Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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International trend
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Site characteristics
Breeding biology
Fecundity
Food resources
Nonbreeding season
Breeding species
Hybrid scores
Ring codes
Future

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 - past & future

POPULATION SIZE

Obviously, Caspian Gull is a relatively early breeding species in this colony, and many birds arrive in March, when observing adults at nest location is not hampered by tall green vegetation. Therefore, estimations for the population size are assumed to be accurate.
From the kayak, at approx 40 meters distance, we observed guarding birds on the breakwaters. We then landed, searched for the eggs and placed code flags on a bamboo stick near the nest. We monitored 41 coded nests in 2020. Several nests appeared to belong to either Herring Gull or Lesser Black-backed Gull. A total of 32 nests had at least one parent Caspian Gull.
We also marked codes using paint spray, on blocks that were easily visible from the water.

For most nests, the big distance to neighbouring nests made countings easy. However, for some location we found clusters of nests, and especially in these clusters we may have missed breeding pairs.
In 2020, we did not estimate breeding numbers for neither Herring, nor Lesser Black-backed Gull.

Table 1 below:
Number of observed individuals (not pairs, not necessarily breeding) of 3 gull species at colony Kreupel - Flevoland, the Netherlands.
Note: decreasing numbers for Herring Gull may be related to the recent realisation we have to split the silvery-backed breeders into two species, Herring Gull and Caspian Gull. Also, breeding numbers for Herring Gull already fluctuated quite a lot, therefore we have to see if this is a 'genuine decrease' for that species.

Table 2 below:
Breeding gull species at colony Lelystad - Flevoland, the Netherlands. Caspian Gull pairs is with at least 1 partner = cachinnans.

Below: Observations of Larus cachinnans outside the breeding season at location 'Oostvaardersdijk' - Lelystad, the Netherlands.

(To add: bar graph with data).

Indien bekend: staafdiagrammetje aantalsontwikkeling kolonie.
Waarn.nl plot kaartje winterwaarnemingen Flevo.
Indien bekend staafdiagrammetje ontwikkeling Kreupel.
Broedende cachen in Nl tussen 2015-2019 indien bekend. Kaartje daarvan.
Kaartje Waarn.nl met mei-juli data adulte cachen in Nl?

Cachinnans breeding in the Netherlands - season 2019 in Flevoland.

In 2020, we extensively monitored breeding Caspian Gulls at colony Lelystad. However, the previous year, breeding season 2019, Albert de Jong also paid three visits to Lelystad, and, together with Roland-Jan Buijs, ringed several chicks on May 16 2019.

For consistency, nests are coded as in 2020

nest 002, one parent is 7CY cachinnans y[PNED].

nest 005, one parent is 8CY cachinnans y[PLDP].

nest 006, one parent is 9CY cachinnans y[PESV].

nest 008, one parent is adult female cachinnans g[XLDT].

nest A2019 with cachinnans.

nest B2019 with cachinnans.

nest C2019 with cachinnans.

nest D2019 with cachinnans.

nest E2019 with cachinnans.

nest F2019 with cachinnans.

nest G2019 with cachinnans.

Caspian Gull Larus cachinnans P:G76 3CY at Lelystad colony. A potential breeder in the near future?
June 02 2020, Lelystad, the Netherlands.

Ringed as pullus on May 13 2018 in a mixed "Caspian Gull colony" at WYSPA NA RZ.WISŁA,KĘPA ADBRZESKA, OTWOCK POLAND. Ringer: Marcin Sidelnik.