California Partners in Flight Coniferous Forest Bird Conservation Plan Species Account

SPECIES: Dark-eyed Junco, Junco hyemalias

February 2002

Prepared by: Jim DeStaebler, Point Reyes Bird Observatory, jdestaebler@prbo.org

Section 1: Species account outline.

SUBSPECIES STATUS:

Subspecies thurberi is a widespread breeder and winter resident in California. Resident population J. h. pinosus lives in the central coast of California. Western sub-species of the Dark-eyed Junco (DEJU) wintering in California may include J. h. shufeldti which breeds in central and Canadian Rockies and inter-mountain west; J. h. simillus, which breeds on the North-West coast to British Columbia; and J. h. oreganos, which breeds on the pacific coast north of Puget Sound (Pyle 1997). Smaller numbers of other subspecies also regularly occur.

MANAGEMENT STATUS:

No Special status. Protected under the migratory bird act.

Historical references:

Current breeding distribution:

Expert opinion:

Point count: Data not compiled.

Mist netting:

Nest searching:

Spot mapping: Data not compiled

Area search: Data not compiled

Breeding Bird Atlas: With the exception of the Marin County Breeding Bird Atlas, these were not consulted.

BBS Routes: Individual routes were not examined for persistence of breeding populations or range expansions.

ECOLOGY:

Average territory size: 2-3ac per pair in New York (Phelps 1968). See Breeding Density.

Time of occurrence and seasonal movements.

Arrival date on breeding grounds: In Sierra Nevada, breeding season from early May to mid August (USDA 1980)

Departure date from breeding grounds:

Extent of wintering in CA:

Migration stop-over needs/characteristics: no data available

Stop-over period:

Habitat use:

Routes: Low to high elevation movement suggests watercourses and mountain passes may be the typical routes taken (Bent, 1968)

Nest type: Open cup woven with grasses and rootlets, usually on ground, often protected by some large object such as a branch, log or rock (Bent 1968).

Foraging strategy:

Displays: Breeding courtship displays and flock dynamics both involve flashing the white outer rectrices of the Juncoís tail. In flocks, this may signal age or sex dominance.

Social Organization:

Typical breeding densities:

Mating system:

Clutch size: Three to four eggs in a clutch (Bent 1968). Incubating sex: Female

Incubation period: Nestling period:

Development at hatching: altrical

Number of broods: Two broods not remarkable, though Bent doubted a claim of three of four broods being common.

Who tends the young: Male and female tend young.

Diet: Young are fed insects and vegetable matter.

Major food items:

Wintering ground needs and distribution:

BREEDING HABITAT AND NEST SITE CHARACTERISTICS:

Overview of breeding habitat:

Nest Site.

Substrate (species): Data from nest vegetation sampling not compiled

Height of nest: On the ground

Height of plant: Data from nest vegetation sampling not compiled

Nest concealment: Data from nest vegetation sampling not compiled

Vegetation surrounding the nest

Canopy cover: Data from nest vegetation assessment not compiled

Dominant plant species in canopy: coniferous

Average shrub cover:

Dominant shrub species:

Average forb cover:

Dominant forb species:

Ground cover:

Slope:

Aspect:

Tree DBH:

Snags:

Distance to water: near water

Landscape factors

Elevation: Found breeding and wintering at various elevations. Breeding habitat is more related to coniferous woodland and nest substrate than elevation.

Fragmentation: Attracted to edge habitat, clearings and early seral stages. Large-scale removal of forest habitat or land conversion may be harmful (Siegel and DeSante 1999).

Patch size: No data available see territory size.

Disturbance (natural or managed): (e.g. floods, fires, logging)

SPECIAL FACTORS:

Brood parasitisim: Frequency of cowbird parasitism not known.

Dietary: presumed to not limit species health, see foraging above.

Sensitivity to human-induced disturbance: No data available. Use of weedy second growth and suburban habitats for over-wintering may lead to high over-winter mortality from anthropogenic causes. Possible degredation of breeding habitat by grazing and logging.

Pesticide use: No data available.

Predators: As a ground-nesting species, increased predation from mammalian meso-predators could threaten productivity. Attraction to low elevation early succesional habitat for winter could lead to mortality from various suburban sources, i.e. house cats, cars, pollution, children.

Exotic species invasion/encroachment: No data available. As a ground nester dependent on herbaceous vegetation for nest substrate in the breeding season, widespread introduction of exotic annuals could lower productivity.

Other: DeSante reports the apparent drying of the Sierran climate could effect breeding habitat.

POPULATION TREND: http://www.mbr.nbs.gov/bbs/bbs.html

DEMOGRAPHICS:

Age and sex ratios: No information available.

Productivity measure(s): Mist-netting indicates high productivity (Siegel and DeSante 1999) though more information is needed.

Survivorship: Mist-netting in the Sierras reports low survivorship (Siegel and DeSante 1999) though more information is needed.

Dispersal: No information on recruitment is available. See migration.

MANAGEMENT ISSUES:

Further investigation into severity and cause of declines is needed before management issues and recommendations can be soundly made. However, as a ground nesting species dependent on an herbaceous layer for cover, logging, grazing maintenance mowing may affect this species.

