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 135

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 135 positioned on dam 1 at 15 meters east of the bend (was 66-2021) in extensive Blackberry complex. Visible only from nort side.
  • ID certain in 2022: both cachinnans, one adult is female thayeri, which has moved from old location (thayeri 29-2020, 29-2021). Will move to 112-2023 next year.
  • ID certain in 2023: one parent is Caspian Gull, partner is hybrid type. This year the female is not "thayeri", which moved to nest 112.
location April 12th, 2022: location of nest. April 19th, 2022: location of nest. April 27th, 2022: coded nest.
 
eggs April 27th, 2022: 3 eggs in nest. June 2nd, 2022: 2 chicks at nest.  
   
partner 1 May 17th, 2022: female Caspian Gull thayeri. April 19th, 2022: female Caspian Gull thayeri. April 27th, 2022: female Caspian Gull thayeri.
 
partner 1 April 27th, 2022: female Caspian Gull thayeri. May 22nd, 2022: female Caspian Gull thayeri. May 22nd, 2022: female Caspian Gull thayeri.
 
partner 1 May 13th, 2023: hybrid type Caspian Gull. May 13th, 2023: hybrid type Caspian Gull. May 13th, 2023: hybrid type Caspian Gull.
 
partner 2 April 27th, 2022: adult male Caspian Gull. April 12th, 2022: adult male Caspian Gull. April 27th, 2022: adult male Caspian Gull.
 
  April 27th, 2022: adult male Caspian Gull. April 27th, 2022: adult male Caspian Gull. .
   
pullus May 30th, 2022 pullus r[6.2]. May 30th, 2022 pullus r[6.3]. August 2nd, 2022 pullus r[6.2].
 

Visits and data 2022 for nest 135:
Estimation egg laying: A-egg = April 16 2022. Estimating hatching = May 14 2022.

date:              
15-04-2022 Nest ready. Still empty. With adult Caspian Gull.
   
19-04-2022 Adult female thayeri now here.
               
  egg no: width (mm): length (mm): volume (cm3):  water test    
27-04-2022 A egg 50,9 73,4 -- 90 - tip on bottom    
  B egg 50 75,9   float - 1 mm  
  C egg 51,9 74,5 -- 90 - tip on bottom
sum nest: --
   
04-05-2022 Adult breeding at nest.
   
30-05-2022 2 chicks at nest.
    metal darvic mass wing H+B Bill
pullus .5625178 r-6.2 472 115 85,8 33,6
pullus .5625179 r-6.3 411 70 83,6 29,5
02-06-2022 2 adults at nest and 2 chicks, no rings visible.
21-06-2022 Adult thayeri at nest. Easy on bread.
28-06-2022 Adult thayeri at nest. Easy on bread.
12-07-2022 Adult thayeri at nest. Moult: P2/P5. With r-62.
17-07-2022 Adult thayeri at nest.
 
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 hybrid 135-2023 0 0 0,00 0 0 0,00 0 0 0,00 0,00 no
ring pulli: laying A egg: hatch A egg
 
135-2023
dam: dam 1 east
location: was thayeri 2022. In bend on N-side, in blackberry complex. 135 coded on block.
breeders: cach x hybrid
OBSERVATIONS:
9-4-2023 adult: 2 unringed cach present at blocks on N side, in front of location. So search for nest today.
26-4-2023 adult: Unringed cach present, partner breeding.
nest: Exact same location as 2022.
eggs: 1x egg, mini-wind egg. Not measured.
13-5-2023 adult: cach type breeding. Broad medial band P10 suggests some sort of hybrid origin. Note also black on P4 and thick bill, not unlike michahellis.
18-5-2023 nest: failed, 1 rotten egg. No chicks found.