The First Record of Yellow-browed Warbler (Phylloscopus inornatus) for British Columbia. By Rick Toochin.  Revised: June 10, 2023.

The Yellow-browed Warbler (Phylloscopus inornatus) is a widespread Old World Warbler species found breeding in temperate forests from the Ural Mountains in Russia, east to Siberia in Yakutia, Chukotka, the Sea of Okhotsk, and the Amur Delta with the population extending south to Sakhalin Island, and northeastern China (Brazil 2009, Howell et al. 2014). Birds migrate southeast to winter from southern China, northeastern India, into Southeast Asia, the Philippines, and Taiwan (Lewington et al. 1992, Brazil 2009). This species is a rare, but annual vagrant in Europe, with many records from Iceland, particularly from mid-September through October where it often out-numbers all other Siberian vagrants (Lewington et al. 1992, Mullarney and Zetterstrom 2009, Howell et al. 2014). In North America, the Yellow-browed Warbler has been recorded as a casual species in Alaska with several documented records from the Bering Sea region, with at least one from Attu (Gibson and Withrow 2015, e-bird data 2020), and one photographed on September 19, 2014 on Middleton Island (DeCicco et al. 2017).  The Yellow-browed Warbler is a recent addition to the avifauna of British Columbia in the fall of 2019 and is classified as an accidental vagrant. California also got its first state record in the fall of 2019 with a well- photographed bird October 24-25, 2019 in Markleeville (e-bird data 2020). There is also a well-documented record for Baja California Sur, Mexico of a bird that likely wintered from March 25 – April 7, 2007 (Mlodinow and Radamaker 2007). There is also a single record from Eastern North American of a bird well documented on October 21, 2006, in Milwaukee County, Wisconsin (Svingen 2007, Frank 2007). 

The Yellow-browed Warbler is shown in most North American field guides despite its categorization as a casual species. This species is small measuring 10-11 cm in length, and weighing 4.3-6.5 grams (Mullarney and Zetterstrom 2009).  The Yellow-browed Warbler has a noticeable habit of frequently flicking its wings (Brazil 2009). This species is identified as grayish-green above from the back to the rump, off-white below, with the legs medium brown colour (Brazil 2009, Mullarney and Zetterstrom 2009). There is a long and very prominent pale yellow supercilium above a dark eye-stripe (Brazil 2009, Mullarney and Zetterstrom 2009). On the wings there is a broad yellowish-white wing-bar on the tips of the greater coverts, and a shorter, less conspicuous second bar on the tips of the median coverts; the prominence of the wing-bar on the greater coverts is enhanced by a darkish wing (Brazil 2009, Mullarney and Zetterstrom 2009).  The tertials are dark centered and edged yellowish-white (Brazil 2009, Mullarney and Zetterstrom 2009). The sides of the crown are a shade darker gray-green than the back, often giving the head a hint of a pale crown-stripe (Brazil 2009, Mullarney and Zetterstrom 2009). 

 

The Yellow-browed Warbler gives an up-slurred “swee-eet” call similar to a Pacific-slope Flycatcher (Empidonax difficilis) (Howell et al. 2014, Dunn and Alderfer 2017).

 

In the context of birds found commonly in British Columbia, there are no other common species that should cause confusion. The Golden-crowned Kinglet (Regulus satrapa), which measures 10 cm in length, 18 cm wing spread, and weighs 6 grams is distinctly different from the Yellow-browed Warbler (Sibley 2000). The Golden-crowned Kinglet has yellow and black crown stripes on females, and red and yellow with black crown stripes on the male (Sibley 2000, Dunn and Alderfer 2017). In both sexes the dark eyes are bordered above and below by a single white stripe. Calls given are a series of high thin “tsee” notes. The Ruby-crowned Kinglet (Regulus calendula) is also a small species that measures 11 cm in length, 19 cm wing spread, and weighs 6.5 grams (Sibley 2000). This species is grayish-green overall, but has definite distinct eye arcs both in front and behind the eye (Dunn and Alderfer 2017). Males have a red patch on the crown (Sibley 2000). This species does flick its wings regularly (Sibley 2000). The call is a scolding “je-ditt” note (Dunn and Alderfer 2017).

The Yellow-browed Warbler is an accidental vagrant to British Columbia with a recent well- photographed record of a bird found by Geoffrey Newel and Jeff Gaskin in broad-leaf forested habitat at Panama Flats, near Victoria from October 18-23, 2019 (L. Haviland Pers. Comm.). The bird was well photo-documented and was observed by people from all over British Columbia, and from across North America (L. Haviland Pers. Comm.). The timing of this record fits perfectly with vagrancy records from Europe where the Yellow-browed Warbler is classified as amongst the most regularly occurring vagrants from Siberia, mainly from mid-September to late October and early November (Lewington et al. 1992, Mullarney and Zetterstrom 2009, Howell et al. 2014). In Iceland, this species appears to be increasing in the fall where there are close to 100 records, occurring from mid-September to early November (Lewington et al. 1992, Howell et al. 2014). In Asia, this species appears to be more continental in spring migration than coastal, which likely accounts for the lack of spring vagrancy records from Alaska (Howell et al. 2014). Yellow-browed Warblers appear to be a classic mis-orientated, possibly, reverse migrant vagrant which accounts for them so far appearing as a fall vagrant only in Alaska (Howell et al. 2014). To date the 9 Alaskan records span from late August to mid-October (Howell et al. 2014, Gibson and Withrow 2015, DeCicco et al. 2017, e-bird data 2020). It is likely that in the future the Yellow-browed Warbler could occur again in the fall migration period in the province with a record likely coming from a known passerine vagrant trap on Haida Gwaii, anywhere on Vancouver Island or possibly along the west coast of the mainland of British Columbia.

  

I wish to thank Louis Haviland for tracking down the details of the British Columbia observation and Don Cecile for reviewing the manuscript. I also want to thank Peter Candido and Geoffrey Newell for allowing me to publish their excellent pictures of the Yellow-browed Warbler. All photos are used with permission of the photographer and are fully protected by copyright law. Photographs are not to be reproduced, published or retransmitted on any website without the authorization of the photographer.

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