Tanagers — Family Thraupidae
Hepatic Tanager Piranga flava
The Hepatic Tanager enjoys a broad range, spreading from Arizona and New Mexico south to Argentina. In California, however, there are only a few breeding pairs, in the San Bernardino Mountains and the mountains of the eastern Mojave Desert. In San Diego County the species is a vagrant, with 22 reported so far, all in fall and winter.
Migration: Fourteen Hepatic Tanagers have been reported in San Diego in fall, 12 from Point Loma (S7), two from the Tijuana River valley. Dates for these are mainly in late September and October; one at Point Loma 10–18 September 1988 (J. Oldenettel, AB 43:170, 1989) was exceptionally early. One that returned three successive years to winter at Point Loma arrived as early as 4 October in 1985 (V. P. Johnson, AB 40:160, 1986). It also set the record for late departure, being seen as late as 8 April in 1985 (R. E. Webster, AB 39:351, 1985). Two early spring records are also of birds that possibly wintered locally: Point Loma 9 April 1966 (AFN 20:547, 1966) and Agua Caliente Springs (M26) 9 March 1974 (AB 28:694, 1974). A unique vagrant in late spring was at Point Loma 11 June 2002 (R. E. Webster, NAB 56:358, 2002).
Winter: Six Hepatic Tanagers are known to have wintered in San Diego County. At Poway (M11), one first seen 18 December 1960 was collected 31 December, providing California’s first record of the Hepatic Tanager and San Diego County’s only specimen (Huey 1961b). Other sites where the species has wintered are the grounds of the Rosicrucian Fellowship, Oceanside (H5; female in three consecutive winters, 1977–79; male in four consecutive winters, 1978–81), the Mission Hills area of San Diego (R8/R9; 1967–68, AFN 22:480, 1968), Point Loma (male in three consecutive winters, 1983–86), and Bonita (T11; 1987–88, G. McCaskie, AB 42:323, 1988).
Taxonomy: Piranga f. hepatica Swainson, 1827, is the subspecies of the Hepatic Tanager reaching California; it ranges from Arizona south through the Sierra Madre Occidental of Mexico.
Summer Tanager Piranga rubra
One of the more exciting events of the San Diego County Bird Atlas’ five-year term was the first discovery of the Summer Tanager nesting in the county. Though the population in the species’ core California range along the Colorado River collapsed, leading to its designation as a species of special concern by the California Department of Fish and Game, the Summer Tanager has pioneered west, colonizing new sites in the Mojave Desert and on the Kern River. The tanager’s arrival as a nesting bird in San Diego County is part of this trend. The western subspecies occurs as a rare and localized summer visitor only, in mature riparian woodland, but the eastern subspecies of the Summer Tanager occurs as a rare migrant and winter visitor every year, usually in ornamental trees near the coast.
Breeding distribution: The Summer Tanager inhabits mature riparian woodland, especially where Fremont cottonwoods form a fairly continuous canopy. The largest colony in San Diego County is along San Felipe Creek, from 1.5 miles west of Scissors Crossing to Sentenac Ciénaga (J22/J23). Here, the species was first noted 20 May 1998 (E. C. Hall) and increased to seven nesting pairs in 2001, eight in 2002, then dropped to five in 2003 (P. D. Jorgensen, J. R. Barth). Thorough surveys in the last three years were made possible when the area was added to Anza–Borrego Desert State Park. Nearby were two pairs along Banner Creek near Banner (K21) in 2001 (feeding fledglings 16 July 2001, P. D. Jorgensen) and one singing male along San Felipe Creek near Paroli Spring (I21) 9 June–21 July 2000 (J. O. Zimmer, P. D. Jorgensen). Elsewhere in the Anza–Borrego Desert, the Summer Tanager occurs in Coyote Creek Canyon at both Middle Willows (C22; singing male 28 May 1998, P. D. Jorgensen) and Lower Willows (D23; only single birds 2000–2001, but at least one pair and up to four males 13 May–9 July 2002, J. R. Barth). In Borrego Palm Canyon, near the confluence of the middle and south forks (F23), there was one individual in the summers of 1997 and 2001, a singing male and a female carrying insects 30 June–3 July 2000 (L. J. Hargrove). Along Vallecito Creek near Campbell Grade (M23), one on 11 May 2001 was on a date when the species is still migrating, but in riparian woodland similar to that where it nests elsewhere on the desert slope (R. Thériault).
