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 034

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 034 positioned at breakwater 1, called "branch-nest" (3 white stripes on dead branch), between y[PNED] and T-split. Two meters from nest 33.
  • ID in 2020 certain, male is Caspian Gull cachinnans, female is Herring Gull argenteus. Same pair in 2021.
location May 7th, 2020: nest location - stripes on branch. May 7th, 2020: 3 eggs. March 23rd, 2021: nest location - stripes on branch.
 
partner 1 May 7th, 2020: female argenteus. May 7th, 2020: female argenteus x male cachinnans. March 23rd, 2021: female argenteus.
 
partner 2 May 7th, 2020: male cachinnans. May 7th, 2020: male cachinnans. March 23rd, 2021: male cachinnans.
 
pullus May 21st, 2021: pullus b[F|8]. May 21st, 2021: pullus b[F|9]. May 21st, 2021: pullus b[F|+].
 

Visits and data.

date: egg no: width (mm) length (mm) volume (cm3):  water test on May 7th:  
07-05-2020 A 50,8 70,3 91,34 90 - tip at bottom. 3 eggs in the nest, one partner argenteus, one partner cachinnans.
  B 49,8 73,9 92,28 90 - tip at bottom.  
  C 47,3 76,3 85,95 90 - tip at bottom.
      sum nest: 269,57    
21-05-2020 eggs     Still 3 eggs present.
         
date:        
24-03-2021 2 adults at this location.
         
06-05-2021 2 adults guarding at blocks. Red flag "71" placed to mark location.
  egg no: width (mm) length (mm) volume (cm3):  water test on May 6th:  
  A 50,7 74,5 96,42 90 - tip at bottom.  
  B 50,3 70,3 89,56 90 - tip at bottom.  
  C 50,4 71,1 90,93 90 - tip at bottom.  
      sum nest: 276,91    
   
13-05-2021 no visit, Camilla is trapping a Spoonbill.
         
15-05-2021 nest with 3 eggs. Flag put up again, for it was not visible.
         
    metal ring plastic head + bill:    
28-5-2021 pullus .5559422 b-F|8 64    
  pullus .5559423 b-F|9 52    
  pullus .5559424 b-F|+ 62    
         
08-06-2021 1 adult at this location.