Population status

Western Bluebird
(Sialia mexicana)

The Breeding Bird Survey (BBS) is the best source of data to monitor the Western Bluebird in Canada. However, the survey covers only about 30% of the Canadian population. Results of the BBS suggest this species has undergone a large increase in population since about 1970. Results from the Christmas Bird Count (CBC) also suggest that Western Bluebird numbers have shown a large increase over this time period; these results help corroborate those of the BBS, although the precision of the CBC trend estimate is quite low. The population increase has come despite the disappearance of small costal populations of Western Bluebirds in British Columbia (Campbell et al. 1997). At the continental level, BBS and CBC results from throughout North America both suggest a population increase relative to 1970.

Breeding Bird Survey (BBS) - Canadian analysis

Additional information on: Breeding Bird Survey (BBS) - Canadian analysis

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Table 1: Population trends by geographic area
Geographic area	Time Period ^{Table 1 - footnote 1}	Annual trend ^{Table 1 - footnote 2}	Intervals ^{Table 1 - footnote3}
Geographic area	Time Period ^{Table 1 - footnote 1}	Annual trend ^{Table 1 - footnote 2}	Lower	Upper
Canada Select to view graph of the geographic area: Canada 1970-2012; Breeding Bird Survey (BBS) - Canadian analysis	1970-2012	8.2	5.5	11.5

Breeding Bird Survey in North America (BBS) - U.S. analyses

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Table 2: Population trends by geographic area
Geographic area	Time Period	Annual trend ^{Table 2 - footnote 1}	Limits
Geographic area	Time Period	Annual trend ^{Table 2 - footnote 1}	Lower	Upper
North America Select to view graph of the geographic area: North America 1966-2012; Breeding Bird Survey in North America (BBS) - U.S. analyses	1966-2012	0.8	-24.9	1.6

Christmas Bird Count (CBC)

Additional information on: Christmas Bird Count (CBC)

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Table 3: Population trends by geographic area
Geographic area	Time Period	Annual trend ^{Table 3 - footnote 1}	Limits
Geographic area	Time Period	Annual trend ^{Table 3 - footnote 1}	Lower	Upper
Canada Select to view graph of the geographic area: Canada 1965-2012; Christmas Bird Count (CBC)	1965-2012	9	4.1	14.9

References

Campbell, R.W., N.K. Dawe, I. McTaggart-Cowan, J.M. Cooper, G.W. Kaiser, M.C.E. McNall, and G.E. J. Smith. 1997. The Birds of British Columbia. Volume 3: Passerines, Flycatchers Through Vireos. UBC Press, Vancouver, BC.
Guinan, J.A., P.A. Gowaty and E.K. Eltzroth. 2008. Western Bluebird (Sialia mexicana), The Birds of North America Online (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York. Guinan, J.A., P.A. Gowaty and E.K. Eltzroth. 2008. Western Bluebird (Sialia mexicana), The Birds of North America Online (A. Poole, Ed.). Cornell Lab of Ornithology, Ithaca, New York. (Link)