song Sparrows, the grazing of mid-elevation meadows may have reduced the relative proportion of herbaceous to woody vegetation in these meadows, thus favoring Song Sparrows over Lincoln's Sparrow. The increase of Song Sparrows on the west slope is also interesting in light of the fact that they have probably declined considerably in the Central Valley as a result of destruction of riparian habitat and channelization of streams. Song Sparrows are very susceptible to cowbird parasitism, which must be considered a major risk to the species. Other risks include continued grazing of montane meadows and degradation of montane riparian habitats. The current population trend in the Sierra is likely relatively stable. However, the population dynamics of this species need to be monitored closely in the Sierra, especially in conjunction with similar monitoring efforts on the Lincoln's Sparrow.

 

LINCOLN'S SPARROW - Melospiza lincolnii

Stat: SD-NTMWest: fS,uT,rW. East: rS,uT,rW.

Dist: T West: N:4-9; T:F-10; W:F-4. East: N:8-10; T:B-7.

Sign: CAN/WMT-3. Ssp. alticola - WMT-6 (but occurs only north to Oregon and Idaho; thus, except for its range in the Cascades and the Sierra, could be better considered RM/GB-8). The Lincoln's Sparrow is fairly common in the Sierra which must be considered to be an extremely important part of the species range in California.

Hab: R: 3-WTM,MRI; 2-[MCN],[RFR],[LPN].

F: 3-WTM,MRI; 2-[MCN],[RFR],[LPN].

Sp: Prefers dense, fairly tall herbaceous growth edged or intermixed with willows in wet or boggy meadows, generally in fairly wooded situations. May prefer smaller meadows that are more enclosed by forest than Song Sparrow, and, compared to Song Sparrow, seems toprefer meadows with a higher proportion of herbaceous than woody growth.

Abundance: BBS: 5 routes;0. 34 birds/route. MAPS: 6. 59 ad/600 nh

Trends: BBS: UN; 1. 9% per year

Demographics: MAPS: Prod. index: 47. 9% yg. Ann. surv. rate: 0. 486 (0. 085);

Cap. prob. : 0. 577 (0. 103).

Potential risks and suggested causes of population trends: This species seems to be shifting its breeding range upward in elevation on the west slope of the Sierra. It is now absent as a breeder from certain relatively low elevation meadows (such as Yosemite Valley) where it formerly was a prominent nesting species. Moreover, during the past 20 years, the species has expanded its upper elevational limit to 10,000' where it now nests regularly at Tioga Pass (M. Morton unpub. data) and occasionally in the Hall Natural Area (D. DeSante unpub. data). This elevational range change may be related to a general warming and drying trend in the Sierra. It may also be tied to the similar elevational range change in the congeneric Song Sparrow. Drying of meadows and grazing could have made lower elevational meadows more favorable to Song than to Lincoln's Sparrows. Alternatively, the larger and, perhaps, more aggressive Song Sparrows could be directly excluding Lincoln's Sparrows from lower elevation meadows by interference competition. Because of the relatively few BBS routes in the Sierra on which Lincoln's Sparrows were recorded, their Sierran population trend must be considered to be unknown despite the apparent increasing trend of 1. 9% per year. Interestingly, Lincoln's Sparrows seem to show a lower mean MAPS productivity index than Song Sparrow (47. 9% vs. 57. 2% young) but a higher mean adult survival rate than Song Sparrow (0. 524 vs. 0. 356), although neither of these differences are statistically significant. The lower survival rate for Song Sparrow, a much shorter-distance migrant than Lincoln's Sparrow, was apparently due to low survival during the winter of 1992-93, a year of heavy rains in California and heavy snowfall in the Sierra. Degradation of montane meadows due to grazing, logging, and climate change are major risks to this species in the Sierra. Cowbird parasitism is another major risk.

 

WHITE-CROWNED SPARROW - Zonotrichia leucophrys

Stat: SD-NTMWest: cS,fT,uW. East: cS,cT,rW.

Dist: T West: N:7-11; T:F-10; W:F-4. East: N:8-11; T:B-10; W:B-7.

Sign: CAN-WMT-3. Ssp. oriantha - WMT-6. White-crowned Sparrows are apparently absent from the northernmost part of the Sierra, presumably because maximum elevations are too low to provide substantial habitat for this species. The Sierra represents a very important part of the breeding range of White-crowned Sparrows in California. White-crowned Sparrows of the race oriantha do not winter in the Sierra or, for the most part, even in California -- rather, they winter almost exclusively in northern Mexico and Baja California. Sierran wintering birds are gambelli that breed in northern Canada.

Hab: R: 3-SCN,WTM,MRI,ADS; 2-(DFR),LPN,ASP.

F: 3-(DFR),SCN,WTM,MRI,ADS,RSP; 2-MHW,MHC,PPN,JPN,LPN,ASP,EPN,PJN,JUN,

PAS.

Sp: Requires montane meadows with low, dense willow thickets, generally along upper stream courses and around the edges of lakes. Reaches maximum densities in meadows at or just above treeline, but nests locally in meadows at lower elevations.

Abundance: BBS: 4 routes;0. 67 birds/route. MAPS: 1. 87 ad/600 nh

Trends: BBS: DT;-8. 8% per year**

Demographics: MAPS: Prod. index: 39. 9% yg.

