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 N|U 5CY, May 01 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-N|U and metal NLA 5.641.023, ringed as breeding 5CY Larus cachinnans on May 01 2025 at Lelystad, the Netherlands. Ringed by Roland-Jan Buijs ringing team (Mars Muusse / Thijs Horst / Fred Cottaar).

Recoveries:
31-05-2025 Lelystad (Bataviahaven), Flevoland, NL 5.230,00 N 525,00 E colourring read T. Horst & M. Muusse
13-06-2025 Lelystad (Bataviahaven), Flevoland, NL 5.230,00 N 525,00 E colourring read Thijs Horst
29-06-2025 Lelystad (Bataviahaven), Flevoland, NL 5.230,00 N 525,00 E colourring read T. Horst & M. Muusse

Data for nest g-M|9 & g-N|U 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
g-M|9 cach cach 71,2 49,9 67,1 48,9 66,5 48,5 3
dam: dam 2 T
location:
end of pier at T-split dam 2, underneath green lighthouse, new nest.
parents: New. Both Caspian Gulls trapped this season, now male is g-M|9 and female is g-N|U.
ringed:
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
28-04-2025 g-M|9 6254495 dam 2 lighthouse PONT M >4CY 463 1241 137,1 65,6 72,7 21
01-05-2025 g-N|U 5641023 dam 2 lighthouse PONT F 5CY 443 966 122,5 55,1 70 18,2  
31-05-2025 g-R|P 5641911 g-M|9 en g-N|U PONT pullus 522 ringed pullus
14-06-2025 g-R|P dam 2 WATER PONT pullus 746 CONTROL
OBSERVATIONS:
28-04-2025 nest
3 eggs, measured.
nest
male cachinans trapped on nest, now g-M|9
01-05 adult
trapped female, Male present as well
egg 3x eggs
31-05 chicks
trapped one chick, other 2 not found
09-06 chicks
g-R|P present and trapped, not measured
14-06-2025 chicks
g-R|P caught on water, probably only chick.

Visits and data for nest g-M|9 & g-N|U 2026.

2026 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-M|9 & g-N|U cach cach 72 50,6 68,8 49,4 67,2 50,3 3
 
ringed:
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
10-05-2026 Y-0:U .5646709 g-M|9 & g-N|U PONT   PULL 81  
10-05-2026 Y-0:V .5646710 g-M|9 & g-N|U PONT   PULL 121  
10-05-2026 Y-0:T .5646708 g-M|9 & g-N|U PONT   PULL    
               
OBSERVATIONS:
04-04-2026 nest 3 eggs, measured. Nest now 40 mtr towards centre of dam 2 Split.
27-04-2026 parents Both present.
10-05-2026 pullus 2x pullus ringed. 3rd chick not found.
26-05-2026 pullus 3rd pullus trapped at water, and ringed. Code is recycling from dead chick nest g-A|G (found dead on May 26 2026). Wet chick, not weighted.
  pullus Y-0:U also trapped at water.
  parents For several weeks now, it seems a 4CY Caspian Gull supports this nest: alarming and guarding at dam. Some cooperation???

below: Caspian Gull cachinnans N|U 5CY, May 01 2025, colony Lelystad, the Netherlands. Picture: Thijs Horst & Mars Muusse.

Some very small dark markings in primary coverts.

date darvic metal nest species sexe age wing mass head+ bill bill tarsus gonys barcode greyscale comments
1-5-2025 G-N|U .5641023 dam 2 T, green lighthouse PONT F 5CY 443 966 122,5 55,1 70 18,2   25B00661 Trapped by ringer.