David F. DeSante
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This appendix summarizes the status, distribution, abundance, population trends, and demographics of the landbirds of the Sierra Nevada ecosystem, as well as the significance of the Sierra to each species' and subspecies' overall range and range in California. This report also attempts to define the risks that each Sierran species currently faces and to speculate on the causes of current population trends. The species accounts presented here were originally developed in 1995 as part of a report to the Sierra Nevada Ecosystems Project. They remain unaltered, except that BBS data analyses and MAPS survival estimates have been updated to incorporate more recent data.
Included in this report are all species of landbirds known or strongly suspected to have bred at least once in the "Sierra proper" (as defined in the main body of this report) with the exception of diurnal raptors (order Falconiformes) and gallinaceous species (order Galliformes). Included, therefore, are the orders Columbiformes, Cuculiformes, Strigiformes, Caprimulgiformes, Apodiformes, Coraciiformes, Piciformes, and Passeriformes. Species of landbirds (defined as above) that breed (or formerly bred) in the Central Valley and, perhaps, the lowermost foothills of the west slope of the Sierra that are excluded from this report include: Spotted Dove (Streptopelia chinensis), Yellow-billed Cuckoo (Coccyzus americanus), Burrowing Owl (Speotyto cunicularia), Short-eared Owl (Asio flammeus), Lesser Nighthawk (Chordeiles acutipennis), Bank Swallow (Riparia riparia), Yellow-billed Magpie (Pica nuttallii), Northern Mockingbird (Mimus polyglottos), Bell's Vireo (Vireo bellii), Tricolored Blackbird (Agelaius tricolor), and Hooded Oriole (Icterus cucullatus).
All but two of these species, Spotted Dove and Yellow-billed Magpie, also breed (or formerly bred) just east of the Sierra or in the Valley of the South Fork of the Kern River. I know of no breeding records for the Sierra proper for any of the above 11 species, although some of them, including Burrowing Owl, Short-eared Owl (possibly), Bank Swallow, Yellow-billed Magpie, Northern Mockingbird, and (possibly) Tricolored Blackbird, have occurred in the Sierra proper as transients. In addition, Rock Dove, Black-chinned Hummingbird, Say's Phoebe, American Crow, Common Yellowthroat, Blue Grosbeak, Lark Sparrow, and American Goldfinch should, perhaps, be included in this same category because, except for a single, old nesting record of Blue Grosbeak at 1,700' along the Merced River, I know of no verified breeding records for any of these species for the Sierra proper. Nevertheless, I have included them in this report because summer records in the Sierra indicative of possible or probable breeding exist for all of them.
Nine additional species of landbirds that breed (or formerly bred) just east of the the eastern base of the Sierran escarpment, in the Valley of the South Fork of the Kern River, or near Walker Pass, Kern County, are also excluded from this report: Costa's Hummingbird (Calypte costae), Ladder-backed Woodpecker (Picoides scalaris ), Brown-crested Flycatcher (Myiarchus tyrannulus; which, I believe, has bred at least once in the Valley of the South Fork of the Kern River), Eastern Kingbird (Tyrannus tyrannus; which has bred once in the Honey Lake Basin), Cactus Wren (Campylorhynchus brunneicapillus), LeConte' Thrasher (Toxostoma lecontei), Gray Vireo (Vireo vicinior), Summer Tanager (Piranga rubra), and Scott's Oriole (Icterus parisorum). As with the former 11 species, I know of no breeding records for the Sierra proper for any of these nine species. Moreover, of all these nine species, only Costa's Hummingbird has been recorded in the Sierra proper. In addition, Sage Thrasher should, perhaps, be included in this same category as I know of no verified breeding record for the Sierra proper. Nevertheless, I have included it in this report because summer records in the Sierra indicative of possible breeding may exist.
