The 118th CBC in British Columbia

People came out in droves for the 118th Christmas Bird Count in British Columbia. All told 2907 counters spent 5787 hours traveling 26,681 kilometers to count birds across BC. A total of 633 feeder watchers spent 1145 hours counting birds in their back yards and a dedicated few braved the night to spend 61 hours and travelled over 370 kilometers looking for owls. Regionally 94 count circles were covered and 564,312 individuals of 214 species were counted. Once again Victoria topped the charts with species (144) and effort. The Victoria circle had more observers (265), travelled further (1062 kilometers) and spent more time in the field (570 hours) than any other circle. They also racked up 95 kilometers of owling with 43 individuals of six owl species to show for it. Further north on Vancouver Island the Parksville-Qualicum count tallied an impressive 100 hours of backyard bird observation. Although overall turn out, species totals and number of birds counted were not out of the ordinary, distributions of species across BC this winter certainly were odd.

Many counts observed record high numbers of waterfowl, grebes, and shorebirds while others encountered record lows. At the same time many northern species appeared in large numbers across the province. BC’s most northerly count, Atlin, encountered both Mallard (1) and Barrow’s Goldeneye (9) for the first time this year and they also encountered their first Hoary Redpolls (10). White-winged Crossbills were unusually common along the coast, and Common Redpolls were widespread and abundant across the province occurring in 71 counts. This same pattern was seen within shorebirds. The more southerly wintering Spotted Sandpiper (24) and more northerly Surfbird (1523) were both more abundant than they have ever been in BC.

These interesting patterns may have been the result of unusual Jetstream activity (Figure 1). For much of December the Jetstream looped north over BC and came back down over the Rockies. This resulted in warm weather over much of BC and cold temperatures across the rest of the country. This may have allowed many birds that would usually have moved further south to remain in BC into December while birds in northern and eastern Canada were forced west and south into BC by the cold temperatures. Late December saw the Jetstream shift south again and cold temperatures swept back into the province so that counts in January didn’t observe as many southern species and were low on water birds.

Another result of this odd weather was an influx in winter rarities. Cranbrook picked up a Brown Thrasher on count week, Duncan spotted a Northern Mockingbird, and a Brambling popped up in Greater Masset. A Winter Wren, Say’s Phoebe, and Blue-winged Teal were all photographed on the Kelowna count. Wilson’s Warblers were spotted in Vancouver, Victoria, and Powell River. Victoria also picked up a Great Egret, Mountain Bluebird, and a count week Tennessee Warbler. Common Yellowthroats appeared on the Vancouver and Revelstoke counts and a Bullock’s Oriole made an appearance in Sooke. A Costa’s Hummingbird was around for the count in Powell River and a Summer Tanager was spotted on count week for Vancouver.

Photo: Figure 1: Jetstream images from early (left) and late (right) December 2017. For much of early December much of BC was below the Jetstream while it dipped below the rest of Canada. This brought unseasonably warm weather to much of BC and cold to the rest of Canada. California Regional Weather Server (http://squall.sfsu.edu/crws/archive/ jet_ arch.html). Photo: Jeremiah Kennedy

Other odd distributions and numbers this year were Chestnut-backed Chickadees, which, although not overly abundant, were seen on more counts than ever before. Sharp-tailed Grouse were scarce with only two seen across the entire province and Horned Larks were present in small flocks across much of the south.

Anna’s Hummingbirds were much more abundant than they have ever been, up to 3473. This is 600 more than the next most prolific year (2015-16). This marks another leap in the irruption of Anna’s Hummingbirds across western BC, which have exploded from 45 individuals on six counts in 1990 (Figure 2). This, however, pales in comparison to Eurasian Collard-Doves, who have gone from 0 birds in 2002 to 4882 birds on 70 counts this year (down from last year’s record 5601 on 72 counts; Figure 2). Though they were first detected on a BC CBC in the early 2000s, collared-doves were found in over half of BC’s counts by 2011.  Now they are one of the most widespread species in the winter in BC. Though their rapid spread across BC seems to be plateauing they may yet increase in numbers in areas where they have just arrived. Stay tuned for another update next year.

A big thanks to all the compilers and participants this year who volunteered their time to make the 118th Christmas Bird Count possible.

Photo: Jeremiah Kennedy
Photo: Figure 2: Number per party hour (top) and number of counts with species detected (bottom) for Anna’s Hummingbird and Eurasian Collard-Dove for Christmas Bird Counts across BC from 1970-71 to 2017-18. Data accessible from the Audubon CBC portal (http://netapp.audubon.org/ CBCObservation/Historical/ResultsBySpecies.aspx?1). Photo: Jeremiah Kennedy
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