Larus cachinnans in the Netherlands

(last update: December 24, 2021)

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Nests at De Kreupel 2021
nest r-02P4 20
nest w-201U 21
nest g-XLHD 21
nest r-KA 21
nest r-KB 21
nest r-KC 21
nest r-KD 21
nest r-KE 21
nest r-KF 21
nest r-KH 21
nest r-KJ 21
nest r-KK 21
nest A01 21
nest C03 21
nest C04 21
nest C06 21
nest D01 21
nest D03 21
nest D05 21
nest D06 21
nest D07 21
nest D08 21
nest E01 21
nest H01 21
nest L01 21
nest L02 21
nest L05 21
nest L06 21
nest L07 21
nest M01 21
nest M04 21
nest M06 21
nest Q01 21

Lelystad:
nest y-PNED
nest y-PESV
nest y-PLDP
nest y-PHSV
nest y-P:A02
nest y-P:U60
nest zy-MT
nest r-FB
nest r-FC
nest 001
nest 003
nest 006
nest 009
nest 011
nest 012
nest 013
nest 014
nest 015
nest 016
nest 016B
nest 017
nest 018
nest 019
nest 021
nest 025
nest 027
nest 028
nest 029
nest 031
nest 032
nest 033
nest 034
nest 035
nest 036
nest 037
nest 038
nest 039
nest 040
nest 041
nest 042
nest 044
nest 045
nest 046
nest 047
nest 048
nest 053
nest 055
nest 056
nest 058
nest 060
nest 062
nest 063
nest 065
nest 066
nest 067
nest 072
pair A
pair B

Cachinnans breeding in the Netherlands - nonbreeding season

In colony de Kreupel and in colony Lelystad we have ringed both Caspian and Herring Gulls. Some notes:

• For the after season dispersal we only use data for Caspian Gull or hybrid Caspian Gull birds, no other species.
• In the plots, we do not include observation of juveniles within the colony or within the very near vicinity of the colony, as this is no dispersal.
• We do include all observations of immature birds (2CY, 3CY) within the colony or within the very near vicinity of the colony.

DISPERSAL OF RINGED CHICKS

Below complete set of observations plotted (criteria, see above).
Period: up to November 2021.
Most southern bird - Caspian Gull cachinnans FV, November 07-11 2021, Caleta de Vélez (Harbourt), Málaga, Spain.
Recoveries east of colonies = 0 birds.
Observations abroad, U.K. = 10 birds, 50% of them at Cromer - Cley coastline.
Observations abroad, Belgium = 2 birds.
Observations abroad, France = 2 birds.
Observations abroad, Spain = 5 birds.
Observations abroad, Portugal = 3 birds.

Below: observations outside the colony, of ringed juveniles within the first 2 months (July - August).
Strong concentration of observations at Cromer - Cley, U.K., which is an almost direct line westwards from the colonies.

Below: observations outside the colony, of ringed juveniles in the period September - October.
This period still regarded as 'migrating months'.
Long distance birds already at Iberian coastline, including Caspian Gull cachinnans F|5 which reached Praia do Molhe Leste - Peniche, Portugal already by September 3rd, 2020.

Below: observations of ringed birds in the 1st winter period 1CY November - 2CY March.
This period regarded as 'first winter'.
Observations within 50 km range from colony = 7 birds.

Below: observations of ringed birds in the 1st summer period 2CY April - 2CY August.
This period regarded as 'first summer', birds in complete moult.
Observations within 50 km range from colony = 7 birds (100% of the observations).
No observations from abroad.

Below: observations of ringed birds in the period 2CY September - 2CY October.
Migration period, nonetheless most observations close to colonies.
Observations = 6 birds, of which 1 bird in NW France (is Caspian Gull cachinnans F9 which was still near the colony 3 weeks earlier).

Below: observations of ringed birds in the period 2CY November - adult December.
All observations of birds older than 2CY November, since we hardly have ringed pulli which have reached that age. have
Observations = 7 birds, of which 3 birds ringed at the nest as breeding adults. All 3 birds rather close near the colonies.

FOOD RESOURCES IN WINTER

Many observations along coastlines, which may indicate food trips by following fishing vessels.

FOOD COMPETITION IN WINTER

In summer in the North Sea region, fishing vessels often followed by Lesser Black-backed Gulls, a species that migrate south in winter and maybe leaving open a position for Caspian Gulls?