California Partners in Flight Coniferous Bird Conservation Plan for the Golden-crowned Kinglet

California Partners in Flight Coniferous Bird Conservation Plan for the Golden-crowned Kinglet

15 December 2000

Prepared by: John C. Robinson, USDA Forest Service, 1323 Club Drive, Vallejo, CA 94592 (707) 562-8929

Summary Derived from species account author and 6/22/00 meeting.

SPECIES: Golden-crowned Kinglet (Regulus satrapa)

SUBSPECIES STATUS:

There are from four to six subspecies of Golden-crowned Kinglet that are currently recognized (Bent 1939; Clements 2000; Ingold and Galati 1997):

(Regulus satrapa satrapa)
(R. s. olivaceus)
(R. s. apache)
(R. s. aztecus)
(R. s. amoenus)
(R. s. clarus)

R. s. satrapa was identified by Bent (1939) as the Eastern Golden-crowned Kinglet. Bent (1939) and Grinnell and Miller (1944) identified R. s. olivaceus as the Western Golden-crowned Kinglet and described its breeding range to include California; however, Ingold and Galati (1997) maintain that the breeding range of this subspecies only extends from the "Sitka area of se. Alaska and w. British Columbia (west of Cascades) south to w. Oregon". R. s. apache was described as the Arizona Golden-crowned Kinglet by Bent (1939), who also summarized its breeding range as occurring in the White Mountains and adjacent ranges in east-central Arizona. In contrast, this subspecies is considered by Ingold and Galati (1997) to be the subspecies which breeds in California; the breeding range described for this subspecies extends from "s. Alaska (north and west of olivaceus) and s. Yukon south through Cascade and Rocky Mtn., Coast Ranges of California, and Sierra Madre Occidental to s. Jalisco" (ibid.).

R. s. amoenus is considered to be a synonym of R. s. apache. R. s. aztecus is considered to be a very local resident of higher mountains in central Mexico, where it inhabits fir forests. R. s. clarus is also considered to be resident in the high mountains of se. Chiapas (Mexico) and s. Guatemala, but not all authorities recognize the validity of this subspecies (Ingold and Galati 1997).

For the purposes of this species account, it is assumed that the birds breeding in California are representatives of R. s. apache, as described by Ingold and Galati (1997). During the winter, both this subspecies and R. s. olivaceus occur in California (ibid.). Grinnell and Miller (1944) summarized the status of Golden-crowned Kinglet in California as follows: "summer resident in higher mountains and along northern coast; winter visitant west of the Sierran crests in lowlands from October to mid-March."

MANAGEMENT STATUS:

No special status. Protected under the Migratory Bird Treaty Act.

RANGE IN CALIFORNIA

1. Historical References

Close to five million Golden-crowned Kinglets were once thought to occur in northwestern California (Ingold and Galati 1997). Grinnell and Miller's (1944) description of the California range of the Golden-crowned Kinglet is essentially similar to the range described in 1994 by Small (see Current Breeding Distribution, below). 2. Current Breeding Distribution The current breeding range in California, as summarized by Small (1994), extends southward from the Oregon border to or through the following locations: a. The Klamath Mountains Region

b. The Northern Coast Range along the coast south to central Sonoma County

c. The Inner Coast Range to at least Mendocino County, and then from Marin County south through Santa Cruz County

d. The Warner Mountains (where it is rare and local, and identified as a possible breeding bird)

e. The Cascades-Sierra axis (where it is found on both slopes) to as far south as extreme northern Kern County and central Inyo County

Small (1994) also considered it to be rare and local as a breeding species in the higher elevations of the White Mountains, and a regular but rare to uncommon local breeding bird in the Mt. Pinos area of Kern & Ventura Counties and in the San Bernardino and San Jacinto Mountains. During the fall and winter, it can be found in many of these same areas (as well as in the lowlands and foothills outside of its breeding range) where its abundance ranges from rare to uncommon to sometimes locally common. ECOLOGY

