Larus cachinnans in the Netherlands
(last update: August 16, 2020)
Albert de Jong
Merijn Loeve
Roland-Jan Buijs
Thijs Horst
Leon Kelder
Mars Muusse
Cachinnans - nest Lelystad PLDP (2020: 005, 2021: 052, 2022: not breeding, 2025: blocks dam 1)
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 005 positioned in dense Blackberry vegetation, in vicinity of Spoonbill nests, on artificial breakwater 1 at T-split.
- Certainty on ID in 2020, breeders are Caspian Gull cachinnans, one partner is ringed yellow PLDP and one unringed partner. Neighbours of yellow PESV (nest 006).
- In 2021: same 2 partners, again Caspian Gulls cachinnans. Bird has moved to nest location of y[PESV]-2020. PESV not present in 2021.
| location | Nest in vegetation: 2020. | Nest: April 16th, 2021. | April 01 2022 at Almere dump. Not breeding this year at Lelystad. |
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| eggs | Eggs April 15th, 2020: 2 eggs clutch. | Eggs April 27th, 2020: 2 eggs clutch. | Eggs April 16th, 2021: 3 eggs clutch. |
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| nest | April 23 2025: 3 eggs (full clutch) | . | . |
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| partner 1 | May 7th, 2020: cachinnans y[PLDP]. | May 7th, 2020: cachinnans y[PLDP]. | April 15th, 2020: cachinnans y[PLDP]. |
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| partner 1 | March 16 2025: male cachinnans y[PLDP]. | May 31 2025: male cachinnans y[PLDP]. | May 31 2025: male cachinnans y[PLDP]. |
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| partner 2 | May 7th, 2020: cachinnans unringed. | May 6th, 2021. | April 23 2025: female cachinnans g-M|2. |
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| partner 2 | April 23 2025: female cachinnans g-M|2. | April 23 2025: female cachinnans g-M|2. | . |
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| pulli | June 2nd, 2020 pullus unringed. | May 28th, 2021: pullus b[F|5] probably C-chick. | July 09 2025: chick g-T|K. Fledged. |
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| May 13 2025: chick g-T|L. Fledged. | May 25 2025: chick g-T|M. Fledged. | . | |
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Visits and data 2020:
| date: | egg no: | width (mm) | length (mm) | volume (cm3): | ||
| 15-04-2020 | A | 50,4 | 71,9 | 91,96 | 2 eggs in nest. | |
| 15-04-2020 | B | 50,8 | 73,05 | 94,92 | ||
| sum nest: | -- | |||||
| 27-04-2020 | eggs | Controlled: still 2 eggs. | ||||
| 07-05-2020 | pullus | Nest is empty. Small chick next to nest (7 days old). | ||||
| 21-05-2020 | pulli | Empty nest, no pulli found, but lots of shit-traces. | ||||
| 02-06-2020 | pulli | Parent y[PLDP] with 2 chicks close by. | ||||
| Visits and data 2021: | ||||||
| 30-03-2021 | PLDP and partner both present at blocks near waterfront. | |||||
| 16-4-2021 | egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 16th, 2021: | |
| A egg | 51,3 | 75,2 | 99,64 | 45 - tip bottom | 3 eggs in nest. 2 partners at nest, one is y[PLDP]. | |
| B egg | 50,6 | 77,2 | 99,52 | 35 - tip bottom | ||
| C egg | 50,5 | 77 | 98,87 | 30 - tip bottom | ||
| sum nest: | -- | |||||
| 24-04-2021 | partner 2 is unringed. Code of nest changed to 52. | |||||
| 26-04-2021 | No visit, Camilla is trapping Spoonbills here. | |||||
| 06-05-2021 | 2 chicks of few days old. 1 egg is hatching. | |||||
| 13-05-2021 | No visit, Camilla is trapping Spoonbills here. | |||||
| 15-05-2021 | mass (gr) | head + bill (mm) | ||||
| pullus | 142 | -- | ||||
| pullus | 221 | 65,5 | measurements Monika Ballmann. | |||
| 28-05-2021 | metal | tibia | mass (gr) | head + bill (mm) | ||
| pullus | .5559418 | b-F|5 | -- | 87 | probably C-chick. | |
| 08-06-2021 | PLDP attacks us. Partner also present. No chick visible. | |||||
Data for this nest 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 | |
| PLDP & g-M|2 | cach | cach | 70,7 | 47,6 | 70,5 | 48,1 | 70 | 50,3 | 3 | |||||
| dam: | dam 1 blocks
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| location: | blocks west part, red flag placed: nest is 2 mtr W,
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| parents: | returned, after 3 years.
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| rings: | ||||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale | |
| 23-04-2025 | g-M|2 | 5,641,003 | Nest PLDP | cach | F | >4CY | 442 | 953 | 122 | 56,7 | 62,7 | 18 | 6 | Fred Cottaar |
| 13-05 | g-T|K | 5641080 | PLDP | PONT | pullus | 350 | ||||||||
| 13-05 | g-T|L | 5641081 | PLDP | PONT | pullus | 409 | ||||||||
| 13-05 | g-T|M | 5641082 | PLDP | PONT | pullus | 590 | ||||||||
| 14-06 | G-T|K | PONT | pullus | 766 | ||||||||||
OBSERVATIONS:
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| 16-03 | nest | PLDP again in colony! Blocks dam 1, most western (between nest 53 - nest 22 black shoe),
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| 21-03 | nest | PLDP present same location as 16-3-2025
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| 04-04 | nest | PLDP present, on small part of blocks dam 1, on top of dam
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| 21-04 | nest | PLDP present
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| 23-04 | eggs | 3 eggs, measured,
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| adult | trapped female, now g-M|2, incubating 3 eggs at PLDP,
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| 28-04 | eggs | 1 egg hatching
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| 01-05 | adult | 2x present
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| 05-05 | chick | 3x chicks present
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| 08-05 | adult | both partners present
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| 13-05 | chicks | 3x chicks ringed
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| food | T|K fish bolus, T|M zwartbekgrondel
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| 16-05 | chick | g-T|K found and measured
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