Finally, all species of landbirds that occur in the Sierra proper only as winter residents or visitants, rare summer visitors, passage migrants, or vagrants have been excluded from this report. Noteworthy in this regard are Rufous Hummingbird (Selasphorus rufus ), Varied Thrush (Ixoreus naevius), Cedar Waxwing (Bombycilla cedrorum), Townsend's Warbler (Dendroica townsendi), and Golden-crowned Sparrow (Zonotrichia atricapilla), all of which migrate through or winter in the Sierra in substantial numbers. In addition, Bohemian Waxwing (Bombycilla garrulus) and Northern Shrike (Lanius excubitor ) appear to be irregular winter visitants to the Sierra proper, while Allen's Hummingbird (Selasphorus sasin) and American Redstart (Setophaga ruticilla) may be regular passage migrants in small numbers. In summary, this report deals with 146 species of landbirds that may be considered to comprise the breeding landbird fauna of the Sierra Nevada.
Major sources of information used in the preparation of this report were:
The Distribution of the Birds of California (Grinnell and Miller 1944) for status and habitat information for Sierran birds and for detailed distributional information for California for all species and subspecies found in the Sierra and in California.
The AOU Checklist of North American Birds (American Ornithologists' Union 1983 and Supplements appearing every two years in the Auk) for taxonomy and nomenclature and for continental aspects of bird distribution.
The AOU Checklist of North American Birds (American Ornithologists' Union 1957) for subspecific taxonomy and nomenclature and for the continental distrbutions of all subspecies that occur in the Sierra.
Distributional Checklist of North American Birds (DeSante and Pyle 1986) for supplemental state-by-state status and abundance information of North American birds.Birds of Yosemite and the East Slope (Gaines 1988 and revised 1992) for detailed status, abundance, habitat, and life history information on central Sierran birds.
Discovering Sierra Birds (Beedy and Granholm 1985) for supplemental status, abundance, habitat, and life history information on birds of the west slope of the entire Sierra.
Of these, Grinnell and Miller (1944) and Gaines (1988) provided the bulk of the information used in the preparation of this report.
2. Databases Data from the North American Breeding Bird Survey (BBS) from the Sierra Nevada phyiographic province from 1966-1996 were used to determine abundance categories and population trends for Sierra birds. Discussion of the methods and important limitations of these data are presented in the main body of this report.
Monitoring Avian Productivity and Survivorship (MAPS) data from the 12 constant-effort mist-netting stations operated during various summers in the Sierra Nevada between 1990-1994 (for productivity indices) and 1993-1996 (for survival estimates). The MAPS program is coordinated and administered by The Institute for Bird Populations. Data used in this report include summary regional adult population size and productivity indices and estimates of annual survival rates and recapture probabilities.
Additionally, data on the population dynamics of subalpine Sierran birds in the Harvey Monroe Hall Natural Area of the Inyo National Forest were used to provide supplemental and incidental information for this report. These data were collected by the author (and assistants) during 22 years (1977-1998) of spot mapping, nest monitoring, and limited color-banding-resighting studies.
All inferences regarding potential risks faced by Sierran birds and possible causes of population trends and all suggestions regarding management actions to reduce risks or reverse negative trends are entirely the opinion and responsibility of the author unless supporting references are cited.
The results of this survey and synthesis are presented below. The accounts are organized as follows:
1. Species common and scientific names: Nomenclature and order of listing follow AOU (1983) as updated every two years in The Auk . 2. Stat: Status in the Sierra. The migratory status of the species in the Sierra is provided first. Codes follow the criteria in Table 10 of the main body of the report.
Next, status and abundance codes are presented separately for the west and east slopes of the Sierra. These codes were taken, with some modification, from Gaines (1988) and are most appropriate for the central Sierra, but are generally applicable to the entire range. Definitions of Gaines' codes, in turn, were borrowed from DeSante and Pyle (1986) and are as follows:
R = Resident and confirmed breeder.
S = Summer resident and confirmed breeder.
S* = Summer resident with no evidence of breeding.
T = Transient. Includes passage migrants and up- or down-slope visitors during spring, summer, or fall. Abundance classifications given for transient status reflects the species' abundance at higher and/or lower elevations than the breeding range.
W = Winter resident or winter visitor.
c = common or abundant
f = fairly common
u = uncommon
r = rare
x = exceptionally rare; less than 10 total records during the season over all years.
Prefixes to abundance codes:
l = local. Found at but a few discreet locations within its range.
i = irregular.
