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 058

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 058 on breakwater dam 1 south section, 'nest with buoy', behind willow, easternmost cachinnans nest in south section. Easy to trap the adults here in future (season 2022?).
  • ID uncertain in 2021, one is 4CY-type and match pure Caspian Gull cachinnans. Other is 5CY uncertain cachinnans, with "hybrid type" P10 pattern and bill shape rather bulbous.
  • ID uncertain in 2022, one is 5CY Caspian Gull cachinnans. Other is unknown.
location April 24th, 2021. April 24th, 2021. April 24th, 2021.
 
eggs May 13th, 2021: A egg hatching. May 13th, 2021: A & B chicks hatched. May 4th, 2022: 2 eggs.
 
partner 1 April 26th, 2021: moulting cachinnans parent, "4CY". April 26th, 2021: moulting cachinnans parent, "4CY". April 26th, 2021: moulting cachinnans parent, "4CY".
 
partner 1 April 11th, 2022: cachinnans 5CY. April 11th, 2022: cachinnans 5CY. May 17th, 2022: cachinnans 5CY.
 
partner 2 May 13th, 2021: 5CY, P10 tongue without angle. May 13th, 2021: 5CY, P10 tongue without angle. May 13th, 2021: 5CY.
 
pulli May 28th, 2021: cachinnans pulli b[F|V] and b[F|W]. May 17th, 2022: hick r[5.F]. .
   
prey May 17th, 2022: carp and Rudd. . .
     

Visits and data.

date:            
24-04-2021 One partner is sub-adult. Nest allows trapping breeders, easily. 3 eggs in nest.
  egg no: width (mm) length (mm) volume (cm3):  water test on April 24th:   
  A egg 46,2 75,3 80,92 60 - tip bottom  
  B egg 48,3 73,7 86,57 35 - tip bottom  
  C egg 48,9 72,9 87,77 25 - tip bottom  
  sum nest: 255,26    
   
26-04-2021 Breeding bird is moulting sub-adult (4CY). Also 5CY present on bread, but really bird of nest 58?
   
13-05-2021 Partner 2 is 5CY bird! 4CY also patrolling over nest. 5CY bird chasing neighbour Lesser Black-backeds.
  3 eggs just hatching.
   
15-05-2021 C egg with small cracks, will hatch soon.
  1 hatched chick, still wet, hatched this morning.
  1 hatched chick (1 day old). Mass = 66 gr.
   
28-05-2021   metal tibia mass head + bill  
  pull .5559407 b-F|V >400 82,8  
  pull .5559408 b-F|W >400 84,4  
   
08-06-2021 2 partners at nest. Chasing neighbouring Lesser Black-backeds.
   
26-06-2021 No activity.
   
date:  
   
11-04-2022 1 egg in nest
   
15-04-2022 egg no: width (mm) length (mm) volume (cm3):  water test:  
  A egg 49,6 71,3 -- not necessary.  
  B egg 50 66,3 --    
   
19-04-2022 5CY cachinnans at nest.
   
04-05-2022 2 eggs
   
09-05-2022 1 pullus, hatched this morning, exactly as scheduled. 2nd egg disappeared (predated?).
   
17-05-2022   metal tibia mass head + bill  
  pull .5625105 r-5F 231 --  
  prey: many small Carp and probably Rudd.
   
22-05-2022 5CY cachinnans at nest.