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 017B

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 17B positioned high on breakwater dam 2, within dense Blackberry vegetation. In 2022: code 17B sprayed again on the block.
  • ID certain in 2021, one parent photographed, characteristics match pure Caspian Gull cachinnans.
  • ID certain in 2022, both parents are Caspian Gull cachinnans.
  • ID certain in 2023, Caspian Gull cachinnans are same as in 2022.
  • ID certain in 2024, female Caspian Gull cachinnans is same as in 2022/23.
location Nest location April 24th, 2021. April 29th, 2022: nest (from north). .
   
eggs April 29th, 2022: full clutch, nest with 3 eggs. April 9th, 2023: full clutch, nest with 3 eggs. April 21st, 2024: full clutch, nest with 3 eggs.
 
partner 1 April 24th, 2021: cachinnans female. April 19th, 2022: cachinnans female. April 19th, 2022: cachinnans female.
 
  May 13th, 2023: cachinnans female. May 13th, 2023: cachinnans female. .
   
  April 23rd, 2024: cachinnans female. April 23rd, 2024: cachinnans female. April 23rd, 2024: cachinnans female.
 
  May 02 2024: same male cachinnans as 2023. May 02 2024: same male cachinnans as 2023. May 02 2024: same male cachinnans as 2023.
 
partner 2 May 1st, 2022: cachinnans male. April 19th, 2022: cachinnans male. May 1st, 2022: cachinnans male.
 
  May 13th, 2023: "dark eyed" cachinnans male. May 13th, 2023: "dark eyed" cachinnans male. May 02 2024: same male cachinnans as 2023.
 
  May 02 2024: same male cachinnans as 2023. May 02 2024: same male cachinnans as 2023.  
   
chicks May 9th, 2022: pullus r[C.V]. May 9th, 2022: pullus r[C.W]. May 9th, 2022: pullus NLA 5.625.072.
   
  May 11th, 2023: pullus r[8.G]. May 27th, 2023: pullus r[8.G]. June 18th, 2023: pullus r[8.R].
 
pullus June 18th, 2024: g-A|K. May 31st, 2024: g-A|L. .
   
food: May 14th, 2024: fish bolus of chick g-A|L. . .
     
       

Visits and data 2021:

date:                
24-04-2021 Patrolling adult and landing at location. We did not climb the dam to search.
06-05-2021 No bird present.
15-05-2021 No bird present.
28-05-2021 No visit.
26-06-2021 No visit.
   
Visits and data 2022:
Estimation egg laying: A-egg = April 08 2022. Estimating hatching = May 06 2022.
                 
15-04-2022 A egg 68,1 50,4 tip bottom - 40 2 blue eggs.      
  B egg 65,6 49,7 tip bottom - 40        
  C egg 68,7 50,6 tip bottom - 40        
   
19-04-2022 2 parents present at nest.
   
29-04-2022 A egg     float - 1 mm        
  B egg     float - 1 mm        
  C egg     float - 1 mm        
   
01-05-2022 female is cachinnans.
   
09-05-2022 pullus r-C.V   NLA 5625070        
  pullus r-C.W   NLA 5625071        
  pullus --   NLA 5625072 pullus too small for plastic.
   
    colour   metal mass wing head + bill bill
17-05-2022 pullus r-C.V   NLA 5625070 257      
   
30-05-2022 pullus r-C.V   NLA 5625070 615 175 95,1 39,3
  food: fish is Roach
   
02-06-2022 male alarming.
   
17-06-2022 No birds near nest, r-CW flying around at north side.
   
21-06-2022 No activities near nest, r-CV & r-CW & 3rd chick (only mmetal?) swimming at north side. If so, then 3x chicks fledged from this nest.
   
12-07-2022 R-CV & r-CW photographed.
                 
17-05-2022 R-CW photographed.
 
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 17B-2023 67,8 50,4 86,71 69,2 48,5 81,96 68 51,3 90,10 258,78 same as 2022
ring pulli: 10-mei laying A egg: 5-apr hatch A egg: 3-mei
     
catch: date: metal: darvic: mass: wing: head+bill:      
Pullus 11-5-2023 NLA 5556462 r-8.G -- -- --
Pullus 11-5-2023 NLA 5556463 r-8.R -- -- --
Pullus 27-5-2023 NLA 5556462 r-8.G dead >7 days ago
Pullus 18-6-2023 NLA 5556463 r-8.R 1133 356 131,9
 
17B-2023
dam: dam 2 central
location: on S-side "17B" coded on block, path to top of dam, in Blackberry complex.
breeders: cach x cach
OBSERVATIONS:
04-04-2023 adult: 2 cach present.
09-04-2023 adult: 2 cach present.
nest:  Nest with 3 eggs. No watertest, ring chicks in 1st session.
26-04-2023 adult: 1 cach present.
nest:  3 eggs. Not measured.
11-05-2023 pulli: 2 chicks ringed, is there a 3rd chick?
13-05-2023 adult: pair present, same as 2022. Female spot on P10. Male dark eye.
18-05-2023 nest:  nest empty, no chicks found.
27-05-2023 pulli: dead chick near nest: r-8G.
18-06-2023 nest:  no birds present. R-8R trapped in water with net & measured. Fledged: 1 chick.
25-06-2023 pulli: r-8R 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:
  cach cach 69,4 50,6 89,47 65,9 51 86,30 65 49 78,58 254,35
017B-2024 # eggs A-egg hatch # ringed chicks # all chicks # fledged chicks comments
  3 17-4-2024 15-5-2024
   
dam: dam 2 central
location: 17B-2021, 2022, 2023
parents? Same birds
   
ring pulli: 21-May
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
02-05-2024 g-A|K .5631214 nest 17B PONT 1CY 63          
02-05-2024 g-A|L .5631214 nest 17B PONT 1CY 63          
14-05-2024 g-A|L .5631215 nest 17B PONT 1CY 409 CONTROLL        
                           
OBSERVATIONS:
21-04-2024 eggs: 3 eggs, measured. 
02-05-2024 eggs: 1x blue egg.
chicks: 2x chick ringed: g-A|K & g-A|L.
05-05-2024 chicks: blue egg gone, but only 2x ringed chicks found in vegetation.
14-05-2024 chicks: g-A|L is 409 gr. CONTROLL.
food: Blous: fish.
31-05-2024 chick: g-A|L at nest.
04-06-2024 nest: no chick found.
18-06-2024 chicks: g-A|K & g-A|L at water, and maybe the 3rd chick as well. Fledged: "at least" 2 chicks, likely 3 chicks.