Hummingbirds — Family Trochilidae
a Mexican species, the Broad-billed Hummingbird breeds no closer to California than southeastern Arizona. Yet it has crossed
as a vagrant to California over 75 times, yielding
16 more or less well-supported records for San Diego County, all in fall and winter.
Migration: Eight of San Diego County’s Broad-billed Hummingbirds
have occurred in fall between 9 September and 9 November. Of these,
one was at Point Loma 22 October 2001 (R.
E. Webster, Garrett and Wilson 2003), seven were in the Tijuana
River valley (two on 9 November 1963, single birds 14 October 1962, 20–23
September 1977, 8–9 October 1981, 9–11 September 1983, and 5–8 October
Evidence for all but those in 1963 has been submitted
to and accepted by the California Bird Records Committee. The committee
rejected a spring report published in American Birds (Patten et
Winter: The county’s
nine winter records of the Broad-billed Hummingbird, from 10 November
to mid March, are more widely scattered. Seven are from the coastal
lowland, from San Diego mid November 1961–mid March 1962 (Dunn 1988),
from Spring Valley (R12) 8–10 March 1979 (M. Thornburgh, AB 33:314, 1979),
from Balboa Park (R9) 28 November 1979–29 February 1980 and returning
in at least four of the five subsequent winters (Bevier 1990), from Rancho
Santa Fe (L8) 18 December 1982–15 January 1983 (L. R. Santaella,
AB 27:339, 1983), from Coronado (S9) 11 January–28 February 1986
(R. E. Webster, Bevier 1990), from San Elijo Lagoon 5–10 January 1998
(M. B. Stowe, R. T. Patton, Erickson and Hamilton 2001) and from Upper
Otay Lake (U13) 12 December 1999–10 March 2000 (G. Morse, D. Griffin,
McKee and Erickson 2002). Two records are from Agua Caliente Springs
(M26) in the Anza–Borrego Desert, 16 January–10
(G. McCaskie, Luther 1980) and 15–21
March 1982 (D. Dewey, AB 36:894, 1982).
Taxonomy: No specimen is preserved
from San Diego County (or anywhere in California), but the birds at Balboa Park and Upper Otay Lake were photographed.
Presumably the subspecies reaching us is C. l. magicus (Mulsant
and Verreaux, 1872).
exquisite Xantus’ Hummingbird is endemic to Baja California, resident from Cabo San
Lucas north to the Sierra San Francisco, still over 350 miles south of
the international border. Nevertheless, there are three records
of vagrants farther north, one from British Columbia (Toochin 1998), one of
a female that, despite the lack of a male, built a nest in Ventura County (Hainebach 1992), and one
rather shaky report of a male from the Anza–Borrego Desert.
Winter: Richard Klauke of Alberta reported a male at Yaqui
Well (I24) 27 December 1986. Although the record
has been accepted by the California Bird Records Committee (Pyle and McCaskie
1992, McKee and Erickson 2002), the bird was seen by only a single observer
who did not take notes at the time of the observation.
breeding range of the Violet-crowned Hummingbird barely extends across
the Mexican border into extreme southeastern Arizona, and the species is one
of the rarest vagrants to California, with only five records
through 2002. One of these is for San Diego County, of a bird that remained
for an entire month, to be seen and enjoyed by over 500 spectators.
Violet-crowned’s combination of features is not shared with any other
hummingbird recorded north of the Mexican border: black-tipped red bill,
bronze-green upperparts, and entirely whitish underparts. The violet
of the crown may be subdued and inconspicuous, not contrasting strongly
with the back.
Migration: The single record of the
Violet-crowned Hummingbird in San Diego County is of one that stayed around
the home of Frank and Betty Scheible in Carlsbad east of La Costa (J9) from
3 November to 3 December 1996 (C. Mann, A. Klovstad;
McCaskie and San Miguel 1999). Abundant flowers of the Cape honeysuckle sustained the
bird. The Scheibles graciously opened their home to the crowds of
eager birders from throughout California who arrived to see this
Taxonomy: Though there are no specimens
of the Violet-crowned Hummingbird from California, photographs strongly suggest
the greenish-tailed northern subspecies A. v. ellioti (Berlepsch,
Magnificent or Rivoli’s Hummingbird
large hummingbird breeds in high mountains north to central Arizona and is partially migratory.
But until 2003 the only reports from California were inadequate for giving
the species a place on the state bird list. Then, within months
of each other, two appeared, both well photographed: the second in Eureka, the first in San Diego.
Migration: California’s first well-documented
Magnificent Hummingbird was an immature male at Kate Sessions Park (Q8)
11 October 2–29 November 2003 (N. Shrout).
Costa’s and Anna’s Hummingbirds, the Black-chinned has a rather conventional
biology, occurring in San Diego County as a fairly common migrant and
summer resident, in the latter role mainly in riparian and oak woodland.
Like other hummingbirds the Black-chinned feeds on nectar, but its special
relationship to a plant is not for food but for nesting material.
