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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Cachinnans - nest r-C.G (was y-PHSV)

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 064 "PHSV" on breakwater dam 1 south section, north side of dam (unvisible from parking lot). Easy to trap the adults here in future (season 2022?).
    In 2022 nest moved 10 meters west, into Blackberry bush.
    In 2023 nest is at location of 2022.
    In 2024: nest moved 3 meters west, now underneath the large tree.
  • ID certain in 2021, both breeders are Caspian Gull cachinnans, y[PHSV] is 11CY and unringed adult partner.
  • ID certain in 2022, Caspian Gull cachinnans, y[PHSV] with same partner as previous season, though wingtip pattern slightly changed.
  • ID certain in 2023, Caspian Gull cachinnans, r-C.G with different partner.
  • ID certain in 2024, Caspian Gull cachinnans, r-C.G with male adult Caspian Gull.
location May 13th, 2021. April 15th, 2022: nest moved 10 meters westwards. June 21st, 2022: 2nd attempt, 40 meters eastwards.
 
eggs April 24th, 2021. May 13th, 2021: hatching chicks. May 15th, 2021.
 
eggs May 9th, 2022: hatching date. May 17th, 2022: all 3 chicks dead in nest. June 21st, 2022: 1 egg in 2nd attempt by partner 2.
 
  April 12th, 2024: 1 egg, behind tree. April 21st, 2024: 3 eggs clutch. .
   
partner 1 April 26th, 2021: partner y[PHSV]. April 26th, 2021: partner y[PHSV]. May 13th, 2021: partner y[PHSV].
 
partner 1 May 9th, 2022: female cachinnans y[PHSV] now r[C.G]. May 9th, 2022: female cachinnans y[PHSV] now r[C.G]. May 9th, 2022: female cachinnans y[PHSV] now r[C.G].
 
partner 1 May 3rd, 2023: female cachinnans r[C.G] trapped. April 27th, 2023: cachinnans r[C.G] on bread. June 18th, 2023: cachinnans r[C.G] offensive.
 
partner 1 March 08 2024: r-CG. March 08 2024: r-CG. .
   
partner 2 April 26th, 2021: unringed partner. April 26th, 2021: unringed partner. April 26th, 2021: unringed partner.
 
partner 2 May 13th, 2021: unringed partner. May 13th, 2021: unringed partner. May 28th, 2021: partner with fishline.
 
partner 2 April 11th, 2022: unringed male. April 11th, 2022: unringed male. April 27th, 2022: unringed male.
 
partner 2 April 27th, 2023: unringed male. April 27th, 2023: short P10 with thayeri (right). April 27th, 2023: normal on left wing.
 
partner 2 May 2nd, 2024: unringed male. May 2nd, 2024: unringed male. May 2nd, 2024: unringed male.
 
pulli May 28th, 2021: cachinnans pullus b[F|X]. May 28th, 2021: cachinnans pullus b[F|Y]. May 28th, 2021: cachinnans pullus b[F|Z].
 
pullus July 8th, 2023: fledged r-8.1. May 18th, 2023: metal only 5.556.486. .
   
pullus May 14th, 2024: pullus g-C|G. May 14th, 2024: pullus g-C|H. May 14th, 2024: pullus g-C|J.
 

Visits and data.

date:            
24-04-2021 2 partners present, one is y[PHSV] and unringed adult. Nest allows trapping breeders, easily. 3 eggs in nest.
  egg no: width (mm) length (mm) volume (cm3):  water test on April 24th:   
  A egg 49,4 75,7 93,01 45 - tip bottom  
  B egg 50,6 76,6 98,75 45 - tip bottom  
  C egg 51,6 73,7 98,80 65 - tip bottom  
  sum nest: 290,56    
   
26-04-2021 Both partners present. Partner 2 with small black spot on primary coverts.
   
13-05-2021 Both partners present.
  1 chick: 1,5 days old.
  1 chick: hatching
  1 egg: still in tact.
   
15-05-2021 1 chick: mass = 88 gr.
  1 chick: mass = 107 gr.
  1 egg just hatching.
   
28-05-2021   metal tibia mass head + bill  
  pull .5559409 b-F|X >400 85  
  pull .5559410 b-F|Y >400 88,5  
  pull .5559411 b-F|Z >400 78,3  
  Partner 2 has fishgear in beak.
   
08-06-2021 2 partners at nest. partner 2 has no longer hooked with fishline.
   
26-06-2021 No activity.
   
 
Visits and data for y-PHSV 2022:
Estimation egg laying: A-egg = April 11 2022. Estimating hatching = May 09 2022.
   
15-04-2022 2 partners present, one is y[PHSV] and unringed adult. Nest has moved 10 meters to Blackberry complex. 2 eggs in nest.
  egg no: width (mm) length (mm) volume (cm3):     
  A egg 50,9 77,8 --    
  B egg 50,2 70,9 --    
             
19-04-2022 1 adult at nest.
             