Potential risks and suggested causes of population trends: Because most BBS routes do not transect the subalpine habitat most favored by White-crowneds, these results must be interpreted as indicating merely that White-crowneds are declining rapidly in, at least, the lower elevations of their breeding range in the Sierra. In this regard, it appears that White-crowneds may have been disappearing from lower elevations for quite some time. Prior to the 1920s, White-crowned Sparrows bred in Yosemite Valley at 4,000' elevation, but have not bred at that elevation since then. While this species may still nest locally at relatively low elevations on the west slope (such as at 6,600' at Perazzo Meadow in the Tahoe National Forest; DeSante, unpub. MAPS data) most current breeding locations are at or above the 8,000' elevation level. Thus, we have a third Sierran sparrow of wet montane meadows (the others are Song and Lincoln's) whose lower and/or upper elevational range limit seems to be increasing in the Sierra. Additionally, however, White-crowned Sparrows in the subalpine Tioga Pass area have been declining at a substantial rate over the past 20 years (M. Morton, pers. comm. ) and possible declines have been noted in the Hall Nature Area as well (DeSante unpub. data). Possible risks and potential causes for the decline in White-crowned Sparrows, and for the increasingly higher elevational range limits for all three montane meadow sparrows, are "natural" successional dynamics of montane meadows (do montane meadows naturally dry up in the absence of climate change?), climate changes with a warming and drying tendency, and grazing pressures on montane meadows. Cowbird parasitism could also be a risk. And, of course, degradation of grasslands and brushlands on the species wintering range in northern Mexico could also be a risk.

 

DARK-EYED JUNCO - Junco hyemalis

Stat: SDM West: cS,cT,icW. East: cS,cT,icW.

Dist: T West: N:3-10; T:F-10; W:F-4. East: N:7-10; T:B-10; W:F-8.

Sign: CAN/WMT-3. Ssp. thurberi - CAL-10 (although extends slightly into southern Oregon). This species is extremely abundant in the Sierra which, thus, constitutes a very important portion of its range in California.

Hab: R: 3-MHW,MHC,PPN,DFR,MCN,JPN,RFR,LPN,SCN,ASP,EPN,PJN,MRI,ADS; 2-MCP.

F: 3-MHW,MHC,PPN,DFR,MCN,JPN,RFR,LPN,SCN,ASP,EPN,PJN,MRI,ADS,RSP; 2-[WTM],MCP.

Sp: While common in virtually all forested habitats, juncos reach their greatest abundance in relatively moist situations in somewhat open forests, at openings in forests, and at meadow and streamside edges. They also nest in dense, mature or old-growth forests provided that there is sufficient herbaceous growth. Tree species that are leastpreferred or somewhat shunned in the Sierra are oaks in pure stands not mixed with conifers, digger, knob cone, and pinyon pines, and junipers. Responds well to human activities, becoming very common around campgrounds.

Abundance: BBS: 17 routes; 26. 50 birds/route. MAPS: 12. 50 ad/600 nh

Trends: BBS: DD;-2. 8% per year**

Demographics: MAPS: Prod. index: 68. 8% yg. Ann. surv. rate: 0. 397 (0. 067);

Cap. prob. : 0. 502 (0. 094).

Potential risks and suggested causes of population trends: It is surprising that this extremely widespread and bundant Sierran species (third in BBS abundance index behind American Robin and Mountain Chickadee) is definitely declining at a substantial rate (interestingly, American Robin and Mountain Chickadee are also definitely declining). Because the species reaches maximum densities in relatively moist habitats, a general drying-out of the Sierran climate could be one potential risk. Forestry practices that result in a net loss of forest would presumably result in a net loss of juncos, all else being equal. Cowbird parasitism could be a minor risk. However, I am hard-pressed to suggest a more specific cause for this apparent decline. The high MAPS productivity index may reflect the large amount of up-mountain dispersal in young juncos, while the relatively low adult survival rate (very similar to Song Sparrow) possibly reflects relatively low survival in hard winters.

 

BLACK-HEADED GROSBEAK - Pheucticus melanocephalus

Stat: NTM West: cS,rT,xW. East: uS,rT.

Dist: T West: N:F-6; T:F-10; W:4. East: N:B-8; T:B-10.

Sign: WEST-4. Ssp. maculatus - PAC-7. This species is very common in the Sierra which provides an important part of its overall range.

Hab: R: 3-MHW,MHC,MRI,RSP; 2-PPN,MCN,EPN,PJN.

F: 3-MHW,MHC,MRI,RSP; 2-PPN,MCN,EPN,PJN.

Sp: This species generally requires the presence of broad-leaved trees,be they oaks, riparian alders, willows, or cottonwoods, or aspens. They also nest commonly in coniferous forests below the red firzone, provided that at least a few broad-leaved trees are present. Although they seem to prefer deciduous oaks, they also occur quite commonly in canyon and interior live oaks. They occur commonly inboth dry and moist habitats and occur in both open and fairly dense forests. They appear, however, to avoid the interior of dense old-growth forest, perhaps because of an absence of a deciduous element. Adapts fairly well to the presence of human activities and habitations.