Fuzz from the leaves of the western sycamore is typically the basis of
the Black-chinned Hummingbird’s nest, and the abundance of the hummingbird
seems to parallel that of the sycamore.
The Black-chinned Hummingbird is fairly widespread over San Diego County’s coastal slope but strongly
concentrated in the county’s northwest corner. In this region it
can be quite common, with daily counts as high as 33 along the Santa Margarita
River north of Fallbrook (C8) 24 May 2001 (K. L. Weaver). Weaver’s
breeding-bird censuses of an 11.7-hectare plot of riparian woodland in
this area revealed four to nine females each year from 1989 to 1994 (average
0.5 per hectare). In coast live oak woodland the density is even
higher; a census of this habitat in the Santa Margarita Ecological Reserve
(C9) in 1989 yielded 1.8 per hectare (Weaver 1990). Farther south
and east the species becomes more localized to the larger riparian strips
in the coastal lowland and groves of oak woodland in the foothills.
Few Black-chinned Hummingbirds occur above 3500 feet elevation, and the
species is largely if not completely absent as a breeding bird from the
Campo Plateau east of Pine Valley and Campo. Yet it
breeds rarely even as high as 5500 feet on the north slope of Hot Springs
Mountain (active nest 19 June 1999, K. L. Weaver, C. R. Mahrdt).
The apparent breeding range barely spills over onto the desert slope at
San Ignacio at the head of the middle fork of Borrego Palm Canyon (one
on 18 June 1999, K. L. Weaver, C. R. Mahrdt) and in upper San Felipe Valley
(two at the south base of Cerro de la Hechicera, H20, 23 May 1999, A.
P. and T. E. Keenan; one near Paroli Spring, I21, 26 April 1999, J. O.
Nesting: To build their nests, female
Black-chinned Hummingbirds gather plant down and mat it together with
spider webs. The fuzz from the blades and petioles of sycamore leaves
are the dominant material in San Diego County, giving the nest the golden-buff
color of that fuzz. The amount of lichen and other flaky material
used to decorate the nest is variable but is often little or none, making
the nest look like a smooth orange sponge. But the birds use the
fluff from willow and cottonwood trees as well, sometimes to the exclusion
of sycamore fuzz, so we noted some grayish-white nests too. Not
surprisingly, we noted many nests in sycamore trees but even more in coast
Our observations from 1997 to 2001 corresponded to egg laying from late
April to the beginning of July, the same interval documented by 96 egg
sets collected in San Diego County from 1895 to 1942.
Migration: The Black-chinned Hummingbird’s
spring migration takes place largely in April. From 1997 to 2001,
the earliest date reported ranged from 15 March (2001, two at Whelan Lake, J. Smith) to 2 April.
The Black-chinned Hummingbird is a rare migrant through the Anza–Borrego
Desert, recorded as late as 12 May (1997, three at Agua Caliente Springs,
M26, E. C. Hall) and 21 May (1995, one at Lower Willows, D23, L. Clark,
C. Sankpill). At the latter location, a riparian oasis, the species
could nest irregularly.
Fall migration begins by 11 July with reports from nonbreeding localities
on that date from Bucksnort Mountain (C20) in 1999 (P. Flanagan) and Cuyamaca
Rancho State Park (N20) in 1998 (B. Siegel). Fall migration peaks
in late August and early September. Adult males depart in August,
weeks before the last females or immatures are seen (and heard) in early
October. The latest recorded dates are 10
October (1981, Tijuana River valley,
E. Copper, AB 36:218, 1982) and 12 October (1980, one at Point Loma, AB 35:227, 1981).
Winter: The Black-chinned Hummingbird
is casual in California in winter, not yet confirmed
with a specimen. Most reports are likely misidentifications.
The best-supported records are of birds, none adult males, identified
by call by observers aware of the species’ rarity at this season.
In San Diego County such records are of one at La Jolla 13 January 1990 (J. O'Brien, AB 44:330, 1990), two
at Point Loma 28 December 1986 (J. Oldenettel, AB 41:330, 1987), and six
in Balboa Park, although four of these are likely of a single individual
that returned annually to the same canyon from 1979 to 1982 (AB 27:339,
1983). All wintering birds were in ornamental trees including flowering
Conservation: In contrast to Anna’s and
Costa’s, the Black-chinned Hummingbird has undergone no obvious changes
in its distribution or abundance in San Diego County. Breeding birds have
moved into developed areas built over former sage scrub on only a small
scale, where sycamores or cottonwoods have been used in landscaping, as
in Greenwood Cemetery, San Diego (S10) or Hilltop Park, Chula Vista (U11).
Where native trees have been retained amid low-intensity
development, the Black-chinned Hummingbird remains, though it may be outcompeted
by Anna’s Hummingbird around feeders, as is Costa’s (Stiles 1973).
birds have taken to man-made surroundings more thoroughly than Anna’s
Hummingbird. In its range, Anna’s is by far the most abundant hummingbird
in gardens and at feeders while still remaining common in native sage
scrub, chaparral, and riparian and oak woodland. Where feeders and
ornamental plants fuel it year round, Anna’s Hummingbird is a permanent
resident; in natural habitats, many birds depart for the fall. During
winter they return, and some begin nesting as early as December.
