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 "Blue Bucket" (026)
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 026 positioned on blocks dam 1, far east (was 34-2021?). Cluster of Caspian Gull nests (With Lessies and Herrings) between blocks.
In 2023-2025 again a nest at this location. - ID certain in 2022: both cachinnans.
- ID in 2023: unknown. Dense cluster of nests between boulders.
- ID in 2024: male is Caspian Gull, female is hybrid-type. Chicks C|4 and C|5 are hybrid type juveniles.
- ID in 2025: male is Caspian Gull, female is Herring Gull. Chicks R|R and T|D are hybrid juveniles.
| nest | April 15th, 2022: nest location. | April 15th, 2022: 1 egg. | May 17th, 2022: 1 egg infertile. |
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| nest | April 21st, 2024: 3 eggs clutch, nest "Blue Bucket". | April 21st, 2024: 3 eggs clutch. | April 28th, 2025: Caspian Gull at nest. |
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| nest | April 23 2025: 3 eggs (full clutch). | April 23 2025: 3 eggs (full clutch). | . |
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| partner 1 | April 27th, 2022: partner 1 is sub-ad cachinnans. | April 27th, 2022: partner 1 is sub-ad cachinnans. | April 19th, 2022: partner 1 is sub-ad cachinnans. |
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| partner 1 | April 23 2024: Caspian Gull (foreground = 34). | May 14 2024: partner 1. | April 1st, 2025: Caspian Gull (foreground = 34). |
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| partner 1 | April 25 2025: Caspian Gull. | April 25 2025: Caspian Gull. | April 25 2025: Caspian Gull. |
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| partner 2 | May 17th, 2022: partner 2 is female cachinnans. | May 17th, 2022: partner 2 is female cachinnans. | June 18th, 2024: partner 2 is female hybrid-type. |
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| pullus | May 17th, 2022: 2 chicks ringed metal NLA. | May 30th, 2022: pullus r-7E. | May 30th, 2022: pullus r-7F. |
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| pullus | May 27th, 2023: pullus g-8|0. | May 27th, 2023: pullus g-8|4. | May 27th, 2023: pullus g-8|5. |
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| chicks | May 31 2024: chick g-C|4. | May 31 2024: chick g-C|5. | June 29 2025: g-T|D, hybrid juvenile. |
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| chicks | June 30 2025: g-R|R, hybrid juvenile. | . | . |
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| food | May 30th, 2022: fish bolus. | June 04 2024: fish bolus from g-C|5. | . |
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Visits and data 2022 for nest 26:
Estimation egg laying: A-egg = April 15 2022. Estimating hatching = May 13 2022.
| date: | |||||||
| egg no: | width (mm): | length (mm): | volume (cm3): | ||||
| 15-04-2022 | A | 48,7 | 72,0 | -- | 1 egg. | ||
| sub-adult Caspian near nest. | |||||||
| 19-04-2022 | sub-adult Caspian near nest. | ||||||
| egg no: | 3 eggs. | ||||||
| 27-04-2022 | A | - | - | tip bottom - 90 | |||
| B | 49,6 | 70,2 | tip bottom - 70 | ||||
| C | 50,0 | 72,5 | tip bottom - 90 | ||||
| metal | |||||||
| 17-05-2022 | pullus | 5625117 | 2 days old. | ||||
| pullus | 5625118 | ||||||
| 1x egg: infertile. | |||||||
| metal | colour | mass | wing | head + bill | Bill | ||
| 30-05-2022 | pullus | 5625117 | r-7.E | 612 | 126 | 95,7 | 38,1 |
| pullus | 5625118 | r-7.F | 522 | 96 | 88,2 | 36,6 | |
| 1x egg: infertile. | |||||||
| 02-06-2022 | r7E & r7F present. | ||||||
| 17-06-2022 | r7E & r7F present. | ||||||
| 21-06-2022 | r7E & r7F present | ||||||
| 28-06-2022 | r7E & r7F present | ||||||
| 12-07-2022 | r7E & r7F present | ||||||
| Male cachinnans 4CY & female cachinnans. | |||||||
| 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? |
| ? X ? | 26-2023 | 0 | 0 | 0,00 | 0 | 0 | 0,00 | 0 | 0 | 0,00 | 0,00 | nn |
| ring pulli: -- | laying A egg: -- | hatch A egg: -- | ||||||||||
