Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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

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Cachinnans - nest Lelystad 044

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 044 discovered late in season (May 28th, 2021), when chick was ringed. Positioned at breakwater dam 2, 4 meters west of nest 48 (was nest 15B), still east from nest 14.
    Just behind blocks. Red mark "44" sprayed on block.
  • Location in 2022 is behind prunus trees, 10 mtr from waterfront, 20 mtr east of nest 14. In 2023 same location.
  • ID 2021 uncertain: partners unknown. One partner seems to be hybrid type "River Gull"
  • ID 2022: female Herring Gull and male hybrid type (same as male nest 44-2021).
  • ID 2023: same adults as 2022.
location May 28th, 2021. April 29th, 2022: code sprayed. April 29th, 2022: behind prunus trees.
 
nest April 29th, 2022: 3 eggs. April 26th, 2023: 3 eggs. .
   
partners May 1st, 2022: Herring and River Gull. May 1st, 2022: Herring and River Gull. June 18th, 2022: Herring and River Gull & g-7|X.
 
partner 1 June 8th, 2021. June 8th, 2021. June 8th, 2021.
 
partner 1 June 8th, 2021. June 8th, 2021. .
   
partner 1 April 29th, 2022: male hybrid type. April 29th, 2022: male hybrid type. April 29th, 2022: male hybrid type.
 
pullus May 28th, 2021: pullus b[F|T]. May 17th, 2022: 2x pullus only metal ring. May 30th, 2022: pullus r[6.Y].
 
  June 25th, 2023: g[7|W]. June 25th, 2023: g[7|X]. June 25th, 2023: g[8|N].
 

Visits and data.

date:            
    metal tibia ring mass head + bill  
28-05-2021 pull .5559405 b-F|T 443 69,6 Prey: worms.
   
08-06-2021 Higher on dam, 7 meters behind block 44, an adult Herring Gull type (hybrid type, we refer to as 'river gull') which may be one of the parents.
   
26-6-2021 Not visited.

Visits and data 2022 for nest 44:
Estimation egg laying: A-egg = April 19 2022. Estimating hatching = May 17 2022.

15-4-2022 empty nest
               
    length (mm) width (mm) volume (cm3):  water test on April 29th:     
29-04-2022 A egg 68,2 49,0 -- 80 gr - tip bottom    
  B egg 66,7 49,4 -- 85 gr - tip bottom    
  C egg 66,0 51,0 -- 80 gr - tip bottom    
One parent is argenteus (female partner)  
   
01-05-2022 female Herring Gull argenteus next to nest. River Gull male at blocks, guarding.
   
04-05-2022 Herring Gull at blocks near nest.
   
    metal darvic mass wing H+B bill
17-05-2002 pullus NLA 5625134 - 78 < 2 days od    
  pullus NLA 5625135 - 71      
A-egg is hatching.
 
    metal darvic mass wing H+B bill
30-05-2002 pullus NLA 5625176 r-6.Y 302 49 70 26,1
 
28-06-2022 1x Juvenile present, but no good view on legs to read the ring code.
 
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?
hybrid x teus 44-2023 68 51,3 90,10 67,6 51,2 89,22 66,7 50,6 85,99 265,31 same as 2022
ring pulli: 25-mei laying A egg: 20-apr hatch A egg: 18-mei
     
catch: date: metal: darvic: mass: wing: head+bill:
Pullus 18-5-2023 5.556.414 g-7|W 68 -- 50
Pullus 18-5-2023 5.556.415 g-7|X 46 -- 49
Pullus 18-5-2023 5.556.416 nn 48 -- 46,1
Pullus 27-5-2023 5.556.415 g-7|X 328 -- --
Pullus 27-5-2023 5.556.416 g-8|N 227 -- --
Pullus 18-6-2023 5.556.415 g-7|X 975 280 113,3 hybrid / Herring
Pullus 25-6-2023 5.556.416 g-8|N 870 286 105,9 hybrid / Herring
Pullus 25-6-2023 5.556.415 g-7|X 982 330 119,2 hybrid / Herring
   
44-2023 nest behind prunus
dam: dam 2 central
location: Is nest 44-2022. 20 mtr E of nest 14, behind trees.
breeders: River Gull-type (hybrid) x argenteus
OBSERVATIONS:
04-4-2023 adult: 2 adults at nest site.
09-4-2023 nest: no eggs, nest is ready.
26-4-2023 nest: 3 eggs measured, and water test: A: 50 - tip bottom
B: 30 - tip bottom
C: 40 - tip bottom
11-5-2023 nest 3 eggs.
18-5-2023 pulli: 3x chicks ringed. 2x colour rings, 1x metal (too small for darvic ring).
27-5-2023 pulli: 2x chick measured, 1x extra colour ring g-8|N.
18-6-2023 pulli: swimming: G-7|X trapped. Measured. Herring Gull-type wing pattern.
25-6-2023 pulli: 2 chicks swimming g-7|X and g-8|N. Fledged: 2x juveniles.