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 Lelystad r-F.C (043-2021; 104-2022)

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 in 2021 is nest 043 at T-split bend below nest 21. Nest positioned behind large trunk. Male often guarding on blocks. Neighbour is Lesser Black-backed Gull, nest only 3 meters apart.
  • Location in 2022 is nest 104 at dam 1 east, neighbour of y-PNED (20 meters away). Nest positioned high on dam 1. Nest in 2022 is about 200 mtrs east of position in 2021.
  • ID for nest 043 certain in 2021, both partners are Caspian Gull cachinnans. Male ringed in 20212: r[F.C].
  • ID for nest 104 certain in 2022, both partners are Caspian Gull cachinnans. Unringed female is not partner 2021, but a different bird.
location 2021 June 8th, 2021: situation at T-split northwest. June 8th, 2021: neighbour LBBG at 3 meters. .
   
location 2022 April 27th, 2022: east on dam 1. April 27th, 2022: nest. April 27th, 2022: 2 eggs in nest.
 
partner 1 May 28th, 2021: male cachinnans r[F.C]. May 28th, 2021: male cachinnans r[F.C]. May 28th, 2021: male cachinnans r[F.C].
 
partner 1 April 27th, 2022: partner 1 = cachinnans r-F.C. May 1st, 2022: partner 1 = cachinnans r-F.C. May 4th, 2022: partner 1 = cachinnans r-F.C.
 
partner 2-2021 June 8th, 2021, P10 right wing with thayeri. June 8th, 2021, P10 right wing with thayeri. June 8th, 2021, P10 right wing with thayeri.
 
partner 2-2022 April 27th, 2022: partner 2 = cachinnans (new partner). April 27th, 2022: partner 2 = cachinnans. April 27th, 2022: partner 2 = cachinnans.
 
pulli 2021 June 26th, 2021: pullus cachinnans r[F.3]. June 26th, 2021: pullus cachinnans r[F.3]. June 26th, 2021: pullus cachinnans r[F.4].
 
pulli 2022 May 17th, 2022: chick r-5.8. May 17th, 2022: chick r-5.9. July 12th, 2022: chick r-5.8.
 

Visits and data.

date:                  
28-05-2021 Decided to put out a cage to trap a breeding adult here. Successful. Adult male cachinnans trapped today.
  2 eggs in nest.              
  egg no: width (mm) length (mm) volume (cm3):  water test on May 28th:         
  A egg 74,5 50,4 95,28 90 - floating 2 mm        
  B egg 66,4 46,5 72,29 90 - floating 2 mm        
  sum nest: --          
  metal tibia mass (gr) head + bill (mm) wing (mm) tarsus (mm) bill (mm) gonys (mm)
  adult .6213012 r-F.C 1332 135,6 464 71 66 19,3
   
08-06-2021 2 partners at nest. male guarding at blocks. Large female at nest. 3 meters to the west is LBBG nest (also behind trunk).
   
    metal tibia mass (gr) head + bill (mm) wing (mm)  
26-06-2021 pullus .5550699 r-F.3 714 98,3 151 cachinnans
  pullus .5550700 r-F.4 466 87,2 110 cachinnans
               
Visits and data 2022 for nest r-FC:
Estimation egg laying: A-egg = April 14 2022. Estimating hatching = May 12 2022.
               
  r-F.C former breeder at T-split, now breeding in eastern part of dam 1, neighbour of y-PNED.
15-04-2022 1 egg in nest. Nest coded "104".
  egg no: width (mm) length (mm) volume (cm3):  water test on May 28th:     
  A egg 72,6 50,8 -- 00 - flat on bottom    
19-04-2022 y-PNED close near nest "104", but apparently not the partner.
27-04-2022 2 egg in nest. Extra yellow-black flag placed.
  r-FC present at nest.
  egg no: width (mm) length (mm) volume (cm3):  water test on May 28th:     
  A egg     -- 90 - tip on bottom    
  B egg 72,2 49,2 -- 80 - tip on bottom    
01-05-2022 r-FC present at nest.
17-05-2022 2 chicks in nest. One throws up food: fish.
  Food: Rounded Gobt 5,19 gr.
  metal darvic mass        
  .5625144 r-59 101        
  .5625145 r-58 142        
28-06-2022 r-5.8 photographed. No trace of sibling r-59.
12-07-2022 r-5.8 photographed. No trace of sibling r-59.