Audouin's gull is considered by many to be the most beautiful of all gulls and it's also one of the rarest in world terms, with a population (I think) of about 10,000 pairs. It's strictly pelagic and does not usually occur inland or scavenge on rubbish tips like many other species of gull. Audouin's gull provided me with possibly the highlight of this trip, I've never seen so many in the region before. In Portugal I saw at least 45 individuals at seven sites where I had never recorded them before, from Faro to as far west as Carrapateirra, just north of Cape St. Vincent. Then when we moved towards Doñana and Seville we came across the largest flock I have ever seen away from the breeding sites, a minimum of 148 birds in the marina at Mazagon, Huelva. Some birds at the latter location sported white darvic rings and one of these I was able to read, which has provided me with at least some information as to the origin of these birds, see below. I'm not really sure if these are unusual numbers and if they are, why they should be occurring now, but certainly in 30 years of visiting the area I've never seen so many.
CAA7 was ringed on 14 June 2016 as a chick in the breeding colony at Port de Tarragona, Spain, about 100km south west of Barcelona. That stretch of coastline including the Ebro Delta has the largest concentration of breeding Audouin's gulls in the world. Whilst looking into this, I came across this scientific paper:
Oro, D. & Martinez, A. 1994. Migration and dispersal of Audouin's Gull Larus audouinii from the Ebro Delta colony. Ostrich 65:225-230
Interestingly there is a table in this paper which shows (with a little maths!) that between 1985 - 1992 out of 242 recoveries in the period July - October, 64 were from SW Iberia (i.e. the Atlantic side of Gibraltar), whereas in the period November - February from 98 total recoveries, only 2 were from SW Iberia. So from that information at least it would appear that in February 2019 there may well have been unusually high numbers of Audouin's gulls in Algarve and western Analucia.
Mazagon marina, Spain.
Interesting that virtually every bird is an adult.
The walk from Carrapateirra is stunning, taking in the magnificent Praia da Bordeira. What a place to see Audouin's gull, what a place for a walk!
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