Abundance: BBS: 17 routes;10. 54 birds/route. MAPS: 3. 13 ad/600 nh

Trends: BBS: PD;-1. 4% per year

Demographics: MAPS: Prod. index: 22. 9% yg.

Potential risks and suggested causes of population trends: I cannot suggest a reason for this possible decline except to mention the risks that it (and many other species that are not declining) faces. Loss of riparian and oak habitat may be one risk. Logging practices that cause general loss and degradation of forest habitat is another risk. High levels of nest predation (because males sing from the nest) may be another risk, especially in the face of forest fragmentation. Cowbird parasitism may be yet another risk. And, of course, habitat loss and degradation on the wintering grounds could be another risk. However, because many Sierran Neotropical migrants seem to have relatively stable or increasing population trends, wintering ground risks, if they are the cause, must be species-specific to black-headed Grosbeaks or area-specific to where Sierran birds winter. In this respect it is of interest that Black-headed Grosbeaks seem to show an increasing trend over the western U. S. as a whole (DeSante and George 1994).

 

BLUE GROSBEAK - Guiraca caerulea

Stat: NTM West: rS,xT. East:

Dist: T West: N:F-2; T:F-4. East:

Sign: US-2. Ssp. salicaria (spelled salicarius by Grinnell and Miller [1944]) - CAL-10. A species of valley bottoms, the Blue Grosbeak nests in the Central Valley and in the Owens Valley north to Independence. Presumably, it formerly or still nests in riparian areas along streams and rivers at very low elevations on the west slope. However, the only positive "Sierran" breeding record of which I am familiar is at 1700' elevation along the Merced River (Gaines 1988). Thus, like the Common Yellowthroat, it may not actually breed in the Sierra proper.

Regardless, the Sierra constitutes an extremely unimportant part of the species range.

Hab: R: 2-[MRI].

F: 2-[MRI],PAS. .

Sp: Requires low thick vegetation, perhaps with scattered trees, adjacent to open weedy fields in riparian situations.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: Was very likely formerly much more common in riparian situations in the lower foothills of the west slope than it is today. Loss of riparian habitat to logging, dams and water diversions, grazing, and agricultural and residential development probably long ago eliminated most individuals of this species. These risk continue through the present. An additional more recent risk is cowbird parasitism. Because the species is so rare in the Sierra, we have no idea of current population trends; if it is still extant, the trends are probably negative, although the species may now be holding its own in the Central Valley.

 

LAZULI BUNTING - Passerina amoena

Stat: NTM West: lfS,uT. East: fS,rT.

Dist: T West: N:F-6; T:F-10. East: N:B-8; T:B-10.

Sign: WEST-4.

Hab: R: 3-MRI; 2-MHW,MHC,WTM,(MCP).

F: 3-MRI; 2-MHW,MHC,WTM,(MCP),(RSP).

Sp: Prefers broken chaparral, brushy open oak woodlands, or brushy riparian habitat. Often occurs in relatively dry habitats on the more moist west slope and in or near riparian habitat on the drier east slope. Occurs on the edges of a wide variety of coniferous habitats but, invariably, oaks, riparian habitat or meadows, or montane chaparral is present. Up-slope dispersal concentrates birds in montane meadows and montane riparian habitats.

Abundance: BBS: 10 routes;1. 08 birds/route. MAPS: 2. 41 ad/600 nh

Trends: BBS: PS;-0. 6% per year

Demographics: MAPS: Prod. index: 25. 4% yg.

Potential risks and suggested causes of population trends: Risks include loss

of oak woodland and riparian habitat, degradation of meadows due to grazing

and other causes, and cowbird parasitism. Problems on the wintering grounds could also constitute a major risk. Most forestry operations may not be detrimental to this species; some could be favorable. The possibly stable BBS trend may indicate that positive and negative factors are tending to cancel each other out in the Sierra.

 

RED-WINGED BLACKBIRD - Agelais phoeniceus

Stat: SDM West: lcS,rW. East: lcS,rW.

Dist: T West: N:F-9; W:F-2. East: N:B-8; W:B-7;

Sign: CONT-1. Ssp. californicus foothills along west slope, probably entirely at elevations below 2,000' - PCAL-11; nevadensis east slope and locally now nearly throughout the west slope at elevations generally above 3,000' - RM/GB-8 (but essentially nearly limited to the Great Basin). The race aciculatus breeds in the South Fork of the Kern River Valley, but apparently does not occur upslope to the north in the Sierra proper. Considering this species' distribution and abundance in

California and elsewhere outside the Sierra, the Sierra is very unimportant to the species overall populations.

Hab: R: 3-WTM,PAS.

F: 3-WTM,PAS,RSP.

Sp: The race nevadensis is nearly restricted in the Sierra to marshes and wet meadows for breeding. It ranges widely to meadows and to campgrounds and other centers of human activity for foraging. The race californicus breeds in a wide variety of grassy or marshy habitats along the western base of the Sierra including agricultural lands and pasturelands as well as foothill grasslands.

Abundance: BBS: 10 routes;2. 02 birds/route. MAPS: 0. 25 ad/600 nh

Trends: BBS: PS; -0. 7% per year

Demographics: MAPS: Prod. index: 8. 1% yg.