Anna’s Hummingbird nests earlier than any other San Diego County bird.
Hummingbirds breed widely over San Diego County, lacking only in the more
sparsely vegetated parts of the Anza–Borrego Desert. But they are most
abundant in the coastal lowland and lower foothills. High counts
come from both heavily urbanized areas (41 in Pacific Beach, Q7, 1
J. C. Worley) and native habitats (40 in Boden Canyon, I14, 24
R. L. Barber). It is likely that many of the Anna’s Hummingbirds
seen in the mountains in summer are postbreeding dispersers from lower
elevations. Nevertheless, some do nest in montane forest, as illustrated
by a female building a nest about 4200 feet elevation at Heise County
Park (K20) 19 May 1998 (E. C. Hall) and by fledglings at about 4500 feet
elevation in Lower Doane Valley (D14) 12 July 1998 (J. O. Zimmer) and
about 4000 feet on Volcan Mountain (J20) 24 June 2001 (A. P. and T. E.
In the Anza–Borrego Desert Anna’s Hummingbird is locally common in developed
areas, with up to 17 in the north Borrego Valley (E24) 12
(P. D. Ache). We confirmed the species’ nesting in all desert atlas
squares with substantial agricultural or residential development, as well
as in many canyons draining the desert slope of the mountains. In
other parts of the desert Anna’s Hummingbird is rare and much outnumbered
by Costa’s. Nevertheless, occasional birds nest in the desert far
from oases: we found nests with nestlings in Smoke Tree Wash (E28) 25
(P. D. Jorgensen), in upper Pinyon Canyon (K26) 9
and in Smuggler Canyon (L25) 15 February 1999 (R. Thériault).
Nesting: Anna’s Hummingbirds build
their nests mainly of plant fluff bound together with spider web.
The action of the female in collecting spider webs, grabbing a strand,
backing up by about a foot, moving in to grab another strand, and repeating
the cycle several times, is so characteristic that it proved an easy way
to find nests. The nest is typically decorated or camouflaged with
flakes of lichen and dead leaves, sometimes of paint (Maender et al. 1996).
The sites in which the birds build are so diverse that a pattern is difficult
to discern. They make little effort to conceal the nest, usually
protecting it only by placing it on slender twigs that terrestrial predators
trees are in a female’s territory, she appears to prefer them over shrubs
as nest sites, but in treeless habitats the birds nest in many other plants,
including small shrubs. Eleven of 12 nests found by M. A. Patten
and colleagues in sage scrub around San Diego in 2001 and 2002 were in
laurel sumac. In urban areas man-made artifacts are common nest
sites. Perhaps the most extreme site described by atlas observers
was a nest with nestlings in full sun atop a chain-link fence (M. and
Our observations from 1997 to 2001 show that mid February to early June
is the season when most Anna’s Hummingbirds nest in San Diego County.
Nevertheless, a minority of the birds in the coastal lowland start earlier,
some as early as the third week of December. Our earliest observation
of nest building was at Guajome Lake (G7) 18 December
(P. A. Ginsburg), and a nest with nestlings at Del Mar (M7) 5
(L. Ellis) implies egg laying no later than 20
December. A nest with one egg and one recently hatched chick at
Old Mission Dam (P11) 31 December 1974 (J. L. Dunn) must have been started
about 15 December, and a recent fledgling being fed by its mother in the
Tijuana River valley (V11) 13 December 1998 (G. McCaskie) must have come
from an egg laid about 7 November. Our observations of eggs, nestlings,
and fledglings suggest that egg laying ends rather abruptly in late June,
yet on six occasions we noted nest building from 30 June to 1 August;
perhaps these late attempts are aborted.
Migration: Our field schedule for
this atlas, with an off season from August to November, was not well situated
to detect seasonal changes in Anna’s Hummingbird’s distribution or abundance.
The species is scarce in natural habitats during the fall dry season,
and migration between California and Arizona is confirmed on the basis
of one band recovery (Russell 1996). Yet there are records from
late summer through fall from oases and irrigated areas in the Anza–Borrego
Desert, up to 10 at the Roadrunner Club, Borrego Springs (F24), 10 October
1992 (A. G. Morley). In San Diego County’s mountains Anna’s Hummingbird
increases noticeably from December to January (see under Winter). In urban areas the species is common year round,
though individuals may move.
Winter: From December through February
Anna’s Hummingbird is about as widespread in San Diego County as in spring and summer
but even more concentrated in the coastal lowland. We found it somewhat
more widespread in the Anza–Borrego Desert in winter but sparse or
lacking at the higher elevations. In 28 squares encompassing the
county’s higher mountain ranges, we noted Anna’s Hummingbird only seven
times in December (maximum two individuals per day) versus 27 times in
January (maximum 12 per day on 31 January) and 32 times in February (maximum
25 per day). Three Anna’s Hummingbirds had returned to the summit
of the county’s highest peak, Hot Springs Mountain, by 13
when there was still much snow and no plants in bloom (K. L. Weaver).