Summer Tanagers colonized the Santa Margarita River north of Fallbrook (C8) in 2000. The following year there were five pairs, with at least two confirmed breeding on the basis of males carrying insects 24 July 2001 (K. L. Weaver). The only other Summer Tanager nestings known from the coastal slope of southern California are from Soledad Canyon and near San Dimas, Los Angeles County, beginning in 1995 (Los Angeles County bird atlas data). Along the Santa Margarita River the birds are associated more with tall sycamores than with cottonwoods. Along the San Luis Rey River, one Summer Tanager was near Pala (D11) 2 July 1993 (J. C. Lovio, AB 47:1151, 1993), at least one remained in Wilderness Gardens (D11/D12) 13 May–4 June 2000 (K. L. Weaver et al.), and a pair was in nearby Marion Canyon (D12), elevation 1600 feet, 18 June–17 July 2001 (K. L. Weaver). Up to three Summer Tanagers have occurred irregularly in summer along the San Diego River at Old Mission Dam (P11) since 1968 (one 8–13 August 2000, M. B. Stowe). An apparent pair of Summer Tanagers, the male singing, on Cuyamaca Peak (M20) 10–18 June 2000 (G. L. Rogers, G. Hazard) was in pine/oak woodland seemingly inappropriate for nesting. An earlier parallel record was of one at Pine Hills (K19) 22–24 June 1987 (V. P. Johnson, AB 41:1489, 1987).
Other records from April to June more likely represent late winter visitors or spring vagrants of the eastern subspecies, but some could be pioneers of the western subspecies, especially one near the confluence of Cottonwood and La Posta creeks (S22) 9 May 1998 (R. and S. L. Breisch) and one at Seventeen Palms (G29) 2 May 1997 (G. Rebstock, K. Forney). The subspecies are readily distinguished only with the bird in hand.
Nesting: Although the Summer Tanager typically builds its nest far out on the longer branches of trees, over an opening (Robinson 1996), five nests found along San Felipe Creek 2000–2002 were near the trunks or major branches of often spindly trees, cottonwood and red willow, 30–50 feet above the ground (P. D. Jorgensen, J. R. Barth). These nests were built of a dark material and so sparsely lined that light passed through them (P. D. Jorgensen).
Reflecting its name, the Summer Tanager nests in midsummer. Data from San Felipe Creek, including those from 2002 not plotted here, imply the Summer Tanager lays from early June (fledgling 29 June 2002) to early July (nest building 3 July 2002, J. R. Barth). Along the Santa Margarita River, nesting appears even later, with three observations of adults carrying insects 24 July–5 August (K. L. Weaver). The lateness there may be due to the birds taking longer to find each other in a sparse, newly colonizing population.
Migration: Data are still skimpy, but breeding Summer Tanagers evidently arrive in late April or at the beginning of May. The earliest dates are 26 April 2003 at Scissors Crossing (J. R. Barth) and 1 May 2001 at Lower Willows (D. C. Seals). In 2002, when arrival of Summer Tanagers along San Felipe Creek was watched for almost daily, the first appeared 1 May (R. Thériault). Five were still at Scissors Crossing 8 September 2000 (P. D. Jorgensen). Along the lower Colorado River, specimens have been collected as late as 24 September (SDNHM 9990, 33708, 33718).
The eastern subspecies of the Summer Tanager follows a completely different pattern. In spring, its schedule is like that of other eastern vagrants, shifted late in the season. Records extend from at least 11 May (1992, one male found dead at Coronado, S9, SDNHM 48027) to at least 18 June (1998, one near Chollas Reservoir, R11, P. Unitt). One at Solana Beach (L7) 13 July 1991 (R. T. Patton, AB 45:1162, 1991) was most likely a vagrant from the east as well. The Summer Tanager occurs annually in spring, with nine records 1997–2001.
In fall, the eastern subspecies begins showing up definitely by 19 September (1932, one at Point Loma, S7, SDNHM 16134) and presumably by 9 September (1977, four in the Tijuana River valley, L. C. Binford; 1994, one in Borrego Springs, G24, P. D. Jorgensen). It is more numerous in fall than in spring, though still to be considered rare. There is no clear break between fall and winter records, though one at Yaqui Well (I24) 22 November 1962 (AFN 17:71, 1963) was still migrating. Winter visitors may remain into early April (one at Bonsall, F8, 7 April 2000, P. A. Ginsburg; one at Point Loma 7 April 2000, V. P. Johnson; one at El Cajon, Q13, 8 April 1998, K. Neal).
Winter: The Summer Tanager winters annually in San Diego County’s coastal lowland, in much the same habitat as the Western Tanager: exotic flowering and fruiting trees, mainly in urban parks. Numbers are somewhat smaller than those of the Western Tanager, but 22 wintering individuals were reported 1997–2002. Winter records extend inland as far as Bonsall (F8; one on 17 January 2000, P. A. Ginsburg), Santee (P12; up to two from 12 January to 3 February 2001, M. B. Mulrooney), and 0.9 mile east of Dictionary Hill (S13; one from 12 to 19 January 2002, R. Norgaard). The Summer Tanager was recorded on 30 of 39 San Diego Christmas bird counts 1963–2001, with a maximum of five in 1984. It is less frequent on the Oceanside and Rancho Santa Fe counts, with up to three on the latter in 1990.
