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 - Lelystad nest r-5X
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-5X positioned on dam 2, underneath VHF sign.
- ID certain in 2025: male is 4CY cachinnans r-5X (pullus nest near 112-2022).
- ID 2026: one parent is female hybrid Caspian Gull, trapped. Now Y-0:X.
| location | dam 2: VHF 20 sign. | dam 2: VHF 20 sign. | . |
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| partner 1 | July 09 2025: 4CY r-5X. | June 25 2025: 4CY r-5X. | April 23 2025: 4CY r-5X. |
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| partner 2 | May 05 2026: female hybrid Y-0:X. | May 05 2026: female hybrid Y-0:X. | May 05 2026: female hybrid Y-0:X. |
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| eggs | April 22 2026: 1 egg. | . | . |
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| chicks | June 29 2025: chick G-N|7. | . | . |
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Data for nest r-5X in 2025:
| r-5X (Caspian Gull, pullus nest 112-2022) | ||
dam: 2 underneath VHF sign
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| OBSERVATIONS: | ||
| 13-05-2025 | nest | 1 egg in nest, 1 egg outside nest
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| date: | darvic | metal | nest | species | sexe | age | wing | mass | head+ bill |
| 29-06-2025 | G-N|7 | .5641056 | R-5X | PONT | pullus | 209 | 393 | 95,9 |
Visits and data nest r-5X & y-0:X (2026)
| 2026 | 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 | |
| r-5X & y-0:X | cach | hybrid | 74,1 | 47,3 | 71,0 | 46,9 | 68,0 | 47,0 | ||||||
| ringed: | ||||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | tarsus | head+ bill | bill | gonys | mass | ||
| 05-05-2026 | Y-0:X | 5.646.671 | nest r-5X | HYBRID | F | >4CY | 417 | 67,7 | 119,7 | 54 | 18,8 | 822 | ||
OBSERVATIONS:
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| 22-04-2026 | nest | 1 egg, measured. | ||||||||||||
| 26-04-2026 | nest | 3 eggs, measured. | ||||||||||||
| parents | 1x unringed hybrid Caspian Gull. | |||||||||||||
| 05-05-2026 | parents | trapped unringed hybrid Caspian Gull, now y-0:X. | ||||||||||||
| 10-05-2026 | nest | 3 eggs. | ||||||||||||