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 033
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 033 positioned at breakwater 1, two meters from nest 34. High on breakwater, between large blocks.
- ID in 2020 certain, both Caspian Gull cachinnans, one parent has sub-adult patterns in wing.
- ID in 2021 certain, both Caspian Gull cachinnans. But are these the same two birds as in 2020?
- ID in 2023 certain, both Caspian Gull cachinnans.
- ID in 2024 certain, both Caspian Gull cachinnans.
| location | April 21st, 2024: 3 eggs clutch. | April 23rd, 2024: Caspian Gull guarding nest. | May 14th, 2024: Caspian Gulls. |
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| partner 1 | May 7th, 2020: male cachinnans. | May 7th, 2020: male cachinnans. | April 26th, 2021: male & female cachinnans. |
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| partner 2 | April 26th, 2021: male cachinnans. | May 13th, 2023: male cachinnans. | May 13th, 2023: male cachinnans. |
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| partner 2 | June 2nd, 2020: hybrid-type female cachinnans, wrong bird? | June 2nd, 2020: hybrid-type female cachinnans. | April 26th, 2021: female cachinnans. |
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| May 13th, 2023: female cachinnans. | May 13th, 2023: female cachinnans. | May 13th, 2023: female cachinnans. | |
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| pullus | May 21st, 2020: pullus n[F|5]. | May 21st, 2020: pullus n[F|6]. | June 25th, 2023: juvenile g-7|D. |
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| pullus | July 15th, 2023: juvenile g-9|B. | May 31st, 2024: chick g-A|U. | May 7th, 2024: chick g-A|V. |
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| pullus | May 7th, 2024: chick g-A|W. | June 04 2024: food g-A|V is fish. | . |
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Visits and data 2020.
| date: | egg no: | width (mm) | length (mm) | volume (cm3): | pulli: | |
| 07-05-2020 | A | wet chick - 1 day old. | 1 egg & 2 chicks in the nest, both partners cachinnans. | |||
| 07-05-2020 | B | chick - 3 days old. | ||||
| 07-05-2020 | C | hatching egg - tiny hole. | ||||
| 21-05-2020 | pulli | Nest empty, two chicks found, ringed n[F|5] & n[F|6]. | ||||
| data for 2021. | ||||||
| 26-04-2021 | male and female Caspian Gull present. One with subadult pattern. No marking placed near look-out stone. | |||||
| 13-05-2021 | no visit, Camilla is trapping a Spoonbill. | |||||
| 15-05-2021 | location visit. Walking between stones not certain which is the correct nest. Many surrounding Lesser Black-backed nests. | |||||
| 28-05-2021 | location visit to do ringing, but uncertainty about exact location. We should spray and mark this location in the future to have a clue. | |||||
| 08-06-2021 | no visit. | |||||
| egg sizes & volume 2023 | ||||||||||||
| SPECIES | NEST | A_length | A_width | A_volume | B_length | B_width | B_volume | C_length | C_width | C_volume | TOTAL NEST: | known parents? |
| cach x cach | 33-2023 | 77 | 49 | 93,09 | 70,7 | 49,2 | 86,17 | -- | -- | -- | -- | male of 2022, female possibly |
| ring pulli: -- | laying A egg: -- | hatch A egg: -- | ||||||||||
| catch: | date: | metal: | darvic: | mass: | wing: | head+bill: | ||||||
| Pullus | 18-05-2023 | 5.556.496 | G-7|D | -- | -- | 79 | ||||||
| Pullus | 27-05-2023 | 5.556.496 | G-7|D | 589 | -- | -- | ||||||
| Pullus | 27-05-2023 | 5.625.278 | G-9|B | 452 | -- | -- | ||||||
| Pullus | 18-06-2023 | 5.625.278 | G-9|B | -- | -- | -- | ||||||
| Pullus | 18-06-2023 | 5.556.496 | G-7|D | 842 | 335 | 118,8 | ||||||
| 33-2023 | ||
| dam: | dam 1 blocks | |
| location: | !!! Nest is even further east, 1 mtr from Rose-bush. Top of dam, most eastern nest in section. | |
| breeders: | cach x cach | |
| OBSERVATIONS: | ||
| 09-04-2023 | nest: | most western part of blocks. Code 112 on bitumen with arrow, no eggs but nest is ready. |
| adult: | adult cach near nest. Guarding. | |