Potential risks and suggested causes of population trends: The race nevadensis has apparently colonized the western slope of the Sierra in relatively recent times. Previously known from but a few stream courses at middle elevations (Grinnell and Miler 1944), the species is now widely distributed throughout the west slope in almost all wet meadow or marsh situations up to 7,000' and exceptionally, as at Tuolumne Meadows, up to nearly 9,000'. Even more recently, the species has occurred as a possible breeder at Tioga Meadows at 10,000' (M. Morton pers. comm. ). Like Brewer's Blackbirds, Red-wingeds have probably followed human centers of activity into the Sierra and then expanded from these areas into appropriate habitat removed from human activity. They probably face few risks other than a general drying climatic tendency, if it exists.

 

WESTERN MEADOWLARK - Sturnella neglecta

Stat: SDM West: uS,rT,iuW. East: uS,uT.

Dist: T West: N:F-5; T:F-10; W:F-4. East: N:B-7; T:B-10.

Sign: WEST-4. Ssp. confluenta - PAC-7. Grinnell and Miller (1944) did not recognize confluenta and considered the species monotypic.

Hab: R: 3-((DFR)),WTM,PAS; 2-(JUN).

F: 3-((DFR)),WTM,PAS,RSP; 2-(JUN).

Sp: Prefers the drier portions of large meadows, flat or rolling grasslands, and pasturelands. Occurs both where the grass and forbsare in pure growths or intermixed with a scattering of bushes.

Abundance: BBS: 6 routes;0. 49 birds/route. MAPS:

Trends: BBS: UN; 1. 9% per year

Demographics: MAPS:

Potential risks and suggested causes of population trends: Population trends for this species in the Sierra are uncertain, but opening of forests may in general have benefited them. Although they can tolerate a fair amount of grazing, haying operations can be a risk.

 

YELLOW-HEADED BLACKBIRD - Xanthocephalus xanthocephalus

Stat: SD-NTMWest: lrS,rT. East: lfS.

Dist: NW?,TEWest: B:4-6?; T:F-6. East: N:B-7.

Sign: WEST-4. The Sierra does not constitute an important part of the range of this species either as a whole or in California. Known breeding locations on the west slope may be limited to the Portola area and Lake Tahoe, both in the northern portion of the west slope.

Hab: R: 3-WTM.

F: 3-WTM; 2-[PAS].

Sp: Requires extensive beds of tall dense cattails or tules over standing water for breeding. Generally forages nearby in wet

meadows and pastures.

Abundance: BBS: 2 routes;0. 14 birds/route. MAPS:

Trends: BBS: UN; -7. 4% per year

Demographics: MAPS:

Potential risks and suggested causes of population trends: Population trends in the Sierra are unknown, but the species has declined considerably in the Central Valley and southern California due to the draining of marshes. Risks include loss of marshes and wet meadow habitat both in the Sierra and on its winter range.

 

BREWER'S BLACKBIRD - Euphagus cyanocephalus

Stat: SDM West: lcS,lfT,uW. East: cS,lfT,uW.

Dist: T West: N:F-9; T:F-10; W:F-4. East: N:B-8; T:B-10; W:B-7.

Sign: WEST-4. The Sierra does not constitute an important part of the range of this species either as a whole or in California.

Hab: R: 3-WTM,RSP; 2-MHW,MHC,PPN,DFR,MCN,MRI.

F: 3-WTM,PAS,RSP; 2-MHW,MHC,PPN,DFR,MCN,LPN,EPN,PJN,JUN,MRI.

Sp: Strongly associated with human activities and habitations. Nesting usually takes place in the vicinity of meadows, ponds, lakes, streams, or areas of human habitation. Forages widely over meadows and meadow edges, riparian habitats, and the margins of lakes and streams.

Abundance: BBS: 15 routes; 10. 32 birds/route. MAPS: 0. 34 ad/600 nh

Trends: BBS: PD; -1. 8% per year

Demographics: MAPS: Prod. index: 21. 5% yg.

Potential risks and suggested causes of population trends: Despite the apparent decreasing trend, this species has increased greatly in the Sierra in recent years and has increased its elevation range dramatically. In Yosemite Valley, for example, it has increased from six pairs in 1920 to "hundreds" in 1940 (Gaines 1988); the Yosemite Valley population now probably numbers in the thousands. In 1928 they were known to nest as high as 7,300' (Grinnell and Miller 19944); now they nest at least to 8,600' and probably higher. The expansion and population increase of this species in the Sierra is due to the increased human activity there and the increased adaptation of the species to human activities and habitations. I can see no risks that the species faces.

 

BROWN-HEADED COWBIRD - Molothrus ater

Stat: SD-NTMWest: lfS. East: lfS.

Dist: T West: N:F-10. East: N:B-10.

Sign: CONT-1. Ssp. obscurus west slope and southern east slope - SW-9; artimisiae northern and central portions of east slope - RM/GB-8 (but also extends east to Minnesota and Iowa). The Sierra does not constitute a major portion of the species range, either in California or as a whole. However, because of the species potential serious impact upon the populations of smaller open-cup-nesting landbirds, the species' population trends must be carefully monitored in the Sierra.

Hab: R: 3-MRI,RSP; 2-MHW,MHC,PPN,DFR,MCN,JPN,EPN,PJN,JUN,WTM.

