Larus cachinnans in the Netherlands

(last update: August 16, 2020)

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

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Cachinnans - nest Lelystad r-F7 (060-2023, 069-2024)

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 marked with code "60" on tarmac dam.
  • Nest 060 on breakwater dam 1 south section, just on north side, near the top. Easy to trap the adults here.
  • 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, male is probably Caspian Gull cachinnans.
  • ID certain in 2022, male and female are Caspian Gull cachinnans. Early breeders. Most probably same bird as in 2021.
  • ID certain in 2023, male and female are Caspian Gull cachinnans. Early breeders. female trapped on 3-egg clutch, now r-F.7.
  • ID certain in 2024, male and female (r-F.7) are Caspian Gull cachinnans. Nest moved 3 mtr west, at edge Blackberry complex.
location April 24th, 2021: cluster of nests. April 24th, 2021: red spray "60". May 13th, 2021: Angelica nest 60.
 
  April 12th, 2022: Angelica nest 60. April 19th, 2022: Angelica nest 60. May 1st, 2022: nest 60 & neighbours.
 
  April 21st, 2024: situation at cluster. April 21st, 2024: nest r-F7 (069). April 21st, 2024: situation at cluster.
 
eggs April 24th, 2021: 3 eggs in nest. April 11th, 2022: 3 eggs in nest. April 9th, 2023: 2 eggs in nest.
 
partner 1 May 13th, 2021: adult male cachinnans. May 13th, 2021: adult male cachinnans. May 13th, 2021: adult male cachinnans chasing neighbour.
 
partner 1 April 12th, 2022: adult male cachinnans. April 12th, 2022: adult male cachinnans. April 19th, 2022: adult male cachinnans.
 
partner 1 June 18th, 2023: adult male cachinnans. May 13th, 2023: adult male cachinnans. .
   
partner 2 April 24th, 2021: probable parent nest 60. April 19th, 2022: adult female cachinnans. April 19th, 2022: adult female cachinnans.
 
partner 2 May 1st, 2022: adult female cachinnans. May 1st, 2022: adult female cachinnans. June 2nd, 2022: female cachinnans protecting chicks.
 
partner 2 May 3rd, 2023: female r-F.7. May 3rd, 2023: female r-F.7. July 8th, 2023: female r-F.7 & male cachinnans & chick.
 
partner 2 April 26th, 2024: female r-F.7. April 26th, 2024: female r-F.7. April 26th, 2024: female r-F.7.
 
pulli 2021 May 13th, 2021: 2 cachinnans pulli. May 28th, 2021: cachinnans pullus b[F|0]. May 28th, 2021: cachinnans pullus b[F|1].
 
pulli 2022 May 9th, 2022: cachinnans pullus r[C.A]. May 17th, 2022: cachinnans pullus r[C.B]. June 21st, 2022: cachinnans pullus r[C.B].
 
  June 21st, 2022: cachinnans pullus r[C.C]. June 25th, 2023: cachinnans pullus r[8.C]. July 8th, 2023: cachinnans pullus r[8.=].
 
pullus May 14th, 2024: pullus g-C|P. . .
     

Visits and data.

date:                
24-04-2021 Probably 2 partners present, but difficult to allocate birds to the nests. Nest allows trapping breeders, but early nest!
  One partner is fierce male Caspian Gull.
  3 eggs in nest.            
  egg no: width (mm) length (mm) volume (cm3):  water test on April 24th: 
  A egg 50,2 68,3 86,66 90 - floating halfway
  B egg 47,9 64,6 74,63 90 - floating halfway
  C egg     no measurements due to cracks in shell
  sum nest: --        
   
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 60 hide underneath Angelica cover, 45 cm's from nest.
   
15-05-2021 Fish at nest: Rounded Goby 3x. Chick 2 vomited Rounded Goby (pellet taken for analysis).
    mass head+bill (measurements Monika Ballmann)    
  pullus 257 gr 68,2    
  pullus 261 gr 68,5    
                 
    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 6 2022??? Estimating hatching = May 4 2022.

date:              
11-04-2022 3 eggs.        
               
12-04-2022 Picture of adult male Caspian.        
               
  egg no: width (mm): length (mm): volume (cm3):  water test    
15-04-2022 A-egg 51,2 70,1 -- 40 - tip on bottom    
  B-egg 48,9 68,5   30 - tip on bottom  
  C-egg 51,1 70 -- 50 - tip on bottom
sum nest: --
   
19-04-2022 Adult breeding & 1 adult guarding.        
   
  egg no: width (mm): length (mm): volume (cm3):  water test    
27-04-2022 A-egg       5 mm - floating    
  B-egg       5 mm - floating  
  C-egg       5 mm - floating
   
01-05-2022 2 adult Caspians, male has spot on P5.
   