Conservation: The proliferation of exotic
nectar-bearing plants like eucalyptus, tree tobacco, and Cape honeysuckle, not to mention
thousands of hummingbird feeders, has allowed the population of Anna’s
Hummingbird to increase enormously and extend its range (Zimmerman 1973).
Sharp (1907) and Dixon (1912) considered the Black-chinned and Costa’s
Hummingbirds more numerous than Anna’s at Escondido; now Anna’s surpasses
them not only in man-made habitats but in many natural ones as well.
The increase continued into the 21st century. The San
Diego Christmas bird count, for example, averaged 324 Anna’s Hummingbirds
from 1966 through 1975 but 875 from 1997 through 2001, though the number
of party-hours per count was 222–223 for both intervals. All other
counts in the county also show increases, except for Lake Henshaw, where there is great annual
variability. Bolger et al. (1997) found Anna’s Hummingbird to be
more common along the interface between urban development and native scrub
in metropolitan San Diego than in native habitat
away from development.
birds’ lifestyle is to find a territory that can support them reliably
and defend that territory as long as they can. Other species—like
Costa’s Hummingbird—find abundant but ephemeral resources, exploit them
while they last, then move on. Where flowers bloom in abundance,
Costa’s Hummingbirds gather in numbers, then
disappear as the flush fades. The birds capitalize on the desert’s
bloom in late winter and spring, that of sage scrub and chaparral in spring
and summer, especially where wildflowers proliferate following a fire.
Costa’s Hummingbirds breed over most of San Diego County though not at the same
time in all regions. They occur throughout the Anza–Borrego Desert, where they are common
in spring (up to 50 near Whitaker Horse Camp, D23, 12
P. Unitt). Their abundance varies with rainfall and the abundance
of flowers that follows. Our count per hour in eastern San Diego County varied from 0.96 in the
wet 1998 to 0.38 in the dry 2000. In the desert, alluvial slopes,
with their rich flora, offer the best habitat to Costa’s Hummingbird,
while valley floors dominated by halophytes offer little. As a food
source the chuparosa, with its longer flowering season, is the most important
shrub to Costa’s Hummingbird in the Anza–Borrego Desert (Stiles 1973). Ocotillo,
desert lavender, desert thorn, and desert “willow” are also important,
and the birds feed on many other plants as well.
On the coastal slope Costa’s Hummingbird is also widespread, more abundant
in the inland valleys and foothills than in the higher mountains or along
the coast (up to 60 near Tule Springs, N18, 2 July 2001, J. R. Barth,
E. C. Hall, A. P. and T. E. Keenan). In mature sage scrub and chaparral
Costa’s Hummingbird is fairly common, especially where white sage and
Cleveland sage are common.
Cox (1981) suggested that Cleveland sage is specialized for
pollination by Costa’s Hummingbird.
A study comparing recently burned and mature chaparral near Pine Valley
revealed that Costa’s Hummingbirds move into recovering burned chaparral
in large numbers when the habitat is still dominated by herbs and subshrubs,
especially woolly bluecurls, vinegar weed, showy penstemon, sticky nama,
and the slope semaphore or wide-throated yellow monkeyflower. Following
heavy rain in the winter of 1992–93, these plants bloomed so profusely
on recently burned slopes that the hillsides they covered looked purple
from distances over a half a mile. Costa’s Hummingbird was the most
abundant bird in these areas, yet in the following years, as chaparral
shrubs recovered, the fire-following plants dwindled and the number of
Costa’s Hummingbirds fell in tandem. In spite of the brevity
of this irruption, the influx sufficed to make Costa’s Hummingbird the
sixth most common bird in the recently burned areas according to point
counts from 1993 to 1997 (Cleveland National Forest data).
Costa’s Hummingbirds build a typical tiny hummingbird nest, well decorated
with flaky material, making no effort to conceal it. Even on the
floor of the Anza–Borrego Desert nests are often placed
in full sun. The diversity of nest sites atlas observers described
is too great to list, but in chaparral the birds often use the dead flowering
stalks of Yucca whipplei. After they have burst open and
dried, the yucca’s fruits make an ideal tripod for supporting the nest.
We also found, however, numerous nests in trees, including coast live
and Engelmann oaks, cottonwood, and sycamore, habitats where the Black-chinned
and Anna’s Hummingbirds occur alongside Costa’s.
Costa’s Hummingbird’s breeding seasons in the desert and chaparral differ
yet overlap. In the Anza–Borrego Desert the species lays primarily
from February through April. Even earlier nesting is possible, perhaps
when the birds are stimulated by early rains, as attested by a nest with
eggs at Truckhaven Rocks (F28) 9 November 1986 (P. D. Jorgensen) and a
nest with nestlings in the Borrego Valley 3 February 1962 (Bakus 1962).