Numbers vary markedly from year-to-year. The abundance code given for species with an irregular status classification generally reflects abundance when the species does occur. Obviously, in some years, they are present in lower numbers than indicated and, rarely, in higher numbers.
3. Dist: Distribution of the species in the Sierra. First is given a code that describes the species' north-south distribution:
T = throughout the Sierra from north to south (but not necessarily from east to west).
N, C, S = northern, central, southern respectively.
NC = northern and central,
CS = central and southern, etc.
NE = northern part of east slope,
CSE = central and southern part of east slope, etc.Following this, elevational limits (in 1,000' intervals abbreviated as 2 = 2,000', 10 = 10,000', etc.) are given separately for breeding (B), for transient or summer visitant status (T), and for wintering (W). These elevational limits were taken with relatively little modification from Gaines (1988) and, as such are strictly applicable only for the central Sierra. In general, one should add about 1,000' to both the lower and upper elevational limit for the extreme southern Sierra and subtract about 1,000' for the extreme northern Sierra.
F = the lowest foothills of the west slope at less than 1,000' to 1,500' elevation.
B = the eastern base of the Sierran escarpment on the east slope at about 3,000' to 4,000' in the south, 4,000' to 5,000' in the north, and as high as 6,000' to 7,000' on the central part of the east slope.
4. Sign: Significance of the Sierran range of the species to its continental and California range. In other words, the importance of the Sierra to the species overall populations. This importance is indicated by an importance classification system that increases in importance from 1 to 12. Importance classifications are as follows:
CONT-1 = Distributed over much of the entire North American continent north of Mexico, including at least the southern part of Canada. US-2 = Distributed over much of the United States including both the eastern and western parts, but generally absent from Canada.
CAN/WMT-3 = Distributed over much of Canada and the mountains of western U.S. but absent from eastern U.S. except perhaps in the Appalachians.CAN/EUS-3 = An unusual distribution for species absent from most of western U.S. except along the Pacific Coast or locally in the Southwest. WEST-4 = Limited to western North America including at least the southern part of Canada, but widely distributed in the west.
WUS-5 = Rather widely distributed in western U.S., but generally does not occur in Canada. WMT-6 = Occurs over much of western North America, but generally limited to the higher mountains, at least in the U.S. PAC-7 = Generally limited to the Pacific Slope of western North America, and does not generally occur in the Great Basin or Rocky Mountains. RM/GB-8 = Limited primarily to the Great Basin and/or Rocky Mountain region of western U.S., and generally absent from the Pacific Slope. SW-9 = Limited to the southwestern U.S., often including much of California. CAL-10 = Occurs, for the most part only in California, but widely distributed over much of the state.
PCAL-11 = Occurs in only a portion of California.
SIE-12 = Essentially or entirely endemic to the Sierra.
If a species is divided into recognized subspecies, the Sierran range and a separate importance classification is provided for every subspecies that breeds in the Sierra. These importance classifications are usually supplemented by some explanatory text unless they are completely straightforward.
5. Hab: Habitat preferences and descriptions. Habitat preferences for each species for reproduction (R) and feeding (F) are provided for all habitats given a high (3) or medium (2) value classification according to the Wildlife Habitat Relationships (WHR) for California as a whole. These WHR were taken from AVESBASE (Davidson and Manley (1993). I did not record habitats given a low (1) value classification nor did I utilize relationships for cover as I have never been able to appreciate the significance of these classifications. Nor did I utilize habitat size classes or canopy closure classes, because I feel that these aspects of the habitat can be more accurately and effectively conveyed in succinct, integrated, holistic descriptions that incorporate other important variables such as moisture regime, shrub components, and edge vs. interior preferences.
