Great Black-backed Gull (Larus marinus)

(last update: July 12, 2015)

Great Black-backed Gull 4cy March

Great Black-backed Gull is highly variable in immature plumages, and ageing is not always straightforward. In general, 3rd cycle (4CY March) birds often show a complete black band on the bill and normally have a variable number of brown feathers in the wing-coverts. Sometimes there is black in the tail and especially the underwing-coverts are worth checking; immature brown markings may be difficult to detect in the blackish upperwing, but the white underwing-coverts show obvious brown crescents in immature plumage.

below: 2nd cycle birds (3CY January - April)

Great Black-backed Gull (Larus marinus) JH688 2nd cycle (3CY), February 23 & 27 2015, Scheveningen, the Netherlands (Mars Muusse). Ringed as pullus at Buholmskjæret, Kristiansand, Vest-Agder, Norway. Still many immature feathers in the scapular region. Lower tertials with much marbling, a pattern that continues on the secondaries. 2nd generation primaries hardly have white tips and only weak mirror on P10.

Great Black-backed Gull (Larus marinus) BTO J0658 2nd cycle (3CY), February 27 2007, Boulogne-sur-Mer, France (Jean-Michel Sauvage). Ringed as pullus at Burhou near Jersey, U.K. More advanced looking bird with many blackish scapulars. Again, lower tertials are 2nd generation, with much lining; a pattern repeated on the secondaries. Broad tail-band and central primaries brown with very small tips. Weak mirror on P10.

Great Black-backed Gull (Larus marinus) 1UK 2nd cycle (3CY), May 01 2014, Howth, Ireland (Graham Prole). Ringed on the island Irelands Eye, near Dublin, Ireland White on head and underparts after the pre-alternate moult.

below: 3rd cycle birds (4CY January - April)

Great Black-backed Gull (Larus marinus) JH283 3rd cycle (4CY), January 10 2013, Boulogne-sur-Mer, France (Jean-Michel Sauvage). Ringed as pullus at Merra, Lindesnes, Vest-Agder, Norway. Overall adult-like upperparts with various brown feathers mixed in. Tips on primaries larger than in 3CY. Only limited black in tail. Full band on bill.

Great Black-backed Gull (Larus marinus) JA615 3rd cycle (4CY), February 01 2011, Scheveningen, the Netherlands (Theo Muusse). Ringed as pullus at Leiesundholmen, Mandal, Vest-Agder, Norway. Obvious mirrors on P9 and P10. Adult-like inner primaries and secondaries (grey centre with bold white tip).

Great Black-backed Gull (Larus marinus) JA615 4cy: March 13 2011, Scheveningen, the Netherlands.

Great Black-backed Gull (Larus marinus) sub-adult: March 16 2003, Boulogne-sur-Mer, France (50.42 N - 01.34 E).

Great Black-backed Gull (Larus marinus) sub-adult: March 17 2003, Boulogne-sur-Mer, France (50.42 N - 01.34 E).

Great Black-backed Gull (Larus marinus) sub-adult: March 17 2003, Boulogne-sur-Mer, France (50.42 N - 01.34 E).

Great Black-backed Gull (Larus marinus) sub-adult: March 20 2004, IJmuiden, the Netherlands (52.27 N, 04.33 E).

Great Black-backed Gull (Larus marinus) sub-adult: March 20 2004, IJmuiden, the Netherlands (52.27 N, 04.33 E)

Great Black-backed Gull (Larus marinus) sub-adult: March 2000, IJmuiden, the Netherlands (52.27 N, 4.33 E).
An individual much resembling an adult with most of the upper-parts jet-black. Both primary p9 and p10 show a mirror and the tail is predominantly white.