Our latest desert nest, in Borrego Springs (G24), had eggs on 18
(P. D. Ache).
On the coastal slope, Costa’s Hummingbirds lay mainly from mid April to
mid June. The activity we observed in this area from 1997 to 2001
agrees closely with the interval of 13 April–13 June attested by 26 egg
sets collected from 1895 to 1952, except for two exceptionally early records:
an occupied nest in Spring Valley (R12) 1 December 1999 (M. and D. Hastings;
not shown on chart) and a nest at the Chula Vista Nature Center (U10)
in which the eggs hatched 22–23 February 2001 (B. C. Moore).
Migration: The movements of Costa’s
Hummingbird are complex and unconventional, as outlined by Baltosser (1989).
In the Anza–Borrego Desert the species arrives in
numbers by December, remains common through May, and departs largely in
June. On the coastal slope the bulk of the population arrives in
April and remains into July. The species is seen rarely at oases
in the Anza–Borrego Desert through the fall.
Its status in native habitats on the coastal slope at that season is still
unclear, but the birds are seen in urban gardens in fall, perhaps more
often at other times of the year.
Winter: Because most Costa’s Hummingbirds
return to the Anza–Borrego Desert before 1 December, the
distribution we recorded there during winter was similar to that in spring.
The main exception was at the higher elevations of the Santa Rosa and Vallecito mountains,
where the species was lacking before March. The Anza–Borrego Christmas
bird count commonly yields the highest return of Costa’s Hummingbird of
any such count in the United States, up to 157 on 19
During the atlas period the species’ numbers in desert in winter varied
with rainfall in the same way as in the breeding season; the birds responded
immediately by arriving in larger numbers in the wet winter of 1997–98.
On the coastal slope, wintering Costa’s Hummingbirds are uncommon and
local, rarely occurring above an elevation of 1500 feet. Many of
the birds wintering in the coastal lowland are in flowering ornamental
vegetation, but some frequent sites of native semidesert scrub.
Most records from sites at higher elevations, such as Dameron Valley (C16;
one on 12 December 1998, K. L. Weaver) and Pamo Valley (I15; up to three
on 30 December 2000, M. Dudley), are from such habitat, shared with occasional
visitors of other species more typical of desert like Scott’s Oriole and
Brewer’s Sparrow. Following the call of two Costa’s Hummingbirds
at the south base of Spangler Peak (L15) 17
led me to a patch of chuparosa, scarce on the coastal slope. The
garden in the San Diego Wild Animal Park featuring the plants of
Baja California is the most consistent
site for Costa’s Hummingbird on the Escondido Christmas bird count.
Conservation: Any long-term trends in
Costa’s Hummingbird numbers are difficult to discern because of the species’
inherent irregularity. Like other hummingbirds, Costa’s readily
exploits feeders and ornamental plants. The tree tobacco,
an exotic plant that proliferates in disturbed open areas, has become
an important food source for Costa’s and other hummingbirds and has even
allowed Costa’s to extend its range (Baltosser 1989). All the early
writers found Costa’s Hummingbird on San Diego County’s coastal slope only in
spring and summer. On the San Diego Christmas bird count, it was
first noted in 1956; since 1980 the count has yielded an average of 20.
Urban areas may be a refuge for the species in fall, allowing some to
dispense with the need to migrate south or east to regions of summer rain.
Nevertheless, urbanization is not an unmitigated boon to Costa’s Hummingbird.
Anna’s Hummingbird appears far better adapted to the relatively static
environment of urban gardens. Anna’s has increased greatly, and
that larger species dominates and displaces Costa’s at food sources (Stiles
1973). On the basis of surveys from 11 April to 1
Bolger et al. (1997) reported Costa’s Hummingbird to be sensitive to habitat
fragmentation around metropolitan San Diego. This finding may
be due at least in part, however, to a natural preference for sunnier
climate; atlas results show the species tends to avoid the coastal strip,
commonly blanketed with low clouds in late spring and early summer.
The points in fragmented habitat surveyed by Bolger et al. tended to be
closer to the coast than those in unfragmented habitat.
North America’s smallest
bird breeds in western coniferous forests and winters in central Mexico. At the latitude of
San Diego County, its usual nesting habitat
lies at an elevation higher than the tops the
county’s highest mountains. Thus it occurs in San Diego County mainly as a rare spring
migrant. A few birds have occurred in summer on Palomar and Hot Springs mountains and even engaged
in courtship displays, but the species’ nesting in the county has not
yet been confirmed.
Migration: The Calliope Hummingbird
is seen in San Diego County mainly in April, occasionally
as early as the last week of March. Exceptionally early records
are of one in Presidio Park (R8) 5 March 1976 (AB 30:892, 1976) and one
that struck a window in downtown San Diego (S9) 18 February 2000 (L. van Epps, NAB 54:221, 2000, SDNHM 50375).