04-05-2022 3 eggs - little cracks in shell. hatching date will be 6th May.
       
09-05-2022   metal darvic mass wing H+B
pullus NLA 5.625.051 r-C.A 117    
pullus NLA 5.625.052 r-C.B 91    
pullus NLA 5.625.053 r-C.C 137      
       
17-05-2022   metal darvic mass wing H+B
pullus NLA 5.625.051 r-C.A 483    
pullus NLA 5.625.052 r-C.B 388    
pullus NLA 5.625.053 r-C.C 530      
food loads of fish near the nest.
               
02-06-2022 r-CB & r-CC swimming northside of dam, 80 meters from nest. Large chicks, protected by female. r-CB gives up food pellet: fish.
       
17-06-2022 One large chick from nest 60 flies out over Markermeer. And back again.
       
22-06-2022 r-CB & r-CC swimming northside of dam, 200 meters from nest. Large chicks, protected by parent.
         
12-07-2022 Picture of r-CC.
 
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 cach 60-2023 68,2 51 89,31 69,9 51 91,54 66,2 50,2 84,00 264,85 same as 2022
ring pulli: 11-mei laying A egg: 6-apr hatch A egg: 4-mei
     
catch: date: metal: darvic: mass: wing: head+bill: bill: gonys: greytone: tarsus kor:
adult, >5CY 03-5-2023 NLA 6214901 R-F.7 810? 447 125,6 57,5 18 6 female cach
pullus 11-5-2023 NLA 5556469 R-8.=
pullus 11-5-2023 NLA 5556470 R-8.T
pullus 11-5-2023 NLA 5556471 R-8.C
pullus 27-5-2023 NLA 5556469 R-8.= 872 109,3 45,8 14 72,8
 
60-2023
dam: dam 1 west
location: Is nest 60-2021/22. From cluster 60-62-63.
breeders: cach x cach
OBSERVATIONS:
09-04-2023 nest: 2 eggs measured. No watertest, ring chicks in 1st session.
22-04-2023 nest: 3 eggs measured.
03-05-2023 adult: Female partner ringed R-F.7. this year >5CY.
11-05-2023 pulli: 3 chicks ringed.
13-05-2023 adult: both parents are cach.
18-05-2023 pulli: 3 chicks present.
27-05-2023 pulli: 1x control chick.
18-06-2023 adult: R-F7 guarding juveniles.
pulli: R-8= & R-8C present at water. At least 2x fledged.
25-06-2023 pulli: R-8=, R-8C and R-F7 (mother) present.

Visits and data 2024.

NEST code parent 1 parent  2 A_length A_width A_volume B_length B_width B_volume C_length C_width C_volume TOTAL NEST:
r-F7 (060) cach cach 71 50,7 91,89 69 50 86,85 68,7 50,3 87,52
266,26
  # eggs A-egg hatch # ringed chicks # all chicks # fledged chicks comments
  3 16-4-2024 14-5-2024
   
dam: dam 1 south
location: cluster nest 60-62-63. R-F7 no longer on location 60-2023; now breeding 3 mtr westwards. In cluster Blackberries, 2 mtr N of 62, wooden bumper.
parents? Same as 2020-23: r-F7 and male Caspian Gull.
   
ring pulli: 18-May
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
26-04-2024 r-F7 .6214901 nest r-F7 (60) PONT F >6CY 439 933 125,0 58,0 68,0 21,4 6
14-05-2024 g-C|P .5631111 nest r-F7 (60) PONT 1CY 88          
31-05-2024 g-C|P .5631111 nest r-F7 (60) PONT 1CY              
04-06-2024 g-C|P .5631111 nest r-F7 (60) PONT 1CY 205 888 112,7        
                           
OBSERVATIONS:
26-03-2024 adults: Female r-F7 & unringed male cach at nest site 60/62/63-2023.
12-04-2024 eggs: no eggs.
21-04-2024 eggs: 3 eggs, measured.
nest: cluster again: 60, 69, PAM0, n-F|+, and 2 Herrings to follow soon.
26-04-2024 adults: CONTROL: trapped female r-F7 (aimed for the partner), rings not replaced, remains r-F7. This year: >6CY.
02-05-2024 eggs: 3 eggs.
05-05-2024 nest: 3 eggs, not measured.
14-05-2024 eggs: 1x.
chicks: 1x ringed.
31-05-2024 chicks: CONTROLL: g-C|P.
04-06-2024 chick: g-C|P present. measured.
18-06-2024 chick: CONTROLL: g-C|P.