Habitats considered here are those thought to exist in substantial amounts in the Sierra and be of some importance to at least some members of the Sierran landbird community. The order of listing of habitats does not indicate any order of importance to the species, other than the fact that class 3 habitats are listed before class 2 habitats. Rather, forest and woodland habitats are listed first, followed by shrubland or grassland habitats, followed finally by human-created habitats. Forest and woodland habitats are listed generally as they occur from west to east (lower to higher elevations on the west slope followed by higher to lower elevations on the east slope). Shrubland or grassland habitats are listed from high to low moisture regime. Habitats included in this report and their order of listing are: MHW - montane hardwood; MHC - montane hardwood-conifer; PPN - ponderosa pine; DFR - Douglas fir; MCN - mixed conifer; JPN - jeffrey pine; RFR - red fir; LPN - lodgepole pine; SCN - subalpine conifer; ASP - aspen; EPN - eastside pine; PJN - pine-juniper; JUN - juniper; WTM - wet meadow; MRI - montane riparian; MCP - montane chaparral; ADS - alpine dwarf scrub; BAR - barren; PAS - pasture; and RSP - residential-park. Probably because the Wildlife Habitat Relationships presented in AVESBASE are not specific to the Sierra but rather encompass all of California, I often found habitats that I believed to be classified too high for a given species. Such habitats are enclosed in single parentheses () and indicate that the value of the habitat should be at least one class lower. In a few cases I found classifications that I believed were completely erroneous for anywhere in California (or elsewhere for that matter). A prime example was Western Meadowlark, class 3 in Douglas fir forests! Such classifications are enclosed in double parentheses (()) and indicate that the classification is in error. In still other cases, I felt that habitats of high or medium value to a species in the Sierra were missing from the WHR. I added such habitats under the appropriate 3 or 2 heading but enclosed them in brackets  to indicate that they were absent from the WHR.
Finally, I provided a brief narrative description of what I believe to be the key elements of preferred Sierran habitat for each species considered here. These narratives were based extensively on similar descriptions in Grinnell and Miller (1944), Gaines (1988), and, to a lesser extent, Beedy and Granholm (1985). In all cases, I modified these descriptions, when necessary, based on my personal experience.
6. Abundance: Data on relative numbers of Sierran landbirds were compiled from two sources: the North American Breeding Bird Survey (BBS) coordinated by the USDI National Biological Service and the Monitoring Avian Productivity and Survivorship (MAPS) Program coordinated by The Institute for Bird Populations. BBS results are presented as: (1) the number of BBS routes (out of 17 total) in the Sierra Nevada physiographic region (Stratum 66) from which data was used to calculate the regional trend for the species; and (2) the average relative abundance, that is, the mean number of birds seen or heard on the routes used in this analysis (given as birds per route). This latter includes routes on which the species was never recorded provided, of course, that the species was recorded somewhere in the Sierra Nevada on (presumably) at least two BBS routes. These data were taken from the on-line interactive route regression module provided by the BBS, and include data from the 31-year period 1966-1996.
MAPS results are presented as the mean number of adult birds captured per 600 net-hours at all 12 of the MAPS stations operated in the Sierra Nevada over the five years 1990-1995. I used 600 net-hours as the standard for comparison because it represents the amount of effort expended at a typical single MAPS station during a single season (ten 12-meter mist nets operated for six hours per day, for one day per 10-day period, and for ten consecutive 10-day periods from May 21 through August 28). These relative abundance data from MAPS must be interpreted with caution because 10 of the 12 Sierran MAPS stations were located at a forest-meadow interface between about 4,300' and 7,900' elevations. Moreover, mist nets tend to capture birds more efficiently that forage near the ground than those that forage in the canopy.
7. Trends: Population trends are based on 30 years (1966-1996) of BBS data for the Sierra Nevada physiographic region. Trend data, where available, are presented for each species first by one of the following trend classifications:
DI – Definitely increasing LI – Likely increasing PI – Possibly increasing IT – Increasing tendency
DS – Definitely stable LI – Likely stable PI – Possibly stable ST – Stable tendency
DD – Definitely decreasing LD – Likely decreasing PD – Possibly decreasing IT – Increasing tendency
UN – Trend unknown due to small sample size
Criteria for inclusion in each category are described in Table 1 of the main body of this report.
Because of the limited number of years that the MAPS Program has existed in the Sierra and the comparably few stations operated, reliable trend data is not yet available from MAPS.
