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Range
 Western
Kingbird breeds from the southern interior of British
Columbia to southern Manitoba, south throughout the western
half of the United States to northern Baja California,
southern Texas, and northwestern Mexico; occasionally east
to southern Ontario, Arkansas, and Louisiana. Winters mainly
from central coastal Mexico south to Costa Rica, with small
numbers in the states bordering the Gulf of
Mexico.
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Status
On the coast, a rare migrant
and summer visitant to the upper Fraser River delta of the
Georgia Depression Ecoprovince; uncommon spring transient
and very rare autumn transient elsewhere in the ecoprovince,
including southeastern Vancouver Island; accidental in
winter. Very rare migrant and summer visitant to the
southern Coast and Mountains Ecoprovince; very rare
transient to Western Vancouver Island; accidental in the
northern Coast and Mountains.
In the interior, a fairly
common migrant and summer visitant to the Southern Interior
Ecoprovince; uncommon to locally fairly common in the
Southern Interior Mountains Ecoprovince; uncommon in the
Central Interior Ecoprovince; rare in the southern
Sub-Boreal Interior Ecoprovince; accidental in the Boreal
Plains and Northern Boreal Mountains
ecoprovinces.
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Status
Change
 In
North America, the breeding range of the Western Kingbird,
formerly known as the Arkansas Kingbird, has expanded since
1900 (Taverner 1927; Bent 1942). Planted trees, buildings,
and networks of utility poles probably allowed its spread
across the plains (Nice 1924). The increase in abundance and
distribution in British Columbia since the mid-1940s (Munro
and Cowan 1947) is best documented in the Okanagan basin.
There the Western Kingbird found suitable habitat in the
residential and orchard areas that replaced much of the
original sagebrush and antelope-brush. It also followed
highway corridors and farm clearings into higher elevations
that were once dense forests (Cannings et al.
1987).
By the 1950s, the Western
Kingbird was slowly expanding its range eastward across
southern British Columbia (Munro 1950; Butler et al. 1986)
into the east Kootenay, where it was considered a "scarce
summer visitant" (Johnstone 1949). Over the next several
decades it expanded its range northward along clearings and
corridors into the Columbia River valley as far north as
Golden. It now occurs there regularly but locally, in
agricultural areas and around settlements.
Although some northward range
expansion has taken place into the Central Interior and
southern Sub-Boreal Interior, the species still remains an
uncommon to rare summer visitant there (Munro 1945a, 1946,
1947a; Erskine and Stein 1964; Roberts and Gebauer
1992).
On the south coast, the Western
Kingbird has increased its status over the past 25 years
from being of irregular occurrence to one that occurs
annually but in small numbers (Campbell 1969b, 1972; Weber
et al. 1990).
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Nonbreeding
 The
Western Kingbird is widely distributed across southern
British Columbia, including Vancouver Island. It is fairly
widespread in open valley bottoms in the Okanagan, Thompson,
and Kootenay regions, but is scarcer in northern portions of
the west Kootenay. It is more sparsely distributed in the
Cariboo and Chilcotin areas, reaching its usual northern
limit south of Prince George. On the coast, transients occur
infrequently along the west and east coasts of Vancouver
Island, and on the southwestern mainland from the lower
Fraser River valley along the Sunshine Coast north to Powell
River. The species now occurs regularly in the eastern lower
Fraser River valley, near Chilliwack and
Agassiz.
The Western Kingbird frequents
relatively low elevations, from near sea level to 200 m on
the coast and up to 1,300 m in the interior. In the interior
it occurs in open, hot, and dry habitats, including
grasslands, sagebrush flats, open rangelands, and farmlands
within the Ponderosa Pine and Interior Douglas-fir zones. It
is most abundant along forest edges in the Ponderosa Pine
and Bunchgrass biogeoclimatic zones. In grassland areas, it
requires a few large trees or human-made structures for
perch sites. It is particularly numerous along highway and
road corridors, where it typically perches on fences,
utility poles, or telephone lines, often in the vicinity of
farm buildings. It also inhabits treed suburbs and villages.
On the coast, it frequents the edges of pastures, airports,
farmlands, sewage lagoons, beaches, parks, and other open
areas.
Spring arrival of the Western
Kingbird is two to three weeks earlier than that of the
Eastern Kingbird. Migration patterns are similar for both
the interior and the coast. The first migrants may arrive as
early as the second week of April, but birds do not normally
arrive in numbers until the end of April or the first week
of May. Over 55 years, the mean and median date of first
arrival in the Okanagan valley has been 29 April (Cannings
et al. 1987). Peak numbers are reached by the second or
third week of May.
The Western Kingbird is an
early autumn migrant, with the southward movement beginning
in early August and reaching a peak from mid to late August.
Most birds have left the province by late August, with only
a few stragglers remaining into September or later. Most
migrants travel as individuals or in family groups. There is
1 winter record (see Christmas Bird Counts and
REMARKS).
In the interior, the Western
Kingbird has been recorded from 9 April to 4 October; on the
coast, it has been recorded regularly from 15 April to 27
December.
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Breeding
 The
Western Kingbird breeds mainly in the southern interior of
the province from Keremeos to Wardner, north to
Spillimacheen in the east Kootenay and Castlegar in the west
Kootenay, and through the Southern Interior, Central
Interior, and southern Sub-Boreal Interior to Quesnel in the
north and the vicinity of Riske Creek in the west. Local
breeding populations occur on the coast in the Douglas-fir
forests of the Pemberton valley, and in farmlands and
sloughs of the upper Fraser River valley.
The Western Kingbird reaches
its highest numbers in summer in the ponderosa pine forests
of the Southern Interior, from Osoyoos north to Kamloops. An
analysis of Breeding Bird Surveys for the period 1968 to
1993 could not detect a net change in numbers on interior
routes; surveys on coastal routes for the same period
contained insufficient data for analysis. Robbins et al.
