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 PLDP (2020: 005, 2021: 052, 2022: not breeding)

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 005 positioned in dense Blackberry vegetation, in vicinity of Spoonbill nests, on artificial breakwater 1 at T-split.
  • Certainty on ID in 2020, breeders are Caspian Gull cachinnans, one partner is ringed yellow PLDP and one unringed partner. Neighbours of yellow PESV (nest 006).
  • In 2021: same 2 partners, again Caspian Gulls cachinnans. Bird has moved to nest location of y[PESV]-2020. PESV not present in 2021.
location Nest in vegetation: 2020. Nest: April 16th, 2021. April 01 2022 at Almere dump. Not breeding this year at Lelystad.
 
eggs Eggs April 15th, 2020: 2 eggs clutch. Eggs April 27th, 2020: 2 eggs clutch. Eggs April 16th, 2021: 3 eggs clutch.
 
partner 1 May 7th, 2020: cachinnans y[PLDP]. May 7th, 2020: cachinnans y[PLDP]. April 15th, 2020: cachinnans y[PLDP].
 
partner 2 May 7th, 2020: cachinnans unringed. May 7th, 2020. May 6th, 2021.
 
pulli June 2nd, 2020 pullus unringed. May 28th, 2021: pullus b[F|5] probably C-chick. .
   

Visits and data.

date: egg no: width (mm) length (mm) volume (cm3):     
15-04-2020 A 50,4 71,9 91,96   2 eggs in nest.
15-04-2020 B 50,8 73,05 94,92
      sum nest: --
27-04-2020 eggs         Controlled: still 2 eggs.
 
07-05-2020 pullus     Nest is empty. Small chick next to nest (7 days old).
   
21-05-2020 pulli   Empty nest, no pulli found, but lots of shit-traces.
     
02-06-2020 pulli   Parent y[PLDP] with 2 chicks close by.
       
date:      
30-03-2021 PLDP and partner both present at blocks near waterfront.
       
16-4-2021 egg no: width (mm) length (mm) volume (cm3):  water test on April 16th, 2021:  
  A egg 51,3 75,2 99,64 45 - tip bottom 3 eggs in nest. 2 partners at nest, one is y[PLDP].
  B egg 50,6 77,2 99,52 35 - tip bottom
  C egg 50,5 77 98,87 30 - tip bottom
    sum nest: --    
       
24-04-2021 partner 2 is unringed. Code of nest changed to 52.
       
26-04-2021 No visit, Camilla is trapping Spoonbills here.
       
06-05-2021 2 chicks of few days old. 1 egg is hatching.
       
13-05-2021 No visit, Camilla is trapping Spoonbills here.
       
15-05-2021       mass (gr) head + bill (mm)  
  pullus     142 --  
  pullus 221 65,5 measurements Monika Ballmann.
       
28-05-2021   metal tibia mass (gr) head + bill (mm)  
  pullus .5559418 b-F|5 -- 87 probably C-chick.
       
08-06-2021 PLDP attacks us. Partner also present. No chick visible.