8. Demographics: Preliminary demographic data are available for various landbird species from the MAPS Program (DeSante 1992, 1994). These data are presented as follows:
Productivity: Productivity indices are presented for various species as the percentage of young in the catch, which is defined as 100*(the total capture rate of young birds)/(the total capture rate of all birds identified to age). Productivity data for a given species are included only from stations where the species is known to breed. Thus, for example, no productivity data is reported for the Orange-crowned Warbler because this species breeds at lower elevations than those at which all of the 12 Sierran MAPS stations were located. Productivity indices from MAPS are reported for 55 landbird species for which at east 10 aged individuals were captured during the five years of the study. The numbers of aged individuals contributing to these data varied from a low of 12 for Williamson's Sapsucker and Downy Woodpecker to a high of 2,151 for Dark-eyed Junco, and averaged 266.3 for the 55 species.
Survivorship: Estimates of the annual survival rate of adult birds and the capture probability of adults were obtained from modified Cormack-Jolly-Seber mark-recapture analyses (Pollock et al. 1990, Lebreton et al. 1992) using the computer program SURVIV. Estimates were obtained using a model that differentiates between resident and transient adults, and incorporates constant survival and capture probability.
Estimates of annual survival rates and recapture probabilities for adult birds were based on four years (1993-1996) of pooled mark-recapture data from 12 MAPS stations (five in Yosemite National Park and seven on or adjacent to Tahoe National Forest). Estimates of annual survival rates of adult birds (and their standard errors), along with estimates of capture probabilities for adult birds (and their standard errors) are presented in the Species Accounts of each species for which adequate data existed.
9. Potential risks and suggested causes of population trends: The final section in each species account outlines the potential risks that the species faces and, at least for those species undergoing definite or likely population changes, provides suggestions as to possible causes of the changes. As should be evident from the results presented to date, only the barest of beginnings have been established regarding demographic monitoring of Sierran birds. Without detailed habitat specific data on primary demographic parameters it is very difficult to deduce causes of population changes. Thus, most of the material presented in this section must be considered speculative at best. I hope, however, that it can provide some direction for future research efforts and management strategies.
Finally, I must specify non-landbird (as defined here) species of the Sierra that critically need study -- just so I can be assured that they are not somehow missed:
White-tailed Kite - may not breed in the Sierra proper
Swainson's Hawk - may not breed in the Sierra proper)
Blue Grouse Sage Grouse - may not breed in the Sierra proper
LITERATURE CITED IN APPENDIX I
American Ornithologists' Union (AOU). 1957. Check-list of North American birds, 5th edition. American Ornithologists' Union, Washington, D.C. 877 pp.
American Ornithologists' Union (AOU). 1983. Check-list of North American birds, 6th edition. American Ornithologists' Union, Washington, D.C. 877 pp.
Beedy, E. C., and S. T. Granholm. 1985. Discovering Sierra birds: western slope. Yosemite Natural History Association and Sequoia Natural History Association, Calif. 229 pp.
Burnham. K. P., and D. R. Anderson. 1992. Data-based selection of an appropriate biological model: the key to modern data analysis. Pp. 16-30 in McCullough, D. C., and R. H. Barrett, Eds. Wildlife 2001: Populations. Elsevier Applied Science, London, U.K.
Davidson, C., and P. Manley. 1993. AVESBASE: a conservation database for California birds, Version 1.0. Pacific Southwest Region, Forest Service, U.S. Dept. Agriculture, San Francisco, Calif. 104 pp. plus software.
DeSante, D. F. 1990. The role of recruitment in the dynamics of a Sierran subalpine bird community. Amer. Naturalist 136:429-445.
DeSante, D. F. 1992. Monitoring Avian Productivity and Survivorship (MAPS): a sharp, rather than blunt, tool for monitoring and assessing landbird populations. Pp. 511-521 in McCullough, D. C., and R. H. Barrett, Eds. Wildlife 2001: Populations. Elsevier Applied Science, London, U.K.
DeSante, D. F., and K. M. Burton. 1994. The Monitoring Avian Productivity and Survivorship (MAPS) Program, third annual report (1992). Bird Populations 2:62-89.
DeSante, D. F., and T. L. George. 1994. Population trends in the landbirds of western North America. Pp. 173-190 in J. R. Jehl, Jr., and N. K. Johnson (eds.) A century of avifaunal change in western North America. Studies in Avian Biology No. 15.