Conservation: The Summer Tanager’s history in California is remarkable. In the late 19th and early 20th centuries, the species was known as a breeding bird only along the Colorado River, where it was common. In the mid to late 20th century, following the building of the dams and the nearly total elimination of the native riparian forest, the population crashed, until in 1986 only three males were known persisting on the California side (Rosenberg et al. 1991). At the same time the population along the river was in free fall, however, the Summer Tanager began colonizing riparian oases farther west (Johnson 1994). Thus forces acting at cross purposes must be controlling the population.
Even if broad-scale factors are inducing the Summer Tanager to expand its range, there must be habitat to host the pioneers. Thus maintenance and enhancement of mature riparian woodland are essential. Clearing, burning, off-road vehicles, excessive groundwater pumping, and invasion of exotic plants are all continuing threats to Summer Tanager habitat elsewhere in California. Without careful management these factors could degrade the habitat in San Diego County as well. The inclusion of most of the sites in Anza–Borrego Desert State Park and the California Department of Fish and Game’s San Felipe Valley Wildlife Area gives the Summer Tanager a head start in San Diego County.
Taxonomy: I confirmed the identity of the locally breeding population of the Summer Tanager as the western subspecies P. r. cooperi Ridgway, 1869, with the trapping, measuring, and electronic colorimetry of two males and one female at Scissors Crossing in 2002. All five specimens of migrants and winter visitors, however, are the eastern P. r. rubra (Linnaeus, 1758), which is smaller and darker in both sexes. As detailed by Rea (1972), throughout southern California nonbreeding Summer Tanagers are of the eastern subspecies prevails; only one exception is known, from Ventura County. The pattern has only been reinforced further as additional specimens have accumulated.
Scarlet Tanager Piranga olivacea
The Scarlet Tanager is a vagrant to California, as it nests only east of the Rocky Mountains and winters in South America. Nevertheless, there are about 35 records for San Diego County (nearly one third of all for California), three in spring, the remainder in fall.
Migration: The California Bird Records Committee has accepted 26 records of the Scarlet Tanager from San Diego County in fall; another nine have not been submitted or are still pending. The species thus averages about one per year, though with some irregularity. There were none 1970–76 but five in 2001. Most of the reports are from Point Loma; six are from elsewhere near the coast, inland as far as Otay Mesa (V13). Dates of accepted records range from 5 October (2000, Point Loma, G. McCaskie; McKee and Erickson 2002) to 17 November (1969, Point Loma, Bevier 1990); unsubmitted records range from 29 September (1987, Point Loma, R. E. Webster, AB 42:139, 1988) to 30 November (1997, Tecolote Canyon, Q9, K. Radamaker, FN 52:128, 1998). Howell and Pyle (1997) questioned an unseasonably early report, 24–26 August 1994 (NASFN 49:103, 1995).
The three spring records are from Point Loma 26–28 May 1979 (Binford 1983) and 29 May–2 June 1983 (L. R. Santaella; Morlan 1985) and from Coronado (S9) 7 May 1987 (E. Copper; Langham 1991).
Western Tanager Piranga ludoviciana
The Western Tanager’s splash of color marks the peak of spring migration through San Diego County. The birds also nest in the pine–oak forests of the county’s mountains, where they are generally uncommon. In fall migration the Western Tanager is less conspicuous than in spring, but adults pass through in late July and August, immatures largely in September and early October. In winter the species is rare but regular, occurring almost exclusively in urban parks. Indeed, the Western Tanager was the first species known to shift its range to take advantage of this novel habitat.
Breeding distribution: The Western Tanager’s breeding distribution
in San Diego County corresponds to the higher mountains supporting stands
of conifers and black oaks. In this habitat the birds are typically
uncommon; high counts are of 28 (10 singing males) on Middle Peak (M20)
11 June 2000 (R. E. Webster), 12 (10 singing males) near the summit of
Hot Springs Mountain (E20) 18 June 2000 (K. L. Weaver, C. R. Mahrdt),
and 11 (8 singing males) near Palomar Observatory (D15) 1 July 1999 (K.
L. Weaver). In southern San Diego County the downslope limit for
breeding Western Tanagers is around 3600 feet elevation at Pine Valley
(P21; two feeding young 7 July 1998, J. K. Wilson). In the northern
half of the county breeding tanagers extend down to 3200 feet at the northeast
base of Volcan Mountain (H20; fledglings in summer 1999, A. P. and T.
E. Keenan). Apparently a few birds summer around Mesa Grande (3200–3300
feet; H16/H17), where there are many black oaks but few conifers (e.g.,
one tanager along Mesa Grande Road, H16, 17 June 1998, C. G. Edwards).