1. AVERAGE TERRITORY SIZE

The known size of Golden-crowned Kinglet breeding territories ranges from 0.336 to 1.6 ha. Population densities (number of breeding pairs per 40 ha.) reported in California range from 0.8 in lodgepole pine (Pinus contorta) habitat to 58.2 in Douglas fir (Pseudotsuga taxifolia) habitat (Ingold and Galati 1997). 2. TIME OF OCCURRENCE AND SEASONAL MOVEMENTS

a. Arrival Date on Breeding Grounds

Although the Golden-crowned Kinglet is a migratory species, it can be found throughout the winter over much of its California breeding range. It is considered to be a fairly common to common resident in the northwestern interior coniferous and coastal coniferous forests; and in the Warner Mountains and Cascades/Sierra Nevada portion of its breeding range, it is considered to be an irregular to fairly common winter visitor from October to March (Small 1994). Clearly defined arrival dates on the breeding grounds are thus clouded by the presence of these overwintering individuals. Small (1994) inferred that birds in the Warner Mountains and Cascades/Sierra Nevada portions of the Golden-crowned Kinglet's breeding range arrive in April. b. Initiation of Nesting Bent (1939) reported an observation of Golden-crowned Kinglets in Seattle carrying nest material in early April; it was generally believed that the great majority of birds at this location have initiated nesting by the middle of May. The nesting cycle depicted by Ingold and Galati (1997) shows eggs being laid from mid May through early July. c. Departure Date from Breeding Grounds In California, the Golden-crowned Kinglet is resident or present throughout much of its breeding range during the winter, making it difficult to clearly define a period when the species actually departs its breeding grounds. d. Spring Migration Period Not well defined. The number of kinglets in south coastal British Columbia doubles in April, suggesting that birds from the south are arriving at that time. Small (1994) also infers a migratory movement within California commencing sometime in April. e. Fall Migration Period As mentioned above, Golden-crowned Kinglets can be found throughout much of their California breeding range throughout the winter, making it difficult to separate true migrants from resident populations. In northern and central British Columbia, the fall migration starts in August and may continue through late September or early October; migrants in California have been detected as early as late September. Additionally, altitudinal migration (where birds move to lower elevations during the fall and winter) has been documented for Golden-crowned Kinglets in western North America (Ingold and Galati 1997). 3. NEST TYPE The Golden-crowned Kinglet builds an elongated, globular or sac-like nest which can also be described as a deep, cup-shaped structure (Ehrlich et al. 1988; Ingold and Galati 1997). 4. FORAGING STRATEGY The Golden-crowned Kinglet primarily feeds on arthropods (including insects, mites, and spiders), although in the winter months it occasionally supplements its diet with a small amount of vegetable matter. It secures its food by gleaning it from twigs, under bark, conifer needles, or tree trunks. This species is also known to hover in the air to hawk insects or to glean prey from the underside of leaves. They may also forage on the ground (Ingold and Galati 1997). 5. DISPLAYS Agonostic territorial behavior displays include the male defender chasing away intruders and exposing his orange crown-patch to the intruder (this is accomplished by bowing his head toward his opponent). Flicking of the tail is considered to be a communicative mechanism among kinglets, and establishment of the territory is maintained by vigorous singing on the part of the male. The pair bond is maintained by such behaviors as the male bringing food to the female and the female announcing her readiness to copulate by flattening herself out on a twig or nest and fluttering her wings while twittering (Ingold and Galati 1997). 6. MATING SYSTEM Golden-crowned Kinglets utilize a monogamous mating strategy (Ehrlich et al. 1988). Ingold and Galati (1997) described this species' mating system as being apparently serially monogamous (the pair remains together through both nesting cycles in a single breeding season). 7. CLUTCH SIZE Between 5 and 11 eggs may be laid, although the average number ranges from 8-9 (Ehrlich et al. 1988). Bent (1939) reported similar clutch sizes for the Western Golden-crowned Kinglet. 8. INCUBATING SEX (FEMALE/MALE) The female incubates the eggs and broods the young; both sexes feed the young from the time of hatching (Ehrlich et al. 1988; Ingold and Galati 1997). 9. INCUBATION PERIOD Incubation lasts approximately 14-15 days and is usually initiated near the end of the egg-laying period (Ehrlich et al. 1988; Ingold and Galati 1997). 10. NESTLING PERIOD Young are capable of flight when they are about 14-19 days old (Ehrlich et al. 1988). 11. DEVELOPMENT AT HATCHING Young are altricial. 12. NUMBER OF BROODS Golden-crowned Kinglets may produce up to two broods in a breeding season. Construction of the second nest is usually initiated before the young in the first nest have fledged; at this time, the male continues to feed the young from the first brood while the female builds the second nest and lays and incubates the second clutch (Ehrlich et al. 1988; Ingold and Galati 1997). 13. WHO TENDS YOUNG The female broods the young and both sexes feed the young from the time of hatching (Ehrlich et al. 1988; Ingold and Galati 1997). HABITAT

