Larus cachinnans in the Netherlands

(last update: August 16, 2020)

Coordinators:
Albert de Jong
Leon Kelder
Roland-Jan Buijs
Thijs Horst
Merijn Loeve
Mars Muusse

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Cachinnans - nest Lelystad 015

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 015 positioned at breakwater 2, just west of nest 017 (which has a huge mark on a block), hidden behind small prunus (avium?).
  • ID uncertain in 2020, on April 27th, a bird took off the nest with much black on P10 and broad band on P5. This is partner 1 (female). Partner 2 is cachinnans.
  • ID 2021: male 2021 is same male 2020. Also female 2021 is same as female 2020.
  • ID 2022: male cachinnans is the same bird as previous years. Female is Herring Gull argenteus.
  • ID 2023: male cachinnans is the same bird as previous years. Female is Herring Gull argenteus.
  • ID 2024: uncertain, one parent is Herring Gull argenteus.
location Nest on May 7th, 2020. Eggs April 15th, 2020: 3 egg clutch. May 13th, 2021 guarding cachinnans and michahellis (nest45).
 
location April 16th, 2021. Eggs April 16th, 2021: 3 egg clutch. May 15th, 2021: 1 cold egg & Roach (or Rudd hybrid).
 
  May 30th, 2022: again nest behind prunus. May 30th, 2022: 3 eggs.  
   
partner 1 May 7th, 2020: P9-P10 pattern diagnostic. May 7th, 2020: Caspian Gull type. May 13th, 2021: Caspian Gull type.
  \
partner 1 May 13th, 2021: Caspian Gull type. May 13th, 2021: P9-P10 pattern diagnostic. April 4th, 2023: mixed pair present.
 
partner 2 May 7th, 2020. May 7th, 2020. .
   
partner 2 April 26th, 2021: guarding female and male has a look too. April 26th, 2021. April 26th, 2021.
 
partner 2 May 30th, 2022: male cachinnans. May 30th, 2022: male cachinnans. May 14th, 2024: argenteus.
 
pullus May 28th, 2021: b[F|M]. May 28th, 2021: b[F|N]. June 21st, 2022: 2 unringed chicks (but H5N1 restrictions).
 
  July 15th, 2023: unringed hybrid juvenile. . .
     

Visits and data.

date:            
  egg no: width (mm) length (mm) volume (cm3):  water test on April 27th:  
15-04-2020 A 51,5 70,6 94,28 90 - floating, 3mm above surface  
  B 51,8 72,1 97,41 90 - floating, 3mm above surface  
  C 50,7 70,2 90,86 90 - floating, 3mm above surface  
  sum nest: 282,54
27-04-2020     One parent with much black on P10 and broad band on P5.
21-05-2020 pullus     Failed nest. No pulli, no shit, no food left-overs.
         
16-04-2021 egg no: width (mm) length (mm) volume (cm3):  water test on April 16th:  red flag 15 placed near nest.
  A egg 52,6 70,6 98,35 50 - tip bottom  
  B egg 51 72 94,29 40 - tip bottom  
  C egg 50,5 74,5 95,66 35 - tip bottom  
      sum nest: 288,30    
24-04-2021 2 eggs.     1 adult at blocks, guarding from look-out.
26-04-2021 Herring Gull tolerated on block in front of nest. Probably Herring from nest 15B.
  Also, female on look-out and male leaves the nest for a short break or to check everything is okay.
13-05-2021 Female often on look-out block close to block 17, raising confusion if this is the partner of nest 17.
15-05-2021 1 egg cold, unfertile. Measurements Monika Ballmann: 73.2x50.4 (probably labeled C-egg in April)
  2 chicks present in nest: Mass = 232 gr & Mass = 193 gr.
  Food in nest: Roach (this is often a fishermen's by-catch from traps 200 meters from the nest).
28-05-2021   metal tibia mass head + bill 2 chicks ringed.
  pullus .5559385 b-F|M 707 86,3  
  pullus .5559386 b-F|N 730 93,7  
08-06-2021 Both pulli swimming 100 meters from waterfront, right between dams with large bulkships approaching. Protected by 1 parent, made their way back to dam 2.
26-06-2021 Nest abandoned.    

Visits and data 2022:
Estimation egg laying: A-egg = ?. Estimating hatching = June 07 2022.

date:            
  egg no: width (mm) length (mm) volume (cm3):  water test on April 27th:  
30-05-2022 A 47,6 67   90 - floating, 3mm above surface  
  B 47,5 64   90 - floating, 3mm above surface  
  C 47,8 65,9   90 - floating, 3mm above surface  
  sum nest: --
30-05-2022 Adults: Herring Gull female and Caspian Gull male.
17-06-2022 Adult Caspian Gull male present.
21-06-2022 At least 2x unringed chicks present at nest site. No ringing anymore (H5N1 restrictions this year).
17-07-2022 At bread near nest (from the boat) several unringed birds in a flock, including rings from nest 14. No doubt, some are the offspring of nest 15.
17-07-2022 Adult Caspian Gull male is defending.
 
 
egg sizes & volume 2023
SPECIES NEST A_length A_width A_volume B_length B_width B_volume C_length C_width C_volume TOTAL NEST: known parents?
cach x teus 15-2023 67,3 49,2 82,02 68,3 47,2 76,61 65,4 47,4 73,98 232,62 same as 2022
ring pulli: 12-jun laying A egg: 8-mei hatch A egg: 5-jun
     
   
15-2023  
dam: dam 2 central
location: Between prunus trees, between 48 and 17. Near waterfront.
breeders: cach x teus
OBSERVATIONS:
09-04-2023 nest: no eggs, nest is ready. Male cachinnans with broken P5 band.
26-04-2023 nest: empty.
30-04-2023 nest: empty.
11-05-2023 nest: 3 eggs, measured.
18-05-2023 nest: 3 eggs.
27-05-2023 nest: 3 eggs. Late nest, (this year again) the hybrid chicks will not be ringed probably.
25-06-2023 Pulli: 1 large chick present, at least 1 nearly fledged (not classified as fledged yet).

Visits and data 2024.

NEST code parent 1 parent  2 A_length A_width A_volume B_length B_width B_volume C_length C_width C_volume TOTAL NEST:
015-2024 teus teus 68,9 50,3 87,77 64,8 50,9 84,53 64,2 49,6 79,52 251,83
  # eggs A-egg hatch # ringed chicks # all chicks # fledged chicks comments
  3 02-5-2024 31-5-2024
   
dam: dam 2 central
location: was 15 under prunus, between 17 and 48
parents? new?
   
ring pulli: 4 June
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
04-06-2024 .5631148 K / 15 teus 1CY 89          
04-06-2024 .5631149 K / 15 teus 1CY 106          
                           
OBSERVATIONS:
07-05-2024 eggs: 3 eggs, measured.
  nest: complicated locations 3x nests with 3 eggs, letters KLM:  left to right are nest 48 (M), nest 42 (L) & nest 15 (K)
14-05-2024 nest: 3 eggs.
  adult: Herring Gull.
04-06-2024 chicks: 2x ringed.