F: 3-WTM,MRI,PAS,RSP; 2-MHW,MHC,PPN,DFR,MCN,JPN,EPN,PJN,JUN.

Sp: Generally prefers montane meadows, montane riparian habitat, and especially, the presence of grazing animals in pasturelands and around stables for foraging. Also forages extensively at areas of high human use such as campgrounds, picnic areas and lawns around human habitations. Utilizes the surrounding woodlands and forests up to several miles away from foraging areas in search of host

species' nests. Obligate brood parasite that lays its eggs in the nests of smaller (usually) species that raise its young, usually at the expense of their own young.

Abundance: BBS: 15 routes;2. 89 birds/route. MAPS: 0. 24 ad/600 nh

Trends: BBS: DD;-4. 9% per year ***

Demographics: MAPS: Prod. index: 15. 1% yg.

Potential risks and suggested causes of population trends: The spread of cowbirds into California has been well documented. Before 1900 they were virtually unknown in California and by 1915 only one record existed in the Pacific drainage. With the coming of feedlots and irrigated agriculture, they increased phenomenally in southern California and in the Central Valley, where flocks of over 10,000 have been tallied in the recent past. They were first detected on the west slope of the Sierra in Yosemite Valley in 1934, and by the 1960s they had become numerous throughout most of the west slope up to 10,000' elevation. Similar increases undoubtedly occurred on the east slope as well. They were very rare or uncommon there in the 1930s, but flocks of over 100 were recorded in the recent past. Logging, grazing, urbanization, and packhorses and stables undoubtedly contributed to their increase in the Sierra. In my experience, it seems that cowbirds havebeen declining in the Sierra in recent years; BBS data support this notion with a definite decrease of 4. 9% per year over the past 30 years. This decrease may be the result of active efforts to control their numbers or, possibly, to a decrease in the use of horses and the number of stables in the backcountry. Another possibility is that the decrease may represent the "normal" overshoot and return to more equilibrium levels that often accompanies the rapid range expansion and population increase of a pioneering species. Unfortunately, the species faces few identifiable risks in the Sierra.

 

NORTHERN ORIOLE - Icterus galbula

Stat: NTM West: cS,rT. East: fS,xT.

Dist: T West: N:F-4; T:F-7. East: N:F-8; T:F-10.

Sign: CONT-1. Ssp. bullockii - WEST-4. This species is of limited occurrence in the Sierra which is not a very important part of its range.

Hab: R: 3-RSP; 2-MHW,MHC,PPN,MRI.

F: 3-MHW,MHC,MRI,RSP; 2-PPN.

Sp: On the west slope prefers oak woodlands, especially of large, well-

spaced, deciduous oaks, and riparian habitats, especially of cottonwoods and sycamores. Also occurs sparingly in ponderosa pine forest if intermixed with oaks. On the east slope occurs almost exclusively in riparian habitats and in cottonwoods and other deciduous trees planted around ranches and in towns.

Abundance: BBS: 7 routes;0. 36 birds/route. MAPS: 0. 15 ad/600 nh

Trends: BBS: UN; -2. 2% per year

Demographics: MAPS:

Potential risks and suggested causes of population trends: Loss of riparian habitat is a major risk that may be counterbalanced by its tendency to utilize deciduous shade trees and windbreaks around human habitations. May be susceptible to cowbird parasitism.

 

GRAY-CROWNED ROSY FINCH - Leucosticte tephrocotis

Stat: R-SDM West: fS,irW. East: fS,ifW.

Dist: CSW,CSE West: N:9-13; W:10+. East: N:9-13; W:B-10+.

Sign: WMT-6 (but absent in the Rokcy Mountains south of Montana). Ssp. dawsoni - SIE-12 (but also breeds sparingly in the White Mountains).

Absent in the northern Sierra because of absence of high-country breeding habitat.

Hab: R: 3-WTM,ADS,BAR.

F: 3-WTM,ADS,BAR.

Sp: Confined for breeding to alpine cirques surrounded by cliffs and steep talus slopes where they place their nests. Forages in alpine and, less frequently, subalpine meadows, on alpine tundra, along alpine lakeshores, and, importantly, on snowbanks and glaciers where it feeds on upslope, wind-dispersed insects. In winter descends down the east slope where it may occur on rocky or barren ground in sagebrush scrub and even in open pinyon juniper woodland.

Abundance: BBS: MAPS:

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: Population trends in the Sierra are unknown. Drought conditions causing the lack or early melting of snowbanks and decreases in the numbers of upslope wind-borne insects, perhaps due to pesticide use at lower elevations, are possible risks.

 

PINE GROSBEAK - Pinicola enucleator

Stat: R West: ifS,ifW. East: iuR.

Dist: T West: N:7-10; W:6-10. East: N:8-10; W:8-10.

Sign: CAN/WMT-3. Ssp. californica - SIE-12. The Pine Grosbeak as a species in California, and the race californica itself, is endemic to the Sierra and has never, to my knowledge, been recorded away from the Sierra, even in winter. The nearest population of this species to this isolated race occurs in northern Oregon. Thus, like the Great Gray Owl and, to a large extent, Black-backed Woodpecker, American Pipit, and Gray-crowned Rosy Finch, the entire California breeding population is isolated in and endemic to the Sierra.

