Larus cachinnans in the Netherlands

(last update: August 16, 2020)

Coordinators:
Albert de Jong
Leon Kelder
Roland-Jan Buijs
Thijs Horst
Merijn Loeve
Mars Muusse

Home

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

Caspian Gull cachinnans N|X 1CY, 2025, colony Lelystad, the Netherlands. Picture: Picture: Thijs Horst & Mars Muusse.

You can participate in this project too! Please send in your observations of colour ringed birds to: ring@buijsecoconsult.nl

Tibia G-N|X and metal NLA 5.641.026, ringed as pullus Larus cachinnans on May 13 2025 at Lelystad, the Netherlands. Ringed by Roland-Jan Buijs ringing team (Mars Muusse / Thijs Horst / Fred Cottaar).
Mother: adult Caspian Gull g-A|E.
Father: adult Caspian Gull g-M|+.
Nest: gA|E gM+ 2025. In 2025: g-N|X, g-N|Y & g-N|Z fledged. Fledging rate for this nest 2025 = 3,0.

Recoveries:
30-06-2025 Lelystad (Bataviahaven), Flevoland, NL 5.230,00 N 525,00 E colourring read Thijs Horst
09-07-2025 Lelystad (Bataviahaven), Flevoland, NL 5.230,00 N 525,00 E colourring read T. Horst & M. Muusse

Visits and data 2025 for nest g-A|E & g-M|+.

2025 parent 1 parent 2 A_length A_width A_volume B_length B_width B_volume C_length C_width C_volume
TOTAL NEST:
 # eggs
g-A|E cach cach 73,4 48,5 70 49,7 69,2 50 3
dam: dam 1 centraal
location:
dam 1, was nest r-CG 2024, under tree.
parents:
in 2025: ex male r-CG 2024, female is g-A|E (female partner of PAM0 in 2024).
ringed:
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys
28-04-2025 g-M|+ 6254496 nest g-A|E PONT M >4CY 470 1260 140,7 64,4 78,1 20,1
13-05 g-N|X 5641026 g-A|E & g-M|+ PONT pullus 218
13-05 g-N|Y 5641027 g-A|E & g-M|+ PONT pullus 191
13-05 g-N|Z 5641028 g-A|E & g-M|+ PONT pullus 240
09-06 G-N|X 5641026 PONT pullus 850 CONTROL
09-06 G-N|Y 5641027 PONT pullus 950 CONTROL
OBSERVATIONS:
10-04-2025 parents:
at nest: g-A|E female cachinnans. Also unringed cachinnans, which was male partner of r-CG in 2024 at this location.
    Where is cachinnans r-CG which was the female at this nest over the last years? Observed with few new male partners, with hybrid r-6X lately.
    Conclusion: male of r-CG (in 2024) remained at nest location, now bonding with g-A|E, ex-female of y-P:AM0 (2024). R-CG is alive and searching.
21-04 nest:
measured 3 eggs.
adult:
unringed male attacks.
23-04 adult:
attempt to trap unringed male. Failed.
28-04 adult:
trapped adult male cachinnans, now g-M|+. Pictures compared: is male 2024 in this nest.
13-05 pullus
3x pullus ringed.
09-06 chicks
3x pullus on water, 2 caught and measured, 3rd escaped.

below: Caspian Gull cachinnans N|X 1CY, July 09 2025, colony Lelystad, the Netherlands. Picture: Thijs Horst.

below: Caspian Gull cachinnans N|X 1CY, June 30 2025, colony Lelystad, the Netherlands. Picture: Thijs Horst.

below: Caspian Gull cachinnans N|X 1CY, June 09 2025, colony Lelystad, the Netherlands. Picture: Thijs Horst.

below: Caspian Gull cachinnans N|X 1CY, May 13 2025, colony Lelystad, the Netherlands. Picture: Thijs Horst & Mars Muusse.

date darvic metal nest species sexe age wing mass head+ bill bill gonys barcode comments
13-05-2025 G-N|X .5641026 g-A|E & g-M|+ PONT   pullus   218         Ringed pullus
09-06-2025 G-N|X .5641026 PONT pullus 850