(1986) note that British Columbia populations showed the
only persistent decrease between 1965 and 1979, although
that appears to have since changed. From the western region
of the Breeding Bird Surveys, population trends of the
Western Kingbird show an increase in numbers between 1966
and 1988 at an average annual rate of 1.6% (Sauer and Droege
1992).
Few Western Kingbirds breed
above 1,200 m elevation. In the Southern Interior, the open
coniferous forests of the valley bottoms and adjacent
benchlands are dominated by ponderosa pine. The dominant
ground cover is bluebunch wheatgrass. In that environment,
50% of the Western Kingbird nests were in woodlands that had
been altered by humans, while another 30% were in open
forest situations (n = 922).
The adaptability of the Western
Kingbird is revealed by its use of 40 habitat classes within
the basic habitat types. The most frequently used classes
were cultivated farmland (21%; n = 778), orchards or
vineyards (14%), big sage shrubland (9%), arid rangeland
(9%), and open ponderosa pine stands (8%), followed by rural
and suburban sites (8%). In British Columbia, most nest
sites were found in association with roadsides (31%; n
= 407), gardens (13%), and open hillsides
(10%).
In the interior, the Western
Kingbird has been recorded breeding from 9 May (calculated)
to 11 August; on the coast, it has been recorded from 11 May
(calculated) to 11 July.
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Nests: 
 Most
nests (84%; n = 1,138) were situated on power poles.
Nests were built behind transformers; on crossbars between
brackets, wires, and insulators; or on other fixtures on the
pole itself. Other sites included a wide variety of living
and dead coniferous and deciduous trees and bushes; ledges
in buildings, including houses, barns, sheds, garages, and
cabins, as well as bridges; and cliff faces. Munro (1919,
1927) and Green (1928), referring to the Okanagan valley in
British Columbia, state that the Western Kingbird used
abandoned Northern Flicker nest holes (also Pinkowski 1982)
and American Robin nests, the decayed top of fence posts and
trembling aspens, and the eaves troughs of houses. The
heights of 1,075 nests ranged from ground level to 45 m,
with 73% recorded between 6 and 9 m. Nests were mainly
bulky, untidy cups of grasses (93% of nests), string (15%),
twigs (13%), plant fibres, and remains of rootless and
fortes, along with at least 24 other natural and human-made
materials.
Eggs:
Dates for 659 clutches ranged
from 9 May to 25 July, with 52% recorded between 4 and 26
June. Sizes of 107 clutches ranged from 1 to 5 eggs (1E-8,
2E-8, 3E-28, 4E-57, 5E-6), with 53% having 4 eggs. Bent
(1942) reports occasional clutches of 6 or 7 eggs in the
United States. The incubation period in British Columbia is
18 to 20 days.
Nest
Success:
Of 29 nests found with eggs and
followed to a known fate, 21 produced at least 1 fledgling,
for a nest success rate of 71%.
Young: Dates for 443 broods
ranged from 1 June to 11 August, with 55% recorded between
25 June and 6 July. Sizes of 157 broods ranged from 1 to 5
young (1Y-8, 2Y-31, 3Y-63, 4Y-53, 5Y-2), with 74% having 3
or 4 young. The nestling period in British Columbia is 16 to
19 days. There is evidence of double-clutching. In the
Okanagan valley, 1 brood fledged on 19 June and a second
brood, in the same tree but in a different nest, fledged on
11 August (Cannings et al. 1987).
Brown-headed Cowbird
Parasitism: Cowbird parasitism was not found in British
Columbia in 259 nests recorded with eggs or young. Friedmann
and Kiff (1985) and Smith (1972) note that the Western
Kingbird is rarely recorded as a host. British Columbia data
further support the tentative designation of the Western
Kingbird as a rejector species (Rothstein 1975). As
Friedmann et al. (1977) mention, the "paucity of observed
cases of natural parasitism agrees well with this rejector
behaviour of the Western Kingbird."
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Remarks
Anderson (1914)
reported an early brood of three young Western Kingbirds in
the Okanagan valley on 3 May 1913. It is likely this nest
was a misidentified Say's Phoebe (Cannings et al.
1987).
The Western
Kingbird and Eastern Kingbird occur sympatrically over much
of the southern interior of British Columbia. However, the
Eastern Kingbird tends to be found in thicker, wetter
riparian forest and at higher elevations, while the Western
Kingbird favours lower, drier, more open areas with larger
and taller trees. In Manitoba, the Western Kingbird usually
nests in sites having fewer but larger trees than the sites
chosen by the Eastern Kingbird, and its nests are placed
higher than those of the latter species (MacKenzie and Sealy
1981). The two species will nest close to each other in
gardens, along road corridors (e.g., Richter Pass; Campbell
and Meugens 1971), and around farmhouses where a mixture of
favourable habitats occur.
Since the
Western Kingbird also breeds in tall bushes and trees
adjacent to transportation corridors, it is frequently a
victim of highway mortality (Barkley 1966; Campbell
1984f).
In late autumn,
especially October and November, Western Kingbirds should be
carefully scrutinized because of the possibility of
confusion with the Tropical Kingbird (q.v.), which occurs as
a vagrant from the south at that time. We have not included
the record of a single bird seen during the following
Christmas Bird Count because convincing details were
lacking: Victoria 21 December 1963-1 (Anderson
1976b).
For additional
life-history and breeding habitat information, see Bent
(1942), Blancher and Robertson (1984), and MacKenzie and
Sealy (1981).
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Located at:
675 Belleville Street,
Victoria, British Columbia,
CANADA
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Nests