Hab: R: 3-RFR,LPN,(SCN).

F: 3-RFR,LPN,(SCN),(WTM),(MRI).

Sp: Usually remains above 7,000' on the west slope, even in winter, but sometimes descends to 6,000' and, occasionally in very hard winters, descends as low as 4,000'. Apparently absent from the northernmost and southernmost portions of the Sierra.

Abundance: BBS: MAPS: 0. 25 ad/600 nh

Trends: BBS:

Demographics: MAPS: Prod. index: 0. 0% yg.

Potential risks and suggested causes of population trends: The overall population trend for this species in the Sierra is essentially unknown. I know of no risk that it currently faces.

 

PURPLE FINCH - Carpodacus purpureus

Stat: SDM West: cS,ifW. East: xT.

Dist: T West: N:3-8; W:F-5. East: T:B-10.

Sign: CAN/WMT-3 (but absent from the Rocky Mountains and Great Basin). Ssp. californicus - PAC-7.

Hab: R: 3-MHW,MHC,DFR,MCN,RSP; 2-PPN,JPN,((EPN)).

F: 3-MHW,MHC,DFR,MCN,RSP; 2-PPN,JPN,((EPN)).

Sp: Prefers relatively dense and moist forests, forest edges, and meadows in forested situations. Preferred forest types are mixed oak-conifer, Douglas fir, and mixed conifer forests. Ponderosa pine forest is utilized to a lesser extent, especially if dense and

moist, while red fir forest is utilized to an even lesser extent.

Abundance: BBS: 15 routes;4. 76 birds/route. MAPS: 12. 62 ad/600 nh

Trends: BBS: DT;-1. 8% per year

Demographics: MAPS: Prod. index: 38. 8% yg.

Potential risks and suggested causes of population trends: Sierran populations of this species show a decreasing tendency. Forestry practices that open-up the forest, reduce the diversity of tree species, or reduce the complexity of the forest structure are likely risks to this species. Thus, most logging operations are probably detrimental to Purple Finches. Climatic changes that tend toward more xeric conditions are also probably an important risk. .

 

CASSIN'S FINCH - Carpodacus cassinii

Stat: SDM West: cS,iuW. East: cS,ifW.

Dist: T West: N:6-10; W:3-5?. East: N:6-10; W:B-8.

Sign: WMT-6. Cassin's Finches are very common in the Sierra which constitutes an extremely important part of their range, both overall and in California.

Hab: R: 3-(MCN),RFR,LPN,SCN; 2-JPN,EPN.

F: 3-(MCN),RFR,LPN,SCN; 2-JPN,ASP,EPN,WTM,MRI.

Sp: Compared to Purple Finch, this species prefers more open forest and more xeric conditions. Cassin's Finches in the Sierra show a strong preference for open red fir forest and, especially, relatively open lodgepole pine forest, often on the edges of montane meadows. Although Cassin's Finches occur in summer well down into the range of Purple Finches, actual documentation of nesting at these lower elevations is scarce. The winter whereabouts of the majority of the Sierran Cassin's Finch population remains unclear; many individuals may migrate to forests east of the Sierran escarpment.

Abundance: BBS: 14 routes;4. 89 birds/route. MAPS: 1. 52 ad/600 nh

Trends: BBS: LD;-3. 1% per year *

Demographics: MAPS: Prod. index: 41. 1% yg.

Potential risks and suggested causes of population trends: This species shows a likely declining BBS population trend in the Sierra. Populations in the Hall Natural Area seem to have shown a substantial decline over the past 22 years (DeSante unpub. data). Productivity in the subalpine seems to be extremely low, primarily due to heavy nest predation by Clark's Nutcrackers. MAPS productivity indices from lower elevation stations, however, do not seem to be inordinately low. Important risks for this species are difficult to suggest. Most forestry practices may not be overly detrimental to this species, other than reducing the net amount of forested habitat. Climate changes promoting more xeric conditions may be favorable to this species, at least as compared to Purple Finch. Indeed, Cassin's Finches tend to breed in the subalpine in substantially larger numbers in years following light snowpacks than in years following heavy snowpacks (DeSante 1990).

 

HOUSE FINCH - Carpodacus mexicanus

Stat: SDM West: fS,rT,fW. East: lfS,lfT.

Dist: T West: N:F-2; T:F-10; W:F-2. East: N:B-6; T:B-10.

Sign: WUS-5 (if introduced eastern populations are included, the importance classification is US-2). Ssp. frontalis - WUS-2 (or US-2 if introduced eastern populations are included). The Sierra is of negligible importance to populations of this essentially lowland species.

Hab: R: 3-RSP; 2-((DFR)),((MCN)),PJN,JUN.

F: 3-PAS,RSP; 2-MHW,MHC,(DFR),(MCN),(JPN),EPN,PJN,JUN,WTM.

Sp: This is the most desert-loving of the three Carpodacus finches and, by far, the rarest in the Sierra. Strongly prefers the vicinity of human habitations and generally avoids forested areas, occurring only relatively sparingly in oak and pinyon-juniper woodlands. Must have a source of water within its daily cruising range.

