Saturday, March 21, 2015

Common Gull

The Mew Gull complex (Larus canus) is comprised of four subspecies. The New World representative, referred to as the Mew Gull (L.c. brachyrhynchus), breeds in n.w. North America and winters mainly on the Pacific Coast and is exceptionally rare on the Atlantic Coast during the non-breeding season (one has been confirmed nearby in New Brunswick). The Old World birds are the Common Gull (L. c. canus & L. c. heinei) and the Kamtchatka Gull (L. c. kamtschatschensis). (Howell et al., 2014)

The canus Common Gull is regular in NS in winter in small numbers. The province's first was discovered on March 9, 1969 on Sable Island. (McLaren, 2012)

Analysis of this winter's photos of the canus Common Gulls in the Dartmouth area suggest that there have been 4 individuals. I was able to photograph the gull that was frequenting the Sobeys parking lot on Tacoma Drive in Dartmouth on February 27, 2015 (Fig. 1).

Figure 1. Common Gull in Dartmouth - 27 Feb 2014. Photo by Alix d'Entremont

Common Gulls are superficially similar to Ring-billed Gulls. In comparison, a Common Gull has a thinner, less blunt tipped bill that lacks a distinct black ring. Its eyes are dark brown compared to the pale lemon eyes of a Ring-billed as seen in Fig. 2. (Howell et al., 2014)

Figure 2. Common Gull (L) vs. Ring-billed Gull (R). Photo by Alix d'Entremont

Common Gulls have a slightly darker mantle that is clear in Figure 3, along with wider and more contrasting scapular and tertial crescents. The wider scapular crescent on the Common Gull is obvious in Figure 3 as well. (Howell et al., 2014)

Figure 3. Common Gull (L) vs. Ring-billed Gull (R). Photo by Alix d'Entremont

The relatively more extensive white mirror on P10 of the Common Gull is visible in Fig. 4. (Howell et al., 2014)

Figure 4. Common Gull (L) vs. Ring-billed Gull (R). Photo by Alix d'Entremont

The Dartmouth Common Gull was my first Nova Scotian sighting of this bird. I had previously seen Common Gulls in the fjords of Norway in July 2007. Figure 5 shows a number of them with pristine white heads and in the process of moulting their inner primaries. These would also be L.c. canus based on range.

Figure 5. Common Gulls near Flåm, Norway - July 21 2007. Photo by Alix d'Entremont


References:

Howell, S.N.G. and J. Dunn. 2007. Gulls of the Americas. Houghton Mifflin Company, New York, N.Y.

McLaren, I.A. 2012. All the Birds of Nova Scotia: status & critical identification. Gaspereau Press Ltd, Kentville, N.S., Canada

Thursday, March 12, 2015

Fieldfare

The Fieldfare (Turdus pilaris) is a nomadic thrush breeding in temperate and boreal forests from Iceland to e. Russia. There is also a small, fluctuating population breeding in sw. Greenland since the late 1970s. Fieldfares are also regular winter visitors to Iceland from Europe. Birds that arrive to our region are thought to originate from northern Europe, Iceland or Greenland. Cold weather winter movements of this nomad align well with Atlantic Canada sightings that are mostly in late DecFeb. (Howell et al., 2014)

Nova Scotia previously had 3 reports in Oct, one each in Dec, Jan and Feb and one late bird that was found in Apr. Our latest bird was discovered by Kathleen Spicer in an apple tree in her yard in Apple River, Cumberland on 31 Jan 2015, representing Nova Scotia's 8th report. (McLaren, 2012)

Figure 1. Fieldfare in Apple River, Cumberland - 27 Feb 2014. Photo by Alix d'Entremont.

This rare North American visitor scores a Code 4 (Casual) on the ABA Checklist equating to less than annual occurrence in North America. I made the 1000 km trip from Pubnico to Apple River to see the Fieldfare (Fig. 1) at the end of Feb, and was about the 100th birder to so at the time. Listers flew in from as far as the southern US to see this vagrant bird. We are all very grateful for the kindness of both Kathleen and her husband Blaine for being so accommodating to the many birders visiting their private home.

Howell et al. (2014) describe first year Fieldfares as typically duller than adults with whitish tips to retained juvenal greater coverts. The Apple River bird appears fairly vibrant but early photos do show what looks like moult contrast in the greater coverts indicating that it is likely a first-winter bird.

This European visitor (Turdus pilaris) is closely related to our American Robin (Turdus migratorius), both are members of the genus Turdus. They are structurally similar (Fig. 2), but the Fieldfare is slightly larger.

Figure 2. American Robin (L) vs. Fieldfare (R)Photos by Alix d'Entremont.



References:
Howell, S.N.G.,  I. Lewington & W. Russell. 2014. Rare Birds of North America. Princeton University Press

McLaren, I.A. 2012. All the Birds of Nova Scotia: status & critical identification. Gaspereau Press Ltd, Kentville, N.S., Canada