According to Cornell Lab of Ornithology‘s All About Birds webpage on Eurasian Collared-Doves, these birds “made their way to North America via the Bahamas, where several birds escaped from a pet shop during a mid-1970s burglary; the shop owner then released the rest of the flock of approximately 50 doves. Others were set free on the island of Guadeloupe when a volcano threatened eruption. From these two sites the birds likely spread to Florida, and now occur over most of North America.”
When we arrived at Vancouver’s North Shore in September 2011, I saw a few of these doves from time to time. Two years later, I started seeing more of them and far more frequently. And contrary to what I’ve been reading about them in identification guides, they seem to prefer trees to human-made objects to roost and nest. In that sense, they are closer to Mourning Doves than Rock Pigeons. I’m guessing they are progressing north along the Pacific Coast and may even start breeding in large numbers soon in most of Alaska (if that isn’t the case already).
Taken December 19, 2014 in Chief August Jack Park in the City of North Vancouver, BC, Canada with a handheld Nikon D5200 and AF-S Zoom-Nikkor 70-300mm f/4.5-5.6G IF-ED (Top: ISO 720, 300mm, f/5.6, 1/1000; bottom: ISO 800, 300mm, f/5.6, 1/1000). Not baited, called in or set up.