Abundance: BBS: 5 routes;0. 61 birds/route. MAPS:

Trends: BBS: UN;-7. 3% per year

Demographics: MAPS:

Potential risks and suggested causes of population trends: Here is another relatively xerophyllic foothill fringillid that, like the Lesser Goldfinch, May be showing a relatively high decreasing BBS trend. I can suggest no important risks that this species might face in the Sierra.
 

RED CROSSBILL - Loxia curvirostra

Stat: R-SDM West: ifR,ifW. East: ifS,ifW.

Dist: T West: N:8-10; W:F-10. East: N:8-10; W:B-10.

Sign: CAN/WMT-3. Ssp. grinnelli - CAL-10 (but also occurs eastward to southwestern Utah and central-eastern Arizona; thus could almost be classified as SW-9). Although only fairly common in the Sierra, the Sierra represents a very important part of the range of this race, and an extremely important part of the range of the species in California.

Hab: R: 3-(DFR),LPN; 2-PPN,MCN,RFR.

F: 3-PPN,DFR,MCN,RFR,LPN.

Sp: Found most predictably in lodgepole pine forests, where the bulk of breeding is assumed to occur. I know of no verified breeding records below 8,000', but I suspect that they do breed at lower elevations on occasion. Because much of their breeding can occur during the winter months, the breeding ecology of this species is very poorly known in the Sierra. For foraging, also utilizes pinyon, ponderosa, and jeffrey pines, but usually to a lesser extent than lodge poles. When a massive and synchronous failure occurs in the pine seed crops of all of these tree species, crossbills may occur virtually anywhere in search of food or may desert the Sierra entirely.

Abundance: BBS: 7 routes;0. 70 birds/route. MAPS:

Trends: BBS: PI; 5. 9% per year *

Demographics: MAPS:

Potential risks and suggested causes of population trends: This species is extremely irregular and erratic in occurrence from year to year and place to place, being dependent on irregular and unpredictable pine seed crops. Thus, assessment of its long-term population trend is difficult; its apparent BBS increasing tendency should be viewed with caution. Logging operations that reduce the net amount of forest are a risk, as are weather and climate conditions that negatively affect the pine seed crop, especially of lodgepole pines.

 

PINE SISKIN - Carduelis pinus

Stat: SDM West: icS,uT,ifW. East: ifS,uT,rW.

Dist: T West: N:3-10; T:F-10; W:F-9. East: N:7-10; T:B-10; W:B-9.

Sign: CAN/WMT-3. Ssp. pinus - CAN/WMT-3.

Hab: R: 3-DFR,LPN,(SCN); 2-MCN,RFR.

F: 3-DFR,LPN,(SCN),RSP; 2-MHC,PPN,MCN,JPN,RFR,EPN,PJN,WTM,MRI,PAS.

Sp: Occurs and apparently breeds in most types of forest provided that conifers are present. Maximum numbers seem to occur about the edgesof forests, especially forest-meadow edges. Much foraging, however,

occurs in arborescent riparian hardwoods, especially alders, and in the weedy edges of meadows and forest openings, as well as in coniferous trees.

Abundance: BBS: 11 routes;1. 38 birds/route. MAPS: 3. 72 ad/600 nh

Trends: BBS: DT;-3. 2% per year

Demographics: MAPS: Prod. index: 53. 1% yg.

Potential risks and suggested causes of population trends: This species, like most fringillids, is notably erratic and unpredictable in numbers from year to year and place to place. Thus, the BBS trend should be viewed with caution. Significant risks are hard to suggest. Logging operations may not be especially deleterious except to reduce the total amount of forested area. May be subject to widespread epidemics of disease.

 
LESSER GOLDFINCH - Carduelis psaltria

Stat: SDM West: fS,iuT,iuW. East: uS,iuT

Dist: T West: N:F-5; T:F-10; W:F-3. East: N:B-7; T:B-10.

Sign: WUS-5. Ssp. hesperophilus - WUS-5 (but absent in the Southwest east of central Arizona). The Sierra is quite unimportant to this species' populations, both overall and in California.

Hab: R: 3-RSP; 2-MHW,MHC,PPN,(DFR),(JPN),EPN,PJN,MRI.

F: 3-RSP; 2-MHW,MHC,PPN,DFR,JPN,EPN,PJN,WTM,MRI,MCP,PAS.

Sp: Prefers openly wooded habitats, particularly live and blue oak woodlands in the lower foothills and, to a lesser extent, foothill chaparral with scattered trees and foothill riparian woodland. When the species breeds or wanders up-mountain from the foothills, it usually occurs in open mixed oak-conifer forest or ponderosa pine forest, or, more commonly, on the edges of montane meadows, particularly dry meadows. Occurs in, or actually prefers, relatively xeric situations, but must have a source of water within its daily cruising range. Responds fairly well to human habitations.

Abundance: BBS: 9 routes;1. 27 birds/route. MAPS: 0. 54 ad/600 nh

Trends: BBS: DD;-6. 8% per year***

Demographics: MAPS: Prod. index: 39. 7% yg.

Potential risks and suggested causes of population trends: The Lesser Goldfinch is one of the ten species that are definitely declining in the Sierra. I am at a loss to suggest what might be happening with this species. Other than development of its habitat (but it responds fairly well to residential development) and cowbird parasitism, I can suggest no major risk to which they might be susceptible. Obviously, increased monitoring of these apparently declining species, in conjunction with a wide range of other foothill species, is urgently needed.

