Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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


Cachinnans - nest Lelystad 016

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 016 positioned at breakwater 2, eight meters east of nest 017 (which has a huge mark on a block).
  • ID uncertain in 2020, assumed to be hybrid (?) Caspian Gull cachinnans, on P10 patterns with much black and lacking strong hooked angle of white tongue.
  • In 2021 only one observation of an adult cachinnans on look-out with empty nest. Wingtip pattern does not match birds of previous season.
location Nest location on April 15th, 2020: 2 egg clutch. Adult with strong yellow legs, April 16th, 2021. .
partner 1 May 7th, 2020. May 7th, 2020. Adult with strong yellow legs, April 16th, 2021.
partner 2 May 7th, 2020. . .

Visits and data.

date: egg no: width (mm) length (mm) volume (cm3):   
15-04-2020 A 51 71,2 93,24 2 eggs in the nest.
15-04-2020 B 50,5 70,6 90,65  
  sum nest: --
27-04-2020 eggs     3rd egg not measured.
21-05-2020 --   Empty nest. No pulli found, but lots of shit traces (nest recently occupied).
16-04-2021 --   Bird in blocks, look-out near nest. Nest is empty.