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 012

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 012 positioned below blue sign VHF20 at head of breakwater 2. Also many Spoonbills in this section of the colony.
  • Certainty on ID in 2020, both parents are sub-adult Caspian Gull cachinnans. Unsuccessful breeding attempt.
  • Certainty on ID in 2021, both are cachinnans, apparently same parents.
  • Uncertainty on ID in 2022: only one parent known, which is cachinnans.
location Nest location on April 15th, 2020. April 16th, 2021. April 19th, 2022.
 
eggs Eggs April 27th, 2020: 3 eggs clutch (very brownish). April 16th, 2021. April 15th, 2022.
 
partner 1 April 27th, 2020: cachinnans. May 28th, 2021. .
   
partner 1 May 28th, 2021: male cachinnans. June 8th, 2021. June 8th, 2021.
 
partner 2 May 7th, 2020: cachinnans. May 7th, 2020: cachinnans. May 7th, 2020: cachinnans.
 
partner 2 May 13th, 2021. May 13th, 2021. May 13th, 2021.
 
partner 2 April 29th, 2022. April 29th, 2022. .
   
pullus May 28th, 2021: pullus b-F|U. June 8th, 2021. .
   
pullus May 9th, 2022 pullus r[C.L]. May 9th, 2022 pullus r[C.M]. May 9th, 2022 pullus r[C.N].
 

Visits and data.

date:            
15-04-2020 egg no: width (mm) length (mm) volume (cm3):  water test on April 27th:  
  A 50,4 76,7 98,45 90 - tip on bottom 1 egg in nest.
           
27-04-2020 B 50,2 70,9 90,28 90 - tip on bottom Now 3 eggs in nest.
27-04-2020 C 50,6 71,3 92,24 90 - tip on bottom Eggs particularly brownish.
  sum nest: 280,97
21-05-2020 eggs     Nest with 3 rotten eggs. failed breeding attempt.
   
date:        
16-04-2021 egg no: width (mm) length (mm) volume (cm3):  water test on April 16th:  
  A 51,3 73,9 97,92 40 - tip on bottom 3 eggs.
  B 48,8 71 85,13 40 - tip on bottom Also this year: eggs brownish.
  C 51,2 76,3 100,71 35 - tip on bottom  
      sum nest: 283,76    
26-04-2021 No visit, Camilla is trapping a Spoonbill.
06-05-2021 Sub-adult bird is breeding and flies off to attack canoe, then starts patrolling. Photographed.
13-05-2021 Again bird photographed that belongs to this nest.
15-05-2021 Extensive control day for dam 2, including this nest. 3 chicks present, very well hidden in vegetation.
  A 193 gr Mass    
  B 182 gr Mass    
  C 152 gr Mass    
28-05-2021 Both adults on top of blue sign, alarming to chicks to hide. Photographed. Chicks present, but impossible to find them. Later, one chick swimming.
    metal tibia mass head + bill  
  pullus .5559406 b-F|U >400 99 Swimming chick north of dam 2 between fish traps, protected by (flying) parent.
08-06-2021 Sub-adult (5CY, with black in tail) protects 3 swimming chicks, north of dam 2 between fish traps.
26-06-2021 No activity near nest. Abandoned, juveniles fledged.
   
date:  
12-04-2022 2 adults at nest site.
15-04-2022 egg no: width (mm) length (mm) volume (cm3):  water test on April 15th:  
  A 47,2 76,3 -- 90 - float halfway 3 eggs.
  B 52 75,4 -- 3 mm - float  
  C 51,3 75,4 -- 90 - float halfway  
      sum nest: --    
29-04-2022 egg no:       water test on April 29th:  
  A       6 mm - float 3 eggs.
  B       6 mm - float  
  C       6 mm - float  
09-05-2022   metal darvic 3 pulli, 7 days old    
  pullus 5.625.062 r-C.L      
  pullus 5.625.063 r-C.M      
  pullus 5.625.064 r-C.N