1. NEST SITE

a. Nest Substrate

The Golden-crowned Kinglet breeds in boreal or subalpine spruce or fir forests; it also frequents mixed coniferous-deciduous forests, deciduous forests, and pine (Pinus) plantations. Nests in northern Minnesota have been found in balsam fir (Abies balsamea), white spruce (Picea glauca), and black spruce (Picea mariana) trees. In western North America, this species is known to nest in Douglas fir forests (Oregon), spruce-fir forests (Colorado), fir-spruce forests (Utah), and pine-oak (Quercus)-fir forests in western Mexico. b. Height of Nest The nest of the Golden-crowned Kinglet is generally 4-64 feet above the ground (Ehrlich et al. 1988; Ingold and Galati 1997). c. Height of Nest Plant A study in West Virginia concluded that Golden-crowned Kinglets invaded spruce forests when the trees reached heights of 33-49 feet; in Minnesota, this species was found nesting in stands dominated by black spruce that was 56-66 feet in height (Ingold and Galati 1997). d. Plant Species Concealing Nest See "Nest Substrate", above. e. Percent Nest Cover Ingold and Galati (1997) summarize the micro habitat of the Golden-crowned Kinglet's nest as follows:
"Nests ... are suspended by their rims on radiating twigs; no basal support." Nests may be placed in upper tree crowns, a few centimeters from the trunk, and supported by branches that have been incorporated into the walls of the nest near the nest rim. "All nests are well protected by overhanging foliage from wind, rain, and sun. Nests are hidden from view at the top or nest level, but can be partly seen from below." 2. VEGETATION SURROUNDING THE NEST

a. Canopy Cover

Golden-crowned Kinglets typically are found in dense, coniferous forest habitats where moisture or temperature gradients (cool, moist sites) meet the needs of this species. Optimum breeding season habitat has been described as containing more than 70% canopy closure where more than 60% of the canopy cover is provided by a fir type species; moderate canopy closure values ranging from 49-54% were also considered important to the reproductive needs of this species (USDA 1994). In some parts of its North American range the Golden-crowned Kinglet is not necessarily a forest-interior species, and may even nest on the edge of clearings or near houses. b. Average Top Canopy Height See "Height of Nest Plant", above. c. Dominant Plant Species in Canopy Grinnell and Miller (1944) stated that on the coast, Douglas fir and redwood (Sequoia sempervirens) meet the life requisites of the Golden-crowned Kinglet, while in the interior, these needs are met by red, white, and Douglas fir associations; they were observed less commonly in pines, broad-leaved trees, and willows (Salix). Small (1994) stated that this species tends to avoid pine habitats except when wintering in the lowlands. d. Dominant Shrub Species In Minnesota, where the breeding habitat of this species has been best studied, Bebb's willow (Salix bebbiana), bog birch (Betula pumila), red osier dogwood (Cornus stolonifera), and speckled alder (Alnus rugosa) were the more common vegetative species in the under story. Other species present as part of the ground cover included blueberry (Vaccinium angustifolium and V. myrtilloides), arrowwood (Viburnum rafinesquianum), serviceberry (Amelanchier humilus), spreading dogbane (Apocynum androseamifolium), common bracken fern (Pteridium aquilinum), honeysuckle (Lonicera canadensis), and wild sarsparilla (Aralia nudicaulis) (Ingold and Galati 1997). e. Slope In the lower elevations of the Sierra Nevada, Golden-crowned Kinglets were reported as being restricted to dense habitats on cool, north facing slopes (USDA 1994). f. Tree DBH Optimum breeding season habitat has been described as containing trees greater than 13 in. dbh. Medium to large mixed conifer, Douglas fir, redwood, red fir (Abies magnifica), and sub-alpine conifer trees with moderate to dense canopy closure are rated as being of high importance to the reproductive needs of this species (USDA 1994). g. Distance to Water Golden-crowned Kinglets drink at seeps, springs, and streams; and may secure water from snow or frost when other water sources are frozen (Ingold and Galati 1997). Specific information on preferences for proximity to water are not reported; however, this species inhabits environments (cool, dense forests) where moisture is often readily available. 3. LANDSCAPE FACTORS

