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 Lelystad g-N|A (092-2025)
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 092 positioned on artificial breakwater 1 west, opposite yacht harbour, 30 mtr west of yellow sign 2,5 (nest b/w-AJ and b/w-AK). New nest 2024, late, found on June 04 2024.
- Certainty on ID in 2024, both are immature Caspian Gull cachinnans.
- Certainty on ID in 2025, same male cachinnans. New 4CY female at nest. Ringed in 2025, now g-N|A.
| partner 1 | June 04 2024: female Caspian Gulls sub-adult. | June 04 2024: Caspian Gull sub-adult. | May 8th, 2025: female Caspian Gull g-N|A. |
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| partner 1 | April 28 2025: female Caspian Gull g-N|A. | April 28 2025: female Caspian Gull g-N|A. | April 28 2025: female Caspian Gull g-N|A. |
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| partner 2 | June 04 2024: male Caspian Gull sub-adult. | June 04 2024: Caspian Gull sub-adult. | June 04 2024: Caspian Gull sub-adult. |
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| partner 2 | March 25th, 2025: pair Caspian Gull. | May 8th, 2025: male Caspian Gull 5CY. | . |
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| pullus | June 04 2024: chick g-M|G. | June 04 2024: chick g-M|H. | May 25 2025: chick g-T|2. |
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| pullus | June 09 2025: chick g-T|3. | . | . |
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| food | June 04 2024: fish = Roach. | . | . |
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Visits and data 2024.
| NEST code | parent 1 | parent 2 | A_length | A_width | A_volume | B_length | B_width | B_volume | C_length | C_width | C_volume | TOTAL NEST: | |
| cach | cach | ||||||||||||
| 92-2024 | # eggs | A-egg | hatch | # ringed chicks | # all chicks | # fledged chicks | comments | ||||||
| dam: | dam 1 west | ||||||||||||
| location: | near Elderberry, 30 mtr W of sign 2,5. Code 92 sprayed on tarmac. | ||||||||||||
| parents? | New | ||||||||||||
| ringed: | |||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale |
| 04-06-2024 | g-M|G | .5631140 | 92 | PONT | 1CY | 143 | |||||||
| 04-06-2024 | g-M|H | .5631141 | 92 | PONT | 1CY | 122 | |||||||
| OBSERVATIONS: | |||||||||||||
| 04-06-2024 | adult: |
2x Caspian Gull immatures. Location was already suspicious weeks ago, but believed to be socialising birds. | |||||||||||
| pullus: | 2x ringed. | ||||||||||||
| food: | Roach type. | ||||||||||||
Visits and data 2025 nest g-N|A (092).
| 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 | |
| g-N|A (092) | cach | cach | 74,6 | 48,8 | 70,2 | 48,8 | 70,3 | 47,8 | 3 | |||||
| dam: | dam 1 | |||||||||||||
| location: | underneath 'round' tree opposite pumping station, Red jerrycan on boulder at waterfront.
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| ouders: | new female, trapped art nest and ringed g-N|A.
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| ringed: | ||||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale | |
| 28-04-2025 | g-N|A | 5641010 | 92 | PONT | F | 4CY | 446 | 876 | 127,9 | 55,8 | 68,8 | 16,8 | 5,5 | |
| 25-05-2025 | g-T|2 | 5641856 | 92 | PONT | pullus | 114 | ringed pullus | |||||||
| 25-05-2025 | g-T|3 | 5641857 | 92 | PONT | pullus | 130 | ringed pullus | |||||||
| 25-05-2025 | 5641858 | 92 ?? | ?? | pullus | 56 | ringed pullus | ||||||||
| 09-06-2025 | G-T|2 | 5641856
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PONT | pullus | 464 | CONTROL | ||||||||
| 09-06-2025 | G-T|3 | 5641857
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PONT | pullus | 323 | CONTROL | ||||||||
OBSERVATIONS:
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| 25-03-2025 | nest | 2x cach present, 2024 was 2x 4cy cach.
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| 04-04 | nest | 2x cach present, Nest is really way underneath the bush.
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| 21-04 | nest | 1 egg, Not measured, Red jerrycan placed at boulder in front of nest.
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| 25-04 | nest | 2 eggs. | ||||||||||||
| 28-04 | adult | 3 eggs, adult trapped now g-N|A.
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| 08-05 | adult | both partners present.
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| 13-05 | nest | 3 eggs. | ||||||||||||
| adult | tried to trapped unringed male, but again female caught, and released.
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| food | vomit bolus is Roach.
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| 25-05 | chicks | 3x ringed, not sure if 3rd chick belongs to nest.
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| 30-05 | chicks | metal ringed chick found dead, metal ring reused.
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| 09-06 | chicks | 2 chicks found and measured.
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| 30-06-2025 | chicks | g-T|2 found dead, ring can be reused.
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| Conclusion: g-T|2 found dead & g-T|3 not seen after ringing, 3rd metal only (probably this nest) found dead. Likely failed season. | ||||||||||||||