Birds of the Week # 27
The Blue Jay (Cyanocitta cristata) is a passerine bird in the family Corvidae, native to eastern North America. It lives in most of the eastern and central United States; some eastern populations may be migratory. Resident populations are also found in Newfoundland, Canada; breeding populations are found across southern Canada. The blue jay occurs from southern Canada (including the southern areas of provinces from Alberta eastward to Quebec and throughout the Atlantic provinces) and throughout the eastern and central United States south to Florida and northeastern Texas. The western edge of the range stops where the arid pine forest and scrub habitat of the closely related Steller’s jay (C. stelleri) begins, generally in the eastern foothills of the Rocky Mountains. Recently, the range of the blue jay has extended northwestwards so that it is now a rare but regularly seen winter visitor along the northern US and southern Canadian Pacific Coast. As the two species’ ranges now overlap, C. cristata may sometimes hybridize with Steller’s jay. The increase in trees throughout the Great Plains during the past century due to fire suppression and tree planting facilitated the western range expansion of the blue jay as well as range expansions of many other species of birds. From 1966 to 2015, the Blue Jay experienced a population decline along the Atlantic coast, but a greater than 1.5% annual population increase throughout the northern part of its range, including Labrador, Nova Scotia, southern Quebec, and southern Manitoba.
The Northern Mockingbird (Mimus polyglottos) is a mockingbird commonly found in North America. This bird is mainly a permanent resident, but northern birds may move south during harsh weather. This species has rarely been observed in Europe. The mockingbird’s breeding range is from Maritime provinces of Canada westwards to British Columbia, practically the entire Continental United States south of the northern Plains states and Pacific northwest, the Greater Antilles, and the majority of Mexico to eastern Oaxaca and Veracruz. The mockingbird is generally a year-round resident of its range, but the birds that live in the northern portion of its range have been noted further south during the winter season. Sightings of the mockingbird have also been recorded in Hawaii (where it was introduced in the 1920s), southeastern Alaska, and three times as transatlantic vagrants in Britain, most recently in Exmouth, Devon, UK in February and March 2021. The mockingbird is thought to be at least partly migratory in the northern portions of its range, but the migratory behavior is not well understood. In the 19th century, the range of the mockingbird expanded northward towards provinces such as Nova Scotia and Ontario and states such as Massachusetts, although the sightings were sporadic. Within the first five decades of the 20th century, regions that received an influx of mockingbirds were Maine, Vermont, Ohio, Iowa, and New York. In western states such as California, the population was restricted to the Lower Sonoran regions but by the 1970s the mockingbird was residential in most counties. Islands that saw introductions of the mockingbird include Bermuda (in which it failed), Barbados, St. Helena, Socorro Island, the Cayman Islands and Tahiti.
© HJ Ruiz – Avian101