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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Nests at Lelystad 2022
nest y-PNED
nest y-PHSV / r-CG
nest y-P:U60
nest y-X56A
nest y-X71A
nest y-X540
nest y-XCHP
nest w-327:U
nest n-F|N
nest r-6A
nest r-6B
nest r-6C
nest r-CS
nest r-FC
nest w-8Z
nest zy-MT
nest 003
nest 011
nest 012
nest 014
nest 015
nest 017
nest 017B
nest 018
nest 019
nest 021
nest 026
nest 034
nest 035
nest 038
nest 040
nest 044
nest 046
nest 048
nest 053
nest 055
nest 058
nest 060
nest 061Z
nest 062
nest 063
nest 107Z
nest 109
nest 111
nest 112
nest 113
nest 117Z
nest 118Z
nest 123Z
nest 124Z
nest 125Z
nest 126Z
nest 127Z
nest 128Z
nest 129Z
nest 131Z
nest 132 YLG
nest 133
nest 134
nest 135
nest 136
nest 137
nest 138
nest 139
nest 143Z
nest 203
nest 204
nest 207
nest 222Z
nest 227
nest 228Z
nest 229
nest 230Z
nest 231
nest 240Z
nest 244
nest 245Z

Lelystad 2021
nest y-PNED
nest y-PLDP
nest y-PHSV
nest y-P:A02
nest y-P:U60
nest zy-MT
nest r-FB
nest r-FC
nest 001
nest 003
nest 006
nest 011
nest 012
nest 013
nest 014
nest 015
nest 016B
nest 017
nest 018
nest 019
nest 021
nest 034
nest 035
nest 038
nest 040
nest 041
nest 042
nest 044
nest 045
nest 046
nest 047
nest 048
nest 053
nest 055
nest 056
nest 058
nest 060
nest 062
nest 063
nest 065
nest 066
nest 067
nest 072

 

Cachinnans - nest Lelystad 062

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 3 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 uncertain in 2021, female is probably hybrid Caspian Gull cachinnans (broad medial band on P10, thin broken band on P5).
  • ID uncertain in 2022, same female as in 2021 (probably hybrid Caspian Gull cachinnans with broad medial band on P10, thin broken band on P5). Uncertainty about partner.
  • ID uncertain in 2023, same female as in 2021, trapped in 2023, now r-7.L. Uncertainty about partner. Difficult to monitor exact relations in this cluster of nests.
location April 24th, 2021: cluster of nests. May 1st, 2022: adult female at nest. April 24th, 2021: fight over nest 60-62-63.
 
eggs April 24th, 2021: 3 eggs in nest. May 13th, 2021: probable cachinnans egg. April 19th, 2022: 3 eggs.
 
partner 1 April 24th, 2021: adult female type nest 62??? . .
     
partner 2 May 13th, 2021: adult female hybrid type. May 13th, 2021: adult female hybrid type. May 13th, 2021: adult female hybrid type.
 
partner 2 May 1st, 2022: adult female hybrid type. May 1st, 2022: adult female hybrid type. May 1st, 2022: adult female hybrid type.
 
food May 13th, 2021: prey is Pike perch Sander lucioperca. May 13th, 2021: prey is Rudd Scardinius erythrophthalmus. May 17th, 2022: prey is Rudd Scardinius erythrophthalmus.
 
pulli May 13th, 2021: 2 cachinnans pulli. May 28th, 2021: dead chick in nest 62. May 17th, 2022: chick NLA 5.625.104.
 

Visits and data.

date:                
24-04-2021 2 partners present, both are most likely Caspian Gull cachinnans. But difficult to allocate birds to the nests. Nest allows trapping breeders, but early nest!
  3 eggs in nest.            
  egg no: width (mm) length (mm) volume (cm3):  water test on April 24th:       
  A egg 50,5 75,2 96,56 90 - floating, 3mm above surface      
  B egg 51,8 72,8 98,35 90 - floating, 3mm above surface      
  C egg 51,5 73,6 98,29 90 - floating, 2mm above surface      
  sum nest: 293,20        
   
26-04-2021 Pictures taken from canoe, of several birds flying around nests 60-62-63. How to monitor, telescope?
   
13-05-2021 2 chicks of nest 62 hide underneath Thistle Sircium cover, 45 cm's from nest.
  Fish prey: 1 possible Rudd 25 cm's, 1 week old. 1 predated (?) egg which seems to be cachinnans.
   
15-05-2021 Many fish prey left-overs at nest: small Pike perch Sander lucioperca (taken for analysis).
    mass head+bill (measurements Monika Ballmann)    
  pullus 236 gr 64,1    
  pullus 228 gr 64,1    
                 
    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.
   
Visits and data 2022:
Estimation egg laying: A-egg = April 13 2022. Estimating hatching = May 11 2022.
   
12-04-2022 empty nest.
   
15-04-2022 2 eggs in nest.            
  egg no: width (mm) length (mm) volume (cm3):         
15-04-2022 A egg 50,1 68,1 --        
15-04-2022 B egg 51,6 68,4 -- water test on April 27th:       
27-04-2022 C egg 50,3 66,8 -- floating halfway      
  sum nest: --        
   
01-05-2022 Adult at nest 62: very thin line on P5 but clear cachinnans influences
   
09-05-2022 3 eggs: small crack in blue egg.
   
17-05-2022 1 pullus and 2 eggs present.
  prey: half fish at nest probably Rudd.
    metal code darvic mass  
  pullus NLA 5.625.104 - 165 Large pullus (16-18 days old), likely cachinnans from nest 60.
   
22-05-2022 Blue egg still present. No chicks found near nest, but hiding in 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 ? 62-2023 70,1 51,2 92,52 70,3 51,8 94,98 67,9 51,7 91,38 278,88 same as 2022
ring pulli: -- laying A egg: -- hatch A egg: --
 
catch: date: metal: darvic: mass: wing: head+bill: bill: gonys: greytone:
adult 03-05-2023 6214904 r-7.L nn 466 136 59,7 21,6 6 female cach
pullus 18-05-2023 5556422 G-7|3 116 52,6
 
62-2023
dam: dam 1 west
location: Is nest 62-2021/22. From cluster 60-62-63.
breeders: cach x ?
OBSERVATIONS:
09-04-2023 nest: no eggs, nest is ready.
22-04-2023 nest: 3 eggs, water test = tip bottom 90 degrees; tip bottom 50 degrees, tip bottom 45 degrees.
03-05-2023 adult: trapped female cach: r-7.L.
eggs: 3 eggs.
18-05-2023 eggs: 1 rotten egg.
  pullus: 1 chick ringed is G-7|3, 1 chick dead in nest.