27-04-2022 egg no: width (mm) length (mm) volume (cm3):  water test P-moulting adult
  A egg       4 mm - floating  
  B egg       4 mm - floating  
  C egg 51,6 71,7 -- 3 mm - floating  
  sum nest: 290,56    
   
01-05-2022 unringed partner at nest.
   
04-05-2022 PHSV at nest.
   
09-05-2022 3 eggs. One egg hatching with little hole; 1 egg with cracks. Trap adult at nest.
  Female cachinnans y-PHSV trapped. New rings: metal = NLA 5.625.054 & r[C.G].
  Biometrics: wing 446; tarsus 69,3; head+bill 127,8; bill 57,8; gonys 18,3; mass 944 gr.
   
17-05-2022 3 pulli dead in nest. Poisoned? About 4 days dead (avian flu?). Two adults present. End of season...
  mass tarsus        
  94 3,9        
  57 3,2        
  89 4        
   
02-06-2022 unringed male is still present at site. No sign of r[C.G].
   
17-06-2022 unringed male is still present at site. No sign of r[C.G].
   
21-06-2022 unringed male is still present at site. New nest is 40 mtr east of old nest, 1 egg. Also there: a sub-adult Herring Gull which may be the new partner.
  egg no: width (mm) length (mm) volume (cm3):     
  A egg 51,0 75,8 --    
 
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 r-C.G 0 0 0,00 0 0 0,00 0 0 0,00 0,00 r-CG & new male cach
ring pulli:15-mei laying A egg: 10-apr hatch A egg: 8-mei
     
catch: date: metal: darvic: mass: wing: head+bill: bill: gonys: greytone:
adult 03-05-2023 5625054 r-CG 830 ? 438 126,5 56,9 18,6 4 female cach retrap
pullus 18-05-2023 5556486 -- 74 -- 47,2 -- -- -- mass without ring
pullus 18-05-2023 5556487 R-81 77 -- 52 -- -- --
pullus 27-05-2023 5556487 R-81 397 -- -- -- -- --
   
r-C.G (was y[PHSV])
dam: dam 1 west
location: opposite harbour, next to largest willow. In Blackberry bush.
breeders: cach x cach
OBSERVATIONS:
22-4-2023 nest: 2 eggs.
27-4-2023 adult: 2x cachinnans, parent 1 is r-CG, parent 2 is short thayeri P10.
nest: in Blackberry. Location as 2022.
3-mei adult: retrap r-CG on 3 eggs.
11-5-2023 nest: 3 eggs.
18-5-2023 pulli: 2 chicks ringed, 1 egg hatching.
27-5-2023 pulli: 1x control chick R-81.
18-6-2023 adult: r-CG attacks near nest but no chicks found. Presenr are 2x Herring chicks from neighbour nest.
25-6-2023 pulli: r-81 and r-CG present.
   
r-C.G (was y[PHSV])
dam: dam 1 west
location: opposite harbour, next to largest willow. In Blackberry bush.
breeders: cach x cach
OBSERVATIONS:
22-4-2023 nest: 2 eggs.
27-4-2023 adult: 2x cachinnans, parent 1 is r-CG, parent 2 is short thayeri P10.
nest: in Blackberry. Location as 2022.
3-mei adult: retrap r-CG on 3 eggs.
11-5-2023 nest: 3 eggs.
18-5-2023 pulli: 2 chicks ringed, 1 egg hatching.
27-5-2023 pulli: 1x control chick R-81.
18-6-2023 adult: r-CG attacks near nest but no chicks found. Presenr are 2x Herring chicks from neighbour nest.
25-6-2023 pulli: r-81 and r-CG 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-C.G 2024 cach cach 77,1 50,7 99,79 76,8 51,3 101,76 70,6 50 88,87 290,42
  # eggs A-egg hatch # ringed chicks # all chicks # fledged chicks comments
  3 11-4-2024 7-5-2024
   
dam: dam 1 west
location: Same spot: opposite harbour, next to largest willow. In Blackberry bush.
parents? same as 2020-2023
   
ring pulli: 11-May
date darvic metal location / nest# species sexe age wing mass head+ bill bill tarsus gonys greyscale
14-05-2024 g-C|G .5631107 nest r-CG PONT 1CY 204          
14-05-2024 g-C|H .5631108 nest r-CG PONT 1CY 187          
14-05-2024 g-C|J .5631109 nest r-CG PONT 1CY 109          
                           
OBSERVATIONS:
08-03-2024 adult: r-CG on bread.
19-03-2024 adult: r-CG on bread.
12-04-2024 eggs: 1 egg, measured
21-04-2024 eggs: 3 eggs, measured.
23-04-2024 adult: r-CG on bread.
02-05-2024 eggs: 3 eggs.
14-05-2024 chicks: 3x ringed. Fish bolus (yellow) when processed.
food: Fishes: Perch, Goby.
18-06-2024 chicks: 3x chicks present at water and able to fly.
adult: male present.