ASSOCIATED SPECIES:

Managing for DEJU breeding habitat would benefit low or ground nesting species such as Orange-crowned, Wilsonís, Nashville Warblers, Fox Sparrow, Song Sparrow, Spotted Towhee and Green tailed Towhee. Managing for wintering habitat would benefit other flocking seed-eaters such as Song, White-crowned and Gold-crowned Sparrows, American and Lesser Goldfinches.

MONITORING METHODS AND RESEARCH NEEDS: Recommend methods that will address immediate needs as well as those most appropriate to monitor how effective the proposed management recommendations will be.

Non-manipulative over-winter survival and flock movement study. Productivity data from nest-searching in a variety of habitats.

Section 2: Action plan summary. Summarize the above information into concise statements under each section.

STATUS (from subspecies, trend, local extirpations, state and federal lists, etc.)

No special status. Protected under migratory songbird act. Significant national and California decline shown in BBS data (1966-1996).

HABITAT NEEDS (e.g., elevation, patch size, breeding habitat characteristics, disturbance):

Breeds at a wide range of elevations in California, from sea level to near tree line. Preferred breeding habitat is moist coniferous forest edge with an herbaceous understory. Responds favorably to early years of forest regeneration. In winter, uses open areas with large seed crops, including fir, redwood, ornamentals, annual forbs and grasses.

CONCERNS (e.g., productivity, brood parasitism, habitat loss, lack of information, wintering distribution, pesticide use)

Common and widespread species with population decline of unknown cause.

OBJECTIVES (e.g., increase distribution, identify healthy breeding populations, increase available habitat, guide restoration efforts to benefit species)

Identify causes of decline.

ACTION (e.g., acquire and restore habitat, specific management and restoration recommendations, specific research and monitoring needs, specific land protection recommendations):

Further data collection or retrieval of data and analysis. Areas of focus should include possible causes of declines, productivity (parasitism and predation, habitat use and assessment, effect of invasive plants) and over-winter survival (flock size and requirements, predation)

SCIENTIFIC REFERENCES:

Bock, C. E. and J. F. Lynch. 1970. Breeding Bird Populations of Burned and Unburned Conifer Forest in the Sierra Nevada. The Condor, 72:182-189

Chandler, C. R. and R. S. Mulvihill. 1990. Wing-shape variation and differential timing of migration in Dark-eyed Juncos. Condor 92:54-61.

DeSante, D. F. and L. T. George. 1994. Population Trends In The Landbirds of Western North America. Studies in Avian Biology No 15:173-190.

Garrett, K. and J. Dunn. 1981. Birds of Southern California: Status and Distribution. Los Angeles Audubon Society.

Hagar, D. C. 1960. Interrelationships of Logging, Birds, Timber Regeneration in the Douglas Fir Region of Northwestern California, Ecology 41( 1): 116-125.

Hejl, S. J. and R. L. Huto, C. R. Preston, and D. M. Finch. The Effects of Silvicultural Treatments in the Rocky Mountains in Ecology and Management of Neotropical Migratory Birds: A Syntheses and Review of Critical Issues. Ed T. E. Martin and D. M. Finch.

Holbertson, R. L. 1993. An Endogenous Basis for Differential Migration In the Dark-Eyed Junco. The Condor 95:580-587

Johnson, N. K. and C. Cicero. 1985. The Breeding Avifauna of San Benito Mountian, California: Evidence for Change over One-Half Century. Western Birds 16(1):1-23.

McCaskie, G, P. De Benedictis, R. Erickson and J. Morlan. 1979. Birds of Northern California: An Annotated Field List. Golden Gate Audubon Society, Berkley CA.

Nolan, V. Jr. and E. D. Ketterson. 1990. Timing of Autumn Migration And Its Relation to Winter Distribution In Dark-eyed Juncos. Ecology 71(4): 1267-1278.

Phelps, J. H., Jr. 1968. Oregon Junco. In A. C. Bent, Life Histories of North American Cardinals, Grosbeaks, Buntings, Towhees, Finches, Sparrows and Allies. O. L. Austin, Editor. Dover Publications, Inc., NY, NY.

Raphael, M. G. and M. L. Morrison, M. P. Yoder-Williams. 1987. Breeding Bird Populations During Twenty-Five Years of Postfire Succession in The Sierra Nevada. The Condor, 89: 614-626.

Sauer, J. R., J. E. Hines, and J. Fallon. 2001. The North American Breeding Bird Survey, Results and Analysis 1966 - 2000. Version 2001.2

Sauer, J. R., S. Schwartz, and B. Hoover. 1996. The Christmas Bird Count Home Page. Version 95.1. Patuxent Wildlife Research Center, Laurel, MD

Siegel, R. B. and D. DeSante. 1999. Version 1.0. The draft avian conservation plan for the Sierra Nevada Bioregion: conservation priorities and strategies for safeguarding Sierra bird populations. Institute for Bird Populations report to California Partners in Flight.

Swanson, D. Seasonal Population Dynamics of Dark-eyed Juncos from Western Oregon. Journal of Field Ornithology, 63(3): 268-275.

California Wildlife and Their Habitats: Western Sierra Nevada. USDA Forest Service Pacific Southwest Forest and Range Experimental Station. General Techincal Report PSW-37. 1980.