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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Cachinnans - nest Lelystad 112

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 112 positioned on dam 1, just east of bend, 25 mtr west of PNED.
  • ID certain in 2022: parents are male Caspian Gull type (short tongue on P10 may indicate hybrid, otherwise nice cachinnans) and female Caspian Gull.
  • ID certain in 2023: male Caspian Gull same as 2022, female is Caspian Gull thayeri (formerly nest 29-2020, 29-2021, 135-2022).
location April 27th, 2022: nest location. April 27th, 2022: 3 eggs. April 26th, 2023: 3 eggs.
 
location April 26th, 2023: 3 eggs. . .
     
partner 1 May 1st, 2022: partner 1 is cachinnans. May 13th, 2023: female is cachinnans 'thayeri'. May 13th, 2023: female is cachinnans 'thayeri'.
 
partner 2 April 27th, 2022: partner 2 is cachinnans type. April 27th, 2022: partner 2 is cachinnans type. May 4th, 2022: partner 2 is cachinnans type.
 
partner 2 April 26th, 2023: male cachinnans. May 13th, 2023: male cachinnans with partner. .
   
pullus May 9th, 2022: pullus r[C.F]. May 17th, 2022: pullus r[5.W]. May 17th, 2022: pullus r[5.X].
 
pullus July 18th, 2023: juvenile g[7|R]. July 8th, 2023: juvenile g[7|S]. October 10th, 2023: juvenile g[8|Z].
 

Visits and data 2022 for nest 112:
Estimation egg laying: A-egg = April 3 2022. Estimating hatching = May 1 2022.

date:              
12-04-2022 adult near nest.  
               
  egg no: width (mm): length (mm): volume (cm3):       
15-04-2022 A 50,5 72,5 -- 50 - tip bottom 3 eggs  
  B 48,3 64,9 -- 70 - tip bottom  
C 51 71,7 -- 90 - tip bottom
sum nest: --
   
  egg no:     3 eggs, 1 adult has short white tongue on P10: hybrid?    
29-04-2022 A float - 4 mm          
  B float - 4 mm        
C float - 5 mm    
   
01-05-2022 Cach and hybrid type at nest.
   
04-05-2022 Cach at nest.
   
  metal darvic mass H+B      
09-05-2022 .5625057 r-C.F -- --
17-05-2022 .5625121 r-5W 515 85,9
17-05-2022 .5625122 r-5X 618 94,9
17-06-2022 No activity.
21-06-2022 No activity.
28-06-2022 r-CF 7 r-5W pictures. All chicks fledged: 3 out of 3.