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 009

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 009 positioned on open tarmac next to nest 008 on breakwater 1 west of T-split.
  • Uncertainty on ID, male is sub-adult Caspian Gull cachinnans, female is assumed hybrid female argenteus x cachinnans.
  • The male Caspian Gull was not present at this location in 2021.
location Nest location on April 15th, 2020. Eggs April 15th, 2020: 2 eggs clutch. Eggs April 27th, 2020: 3 eggs clutch.
 
partner 1 May 7th, 2020: male cachinnans 5CY? May 7th, 2020: male cachinnans 5CY? May 7th, 2020: male cachinnans 5CY?
 
partner 2 May 7th, 2020: female cachinnans x argenteus? May 7th, 2020: female cachinnans x argenteus? May 7th, 2020: female cachinnans x argenteus?
 
pulli May 21st, 2020 pullus n[F|Z]. May 21st, 2020 pullus n[F|Z]. May 21st, 2020 pullus n[F|0].
 

Visits and data.

datum: egg no: width (mm) length (mm) volume (cm3):  water test on April 27th:  
15-04-2020 A 50,5 67,2 86,29 90 - floating, 3mm above surface 2 eggs in nest.
15-04-2020 B 50,6 71,9 92,69 90 - floating, 3mm above surface
       
27-4-2020 C 47,5 70,9 80,54 90 - hafway in water 3rd egg now as well in nest. Female (hybrid?) at nest.
  sum nest: 259,52
07-05-2020 eggs     All eggs intact.
   
21-05-2020 pullus     Nest empty, but 2 chicks near nest and ringed. Pullus n[F|Z].
21-05-2020 pullus     Nest empty, but 2 chicks near nest and ringed. Pullus n[F|0].