Red-flanked Bluetail makes it to Mexico

Mexico's first Red-flanked Bluetail was found in the Pacific-coast state of Guerrero, in the south-west of the country, in late February.

The bird was found near the village of Lagunillas, some 250 km west of the city of Acapulco, by Michael Carmody and Tim Fitzpatrick on 25 February and seen again there two days later, when it was photographed.

The presence of this species so far south on the North American continent may at first seem scarcely believable. However, Red-flanked Bluetail is a rare but far from unknown vagrant to North America, with several records from western Canada and the western US south to southern California. That said, this is comfortably the most southerly record yet for the continent.

The sighting has been fully documented on eBird, with the above image taken by Will Mertz on 27 February.

But what was the bird's route to south-western Mexico? Presumably it will have arrived in western North America last autumn and migrated south along the Pacific coast to spend the winter in warmer climes. Siberian vagrants are well-known from e.g. the Pribilof Islands, Alaska, and indeed it is that archipelago that boasts the lion's share of North American records of many Old World species (including Red-flanked Bluetail). There are, however, autumn and winter records of an array of Eurasian species, such as Arctic Warbler, Brambling and Rustic Bunting, from western Canada and the western 'lower 48' states.

Rather like its meteoric rise in Europe, Red-flanked Bluetail appears to be becoming a more familiar vagrant in North America, too. Two recent records from British Columbia, Canada, included one in Vancouver from January-March 2013 (the other was in 2017). Just across the US border, in Washington State, one was seen a Ferndale in April 2015. Oregon has also recently hosted ths species, south of Portland in late December 2015.

In California, one famously wintered in Los Angeles from December 2018-March 2019, with another reaching the Farallon Islands in early November 2019 (there is also an older sighting from the archipelago in November 1989). A third was seen as far south as San Clemente Island in December 2011. Records aren't strictly coastal, either. One was near Lewiston, Idaho, from December 2016-January 2017, with another even further inland at Laramie, Wyoming, on 4 November 2019.