The results of two winter censuses of gulls, performed on the Spanish
Mediterranean
coast, in the provinces of Girona, Barcelona, Tarragona,
Castelló and Valencià in 1980
and 1981, are given
The results obtained were:
Species
1980
1981
Estimated minimum
Larus fuscus
5,401
4,807
6,000
Larus argentatus
27,616
21,591
30,000
Larus melanocephalus
15,593
12,571
18,000
Larus minutus
501,000
852,000
1,000
Larus ridibundus
59,321
54,961
75,000
Total:
108,432
94,781
130,000
The main concentrations of gulls were observed in Roses bay (\simeq 15,000 individuals),
Medes Islands (\simeq 15-17,000), Barcelona-Llobregat Delta (\simeq 8-9,000), L'Ametlla-Ebre Delta
(\simeq 22,00), Vinaròs-Castelló (\simeq 20,000), Albufera and surroundings (\simeq 15,000).
The most important novelties observed between this and another census realized
in the same area in the 1977 and 1979 winters (CARRERA et al., 1981a), are:
Larus fuscus: A remarkable increase in the censed figure, due to a better census
of the Castelló province fishing harbours (Benicarló-Grau), where the 50 % of the total
censed on the coast was found.
Larus argentatus: An increase of the censed figure due to a better counting of the
Medes Islands sleeping place and other littoral coast points. By checking the ratio adults/
subadults-immatures by province, we find that the percentage becomes more equal as
we move farther from the principal reproduction centres (province of Girona).
Two new winter recoveries of birds born in the Medes Islands, one in the Camargue
and the other in Castelló, are commented.
Larus melanocephalus: An increase of the censed figure due to a better census of
the fishing harbours of the province of Castelló, that had been subestimated in previous
census.
Larus minutus: The concentration of about 1,000 individuals at the Llobregat Delta
is mantained. Sporadic observations in other places of Catalonia are performed.
Larus ridibundus: The main reasons for the traditional low estimation of this species
are commented. A minimum estimated figure per province is given.
No observation of Rissa tridactyla, Larus canus, Larus marinus, Larus adouinii, is performed