| 26-04-2023 | nest: | Nest with 1 egg, 1 mtr east of old location (27/4: is LBBG!) |
| eggs: | 1x egg, measured. No water test. (27/4: data skipped, wrong nest). | |
| 27-04-2023 | nest: | !!! Nest is even further east, 1 mtr from Rose-bush. Top of dam, most eastern nest in section. |
| eggs: | 2x egg, measured. No water test. | |
| adult: | 2x cach, one was breeding and stepped from this nest. | |
| 11-05-2023 | nest: | nest empty, no chicks found |
| 13-05-2023 | adult: | 2x cach photographed. Behaviour: they have chicks. |
| 18-05-2023 | pulli: | 1 chick found and ringed |
| 27-05-2023 | pulli: | 1x control chick. 1x new ringed chick. |
| 18-06-2023 | pulli: | 2x chicks with 2 adults at nest site. Fledged: 2 juveniles (nest had 2 eggs only from the start). |
| 25-06-2023 | pulli: | both chicks present. Started with 2 eggs, both juveniles fledged. |
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 | 77,5 | 48,6 | 92,17 | 74,4 | 50,5 | 95,53 | 73,9 | 50,2 | 93,77 | 281,47 | ||
| 033-2024 | # eggs | A-egg | hatch | # ringed chicks | # all chicks | # fledged chicks | comments | ||||||
| 3 | 8-4-2024 | 3-5-2024 | |||||||||||
| dam: | dam 1 blocks | ||||||||||||
| location: | Nest is northeast in blocks section, yellow football near nest. Top of dam, most eastern nest in section. | ||||||||||||
| parents? | same as 2023? | ||||||||||||
| ring pulli: | 09-May | ||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale |
| 07-05-2024 | g-A|U | .5631229 | 33 | PONT | 1CY | 70 | |||||||
| 07-05-2024 | g-A|V | .5631230 | 33 | PONT | 1CY | 68 | |||||||
| 07-05-2024 | g-A|W | .5631231 | 33 | PONT | 1CY | 80 | |||||||
| 04-06-2024 | g-A|U | .5631229 | 33 | PONT | 1CY | 254 | 938 | 115,5 | |||||
| 04-06-2024 | g-A|V | .5631230 | 33 | PONT | 1CY | 219 | 715 | 104 | |||||
| OBSERVATIONS: | |||||||||||||
| 12-04-2024 | eggs: | 3 eggs, measured. Yellow football placed between blocks near nest. | |||||||||||
| 21-04-2024 | eggs: | 3 eggs, not measured. | |||||||||||
| 07-05-2024 | chicks: | 3x ringed. | |||||||||||
| 14-05-2024 | nest: | no search, chicks already ringed. | |||||||||||
| adults: | 2x Caspian Gull. | ||||||||||||
| 31-05-2024 | chicks: | g-A|U, g-A|V present. | |||||||||||
| 04-06-2024 | chicks: | g-A|U & g-A|V present, measured. | |||||||||||
| food: | fish bolus by g-A|V. | ||||||||||||
| 18-06-2024 | chicks: | g-A|U, g-A|V present. | |||||||||||
| adults: | 2x Caspian Gull. | ||||||||||||
Visits and data 033-2025.
| 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 | |
| 33 | cach | cach | 74,9 | 49,5 | 70,8 | 48,6 | 2 | |||||||
| dam: | dam 1 blocks.
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| location: | Nest is northeast in blocks section, yellow football near nest, Top of dam, most eastern nest in section.
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| parents: | ||||||||||||||
| ring pulli: | ||||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale | |
| 13-05-2025 | g-N|= | 5641062 | 33 | PONT | pullus | 337 | ||||||||
| 09-06-2025 | g-N|= | 5641062
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PONT | pullus | 1169 | CONTROL | ||||||||
OBSERVATIONS:
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| 16-03-2025 | nest | 2x cach at location 2024, possibly same parents as 2024.
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| 20-03-2025 | nest | 2x cach at location 2024.
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| 23-04-2025 | eggs | 2 eggs, measured.
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| 01-05-2025 | eggs | 1x egg only (very tiny crack), no sign of chick.
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| adult | 2x Caspian Gulls.
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| 08-05-2025 | adult | both partners present.
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| 13-05-2025 | chick | one chick ringed.
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| 09-06-2025 | chick | g-N|= found and measured. Fledged.
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