Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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

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Cachinnans - nest Lelystad 063

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).
  • Location 5 meters west of marked with code "60" on tarmac dam.
  • Cluster of 5 nests within 10 meters range: 3x cachinnans and 2x argentatus, which are extremely difficult to monitor. Next to Angelica is nest 60, next to blackberries complex are nest 62 & nest 63.
  • ID for nest 063 uncertain in 2021, one bird is probably hybrid.
  • ID for nest 063 uncertain in 2022, one bird is probably sub-adult Herring Gull.
location April 24th, 2021: cluster of nests. April 24th, 2021: next to red spray "60". April 24th, 2021: fight over nest 60-62-63.
 
location April 19th, 2022: 2 eggs. May 1st 2022: 2 eggs. May 1st 2022: partner 1 is argenteus.
 
eggs April 24th, 2021: 3 eggs in nest. May 13th, 2021: 3 eggs in nest. May 13th, 2021: Herring Gull nest in background.
 
partner 1 April 24th, 2021: Herring type sub-adult. May 13th, 2021: Herring type sub-adult. May 13th, 2021: Herring type sub-adult.
 
partner 1 May 1st 2022: partner 1 is argenteus. . .
     
pulli May 15th, 2021: hatching date. May 28th, 2021: "Herring type" pullus b-F|2. May 28th, 2021: "Herring" pullus b-F|4.
 
pullus May 17th, 2022: pullus r[5.B] & r[5.E]. . .
     

Visits and data.

date:                
24-04-2021 Probably 2 partners present, but difficult to allocate birds to the nests. Nest allows trapping breeders.
  One partner is hybrid type sub-adult.
  3 eggs in nest.            
  egg no: width (mm) length (mm) volume (cm3):  water test on April 24th:       
  A egg 74,4 51,4 98,97 90 - tip on bottom      
  B egg 74,1 51,1 97,42 35 - tip on bottom      
  C egg 71,3 49,3 87,25 25 - tip on bottom  
  sum nest: 283,64        
   
26-04-2021 Pictures taken from canoe, of several birds flying around nests 60-62-63. How to monitor, telescope?
   
13-05-2021 Still 3 marked eggs in nest 63.
  Again sub-adult near nest, with Herring type wingtip.
   
15-05-2021 Fish at nest: Rounded Goby 3x. Chick 2 vomited Rounded Goby (pellet taken for analysis).
  egg hatching at 75%
  egg hatching at 33%
  egg still complete
                 
    metal tibia head + bill comments:
28-05-2021 pullus .5559412 b-F|0 92,3 Large pullus (16-18 days old), likely cachinnans from nest 60.
  pullus .5559413 b-F|1 95,3 Large pullus, likely cachinnans from nest 60.
  pullus .5559414 b-F|2 75,8 Possibly argentatus, not necessarily from neighbour's nest, b-F|3 broken.
  pullus .5559415 b-F|4 73,2 Possibly argentatus, not necessarily from neighbour's nest, b-F|3 broken.
  pullus .5559416 b-S|3 56,8 Likely argentatus, from neighbour's nest.
  pullus .5559417 b-S|4 57,2 Likely argentatus, from neighbour's nest.
               
08-06-2021 3 adult Caspian Gulls present. No chicks visible from canoe, not on south nor on north side from water. They probably hide in blackberries complex.

 

date:              
15-04-2022 adult Herring gull near empty nest.  
               
19-04-2022 adult Herring gull near empty nest.  
               
  egg no: width (mm): length (mm): volume (cm3):       
27-04-2022 A 51,4 71,7 -- 90 - tip bottom 2 eggs  
  B 51 70,6 -- 90 - tip bottom  
sum nest: --
   
01-05-2022 Herring Gull sub-adult (5CY) guarding at nest.
   
04-05-2022 still 2 eggs; 3rd egg not likely. 5CY Herring Gull = partner 1.
   
09-05-2022 2 eggs.
   
17-05-2022 2 chicks
  metal darvic mass H+B wing    
17-05-2022 .5625102 5-5.B 108 -- -- .
17-05-2022 .5625103 r-5.E 91 -- -- .