Along the San Luis Rey River below Lake Henshaw many mountain birds extend
to unusually low elevations, but the only midsummer record of a Western
Tanager there is of a single male near the San Luis Rey Picnic Ground
(2600 feet; G16) 3 July 1999 (W. E. Haas). In the deep canyons cutting
the southwest face of Palomar Mountain, however, Western Tanagers summer
down to 2000 feet, among big-cone Douglas firs (four singing males along
Pauma Creek, E13, 7 June 2001, P. Unitt; two singing males along Agua
Tibia Creek, D12, 18 June 2001, K. L. Weaver).
Scattered Western Tanagers, evidently nonbreeding, show up rarely at odd localities through the summer (one at Fallbrook, D8, 21 June 2000, M. Freda; one near Puerta La Cruz, E18, 23 June 2000, A. P. and T. E. Keenan; one near Warner’s Ranch, G19, 24 June 2000, E. C. Hall; one at Fernbrook, M14, 24 June 2000, B. Hendricks; two at Torrey Pines State Reserve, N7, 1 July 2001, J. Lesley).
Nesting: Western Tanagers typically nest in the middle to upper levels of trees, often placing the nests atop the outer branches of conifers (Hudon 1999). With the species uncommon and its nest built in the canopy, atlas observers noted few nests. The two described were in a big-cone Douglas fir and a willow, 18 to 25 feet above the ground. Most breeding confirmations were of adults carrying insects, on dates ranging from 20 May to 19 July. These and other data suggest that in San Diego County Western Tanagers lay from early May to early July, a wider spread than the 6–27 June of five egg sets collected 1915–20.
Migration: As a migrant the Western Tanager occurs countywide. From 1997 to 2001 the spring’s first date for arriving Western Tanagers ranged from 3 to 15 April. The earliest record, of two in Boden Canyon (I14) 3 April 1999 (R. L. Barber), is exceptionally early for California. But the recurrence of early April arrivals since 1998 may foreshadow a shift in the species’ migration schedule (cf. also Patten et al. 2003); mid April arrival had long been the rule (Garrett and Dunn 1981). Still, spring migrants do not become common until late April, and their numbers vary from year to year. The birds occasionally concentrate in large numbers, with up to 100 at the University of California, San Diego (O8), 5 May 1999 (L. Myklebust) and 200 at Tecate (V19) 1 May 1999 (M. and B. McIntosh). Past years occasionally saw even larger numbers, up to 500 at Pauma Valley (E12) 16 May 1942 (E. Beemer) and 1000 at Bonita (T11) 1 May 1964 (AFN 18:488, 1964). Migrants are still frequent in small numbers in the first week of June, and stragglers occur through the second week. Latest, if not summering, were one near Rincon (F13) 12 June 1999 (E. Wallace) and one in Carlsbad (I7) 14 June 1998 (E. Garnica).
Adults begin heading south in mid July, possibly even early July (one at Scissors Crossing, J22, 3–6 July 2001, P. D. Jorgensen; two near Rincon, F13, 8 July 2000, M. B. Mosher), and have all departed by the end of August. The immatures, by contrast, begin appearing at low elevations only in late August, then continue in dwindling numbers through October. In fall, adults avoid the coast; only immatures are normally seen there.
Winter: At this season the Western Tanager is confined to the coastal lowland, to parks and residential areas well wooded with exotic trees. It is most numerous in Balboa Park (R9; three west of Highway 163 on 16 December 2000, J. K. Wilson; three on the grounds of the San Diego Zoo 15 December 2001, V. P. Johnson). Wintering birds can often be heard calling from the tops of tall eucalyptus and fig trees near the San Diego Natural History Museum. The highest winter number recorded is 21 on the San Diego Christmas bird count, 19 December 1981. Elsewhere records are scattered from San Onofre (C1; one on 11 January 1999, M. Lesinsky) to the Tijuana River valley (V11; one on 16 December 2000, G. McCaskie). The records farthest inland are from 2.5 miles east of Bonsall (F9; two on 12 December 1999, J. Evans), Kit Carson Park, Escondido (J11; two on 2 February 1999, M. B. Stowe; one on 30 December 2000 and 27–29 December 2001, K. L. Weaver), and El Cajon (Q13; one on 15 January 2001, J. R. Barth). One in Borrego Springs (F24) 1 December 1998 (M. L. Gabel) was likely a late fall migrant, though there are three winter records for the Salton Sink (Patten et al. 2003).
Conservation: No changes to San Diego County’s breeding population of the Western Tanager are known; the species has always been uncommon as a breeding bird. The species’ wintering came only with the planting of exotic trees that flower and fruit through that season. The first winter reports, from National City, were in the 1920s (Johnson 1922, 1928), and only since 1956 have wintering Western Tanagers been noted annually.