During the atlas period our latest was one at Point Loma (S7) 16 May 2001
(G. C. Hazard); in previous years the species was reported as late as
24 May (1982, one in the Tijuana River valley, T. Meixner,
AB 36: 894, 1982) and 25 May (1985, one at Point Loma, C. G. Edwards).
Numbers of Calliope Hummingbirds passing through San Diego County vary somewhat from year
to year. Usually the species is rare and seen singly, but Point
Loma has been the site of concentrations as large as 15 on 30 April 1989 (J.
Oldenettel, AB 43:537, 1989). In the exceptionally dry spring of
2002 Calliope Hummingbirds, like some other migrants, concentrated in
irrigated ornamental plantings in San Diego and were reported continuously
from 9 March to 20 May with up to 12 per day (R. E. Webster, NAB 56:357,
2002). The species is encountered most frequently along the coast,
especially at Point Loma, but occurrences are scattered over the coastal
slope. In the Anza–Borrego Desert the only records are of one along
Coyote Creek 26 March 1979 (B. Cord),
one in nearby Box Canyon (C23) 19 April 2000 (M. B. Mulrooney), one at
the Borrego sewage ponds (H25) 20 April 2002 (G. C. Hazard), two at Yaqui
Well (I24) 26 April 1984 (A. Baker), and two at nearby Tamarisk Grove
18 April 2002 (R. Thériault).
The only fall record is of a single bird in the Tijuana River valley 26
September 1981 (E. Copper). The Calliope Hummingbird migrates in a loop
heading north along the Pacific coast, south along the Rocky Mountains (Phillips 1975), so the
species is not expected in San Diego County in fall. The route
by which the bulk of the population crosses from mainland Mexico to the Pacific coast of
the United States is not well known but probably
largely north of San Diego County.
Before we initiated field work for this atlas, the only summer records
of the Calliope Hummingbird in San Diego County were of a male displaying
to a female on Hot Springs Mountain (E21) 24
(Unitt 1981) and a male near the Palomar Observatory (D15) throughout July 1983 (R. Higson, AB 37:1028, 1983).
Thus the number of possibly breeding Calliope Hummingbirds we noted from
1997 to 2001 was a surprise. On Hot Springs Mountain (E21), at 5040
feet elevation near San Ignacio, K. L. Weaver and C. R. Mahrdt noted one
18 May 2001. Near the north
base of the mountain, at 4850 feet elevation 3.1 miles north-northwest
of the summit (D20), J. M. and B. Hargrove observed a male displaying
to a female 10 May 1999. Around High
Point, Palomar Mountain (D15), at patches of
scarlet bugler and scarlet larkspur, Weaver noted one 13–14 May 1999,
two males and one female 20
May 2000, and one male and two females 12 July 2000. Completely unexpected
was his discovery of a male and female in a small glade at 1900 feet elevation
in Marion Canyon on the southwest slope of Palomar Mountain (D12) 18 June
2001. Nesting of the Calliope Hummingbird may be possible even in
this area; it has been reported exceptionally from foothill oak woodland
at 420 feet elevation in Placer County (Williams
Broad-tailed is the common hummingbird of the Rocky Mountains, but San Diego County lies well outside its normal
migration route. None of the four records is supported by a photograph
or specimen, so the species’ inclusion on the county’s bird list is dubious.
Though adult males can be identified easily if the characteristic trilled
whine of their wings is heard, there is plenty of opportunity for misidentification
of this species, as with all hummingbirds.
Migration: Guy McCaskie now questions
his report of a male in the Tijuana River valley 8
September 1968 (AFN 23:109, 1969). Other published records are of a
male attracted to red balloons at a birthday party near the Palomar Observatory
(D15) 11–12 July 1978 (R. Higson, AB 33:218, 1969), a male at Point Loma
(S7) 14 September 1982 (R.
E. Webster, AB 37:224, 1983), and a female at Point Loma 10 May 1986 (R.
E. Webster, AB 40:524, 1986).
Rufous, the world’s northernmost hummingbird, commutes annually between
the Pacific Northwest and Mexico. It passes through
San Diego County in both directions, taking
advantage of the bloom of desert flowers like ocotillo in spring, of mountain
flowers like the scarlet bugler in late summer, and of exotic plants like
eucalyptus and tree tobacco at both seasons. Hummingbirds of the
genus Selasphorus also occur as rare winter visitors, though hardly
any of these are adult males. Distinguishing the Rufous and Allen’s
Hummingbirds in other plumages usually requires careful study of birds
Migration: The migrations of the Rufous
Hummingbird are early, though not quite so early as those of Allen’s Hummingbird.
Spring migration begins in February (one at Quail Botanical Gardens, K7,
1 February 1999, R. Campbell; two at La Jolla, P7, 5 February 2000, L.
and M. Polinsky), exceptionally late January (one male in Borrego Springs,
G24, 23 January 1993, A. G. Morley; one at Valley Center 27 January 1974,
AB 28:693, 1974). Migration peaks in late March and early April.