a. Elevation

Grinnell and Miller (1944) reported that the Golden-crowned Kinglet bred at elevations as low as 200 feet to as high as 9000 feet. Ingold and Galati (1997) reported breeding elevations as high as 11,328 feet in western North America. b. Fragmentation and Patch Size Information on minimum forested patch size needed for this species is not available. However, this species is adversely affected by logging, and because it prefers dense forests where canopy closures are greater than 40%, any activities which may further fragment or open up the habitat could reasonably have a negative effect on this species (Ingold and Galati 1997; USDA 1994). c. Disturbance (Natural or Managed) The population of Golden-crowned Kinglets did not increase following a spruce budworm outbreak in New Brunswick, Canada (Ingold and Galati 1997). See also SENSITIVITY TO HUMAN-INDUCED DISTURBANCE, below. d. Adjacent Land Use See SENSITIVITY TO HUMAN-INDUCED DISTURBANCE, below. e. Climate Abundance of the Golden-crowned Kinglet is positively correlated with the following variables: winter precipitation, annual precipitation, and minimum temperature. The species can be adversely affected by cold and snow during the winter months; the highest densities at this time of year coincide with areas where temperatures never fall below freezing (Ingold and Galati 1997). 4. SPECIAL FACTORS

a. Brood Parasitism

The Golden-crowned Kinglet may uncommonly serve as host to the Brown-headed Cowbird, and several records of parasitized nests have been described from British Columbia (Ingold and Galati 1997). b. Dietary See FORAGING STRATEGY, above. 5. SENSITIVITY TO HUMAN-INDUCED DISTURBANCE The Golden-crowned Kinglet is quite tame and generally fearless of humans, and will allow close approach (Bent 1939; USDA 1994). As an insect-gleaning species, the Golden-crowned Kinglet may be affected by forest management activities that change tree species diversity (and therefore may impact the prey base). The abundance of Golden-crowned Kinglets has been strongly correlated with the presence of timber stands greater than 150 years in age. For these reasons, it has been surmised that forest management practices (especially clear cuts) that decrease the crown cover of conifers, would adversely affect this species (USDA 1994). 6. PREDATORS Jays (Perisoreus canadensis and Cyanocitta cristata) and red squirrels (Tamiasciurus hudsonicus) are suspected of taking eggs and nestlings from the nest; Golden-crowned Kinglets have also been taken as prey by Sharp-shinned Hawks (Accipiter striatus), Eastern Screech-Owl (Otus asio), and bobcat (Lynx rufus) (Ingold and Galati 1997). 7. POPULATION TREND The national population of Golden-crowned Kinglets, as reported by the U.S. Fish and Wildlife Service's Breeding Bird Survey data (1966-1999), is decreasing at a rate of -0.4% per year (P value of 0.63); in California, Golden-crowned Kinglets are decreasing at a rate of -2.27% per year (P value of 0.18) (Sauer et al. 1999). 8. DEMOGRAPHICS Individuals of this species may live for up to five years. Historical populations of Golden-crowned Kinglets in northwest California were estimated at 4.98 million individuals, whereas population numbers in the mid-1980's were thought to be 45% below those levels (Ingold and Galati 1997). 9. MANAGEMENT ISSUES AND HABITAT/POPULATION OBJECTIVES Basic management objectives for the Golden-crowned Kinglet should be designed to maintain or encourage the development of the habitat that this species prefers. In general, the Golden-crowned Kinglet prefers densely forested stands, and this type of habitat can be especially important to the species in the winter. In contrast, managed forested stands that have been thinned do not appear to provide as great a value to Golden-crowned Kinglets. Golden-crowned Kinglets typically do not favor pure stands of pine or managed forested landscapes where pine trees are being selected for and other species (such as white fir) are being selected against (S. Laymon, pers. comm.). For these reasons, the following management recommendations are provided:

a. Increase tree-species diversity to ensure that an adequate prey base (during the breeding season) is maintained.

