Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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

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Cachinnans - nest Lelystad 035

General remarks:

  • Eggs: Volume measured by Stonehouse (1964) and Spaans & Spaans (1975), which make comparison possible with data from Texel (Camphuysen pers comm 16.04.2020).
  • Nest 035 positioned at breakwater 1 east of nest 28 (5 meters). Code added to lookout block of parent.
  • ID certain in 2020, both parents are Caspian Gull cachinnans.
  • ID certain in 2021, same two parents, Caspian Gull cachinnans.
location April 16th, 2021: partners near nest. April 16th, 2021: partners near nest. .
   
eggs April 27th, 2020: 3 eggs clutch. April 16th, 2021: 2 eggs clutch. .
   
partner 1 May 7th, 2020: cachinnans female. May 7th, 2020: cachinnans female. May 7th, 2020: cachinnans female.
 
  April 16th, 2021: cachinnans female. April 16th, 2021: cachinnans female. April 26th, 2021: cachinnans male.
 
partner 2 May 7th, 2020: cachinnans male. May 7th, 2020: cachinnans male. May 7th, 2020: cachinnans male.
 
  2021: cachinnans male.    
     
pulli May 21st, 2020: pullus n[F|V]. May 21st, 2020: pullus n[F|W]. June 8th, 2021: 2 large unringed chicks.
 
  July 12th, 2022: hybrid pullus nest 141-2022.    
     

Visits and data.

date: egg no: width (mm) length (mm) volume (cm3):  water test on May 7th:  
07-05-2020 A 50,3 70,4 89,68 90 - floating, 7mm above surface 3 eggs in the nest.
07-05-2020 B 50 77,8 97,93 90 - floating, 5mm above surface  
07-05-2020 C 50,6 74,9 96,56 90 - floating, 6mm above surface
  sum nest: 284,17  
         
21-05-2020 pulli     1 egg intact, but embryo dead. Two chicks here, ringed n[F|V] & n[F|W].
         
date:        
16-04-2021 Both adults at the nest, with 2 eggs. One partner sneeks from the nest, other partner guarding at blocks.
  egg no: width (mm): length (mm): volume (cm3):  water test on April 16th:  
  A egg 50,9 71,1 92,75 0 - flat on bottom  
  B egg 51,2 72,9 96,22 20 - flat on bottom  
         
26-04-2021 Both adults at the nest.
         
06-05-2021 Only C-egg measured.
  egg no: width (mm): length (mm): volume (cm3):  water test on April 16th:  
  A egg       5 mm - floating  
  B egg       7 mm - floating  
  C egg 49,4 72,2 88,71 3 mm - floating  
      sum nest: 277,68    
   
13-05-2021 No visit. Camilla is trapping a Spoonbill here.
   
15-05-2021 No visit.
   
28-05-2021 1 old egg in nest (rotten). 2 chicks not found in dense vegetation.
   
08-06-2021 Pictures of 2 large chicks. Attacking parents.
         
26-06-2021 2 large chicks fly away, to open water.