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 244

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 244 positioned on dam 1 south section, 40 meters west of nest 118 (for 2022 is the most western nest).
  • ID uncertain in 2022: immature (5CY) cachinnans, other partner likely (99%) Herring Gull. Offspring 2022 clearly with strong Herring fenotypics.
partner 1: May 17th, 2022: code May 17th, 2022: sub-adult cachinnans May 17th, 2022: sub-adult cachinnans
 
pullus May 17th, 2023: 3 eggs. May 22nd, 2023: 3x metal ring. .
   
pullus May 30th, 2022 pullus r[6.5]. May 30th, 2022 pullus r[6.7]. May 30th, 2022 pullus r[6.8].
 

Data for this nest:
Estimation egg laying: A-egg = May 01 2022. Estimating hatching = May 29 2022.

4-May-22 3 eggs A egg 65,4 51 floating - 4 mm
B egg 67,8 49 floating - 4 mm
C egg 63,4 47,6 floating - 4 mm
sub-adult cachinnans at this nest.
metal darvic mass wing H+B age
22-May-22 pullus .5625150 - 73 27 50,8 2 days, too small for darvic ring.
pullus .5625151 - 68 24 50,2 2 days, idem.
pullus .5625152 - 60 22 47 1st day, idem.
metal darvic mass wing H+B bill
30-May-22 pullus .5625150 r-68 267 45 67,6 26
pullus .5625151 r-67 258 46 68,1 24
pullus .5625152 r-65 244 38 63,6 23
02-Jun-22 probably Herring Gull at this nest? But be aware of other nest close by.
17-Jun-22 adult Herring Gull near nest.
21-Jun-22 pullus darvic mass H+B Bill Tarsus Wing
r-68 888 111 42,2 77,5 255