Even then the species is usually uncommon, though large concentrations
can be seen occasionally around flowering trees or shrubs. Our largest
numbers during the atlas period—up to 40 at Yaqui Flat 7 April 1998 (P.
K. Nelson)—were along the east base of the mountains, a line of concentration
for migrants crossing from the desert to the coast. Rufous Hummingbird
numbers in the desert, however, are irregular, perhaps varying with weather
conditions. The species can be seen more consistently in spring
in the coastal lowland. Most birds have continued north by the end
of April, though stragglers have been seen as late as 12 May (1976, one
male at Point Loma, S7, J. L. Dunn) and 16 May (1999, two at La Jolla, L. and M. Polinsky).
Spring specimens range in date between 1 March (1963, San Luis Rey, G6,
SDNHM 3195; 1990, El Cajon, Q13, SDNHM 46608) and
30 April (1990, Point Loma, SDNHM 46887).
Though the bulk of the population makes a loop route, returning south
along the Rocky Mountains after heading north along the Pacific coast
(Phillips 1975), many Rufous Hummingbirds also go south through southern
California. Because few of the birds at this season are adult males,
especially after early July, the ratio between the Rufous and Allen’s
is uncertain. In the SDNHM collection, there are six specimens of
fall migrant Rufous from San Diego County, five of Allen’s.
Specimen dates of the Rufous range from 19 July (1934, Balboa Park, SDNHM 16536) to October
(no exact date, 1968, Point Loma, SDNHM 37615). Sight records are
as early as 22 June (1970, one banded at Point Loma, AFN 24:717, 1970)
and 23 June (2000, one near Cutca Valley, C14, J. M. and B. Hargrove).
After peaking from July to early August, numbers of Selasphorus
hummingbirds dwindle, with the latest seen typically in early October.
Fall migrants concentrate at patches of native wildflowers in the mountains
(up to 30, including seven male Rufous, near the Palomar Observatory,
D15, 12 July 2000, K. L. Weaver) and at exotic flowering plants in the
coastal lowland (up to 65 at Quail Botanical Garden, K7, 7 July 1997,
C. C. Gorman). There are a few fall records of Selasphorus
hummingbirds in the Anza–Borrego Desert, the maximum being up to six coming
to feeders near the Borrego Palm Canyon campground (F23) 26 July–6 August
1989 (L. L. Jee).
Winter: A few Selasphorus
hummingbirds winter in San Diego County annually, in exotic flowering
vegetation, especially eucalyptus. During the atlas period the number
reported per winter varied from ten in 1998–99 to just one in 2000–01.
Most wintering Selasphorus hummingbirds are in parks, cemeteries,
and well-landscaped residential areas in the coastal lowland, with up
to three in La Jolla (P7) 3 January 1999 (L. and M. Polinsky) and
eight on the San Diego Christmas bird count 20
A few wintering birds have been adult male Rufous, and an immature male
from Carlsbad (I6) 14 January 1994 (SDNHM 48887) is a Rufous.
surprising are three winter records from the Anza–Borrego Desert. One, of a male Rufous
in Borrego Springs (F24) 19 December 1999 (M. L. Gabel), was from an ornamental
planting, but two have been from natural canyons, Glorieta Canyon (H24)
29 December 1985 (L. Grismer, M. Galvan) and Hellhole Canyon (G23) 1 January
1999 (A. G. and D. Stanton).
Conservation: The introduction of diverse
exotic flowering plants has augmented the food supply for migrating hummingbirds
and has allowed a few of the Rufous to cut short their long migration
and winter in southern California. The county’s first
winter record of any Selasphorus hummingbird was on the San Diego
Christmas bird count 2 January 1961.
only in a slender strip along the coast of California and southern Oregon, Allen’s Hummingbird has
a remarkably limited distribution. A migratory subspecies breeding
south to Ventura County passes through San Diego County on its way to and from
a winter range centered on the mountains around Mexico City. Preadapted to suburbia,
a nonmigratory subspecies resident on the Channel Islands spread to metropolitan
Los Angeles and southward through Orange County. It has now reached
San Diego County, where it was found nesting
for the first time at San Onofre in 2001.
Migration: Allen’s Hummingbird is
famous for its migrations being shifted early in the year; the earliest
arriving Allen’s Hummingbirds are the first of any land bird in both spring
and fall. “Spring” migration takes place
largely before the equinox marks the beginning of spring; “fall” migration
begins before the summer solstice and concludes by the beginning of September.
As a spring migrant Allen’s Hummingbird is uncommon in San Diego County; from 1997 to 2001 there
was no report of more than two per day. A concentration as large
as the 200 noted by G. McCaskie in the Tijuana River valley 15
has never been approached since. At this season the species occurs
mainly in the coastal lowland, rarely in the Anza–Borrego Desert (only
two reports 1997–2001), and rarely as high in the mountains as 4000 feet
elevation (one in Corte Madera Valley, R20, 21 February 1999, D. Herron).
