Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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

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Caspian Gull cachinnans 5.N 1CY, May - June 2022, Lelystad, the Netherlands. Picture: Thijs Horst & Mars Muusse.

Red tibia ring r[5.N] and metal NLA 5.625.113, ringed as pullus Larus cachinnans at nest 110 on May 17 2022 in colony Lelystad, the Netherlands. Ringer: Herman Bouman.
ID uncertain, one parent is Caspian Gull cachinnans, other parent unknown (possibly sub-adult Herring Gull?).

Visits and data 2022 for nest 53 (coded 110 in 2022):
Estimation egg laying: A-egg = April 9 2022. Estimating hatching = May 7 2022.

    length (mm) width (mm) volume (cm3):  water test on April 15th:     
15-04-2022 A egg 67,8 50,3 -- 20 gr - tip bottom    
  B egg 68,8 49 -- 20 gr - tip bottom    
  C egg 69,8 50,9 -- 30 gr - tip bottom    
  Code "110" sprayed on block. Within 10 minutes afetr leaving, 4 (!) cachinnans at this spot.
               
    length (mm) width (mm) volume (cm3):  water test on April 27th:     
27-04-2022 A egg -- -- -- 3 mm - floating    
  B egg -- -- -- 3 mm - floating    
  C egg -- -- -- 1 mm - floating    
   
17-05-2022 Ringing chicks (chicks are approx 8 days old): sub-adult cachinnans attacks us. Is this parent 2? Adult cachinnans present too.
    metal darvic mass      
  pullus NLA 5625112 r-5P 180      
  pullus NLA 5625113 r-5N 219      
   
    metal darvic mass wing H+B bill
30-05-2002 pullus NLA 5625187 r-7D 734 175 97,8 39,9
Check: really pullus from this nest?  
One adult cachinnans is guarding near chicks = parent 1. But 3 more cachinnans present; likely nest 110 and 113 combined.
   
21-06-2022 r-7D and r-5P and one unringed chick (sibling?) swim near nest 109. Also stand on blocks.
   
28-06-2022 r-7D and r-5N picture.
   
28-06-2022 r-7D and r-5P picture. All 3 ringed chicks have fledged.

below: Caspian Gull cachinnans 5.N 1CY, June 28 2022, Lelystad, the Netherlands. Picture: Thijs Horst & Mars Muusse.

r[5.N] cachinnans from nest 110. Picture: June 28th, 2022.
Fledged. Sibling r[5.P] & r[7.D] also fledged.

below: Caspian Gull cachinnans 5.N 1CY, May 17 2022, Lelystad, the Netherlands. Picture: Mars Muusse.