Great Black-backed Gull (Larus marinus)
(last update: October 12, 2011)
Great Black-backed Gull adult June
This page is enlarges upon the status of Great Black-backed Gulls in Morocco. see: Morocco Birds Blog.
Larus marinus in Morocco
A new breeding bird species for Morocco and Africa: the Great Black-backed Gull Larus marinus. The species is found breeding in Khniffiss Lagoon, southern Morocco.
Since the discovery of four displaying Cape Gulls [Larus dominicanus vetula] in Khniffis Lagoon, Morocco in February 2008, the site has become a popular destination for Western Palearctic birders. The Cape Gulls were apparently residents and the number increased to a maximum of ten adults in April and May 2009, and breeding took place the same year. In May 2010, after analysing photographs of 'Cape Gulls' from the site in April 2010, it was discovered that all the photographed birds from that month were, in fact, Great Black-backed Gulls [L marinus]. An analysis of as many photographs as could be found from the area revealed that only two [ad 20 May 2009, 2 ads 7 Jul 2010], probably three [2 presumed ads 23 Apr 2009], of the records supported by pictures showed Cape Gulls. All the rest either showed Great Black-backed Gulls or were too poor in quality to show which species they portrayed, while one picture [29 Apr 2010] showed an adult apparent hybrid, probably a Yellow-legged [L michahellis] x Great Black-backed or Yellow-legged x Cape Gull. Up to six adult Great Black-backed Gulls were at Khniffis Lagoon during at least February to July 2010, with one pair apparently nesting, while a pair of Cape Gulls were also apparently on territory on the island in Khniffis Lagoon on at least 7th July. In January 2011, birders aware of the situation made thorough searches in the lagoon by boat and found ten Great Black-backed Gulls, but no Cape Gulls.
Norman van Swelm wrote the following in Frontiers of Identification on 11 Mar 2011:
“Great Black-backed Gull is breeding in Africa according to Olof Jönsson in Birding World 24(2):68-76 just out. In 2009 a presumably full Kelp pair and a mixed pair Kelp Gull L. dominicanus x Atlantic Gull L. atlantis were found nesting after 5-10 Kelp Gulls were seen displaying on the Atlantic coast of southern Morocco.
Lee Evans wrote (also on 11 Mar 2011):
"I have just returned from Khenifiss Lagoon in southern Morocco where these large black-backed gulls breed and studied these birds again after initially believing all 10 were Cape (African Kelp) Gulls. Two individuals are fairly typical adult Cape Gulls, but the other six adults I recorded were pale-eyed, pinkish or pinkish-grey-legged individuals resembling Great Black-backed Gull. They all appeared to be paired up and were displaying and were present at the island breeding colony shared with Atlantic Yellow-legged Gulls.
Rafael Matias wrote (on 14 Mar 2011):
Please take a look at this short note, as it could be relevant for the discussion (just published online): HERE. It's in Portuguese but I think it's quite easy to figure out: Mixed pair of marinus x michahellis in Portugal.
Go-South and the Moroccan Rare Birds Committee (Commission d’Homologation Marocaine) released a small report entitled “African Cape (Kelp) Gull Larus dominicanus and Great Black-backed Gull at Khnifiss”. The report explains how some of the reports analysed by the Moroccan Rare Birds Committee (MRBC) in its reports #15 et #16 (Bergier et al. 2010 and 2011) should be interpreted in light of the article of Jönsson (2011). The following is extracted from that report which includes other analysis of records previously analyzed by the MRBC and a table showing the main differences between the two species in the field.
The status of these two species at Khnifiss has been analyzed by Jönsson (2011):
Update 3: hybrids
Vincent Legrand posted in netfugl a photograph (the one below) of some “large and dark backed gulls” photographed in Khniffis Lagoon on 19 March 2011 with the following comment: “Found just before dusk after 2 full days of intensive research. At least, we saw not less than 13 Great Black-backed Gull on the same spot (2nd winter 2, 3th winter 1, subadult/adult 10 togheter with a strange looking 3th/4th winter GBBGull a Cape Gull-like at more than 30 meters).
As a response to Vincent Legrand’s pictures, Martin Garner posted the following in BirdingFrontiers :
"On the Atlantic coast of Morocco the conundrum of the large and dark backed gulls continues to play out. Both Cape Gulls and Great Black-backed Gulls have been seen, what seems uncertain is how many of each species have occurred at different times. Enter the other element of small pioneering gull colonies: the high incidence of hybridization. You can begin to imagine the problems!
|Great Black-backed Gull (Larus marinus) adult: June 27 2003, Boulogne sur Mer, France (50.42 N - 01.34 E).|