Larus cachinnans in the Netherlands

(last update: August 16, 2020)

Coordinator:
Albert de Jong
Merijn Loeve
Roland-Jan Buijs
Leon Kelder
Mars Muusse

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Cachinnans - nest Lelystad zy-M.T (nest 054)

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).
  • In 2021 nest 054 positioned high on artificial breakwater dam 2, nest between large blocks.
  • In 2022 nest 54 at same location.
  • ID in 2021 certain: female Yellow-legged Gull michahellis hybrid zy-MT is HY=2013 pullus from Wijk bij Duurstede colony, offspring from Herring x Yellow-legged Gull.
    Male of nest 054 is Herring Gull. Offspring from nest 054 will be "Herring Gull backcross F2-hybrids".
  • ID in 20022: again present zy-MT and a Herring Gull.
  • Nest positioned "at the end of the large log" on top of dam. Tip of log painted red with spray. Partners were obvious, well visible on look-out many visits.
location Nest between blocks April 24, 2021. Eggs April 24th, 2021: 3 eggs clutch. May 13th, 2021.
 
  Nest April 29th, 2022. Eggs April 29th, 2022: 3 eggs clutch. May 4th, 2022: situation.
 
partner 1 March 30th, 2021: female zy-MT is hybrid micha-type. April 24th, 2021: female zy-MT is hybrid micha-type. March 30th, 2021: female zy-MT is hybrid micha-type.
 
partner 2 April 24th, 2021: partner is Herring Gull. April 24th, 2021: two partners near nest. May 13th, 2021: Herring Gull.
 
food May 30th, 2022: Roach (?) . .
     
pullus May 28th, 2021 pullus b[S|Y] from neighbour. June 26th, 2021 Lesser Black-backed Gull b[S|Y]. June 26th, 2021 Lesser Black-backed Gull b[S|Y].
 
pullus May 28th, 2021 pullus b[S|X]. June 26th, 2021 pullus r[F.H]. May 30th, 2022 pullus r[6.T].
 

Visits and data.

date:              
30-3-2021 ZY-MT patrolling near nest 054. Controlling air by chasing other birds.
16-4-2021 Nest checked. No eggs.
  egg no: width (mm): length (mm): volume (cm3):  water test on April 24th: laying date:  
24-4-2021 A 50,5 71,1 91,30 20 - tip bottom    
24-4-2021 B 49,8 67,2 83,91 30 - tip bottom  
24-4-2021 C 48,4 63,3 74,66 20 - tip bottom  
sum nest: 249,87
26-4-2021 Both parters on look-out near nest. Herring Gull not ringed.
13-5-2021 Idem.  
15-5-2021 Nest complete, 3 eggs.  
    metal ring darvic ring mass  
28-5-2021 pullus .5559378 b-S|X 109 age: 2 / 3 days old  
28-5-2021 pullus .5559379 b-S|Y 133 Lesser Black-backed Gull graellsii from neighbour's nest.
28-5-2021 pullus .5559380 59 too small for darvic ring  
8-6-2021 both parters on look-out near nest.  
metal ring darvic ring mass head + bill wing  
26-6-2021 pullus .5559379 b-S|Y 676 104,2 293 Pullus LBBG controlled.
26-6-2021 pullus .5550682 r-F.H 734 98,3 225 Likely a chick hatched from a neighbouring nest next to 054.
26-6-2021             Large juvenile flies off to water. Maybe b[S|X]???
               
date:              
29-4-2022 Nest checked. 3 eggs. Code 220 sprayed on boulder.
  egg no: width (mm): length (mm): volume (cm3):  water test on April 24th: laying date:  
  A 50 70,4 -- 35 - tip bottom    
  B 49,8 70 -- 5 mm - floating (wind egg)  
  C 47,9 66,6 -- 10 - tip bottom  
04-05-2022 3 eggs. zy-MT in a cluster of nests with Herring and Lesser Black-backed Gulls. Difficult to pin down birds to a nest.
22-05-2022 3 eggs.
30-05-2022 1 pullus near the nest. zy-MT present.
  metal darvic mass wing H+B Bill  
  .5625171 r-6T 173 40 - -  
  prey: Roach 1x.
02-06-2022 zy-MT and adult Herring Gull present.
17-06-2022 zy-MT and adult Herring Gull present.
21-06-2022 zy-MT and adult Herring Gull present.
12-07-2022 zy-MT and adult Herring Gull present. But within 10 meters range, also 2x Herring adults + 1 chick; 1x Lessie + 1 chick.
17-07-2022 2x adult Herring Gull present. As is r-6T.