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

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Caspian Gull cachinnans B|+ adult, 2025, colony Lelystad, the Netherlands. 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-B|+ (re-use from 2024) and metal NLA 5.641.025, ringed as breeding adult Larus cachinnans on May 01 2025 at Lelystad, the Netherlands. Ringed by Roland-Jan Buijs ringing team (Mars Muusse / Thijs Horst / Fred Cottaar).

Recoveries:
09-07-2025 Lelystad (Bataviahaven), Flevoland, NL 5.230,00 N 525,00 E colourring read T. Horst & M. Muusse
06-09-2025 Lelystad (Oostvaardersplassen), Flevoland, NL 5.227,00 N 524,00 E colourring read Maarten Hotting

Visits and data 2025.

NEST code 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
n-F|+ & g-B|+ cach cach 75,2 50,2 73,6 50,4 71,8 49,2 3
dam:
dam 1 nest 60 cluster
location:
was nest 63, nest PAM0-2024, now n-F|+ in 2025
parents:
new: n-F|+ moved a few meters, up dam 2 towards Blackberry complex,
ringed: darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
23-04-2025 n-F|+ 5,552,921 Nest n-F|+ cach M 6CY 465 1144 137,3 67,7 72,3 19,7 6  
01-05-2025 g-B|+ 5641025 Nest n-F|+ PONT F >4CY 446 880 127 56,9 71,1 17,8 6  
25-05-2025 g-T|+ 5641859 n-F|+ & g-B|+ PONT pullus 380
31-05-2025 g-R|+ 5641922 n-F|+ & g-B|+ PONT pullus 437 FOUND DEAD, RING NOT REUSED
OBSERVATIONS:
20-03-2025 nest
n-F|+ again near nest 60 cluster
04-04 nest
n-F|+ again near nest 60 cluster
21-04 eggs
3x eggs measured,
nest
old PAM0 nest is now for n-F|+,
23-04 adult
CONTROL: trapped male n-F|+, incubating 3 eggs, We aimed for the partner,
28-04 nest
3 eggs, n-F|+ incubating
01-05 eggs 3 eggs
adult
Thijs's Chinaloop for trapping female, 2 times, 1x successful,
08-05 adult
F|+ present
25-05 NEST
1 chick ringed, 1 rotten egg, 3rd chick?
Food
2x roach, 2x duckling
31-05 chicks
g-R|+ ringed, not 100% sure if it belongs to this nest,
09-06 chicks
g-R|+ found dead

Tibia ring G-B|+ was used before in 2024, for pullus Larus cachinnans on May 14 2024 in nest 21-2024. This chick was found dead on June 29 2024 at colony Lelystad. Ring used again on May 01 2025 for adult.

below: Caspian Gull cachinnans B|+ adult, July 09 2025, colony Lelystad, the Netherlands. Picture: Thijs Horst.

below: Caspian Gull cachinnans B|+ adult, May 01 2025, colony Lelystad, the Netherlands. Picture: Thijs Horst & Mars Muusse.

date darvic metal nest species sexe age wing mass head+ bill bill tarsus gonys barcode greyscale comments ringer
1-5-2025 G-B|+ .5641025 Nest n-F|+ PONT F >4CY 446 880 127 56,9 71,1 17,8 6 25B00663 Trapped by ringer. Mars Muusse