Western Bluebird (Sialia mexicana)

Western Bluebird

[order] PASSERIFORMES | [family] Turdidae | [latin] Sialia mexicana | [UK] Western Bluebird | [FR] Merle bleu de l’Oest | [DE] Blaukehl-Huttensanger | [ES] Azulejo Occidental | [NL] Blauwkeelsialia


Genus Species subspecies Breeding Range Breeding Range 2 Non Breeding Range
Sialia mexicana NA, MA w NA to c Mexico
Sialia mexicana amabilis
Sialia mexicana bairdi
Sialia mexicana jacoti
Sialia mexicana mexicana
Sialia mexicana nelsoni
Sialia mexicana occidentalis

Physical charateristics

A bit larger than a sparrow; appears round-shouldered when perched. Head, wings, and tail blue; breast and back rusty red. (In some birds the back is partially or wholly blue.)
Throat blue. Females are paler, duller, with rusty breast, grayish throat and belly. Young birds are speckle-breasted, grayish, devoid of red, but with some telltale blue in wings and tail.

Listen to the sound of Western Bluebird

[audio:http://www.aviflevoland.nl/sounddb/W/Western Bluebird.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 0 cm wingspan max.: 0 cm
size min.: 20 cm size max.: 21 cm
incubation min.: 13 days incubation max.: 14 days
fledging min.: 15 days fledging max.: 20 days
broods: 1   eggs min.: 3  
      eggs max.: 6  


North America, Middle America : West North America to Central Mexico


Scattered trees, open conifer forests, farms; in winter, semi-open terrain, brush, deserts.
Breeds in semi-open areas including pine woods, oak woods, streamside groves, ranch country, sometimes in pinyon-juniper woods, but avoiding hot dry regions. Winters in many kinds of open or semi-open habitats, especially in pinyon
-juniper, also in desert, farmland, others.


Male typically arrives on breeding grounds before female, and defends nesting territory by singing. In courtship, male may flutter in front of female with wings and tail partly spread, while singing. Male may also feed female.
Nest: Site is in cavity, such as natural hollow in oak or pine, old woodpecker hole, birdhouse, sometimes hole in building. Usually nests fairly low, rarely up to 50′ abov
e the ground. Nest in cavity is probably built mostly by female, but male may take part. Nest is a rather loose cup of twigs and weeds, lined with finer grass.
Eggs: 4-6, sometimes 3-8. Pale blue, unmarked; occasionally white. Incubation is by female, incubation period not well known.
Young: Both parents bring food to nestlings. Age of young at first flight is not well known, probably between 2 and 3 weeks. Probably 2 broods per year.

Feeding habits

Mostly insects and berries.
Insects make up majority of diet, especially in summer; feeds heavily on grasshoppers, caterpillars, beetles, ants, also many other insects. Berries and small fruits are important in diet especially in winter; among those eaten are fruits of mistletoe, j
uniper, and elderberry.
Behavior: Often forages by perching fairly low and flying down to ground to capture insects, sometimes hovering briefly before pouncing. May catch
insects in midair, or may seek them among foliage. Perches or flutters among branches to take berries.


This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Western Bluebird status Least Concern


Breeds from southern British Columbia, western United States to mountains of central Mexico. Migration:
Permanent resident in some southern areas; migratory in the north, arriving rather early in spring and lingering late in fall. Winter range varies from year to year depending on food supplies.

Distribution map

Western Bluebird distribution range map

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