b. Manage for habitat that maintains forested landscapes of spruce and/or subalpine fir that are 150 or more years of age. The average canopy cover in such stands should be 70% or greater. However, it should be noted that in some parts of its North American range, the Golden-crowned Kinglet is not necessarily a forest-interior species. In these instances, moderate canopy cover amounts (e.g., 49-69%) may meet the needs of this species. However, land managers are cautioned not to apply this standard over excessively broad areas.

The primary focus of this species account has been on the breeding life stage of the Golden-crowned Kinglet. During migration and in winter, this species is known to inhabit a wider diversity of habitats, including deciduous woodlands and park-like habitats. Because the birds’ wintering range in California encompasses a broader land base than its breeding grounds, it is assumed that the birds have more discretion over where (and in what types of habitat) they choose to spend the winter. Therefore, it seems most practical to concentrate the above management recommendations within appropriate coniferous breeding habitats of the Golden-crowned Kinglet. 10. ASSOCIATED BIRD SPECIES In terms of foraging, shows a high niche overlap with the Black-capped Chickadee (Poecile atricapillus) Chestnut-backed Chickadee (Poecile rufescens), and Ruby-crowned Kinglet (Regulus calendula). Interspecific territorial behavior (where the Golden-crowned Kinglet is aggressive to other species) has been reported for the following species: Blackburnian Warbler (Dendroica fusca), Black-throated Green Warbler (Dendroica virens), Chipping Sparrow (Spizella passerina), Black-capped Chickadee, Boreal Chickadee (Poecile hudsonicus), Pine Siskin (Carduelis pinus), and Red-breasted Nuthatch (Sitta canadensis) (Ingold and Galati 1997). In the winter, kinglets join mixed-species foraging flocks, where it may represent between 33% and 90% of the total birds in such flocks (ibid.). SCIENTIFIC REFERENCES

American Ornithologists' Union. 1998. Check-list of North American Birds. 7th edition. American Ornithologists' Union. Washington, D.C. 829 pp.

Bent, A. C. 1939. REGULUS SATRAPA. Golden-Crowned Kinglet. Pages 382-399 in A. C. Bent. Life histories of North American thrushes, kinglets, and their allies. U.S. National Museum Bulletin, No. 196.

Clements, J. F. 2000. Birds of the world: a checklist. Ibis Publishing Company. Vista, CA. 867 pp.

Ehrlich, P.R., D.S. Dobkin, and D. Wheye. 1988. The Birder's Handbook. Simon and Schuster, Inc. New York. 785 pp.

Grinnell, J. and A.H. Miller. 1944. The distribution of birds of California. Pacific Coast Avifauna Number 27, 608 pp.

Ingold, J. L., and R. Galati. 1997. Golden-crowned Kinglet (Regulus satrapa). In The Birds of North America, No. 301 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and the American Ornithologists' Union, Washington, D.C.

Sauer, J.R., J.E. Hines, I. Thomas, J. Fallon, and G. Gough. 1999. The North American Breeding Bird Survey, Results and Analysis 1966-1998. Version 98.1, USGS Patuxent Wildlife Research Center, Laurel, MD.

Small, A. 1994. California birds: their status and distribution. Ibis Publishing Company, Vista, CA. 342 pp.

Terres, J.K., ed. 1980. The Audubon Society Encyclopedia of North American Birds. Alfred A. Knopf, Inc. New York. 1109 pp.

USDA 1994. Neotropical Migratory Bird Reference Book. Volume 1. U.S. Dept. of Agriculture, U.S. Forest Service. Pacific Southwest Region. 832 pages.

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