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

Home

Cachinnans - nest Lelystad 019

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 019 positioned high on artificial breakwater dam 1, 20 meters west of y-PNED. Nest in dense complex of Blackberry vegetation, with cluster with Spoonbills.
  • Nest marked with red flag. Location is close to nest 36-2020. Subsequent years: nest 19-2022 and 19-2023 at exact same spot on dam 1.
  • ID in 2021 certain: both partners are Caspian Gull cachinnans.
  • ID in 2022 certain: both partners are Caspian Gull cachinnans, likely same as in 2021.
  • ID in 2023 uncertain: one partner is Caspian Gull cachinnans, female might be Herring Gull argenteus. Supported by plumage of juvenile g-8|U with Herring traits.
  • ID in 2024 certain: male is Caspian Gull cachinnans (maybe supposed partner 2022?). Female is Herring Gull argenteus (white prim covs).
location Nest between Spoonbills, April 26, 2021. April 19th, 2022: nest location. June 8th, 2021: partners & 2 chicks at blocks.
 
  April 26th, 2023: nest location. April 26th, 2023: nest location. April 30th, 2024: nest location.
 
eggs Eggs April 16th, 2021: 3 eggs clutch. April 27th, 2022: 3 eggs. April 26th, 2023: 1 egg.
 
eggs April 23rd, 2024: 1 egg. April 23rd, 2024: 1 egg. .
   
partner 1 June 8th, 2021: partner 1 = male cachinnans. June 8th, 2021: partner 1 = male cachinnans. June 8th, 2021: partner 1 = male cachinnans.
 
partner 1 April 27th, 2022: partner 1 = male cachinnans. May 1st, 2022: partner 1 = male cachinnans. May 4th, 2022: partner 1 = male cachinnans.
 
partner 1 April 30th, 2024: male cachinnans. April 30th, 2024: male cachinnans. May 17th, 2024: male cachinnans.
 
partner 2 April 26th, 2021: female in Blackberry complex. June 8th, 2021: partner 2 = female cachinnans. June 8th, 2021: partner 2 = female cachinnans.
 
  April 27th, 2022: partner 2 = female cachinnans. April 27th, 2022: partner 2 = female cachinnans. April 27th, 2022: breeding female cachinnans.
 
partner? On May 6th, 2021, we assumed this to be one of the partners: male Caspian Gull cachinnans. Note different P5 pattern. April 30 2024: near-adult Herring Gull. April 30 2024: near-adult Herring Gull.
 
pullus May 9th, 2022: pullus r[5.U]. May 9th, 2022: pullus r[5.V]. June 18th, 2023: g[8|S]. Head wound.
 
pullus June 18th, 2023: g[8|T]. Checked upon by Herring. July 8th, 2023: g[8|U]. June 4th, 2024: g[M|E].
 
pullus June 4th, 2024: g[M|F]. . .
     

Visits and data.

date:              
  egg no: width (mm): length (mm): volume (cm3):  water test on April 16th: laying date:  
16-04-2021 A 48,4 70,9 83,63 30 - tip bottom   3 eggs in nest.
16-04-2021 B 50,5 70,8 90,91 50 - tip bottom  
16-04-2021 C 49,4 68,8 84,54 55 - tip bottom  
sum nest: 259,07
       
26-04-2021 1 parent present at nest, between Spoonbills.
       
13-05-2021 No visit, Camilla is catching a Spoonbill.
   
06-05-2021 Picture of one partner: male cachinnans.
   
15-05-2021 No visit, thunder coming in.
   
28-05-2021 No visit.
   
08-06-2021 2 large pulli & 2 parents on the blocks near the waterfront at north side. Next time, easy to trap.

