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 064 y[PHSV]

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 064 "PHSV" on breakwater dam 1 south section, north side of dam (unvisible from parking lot). Easy to trap the adults here in future (season 2022?).
  • ID certain in 2021, both breeders are Caspian Gull cachinnans, y[PHSV] is 11CY and unringed adult partner.
  • ID certain in 2022, Caspian Gull cachinnans, y[PHSV] with same partner as previous season, though wingtip pattern slightly changed.
location May 13th, 2021. April 15th, 2022: nest moved 10 meters westwards. June 21st, 2022: 2nd attempt, 40 meters eastwards.
 
eggs April 24th, 2021. May 13th, 2021: hatching chicks. May 15th, 2021.
 
eggs May 9th, 2022: hatching date. May 17th, 2022: all 3 chicks dead in nest. June 21st, 2022: 1 egg in 2nd attempt by partner 2.
 
partner 1 April 26th, 2021: partner y[PHSV]. April 26th, 2021: partner y[PHSV]. May 13th, 2021: partner y[PHSV].
 
partner 1 May 9th, 2022: female cachinnans y[PHSV] now r[C.G]. May 9th, 2022: female cachinnans y[PHSV] now r[C.G]. May 9th, 2022: female cachinnans y[PHSV] now r[C.G].
 
partner 2 April 26th, 2021: unringed partner. April 26th, 2021: unringed partner. April 26th, 2021: unringed partner.
 
  May 13th, 2021: unringed partner. May 13th, 2021: unringed partner. May 28th, 2021: partner with fishline.
 
partner 2 April 11th, 2022: unringed male. April 11th, 2022: unringed male. April 27th, 2022: unringed male.
 
pulli May 28th, 2021: cachinnans pullus b[F|X]. May 28th, 2021: cachinnans pullus b[F|Y]. May 28th, 2021: cachinnans pullus b[F|Z].
 

Visits and data.

date:            
24-04-2021 2 partners present, one is y[PHSV] and unringed 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 49,4 75,7 93,01 45 - tip bottom  
  B egg 50,6 76,6 98,75 45 - tip bottom  
  C egg 51,6 73,7 98,80 65 - tip bottom  
  sum nest: 290,56    
   
26-04-2021 Both partners present. Partner 2 with small black spot on primary coverts.
   
13-05-2021 Both partners present.
  1 chcick: 1,5 days old.
  1 chick: hatching
  1 egg: still in tact.
   
15-05-2021 1 chick: mass = 88 gr.
  1 chick: mass = 107 gr.
  1 egg just hatching.
   
28-05-2021   metal tibia mass head + bill  
  pull .5559409 b-F|X >400 85  
  pull .5559410 b-F|Y >400 88,5  
  pull .5559411 b-F|Z >400 78,3  
  Partner 2 has fishgear in beak.
   
08-06-2021 2 partners at nest. partner 2 has no longer hooked with fishline.
   
26-06-2021 No activity.
   
date:  
15-04-2022 2 partners present, one is y[PHSV] and unringed adult. Nest has moved 10 meters to Blackberry complex. 2 eggs in nest.
  egg no: width (mm) length (mm) volume (cm3):     
  A egg 50,9 77,8 --    
  B egg 50,2 70,9 --    
             
19-04-2022 1 adult at nest.
             
27-04-2022 egg no: width (mm) length (mm) volume (cm3):  water test P-moulting adult
  A egg       4 mm - floating  
  B egg       4 mm - floating  
  C egg 51,6 71,7 -- 3 mm - floating  
  sum nest: 290,56    
   
01-05-2022 unringed partner at nest.
   
04-05-2022 PHSV at nest.
   
09-05-2022 3 eggs. One egg hatching with little hole; 1 egg with cracks. Trap adult at nest.
  Female cachinnans y-PHSV trapped. New rings: metal = NLA 5.625.054 & r[C.G].
  Biometrics: wing 446; tarsus 69,3; head+bill 127,8; bill 57,8; gonys 18,3; mass 944 gr.
   
17-05-2022 3 pulli dead in nest. Poisoned? About 4 days dead (avian flu?). Two adults present. End of season...
  mass tarsus        
  94 3,9        
  57 3,2        
  89 4        
   
02-06-2022 unringed male is still present at site. No sign of r[C.G].
   
17-06-2022 unringed male is still present at site. No sign of r[C.G].
   
21-06-2022 unringed male is still present at site. New nest is 40 mtr east of old nest, 1 egg. Also there: a sub-adult Herring Gull which may be the new partner.
  egg no: width (mm) length (mm) volume (cm3):     
  A egg 51,0 75,8 --