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 x argenteus - nest Lelystad 006

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 006 positioned on artificial breakwater 1 at T-split. Location is nest PLDP - 2020 (in 2021, PLDP moved to nest PESV).
    In 2023 location used by mixed pair Caspian Gull & Herring Gull.
  • Certainty on ID in 2021, breeders are male Caspian Gull cachinnans and female Herring Gull argenteus.
  • Certainty on ID in 2023, breeders are male Caspian Gull cachinnans and female Herring Gull argenteus.
  • No certainty on ID in 2024, 2x Caspian Gull cachinnans and 1x Herring Gull argenteus present.
location April 16th, 2021: male cach & female teus. April 12th, 2024: 1 egg. April 21st, 2024: 3 eggs.
 
eggs April 21st, 2024: 3 eggs. . .
     
nest April 16th, 2021: male cach & female teus. May 6th, 2021: male cach & female teus. June 8th, 2021: too many cachinnans!
 
nest April 27th, 2023. Caspian x Herring nest. April 27th, 2023. Caspian x Herring nest. .
   
partner 1 April 27th, 2023. Caspian "almost thayeri P10". April 27th, 2023. Caspian "almost thayeri P10". April 27th, 2023. Caspian "almost thayeri P10".
 
partner 1 April 26 2024: Caspian Gull is guarding. April 26 2024: Caspian Gull 2023 is neighbour? April 30 2024: Caspian Gull 2023 is neighbour?
 
partner 2 April 26 2024: River Gull type is incubating. April 26 2024: River Gull type is incubating. April 26 2024: River Gull type is incubating.
 
partner 2 May 14 2024: River Gull type. May 14 2024: River Gull type. May 14 2024: River Gull type.
 
pulli May 28th, 2021: pullus, likely wrong nest. May 14th, 2024: pullus g-C|B. .
   

Visits and data.

date:  
16-04-2021 Two adult at nest, photographed. Nest without eggs. Many Spoonbills breeding here, hampering visits in future.
   
24-04-2021 Correction on flag code. Now labeled "6". Nest abandoned, no eggs?
   
26-04-2021 No visit, Camilla is trapping a Spoonbill.
   
06-05-2021 egg no: width (mm) length (mm) volume (cm3):  water test on May 6th: 3 eggs in nest
  A egg 49,2 68,7 83,73 25 - tip at bottom
  B egg 50,7 71,7 92,80 30 - tip at bottom
  C egg 51,9 71,5 96,97 55 - tip at bottom
      sum nest: 273,50
       
15-05-2021 2 eggs in nest. Nest located at 'the flat stone' in dense, inaccessible Blackberry complex.
       
28-05-2021   metal tibia mass (gr) head + bill (mm)
  pullus .5559419 -- -- -- Chick is 1 day old. Only metal ringed. No certianty about species.
  1 egg: just hatching.
  In retrospect: this nest was situated 'too high' at dam 1, likely different nest. Hybrid nest is situated at flat stone, lower and central at dam (see May 15th).
       
08-06-2021 Sitiuation not clear: several cachinnans and argenteus here guarding 3 large chicks. Favorite place for chicks at the blocks near waterfront, below Blackberry complex.
 
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 6-2023 71,2 49,7 88,55 69,7 49,2 84,95 69,7 47,4 78,85 252,35 New nest.
   
006-2023 OLD LOCATION PESV
dam: dam 1 T-split
location: old nest yPESV, N of Elder bush (Vlierstruik), visible from West.
breeders: cach x teus
OBSERVATIONS:
09-04-2023 1 adult Guarding cach type with yellow legs.
27-04-2023 adult: 1x teus and 1x cach at nest location. Quickly returning. Should check for nest here.
Check cach from pictures 2022: this is a known bird (the 'almost thayeri'.)…
13-05-2023 adult: again, the cach with limpy left leg.
27-05-2023 nest: 3 eggs measured.

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:
006-2024     68,9 48,8 82,61 68 49,7 84,57 67 48,6 79,68 246,87
  # eggs A-egg hatch # ringed chicks # all chicks # fledged chicks comments
  3 11-4-2024 7-5-2024
   
dam: dam 1 T-split
location: Nest limping leg "mankevoetje", visible from west. Top of dam (was yPESV-20). Yellow smiley skippy placed near nest & Blue chair S.
parents? same as 2023?
   
ring pulli: 12-May
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
14-05-2024 g-C|B .5631199 nest 6 (stoel Z) PONT 1CY 141          
31-05-2024 g-C|B .5631199 nest 6 (stoel Z) PONT 1CY              
                           
OBSERVATIONS:
12-04-2024 eggs: 1 egg, measured. Yellow smiley skippy placed near nest Mankevoetje.
21-04-2024 eggs: 3 eggs, measured. 
nest: Blue chair placed = Blue chair South
26-04-2024 adults: Caspian Gull female is guarding, River Gull is incubating, partner 1-2023 (limpy leftie) is neighbour with Herring Gull.
30-04-2024 adults: Limy Leftie seems to nest just S of blue chair?
07-05-2024 eggs: 3x.
14-05-2024 chicks: 1x ringed.
eggs: 1x in nest.
31-05-2024 chicks: CONTROLL: g-C|B.