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 065

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 065, 5 meters behind nest 29 (the thayeri) on breakwater dam 1, and 5 meters west of nest 4. marked with blue jerrycan from flotsam and jetsam.
  • ID certain in 2021, both breeders are Caspian Gull cachinnans, and both are sub-adults.
location April 24th, 2021. April 24th, 2021, nest with goose egg. April 24th, 2021.
partner 1 April 24th, 2021, with black in tail. April 24th, 2021, with black in tail. April 24th, 2021, with black in tail.
partner 2 April 24th, 2021, white tail. April 24th, 2021, white tail. .

Visits and data.

16-04-2021 Sub-adult partner present. Goose egg in the nest!?
24-04-2021 2 eggs in nest, one being the goose egg. Goose egg removed from nest. Gull egg measured.
  egg no: width (mm) length (mm) volume (cm3):  water test on April 24th:   
  A egg 49,8 72,3 90,28 45 - tip bottom  
26-04-2021 One partner present.
13-05-2021 Both partners present.
  1 chcick: 1,5 days old.
  1 chick: hatching
  1 egg: still in tact.
15-05-2021 No visit, thunder coming in.
28-05-2021 Alarming parent, with one pullus. But pullus not found in dense vegetation.
08-06-2021 4CY partner leaves nest location, loud alarming approaching canoe.