Visits and data 2022 for nest 19:
Estimation egg laying: A-egg = April 03 2022. Estimating hatching = May 01 2022.

date:              
  egg no: width (mm): length (mm): volume (cm3):       
15-04-2022 A 49,8 68,3 -- 90 - tip bottom 3 eggs  
  B 50,4 69 -- 90 - tip bottom  
C 48,2 68,1 -- 90 - tip bottom
sum nest: --
   
19-04-2022 3 birds present: including female w-327:U without nest.
   
27-04-2022 A -- -- -- 3 mm - floating 3 eggs  
  B -- -- -- 3 mm - floating  
C -- -- -- 4 mm - floating
parent 1 = cachinnans.  
   
01-05-2022 2 parents at nest.  
   
04-05-2022 male = cachinnans.  
   
09-05-2022 Nest is empty, no chicks found, but much shit; the chicks hide in Blackberry complex.
   
    metal darvic mass H+B    
17-05-2022 pullus 5.625.119 r-5V 404 80,5    
  pullus 5.625.120 r-5U 464 82,5  
         
   
17-06-2022 No birds present.
   
21-06-2022 No activity 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 teus 19-2023 74,6 53,1 105,91 0 0 0,00 0 0 0,00 105,91 new birds
ring pulli: 27-05-2023 laying A egg: 26-04-2023 hatch A egg: 24-05-2023
 
catch: date: metal: darvic: mass: wing: head+bill:
Pullus 27-05-2023 5.625.263 g-8|T 160 -- --
Pullus 27-05-2023 5.625.265 g-8|U 80 -- --
Pullus 27-05-2023 5.625.267 g-8|S 125 -- --
Pullus 18-06-2023 5.625.265 g-8|U -- -- --
Pullus 18-06-2023 5.625.263 g-8|T 765 205 103,6 Herring type. With HG parent (?) later this date.
Pullus 18-06-2023 5.625.267 g-8|S -- -- -- Bleeding head wound, not measured.
Pullus 25-06-2023 5.625.265 g-8|U 847 241 109
 
19-2023
dam: dam 1 east
location: Low on N-side of dam. In blackberry complex. Location is nest 19-2020/22, old code still readable.
breeders: cach x teus
OBSERVATIONS:
09-04-2023 adult: 2 unringed cach present at blocks on N side, in front of location. Search for nest today.
26-04-2023 nest: same location, old codes still present. Refreshed with spray.
eggs: 1x egg, egg is cold. Nest abandoned? Egg measured.
comment: This used to be an early nest, 3 eggs should be floating already this date. In retrospect: late, as one parent is now Herring Gull?
13-05-2023 adult: partner 1 = cach adult.
18-05-2023 nest: 3 eggs.
27-05-2023 pulli: 3x chicks ringed and measured.
18-06-2023 pulli: 3x chicks present, but not in category 'fledged', still too young.
pullus: g-8|S with terrible head wound, therefore not measured. Will probably not survive.
pullus: g-8|T between blocks, was checked upon by adult Herring Gull, close to nest site. Hence: at least one parent is Herring!?
25-06-2023 pullus: g-8|U caught and measured.

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:
019-2024 cach teus 75,7 53,3 108,28 77 52,2 105,64 72,6 51,6 97,33
311,25
  # eggs A-egg hatch # ringed chicks # all chicks # fledged chicks comments
  3 22-4-2024 20-5-2024
   
dam: dam 1 east
location: was 19-2023, N side dam.
parents? same as 2023?
   
ring pulli: 24-May
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
04-06-2024 g-M|E .5631137 nest 19 cach x teus 1CY 84 438 86        
04-06-2024 g-M|F .5631138 nest 19 cach x teus 1CY 118 596 89,8        
                           
OBSERVATIONS:
23-04-2024 eggs: 1 egg, measured. 
26-04-2024 eggs: 3 eggs, measured. 
adults: Herring Gull on blocks in front of nest, bird with white primary coverts.
30-04-2024 adults: Herring Gull on blocks in front of nest, bird with white primary coverts.
14-05-2024 adults: Herring Gull poresent again.
04-06-2024 chicks: 2x ringed & measured.