Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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


Cachinnans - nest Lelystad 016B

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 016B positioned high on breakwater dam 2, two meters west of coded block "16" ( huge mark on a block).
  • ID uncertain in 2021, assumed parent photographed on May 13th, 2021 is obvious Caspian Gull cachinnans.
location Nest location on top of dam April 16th, 2021. Nest April 16th, 2021: 2 eggs clutch. Nest April 24th, 2021: 3 eggs clutch.
partner 1 May 13th, 2021: uncertain, but probable cachinnans parent. . .

Visits and data.

16-04-2021 2 eggs egg no: width (mm) length (mm) volume (cm3):  water test on April 16th: 
    A 50,7 67,9 87,88 20 - flat on bottom
    B 49,9 69 86,51 15 - flat on bottom
24-04-2021 3 eggs         water test on April 24th: 
A       little hole, not dipped in water
    B       little scratch, not dipped in water
    C 45,9 64,3 68,21 90 - tip bottom
    sum nest: 242,59  
26-04-2021 no visit.    
13-05-2021 Alarming parent photographed in flight, but is this a parent of nest 16B??? Is cachinnans.
15-05-2021 1 cold egg = coded C-egg. No chicks found in dense vegetation.
28-05-2021 Alarming parent cachinnans. Nest is empty. Chicks not found in dense vegetation.
08-06-2021 Two partners present at look-out near nest.
26-06-2021 2 cold eggs! Strange, as nest was empty a month ago. Probably visit to wrong nest???