DeSante, D. F., and G. R. Geupel. 1987. Landbird productivity in central coastal California: the relationship to annual rainfall, and a reproductive failure in 1986. Condor 89:636-653.
DeSante, D. F., and P. Pyle. 1986. Distributional checklist of North American birds, Vol. 1, United States and Canada. Artemisia Press, Lee Vining, Calif. 442 pp.
Gaines, D. 1988. Birds of Yosemite and the east slope. Artemisia Press, Lee Vining, Calif. 352 pp.
Gaines, D. 1992. Birds of Yosemite and the east slope, Revised ed. Artemisia Press, Lee Vining, Calif. 352 pp.
Garrett, K., and J. Dunn. 1981. Birds of southern California: status and distribution. Los Angeles Audubon Society, Los Angeles, Calif. 408 pp.
Grinnell, J., and A. H. Miller. 1944. The distribution of the birds of California. Pacific Coast Avifauna No. 27. Cooper Ornithiol. Society, Berkeley, Calif. 608 pp.
Hejl, S. J. 1994. Human-induced changes in bird populations in coniferous forests in western North America during the past 100 years. Pp. 232-246 in J. R. Jehl, Jr., and N. K. Johnson (eds.) A century of avifaunal change in western North America. Studies in Avian Biology No. 15.
Hutto, R. L. 1988. Is tropical deforestation responsible for the reported decline in Neotropical migrant populations? American Birds 42:375-379.
Lebreton, J. -D., K. P. Burnham, J. Clobert, and D. R. Anderson. 1992. Modeling survival and testing biological hypotheses using marked animals: a unified approach with case studies. Ecol. Monogr. 62:67-118.
Manley, P., and C. Davidson. In litt. Assessing risks and setting priorities for Neotropical migratory birds in California. Pacific Southwest Region, Forest Service, U.S. Dept. Agriculture, San Francisco, Calif.
Marshall, J. T. 1988. Birds lost from a giant sequoia forest during fifty years. Condor 90:359-372.
McCaskie, G., P. DeBenedictis, R. Erickson, and J. Morlan. 1979. Birds of northern California: an annotated field list. Golden Gate Audubon Society, Berkeley, Calif. 84 pp.
Miller, J. H., and M. T. Green. 1987. Distribution, status, and origin of Water Pipits breeding in California. Condor 89:788-797.
Ohmart, R. D. 1994. The effects of human-induced changes on the avifauna of western riparian habitats. Pp. 273-285 in J. R. Jehl, Jr., and N. K. Johnson (eds.) A century of avifaunal change in western North America. Studies in Avian Biology No. 15.
Pollock, K. H., J. D. Nichols, C. Brownie, and J. E. Hines. 1990. Statistical inference for capture-recapture experiments. Wildlife Monographs No. 107.
Pradel, R., J. Hines, J.-D. Lebreton, J. D. Nichols, and A. Viallefont. In litt. Estimating survival probabilities and proportions of "transients" using capture-recapture data. Biometrics.
Robbins, C. S., J. R. Sauer, R. S. Greenberg, and S. Droege. 1989. Population declines in North American birds that migrate to the neotropics. Proceedings of the National Academy of Sciences (USA) 86:7658-7662.
Serena, M. 1982. The status and distribution of the Willow Flycatcher in selected portions of the Sierra Nevada, 1982. California Dept. of Fish and Game Administrative report 82-5.
Terborgh, J. 1989. Where have all the birds gone? Essays on the biology and conservation of birds that migrate to the American tropics. Princeton University Press, Princeton, New Jersey.
Tomback, D. F. 1982. Dispersal of whitebark pine seed by Clark's Nutcracker: a mutualism hypothesis. Jour. Animal Ecology 15:
Verner, J., K. S. McKelvey, B. R. Noon, R. J. Gutierrez, G. I. Gould, Jr., and T. W. Beck. 1992. The California Spotted Owl,: a technical assessment of its current status. Gen. Tech. Rep. PSW-GTR-133. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Dept. of Agriculture. 285 pp.
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