Larus cachinnans in the Netherlands
(last update: August 16, 2020)
Albert de Jong
Leon Kelder
Roland-Jan Buijs
Thijs Horst
Merijn Loeve
Mars Muusse
Cachinnans - nest r-6L & g-A|A 2025
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 r-6L positioned on dam 1 east section, just west of nest 139 (which is the nest where r-6L was raised in 2022). Also close to nest n-F|T & g-A|A 2024.
- Male r-6L hardly involved in incubation. First nest on south side, failed. Second attempt on north side of dam, also failed.
- ID certain in 2025: male is 4CY cachinnans r-6L (from nest 139-2022), and female is adult cachinnans g-A|A (trapped in 2024 as partner of n-F|T). N-F|T not present anymore.
| nest | April 23 2025: nest with 3 eggs (full clutch). | April 23 2025: nest with 3 eggs (full clutch). | March 16 2025: pair at nest dam 1. |
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| nest | March 16 2025: pair at nest dam 1. | April 04 2025: pair at nest dam 1. | March 25 2025: pair at nest dam 1. |
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| partner 1 | May 05 2025: male 4CY cachinnans r-6L. | April 04 2025: 4CY cachinnans r-6L. | April 04 2025: 4CY cachinnans r-6L. |
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| partner 2 | March 21 2025: adult cachinnans g-A|A. | March 25 2025: adult cachinnans g-A|A. | March 21 2025: adult cachinnans g-A|A. |
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Data for nest r-6L in 2025:
| 2025 | parent 1 | parent 2 | A_length | A_width | A_volume | B_length | B_width | B_volume | C_length | C_width | C_volume | TOTAL NEST:
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# eggs | A-egg |
| r-6L & g-A|A | cach | cach type | 71,7 | 50,5 | 71,2 | 51 | 70,7 | 50,1 | 3 | 4/15/2025 | ||||
| dam: | dam 1 east
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| location: | new, S-side, 15 m W of old nest 139-2024, blue cushion placed.
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| parents: | new | |||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | ||
OBSERVATIONS:
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| 16-03-2025 | nest | |||||||||||||
| 20-03-2025 | nest | both present on soos dam 2, and feeding on bread near poles end dam 2
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| 25-03-2025 | nest | both present on dam 1 opposite side of the dam around nest location g-A|A 2024
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| 01-04-2025 | nest | Both present, same location as 3/25/2025 (barend side of the dam)
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| 21-04-2025 | nest | Both present, same location, g-A|A incubating; r-6L brings in extra nest materials
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| 23-04-2025 | nest | blue fender cushion placed in front of nest between stones
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| adult | g-A|A incubating
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| eggs | 3 eggs, measured
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| 30-05-2025 | nest | 2 eggs, now on other side of dam. First nest failed
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| 09-06-2025 | nest | 2 eggs | ||||||||||||
| 14-06-2025 | nest | 2 eggs | ||||||||||||
| 25-06-2025 | nest | 2 eggs, warm
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| 29-06-2025 | nest | 2 eggs warm no cracks. Season failed.
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