| catch: | date: | metal: | darvic: | mass: | wing: | head+bill: | ||||||
| Pullus | 27-5-2023 | 5.625.275 | g-8|0 | 136 | -- | -- | ||||||
| Pullus | 27-5-2023 | 5.625.276 | g-8|5 | 209 | -- | -- | ||||||
| Pullus | 27-5-2023 | 5.625.277 | g-8|4 | 225 | -- | -- | ||||||
| 26-2023 | ||
| dam: | dam 1 blocks | |
| location: | nest has now red spot, tree stem erected next to nest, which is approx 10 mtr east of nest P:U60, and 2 mtr west of code red R on block. | |
| breeders: | ? X ? | |
| OBSERVATIONS: | ||
| 27-5-2023 | pulli: | 3 chicks ringed and measured. |
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 | 71,1 | 47,7 | 81,45 | 74,3 | 49,1 | 90,19 | 73,6 | 49 | 88,98 | 260,62 | |||
| 026-2024 | # eggs | A-egg | hatch | # ringed chicks | # all chicks | # fledged chicks | comments | ||||||
| 3 | 15-4-2024 | 10-5-2024 | |||||||||||
| dam: | dam 1 blocks | ||||||||||||
| location: | Was nest 26 at blocks east side, now Blue Bucket, 3 mtr SE of Roodflapje, top of dam 1 | ||||||||||||
| parents? | New? | ||||||||||||
| ring pulli: | 14-May | ||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale |
| 14-05-2024 | .5631189 | 26 blauwe emmer | PONT | 1CY | 68 | ||||||||
| 14-05-2024 | .5631190 | 26 blauwe emmer | PONT | 1CY | 69 | ||||||||
| 31-05-2024 | g-C|4 | .5631189 | 26 | PONT | 1CY | CONTROLL | |||||||
| 31-05-2024 | g-C|5 | .5631190 | 26 | PONT | 1CY | CONTROLL | |||||||
| 04-06-2024 | g-C|4 | .5631189 | 26 | PONT | 1CY | 173 | 653 | 94,9 | CONTROLL | ||||
| 04-06-2024 | g-C|5 | .5631190 | 26 | PONT | 1CY | 175 | 738 | 98,0 | CONTROLL | ||||
| OBSERVATIONS: | |||||||||||||
| 21-04-2024 | eggs: | 3 eggs, measured. | |||||||||||
| nest: | Caspian Gull incubating. | ||||||||||||
| 07-05-2024 | eggs: | 3x. | |||||||||||
| 14-05-2024 | chicks: | 2x ringed, only metal. | |||||||||||
| adult: | Caspian Gull | ||||||||||||
| eggs: | 1x hatching | ||||||||||||
| 31-05-2024 | chicks: | 2x ringed, darvic added. | |||||||||||
| 04-06-2024 | chicks: | g-C|4 & g-C|5 present, measured. | |||||||||||
| food: | fish bolus by g-C|5 when processed = Roach. | ||||||||||||
| 18-06-2024 | chicks: | g-C|4, g-C|5 present. | |||||||||||
| adults: | 1x Caspian Gull. In direct surrounding: 2 Caspians and 3 Herrings present. | ||||||||||||
Visits and data 026-2025.
| 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 |
| 26 Blue Bucket | cach | teus | 73 | 48 | 69,6 | 49 | 68,1 | 46,6 | 3 | ||||
| dam: | dam 1 blocks
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| location: | at dam 1 - blocks, east part, nest with blue bucket
next to nest. |
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| parents: | same as 2024, Herring and Caspian.
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| ringed: | |||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | |
| 13-05-2025 | g-T|D | 5641066 | 26 | HYBRID
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pullus | 480 | |||||||
| 13-05-2025 | g-T|F | 5641067 | 26 | HYBRID
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pullus | 414 | FOUND DEAD, RING REUSED
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| 31-05-2025 | g-R|R | 5641912 | 26 | HYBRID | pullus | 989 | ringed pullus | ||||||
| 09-06-2025 | g-R|R | 5641912
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26 | HYBRID | pullus | 966 | CONTROL | ||||||
OBSERVATIONS:
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| 23-04-2025 | eggs | 3 eggs, measured.
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| 28-04-2025 | eggs | hatching. | |||||||||||
| 01-05-2025 | adult | Caspian & Herring Gull present.
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| 13-05-2025 | chicks | 2 chicks ringed, 3rd not found.
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| 31-05-2025 | chicks | 1 chick ringed, 1 found dead.
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| 09-06-2025 | chicks | g-R|R found and measured, G-T|D also present.
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