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 048 (was nest 15B in 2021 & 2022)

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 048 was labeled "nest 15B" in season 2021, then renamed. Positioned at breakwater 2, just west of nest 015 (which has a mark on a block), hidden behind small prunus (avium?).
  • In 2022 and in 2023: exact same location.
  • ID certain in 2021: partners are Herring Gull argenteus and Caspian Gull cachinnans.
  • ID certain in 2022: partners are Herring Gull argenteus and Caspian Gull cachinnans. Same birds as 2021.
  • In 2023: same birds as 2022.
location Nest on May 7th, 2021 (with Albert de Jong) April 16th, 2021. April 26th, 2021.
 
eggs Eggs April 15th, 2021: 1 egg clutch. Eggs April 24th, 2021: 3 eggs clutch. May 9th, 2022: 3e eggs.
 
eggs Eggs June 26th, 2021: 2 eggs clutch as 2nd attempt. April 26th, 2023: 3 eggs clutch. .
   
courtship March 30th, 2021. March 30th, 2021. April 27th, 2023: Caspian Gull x Herring Gull.
 
partner 1 April 16th, 2021: female is Herring Gull. April 26th, 2021. may 30th, 2022: female is Herring Gull.
 
partner 1 April 27th, 2023: Herring Gull. April 27th, 2023: Herring Gull. .
   
partner 2 April 26th, 2021. April 26th, 2021: black on P4. April 26th, 2021.
 
partner 2 March 30th, 2021. April 19th, 2022: Caspian Gull. May 4th, 2022: Caspian Gull.
 
partner 2 April 27th, 2023: Caspian Gull. April 27th, 2023: Caspian Gull. April 27th, 2023: Caspian Gull.
 
pullus May 15th, 2021. May 15th, 2021: 2 chicks + 1 egg. May 28th, 2021: 2 dead chicks.
 
pullus May 30th, 2022: pullus r[6.W]. May 30th, 2022: pullus r[6.X]. July 12th, 2022: hybrid juvenile r[6.X].
 
pullus May 27th, 2023: pullus g[8|P]. July 8th, 2023: juvenile g[8|R], fledged. .
   

Visits and data.

date:            
  egg no: width (mm) length (mm) volume (cm3):  water test on April 16th:  
16-04-2021 A 47,1 71,3 79,64 00 - flat on bottom 1 egg present, red flag 15 placed near nest.
         
24-04-2021         water test on April 24th:  3 eggs. Small branches cut away. Herring Gull and Caspian Gull present.
  A egg     70 - tip bottom  
  B egg 48 70,8 82,13 50 - tip bottom  
  C egg 46,4 70,9 76,86 35 - tip bottom  
      sum nest: 238,63    
26-04-2021 Female Herring Gull breeding. Male Caspian Gull on block in front of nest.
15-05-2021 1 egg hatching.
  2 chicks present in nest: Mass = 59 gr & Mass = 71 gr.
28-05-2021 Two pulli dead in nest (approx 1 week ago, drown after heavy storm?).
08-06-2021 No activity.    
26-06-2021 2 eggs in nest! Still, also 2 dead chicks in nest, but 2nd attempt started.

Visits and data 2022 for nest 48:
Estimation egg laying: A-egg = May 01 2022. Estimating hatching = May 29 2022.

12-Apr-22 adult on block in front of nest 48-2021.
     
15-Apr-22 nest empty, but can be used.
   
19-Apr-22 same guarding adult as picture 12 April, same block.
     
4-May-22 adult cachinnans-type landed.
         
9-May-22     length width
  3 eggs A egg 71,1 48,5
B egg 70,3 48,6
C egg 68,6 46,9
     
17-May-22 3 eggs B & A hatching
C egg still intact
           
metal darvic mass wing H+B Bill
30-May-22 pullus 5625174 r-6.W 235 51 69 26
pullus 5625175 r-6.X 338 65 77 30,5
             
12-July-22 r-6X photo.
             
17-July-22 r-6X photo.
 
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 48-2023 73,2 48,5 86,69 72,4 48,2 84,69 67,5 48,4 79,61 251,00 same as 2022
ring pulli: 20-mei laying A egg: 15-apr hatch A egg: 13-mei
     
catch: date: metal: darvic: mass: wing: head+bill:
Pullus 27-5-2023 5.625.264 G-8|P 394 -- -- is nest 15B, full throat pouch with fish.
Pullus 27-5-2023 5.625.281 G-8|R 435 -- -- is nest 15B
Pullus 18-6-2023 5.625.281 G-8|R 918 301 113,0 hybrid type
   
48-2023 was 15B
dam: dam 2 central
location: Next to prunus, 1 mtr E of code 44 on blocks. 4 mtr from waterfront.
breeders: cach x teus
OBSERVATIONS:
09-4-2023 nest: no eggs, nest is ready.
26-4-2023 nest: 3 eggs measured, and water test: A: 80 - tip bottom
B: 80 - tip bottom
27-4-2023 adult: cach & teus, cach breeding. C: 90 - tip bottom
cach with patterns on P4.
11-5-2023 eggs floating - 5 mm.
27-5-2023 pulli: 2x chicks ringed and measured.
18-6-2023 pulli: 1x control of g-8|R, which is hybrid type. Fledged: 1x juvenile.
25-6-2023 pulli: G-8|R present.