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-M|Z (060-2025, megaphone-2026)
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).
- Location on breakwater dam 1 south section, just on north side, near the top.
- Cluster of 5 nests within 10 meters range, which are difficult to monitor. Next to Angelica is nest 60, next to blackberries complex are nest 62 & nest 63.
- In 2023, male and female are Caspian Gull cachinnans. Female trapped on 3-egg clutch, now r-F.7.
- ID certain in 2024, male and female (r-F.7) are Caspian Gull cachinnans. Nest moved 3 mtr west, at edge Blackberry complex.
- In 2025: nest location 060 occupied by Caspian Gulls, of which we trapped one: now g-M|Z. New info-sheet for nest g-M|Z.
- In 2026: g-M|Z moved westwards. Megaphone placed on top of dam 1.
| location | April 21st, 2024: situation at cluster. | April 21st, 2024: situation at cluster. | April 22 2026: nest "megaphone". |
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| nest | April 21st, 2025: 3 eggs (full clutch). | April 21st, 2025: 3 eggs (full clutch). | . |
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| partner 1 | April 23 2025: male cachinnans: g-M|Z. | April 23 2025: male cachinnans: g-M|Z. | April 23 2025: male cachinnans: g-M|Z. |
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| partner 2 | May 8th, 2025: Caspian Gulls. | April 25 2025: Caspian Gulls. | . |
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Data for nest g-M|Z (060-2025).
| 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 | |
| g-M|Z nest 60 | cach | cach | 72,5 | 50,4 | 72 | 50,3 | 70 | 49,9 | 3 | |||||
| dam: | dam 1 cluster nest 60
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| location: | was temporarily nest 069-2024, with r-F7
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| parents: | new, Caspian Gull trapped this season, now g-M|Z | |||||||||||||
| ringed: | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale | |
| 23-04-2025 | g-M|Z | 5641001 | nest 60 | cach | M | >4CY | 476 | 1240 | 140,9 | 66,9 | 77,3 | 21 | 5 | |
OBSERVATIONS:
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| 4/21/2025 | eggs | 3x eggs measured,
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| nest | unringed adult cach & unringed sub-adult cach
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| 4/23/2025 | adult | trapped male g-M|Z, incubating 3 eggs at nest 60
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| 4/28/2025 | adult | attempted to trap unringed female, failed
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| eggs | 3 eggs | |||||||||||||
| 1/5/2025 | adult | trapped g-M|Z for 2nd time this season
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| food | fish | |||||||||||||
| eggs | 3x, no cracks
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| 8-5-2025 | adult | both partners present
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| 25/5/2025 | nest | 1 dead chick, 2x egg not hatched. Failed season.
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Visits and data 2026 for nest g-M|Z.
| 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 | |
| g-M|Z | cach | teus | 71,5 | 50,5 | 70,5 | 50,2 | ||||||||
| ringed: | ||||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale | |
OBSERVATIONS:
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| 22-04-2026 | nest | Empty. Code sprayed again. Megaphone on top of dam 1 west. | ||||||||||||
| 27-04-2026 | location | Code MZ sprayed on dam. Nest is on North side. | ||||||||||||
| nest | 2 eggs, measured. | |||||||||||||