Status and Occurrence of Loggerhead Shrike (Lanius ludovicianus) in British Columbia
by Rick Toochin and Don Cecile
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Introduction and Distribution
The Loggerhead Shrike (Lanius ludovicianus) is a small elegant passerine species found across North America (Dunn and Alderfer 2011). The bird is classified as Threatened to Endangered throughout much of its northern range due to habitat loss (COSEWIC 2004). In Canada, the Loggerhead Shrike has suffered significant, more than 80%, population declines over the past 35 years (COSEWIC 2004). These declines have been linked to loss of native prairie and pastureland habitats and pesticide residues (COSEWIC 2004). The Loggerhead Shrike eats insects, shrews and small rodents (COSEWIC 2004). It's breeding range in Eastern North America is from southern Wisconsin (Robbins 1990) and from southeast Illinois (Bohlen 1989), southern Indiana (Yosef 1996), and southwestern Ohio (Peterjohn 1989) south to Gulf Coast, and from eastern West Virginia (Buckelew and Hall 1994) and all but eastern portions of both Virginia (Yosef 1996) and North Carolina south to Gulf Coast and all but extreme southern Florida (Robertson and Woolfenden 1992). Remnant breeding populations remain in western and northeastern Lower Peninsula of Michigan (Brewer et al. 1991), southcentral Pennsylvania (Brauning 1992), and portions of southern Ontario. Three isolated populations (40 pairs total) are found in southern Ontario, in what may be a long-standing association with limestone plains bordering the southern edge of the Precambrian Shield (Cadman et al. 1987). Formerly bred throughout southern Quebec, Maritime Provinces (Erskine 1992), most of New England (Laughlin and Kibbe 1985), and mid-western U.S. Local breeding still occurs within this area, increasingly toward the west. In Quebec, only 2 active nests located in 1992, both in southeastern regions (Laporte and Robert 1995).
In central North America the Loggerhead breeds from southern Saskatchewan and southwestern Manitoba (Godfrey 1986), North Dakota (except for northeast corner; Stewart 1975), and portions of southern Minnesota (Janssen 1987), eastern Iowa (Yosef 1996), northwestern and southeastern Missouri (Robbins and Easterla 1992), and northern Arkansas (James and Neal 1986) south through Louisiana, most of Texas (Yosef 1996), New Mexico, and Arizona, and through Mexico to northern Sinaloa on the Pacific slope and Oaxaca in the interior (occasionally farther south); absent from Atlantic slope (Howell and Webb 2010). In central Mexico, breeds at elevations of 1,500–2,400 m (Binford 1989).
In Western North America the Loggerhead Shrike breeds from southeastern Alberta (Semenchuk 1992), western Montana (Bergeron et al. 1992), northwestern Wyoming (Oakleaf et al. 1992), southern Idaho (Stephens and Sturts 1991), south-central Washington (Wahl et al. 2005), eastern Oregon (Gilligan et al. 1994), and California (except for northwest, heavily forested higher mountains, and higher portions of deserts) (Small 1994) south to southern Baja California. In Baja California, breeds from sea level to 3,000 m (Wilbur 1987). In the Channel Islands off California coast, there are a couple of resident sub-species that occur on Santa Rosa, Santa Catalina, and Santa Cruz Island (Lanius ludovicianus anthonyi) and on San Clemente I. (L. l. mearnsi ) which is also referred to by authorities as the San Clemente Loggerhead Shrike (Small 1994).
All Northern populations of the Loggerhead Shrike are migratory (Yosef 1996). Most birds winter from northern California, northern Nevada, northern Utah, central Colorado, southern and eastern Kansas, western Missouri, northern Kentucky, and northern Virginia south through the southern U.S. and in Mexico south throughout breeding range and along Atlantic slope irregularly to Chiapas (Howell and Webb 2010).
In British Columbia there are over 80 records and this species appears to be of annual occurrence, but with the classification of very rare to rare in the Province each year (Toochin et al. 2014a, see Table 1). In local regions the Loggerhead Shrike would be classified as a casual vagrant (Toochin et al. 2014b). There are no definitive breeding records for the Loggerhead Shrike in British Columbia (Campbell et al. 1997). It is unclear if all or some of the birds seen during the spring and summer months are overshoots in migration or could be birds that might end up breeding occasionally in the interior when the circumstances are correct (Cannings et al. 1987, Campbell et al. 1997).
The Loggerhead Shrike is a vagrant species to the Bahama Islands (Sharpe 1897), Bermuda (Amos 1991), and Guatemala (Ericsson 1981). Birds from snowy areas also migrate to where snow is lacking, and leave areas where snow is on ground for more than 10 days of the year (Miller 1931). Sedentary populations generally remain on breeding territories throughout the winter (Yosef 1996).
Occurrence and Documentation
In British Columbia, the Loggerhead Shrike has been recorded on 83 occasions with many birds having been photographed or with historical records collected (Toochin et al. 2014, see Table 1 and 2). This species has been seen from many regions of the Province with Vancouver having 18 records, Vancouver Island having 3 records, the Fraser Valley having 6 records, the Cariboo having at least 1 record, and the Kootenay’s having 13 records (Toochin et al. 2014, see Table 1). The highest numbers of records come from the Okanagan and surrounding dry belt regions with 40 records (Toochin et al. 2014, see Table 1). This is logical given the close proximity of the Loggerhead Shrike’s breeding range in northern Washington and that the habitat is fairly continuous in the region (Wahl et al. 2005). Most records occur in the spring migration period from March to early June with 49 records (Toochin et al. 2014, see Table 2). These records likely indicate birds that are spring migrant overshoots, but it they could also indicate the odd bird moving north to try and breed (Cannings et al. 1987, Campbell et al. 1997). It is clear that any shrike found in southern British Columbia from late March to early June should be scrutinized for the Loggerhead Shrike (R. Toochin Pers. Obs.). This is the prime time of year when Loggerhead Shrikes have occurred and Northern Shrikes become less numerous in southern British Columbia (R. Toochin Pers. Obs). There is only 1 summer record from July for British Columbia (Toochin et al. 2014, see Table 2). This relative lack of summer records could reflect that birds occurring in the spring are overshoots, but it could also reflect a lack of observer coverage during the breeding season. In the future any summer occurrences of the Loggerhead Shrike should be carefully investigated by observers to see if there are two birds involved as there is potential to add a new breeding species for the Province. The Loggerhead Shrike has been found 10 times in the fall migration period between August to November (Toochin et al. 2014, see Table 2). There are 25 winter records, many of these are historical records from the Lower Mainland with most coming from the dry interior region (Toochin et al. 2014, see Table 1 and 2). As more observers carefully check appropriate habitat and scrutinize all late odd looking Northern Shrikes more carefully, it is likely more Loggerhead Shrikes will be found in the future.