 

LAWRENCE'S GOLDFINCH - Carduelis lawrencei

Stat: SDM West: iuS,rT. East:

Dist: T West: N:F-5; T:F-7. East:

Sign: CAL-10. Because this is essentially a California endemic breeding species with a sizeable portion of its range in the foothills of the Sierra, the Sierra is of great importance to the species' overall population. Has occurred east of the eastern base of the Sierran escarpment but, to the best of my knowledge, has never occurred on the east slope of the Sierra proper.

Hab: R: 2-MHW,MHC,((PJN)),MRI.

F: 2-MHW,MHC,((PJN)),WTM,MRI,PAS,RSP.

Sp: Prefers xeric, open oak woodland bordering chaparral in the upper foothills. Seems to reach maximum densities in a mixture of sparse blue oaks, dry chaparral, and scattered digger or ponderosa pines. Needs a daily water source, so conditions may be optimal when such habitat is adjacent to a small stream or seep. When it occurs at higher elevations, prefers habitat similar to, but perhaps drier than, that utilized by Lesser Goldfinch. Seems to respond less well than Lesser Goldfinch to human habitations.

Abundance: BBS: MAPS: 0. 08 ad/600 nh

Trends: BBS:

Demographics: MAPS:

Potential risks and suggested causes of population trends: Development of its habitat and cowbird parasitism are likely risks that the species is facing. Sierran populations of this species, along with other critical foothill species such as Rufous-crowned, Black-chinned, and Sage sparrows, need to be closely monitored.

 

AMERICAN GOLDFINCH - Carduelis tristis

Stat: SDM West: rS,irT. East:

Dist: T West: N:F-1?; T:F-5. East:

Sign: CONT-1. Ssp. salicamans - CAL-10. This species occurs as a breeder only in the lower foothills of the west slope, especially, apparently, in the northern portion of the west slope where it may be much more common than further south. I am surprised that it has occurred on eight BBS routes as there seems to be no breeding records for the Yosemite Sierra (Gaines 1988). Thus, the Sierra is quite unimportant to its overall range or to its range in California, despite the fact that salicamans is virtually an endemic California race. The species occurs as a fairly common fall transient and irregular rare winter resident just east of the east base of the Sierran escarpment, but I know of no records on the east slope of the Sierra proper.

Hab: R: 3-RSP.

F: 3-RSP; 2-PAS.

Sp: On the west slope of the Sierra, strongly prefers riparian habitat, particularly willows and cottonwoods.

Abundance: BBS: 2 routes;0. 02 birds/route. MAPS:

Trends: BBS: UN; -1. 9% per year

Demographics: MAPS:

Potential risks and suggested causes of population trends: This species has been subject to considerable habitat loss and degradation of their foothill riparian habitat. Moreover, the American Goldfinch is probably quite susceptible to cowbird parasitism.

 

EVENING GROSBEAK - Coccothraustes vespertinus

Stat: R-SDM West: ifS,irT,ifW. East: irS,irT,iuW.

Dist: T West: N:4-7; T:F-10; W:F-6. East: N:7-8; T:B-10; W:B-8.

Sign: CAN/WMT-3. Ssp. brooksi - WMT-6. This species is fairly common in the Sierra which is very important to its overall California population. Altitudinal limits of nesting poorly known; may nest as low as 3,000' on the west slope.

Hab: R: 3-MCN,RFR.

F: 3-MCN,RFR; 2-MHW,MHC,DFR,ASP,MRI,RSP.

Sp: Prefers dense, mature forests, primarily of true firs. Utilizes seeds of maples in spring and buds of many species of deciduous trees for food throughout the year. Thus, while often associated with deciduous trees, may not require them for nesting. The ecology of this species in the Sierra is in need of much study.

Abundance: BBS: 11 routes;1. 44 birds/route. MAPS: 0. 47 ad/600 nh

Trends: BBS: DT;-4. 6% per year

Demographics: MAPS: Prod. index: 9. 7% yg.

Potential risks and suggested causes of population trends: Because this species prefers dense, mature forests at mid-elevations, logging may be a serious risk. Otherwise, I am at a loss to explain its decreasing tendency.

 
HOUSE SPARROW - Passer domesticus

Stat: R West: lfR. East: lfR.

Dist: T West: N:F-4; W:F-4. East: N:B-7; W:B-7.

Sign: CONT-1. Ssp. domesticus - CONT-1. Being essentially confined to the immediate vicinity of urban, suburban, and agricultural human habitations, the Sierra is extremely unimportant to this introduced species' overall and California populations.

Hab: R: 3-RSP.

F: 3-PAS,RSP.

Sp: Requires the presence of cities, towns, farms, and ranches for nesting. Wanders more widely for foraging, but usually only within human-modified environments, particularly agricultural lands or pasture lands.

Abundance: BBS: 5 routes;0. 33 birds/route. MAPS:

Trends: BBS: UN; -21. 0% per year

Demographics: MAPS:

Potential risks and suggested causes of population trends: This species has increased greatly in numbers and range since it invaded California 120 years ago. It is likely still increasing in the Sierra as urbanization and development continues apace. The large negative trend may be an artifact of small sample size. I can suggest no obvious risks that the species faces in the Sierra.



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