Specimens range in date from 18 February (1940, La Jolla, P7, SDNHM 18095) to 31 March (1961, Alpine, P17,
SDNHM 30263), with one mist-netted and measured 10 April (1971, Point
Loma, S7, G. McCaskie). The early specimen date is not representative, however,
because the species begins arriving in its breeding range in late January.
Sight records for San Diego County range from 16 January (1988, near San Diego, J. Oldenettel, AB 42:322, 1988)
to 22 April (1997, one at the upper end of Sweetwater Reservoir, S13,
P. Famolaro). An unidentified Selasphorus hummingbird north
of Lake Morena (S21) 10 January 1998 (S. E. Smith) was most
likely an early Allen’s. Two reports in May could be of misidentified
Rufous Hummingbirds or pioneers of the nonmigratory subspecies.
Allen’s Hummingbird is probably more numerous in San Diego County in summer as a southbound
migrant than in late winter as it heads north. But in summer adult
males make up a smaller proportion of the population. Because only
adult males are identifiable in the field, high counts are concentrated
during the last week of June and first week of July (at least 10 in Barker
Valley, E16, 25–29 June 1997, D. Rawlins), the time when most adult males
pass through. Specimens of southbound migrants
range from 30 June (1997, Mission Hills area of San Diego, R9,
SDNHM 50045) to 1 September (1996, La Jolla, SDNHM
Sight records range from 3 June (2000, Horno Area, Camp Pendleton, R.
Breisch; 1997, probable Allen’s along upper Pine Valley Creek, O21, R.
A. Hamilton) and 4 June (1970, two banded at Point Loma, AFN 24:717, 1970)
to 10 September (1998, Point Loma, P. A. Ginsburg). At this season
Allen’s Hummingbirds are scattered over the coastal slope but there are
no reports from the Anza–Borrego Desert.
Selasphorus hummingbirds are rare winter visitors in coastal San Diego County, and some percentage of
these are Allen’s. There are at least ten sight records of apparent
adult males, all within 3 miles of the coast, from late November to early
January, such as one that remained at Del Mar (N7) from fall migration
to 26 December 1999 (B. C. Moore) and one at Point Loma 6
January 2002 (R. E. Webster, NAB 56:224, 2002). More important,
there are two specimens, from Coronado (S9) 29 November 1968 (SDNHM
37875) and La Jolla 22 December 1999 (SDNHM
50350), plus one mist-netted at Point Loma 1 January 1968 (AFN 22:479,
Allen’s Hummingbird was confirmed nesting in San Diego County for the first time in 2001,
when John and Beverly Hargrove noted three, including a displaying male
and a female gathering nest material, at San Onofre State Beach (C1) 20
In the same area, a territorial male had edged a few feet across the line
from Orange County 18 May 1998, when P. A. Ginsburg observed one defending
a clump of bottlebrush.
Further knowledge of Allen’s Hummingbird’s colonization of San Diego County should be based on actual
breeding behavior and observations in late May, during the brief window
between the departure of the last Rufous Hummingbirds and the arrival
of the first migratory Allen’s.
Nesting: Nesting in January, as
seen at San Onofre, is expected for Allen’s Hummingbird in southern California. On the Palos Verdes Peninsula, Los Angeles County, Wells and Baptista (1979)
reported females attending nests or fledglings in all months of the year
except September and October.
Conservation: On the California mainland, the Channel Islands subspecies of Allen’s Hummingbird
was discovered nesting on the Palos Verdes Peninsula in 1966 and was common
there by the following year (Wells and Baptista 1979). From there
the birds began spreading into the Los Angeles basin, reaching Orange County by 1980, when they were
first found nesting at Newport Beach and Costa Mesa. By 1997 they had
spread south along the coast to Laguna Beach, less than 15 miles northwest
of the San Diego county line (Gallagher
1997). They use ornamental vegetation as least as much as native
willow trees, so further spread south along San Diego County’s coast seems
The primitive migration route for Allen’s Hummingbird
was north at low elevations along the coast, then south at high elevations
through the mountains, a strategy geared to the availability of flowers
in each zone (Phillips 1975). With the proliferation of exotic plants
that flower over intervals different from those of native species, this
constraint is relaxed. The spread of the tree tobacco in particular
appears to be allowing southbound Allen’s Hummingbirds to migrate at low
as well as at high elevations.
Taxonomy: The two subspecies of Allen’s
Hummingbird differ in size, especially bill length. The migratory
nominate S. s. sasin (Lesson, 1829) is smaller that the nonmigratory
S. s. sedentarius Grinnell, 1929. See Stiles (1972) for a
key; identifying the bird’s age and sex is a necessary precusor to identifying
the subspecies, as it is for distinguishing the Rufous and Allen’s as
All specimens from San Diego County are sasin except
for one collected at Point Loma 25 April 1971 (SDNHM 37764). Note
that the date of this early pioneer of sedentarius falls outside
the normal migration schedule of sasin.