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 n-F|N
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 n-F|N positioned in section dam 1 south, exactly where 61-2021 was. On top of dam, at edge of small Blackberry complex.
- ID certain in 2022, one partner is female cachinnans. Partner is Dutch 4CY male (hybrid ?) Caspian Gull n-F|N. Bird ringed in 2019 at Lelystad, parents unknown.
- ID certain in 2023: female cachinnans. trapped, now r-7N. Partner is Dutch 5CY male (hybrid?) Caspian Gull n-F|N. Bird ringed in 2019 at Lelystad, parents unknown.
| location | April 12th, 2022: nest high on dam 1. | April 12th, 2022: nest high on dam 1. | May 4th, 2022: 3 eggs in nest. |
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| April 27 2023: female Caspian & 2x Herring from nest 61. | |||
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| partner 1 | May 4th, 2022: Dutch 4CY male hybrid Caspian Gull n-F|N. | May 9th, 2022: male n-F|N trapped on nest. | May 9th, 2022: male n-F|N trapped on nest. |
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| partner 1 | April 09 2023: n-F|N. | April 27 2023: Caspian Gull n-F|N. | July 08 2023: Caspian Gull n-F|N. |
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| partner 2 | May 4th, 2022: female Caspian Gull cachinnans. | April 12th, 2022: both partners. | . |
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| partner 2 | Trapped at nest on May 03 2023: Caspian Gull r-7N. | June 25 2023: Caspian Gull r-7N. | July 08 2023: Caspian Gull r-7N. |
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| pullus | May 30th, 2022: pullus r-7.B. | July 12th, 2022: fledged r-7.B. | July 12th, 2022: fledged r-7.B. |
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| July 08 2023: fledged juvenile r-8F. | July 15 2023: fledged juvenile r-8J. | . | |
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Visits and data:
Estimation egg laying: A-egg = April 19 2022. Estimating hatching = May 17 2022.
| date | |||||||
| 12-04-2022 | Cachinnans-type n-F|N guarding high on dam 2. | ||||||
| 01-05-2022 | Cachinnans-type n-F|N walks from nest in small bush, high on dam 2. Below him is nest 061Z. | ||||||
| Cachinnans female landed next to n-F|N, and this femaler is ringed on tarsus! (in retrospect: never seen again this bird). | |||||||
| 04-05-2022 | Two adults at nest. Female cachinnans and 4CY n-F|N. | ||||||
| 3 eggs | egg no: | width (mm) | length (mm) | volume (cm3): | water test on May 4th: | ||
| A egg | 49,9 | 74 | -- | -- | |||
| B egg | 47,9 | 68,5 | -- | -- | |||
| C egg | 50 | 71 | -- | -- | |||
| 09-05-2022 | 3 eggs. We trapped n-F|N at the nest. No measurements taken. | ||||||
| 17-05-2022 | 3 eggs. | ||||||
| 22-05-2022 | 3 eggs. | ||||||
| 30-05-2022 | n-F|N at nest. 2 chicks. | ||||||
| pullus | metal | darvic | mass | wing | H+B Bill | ||
| .5625183 | r-7.B | 87 | 25 | 53,9 18,4 | |||
| pullus | 1 pullus dead in nest. | ||||||
| 02-06-2022 | Cachinnans-type n-F|N defending nest. | ||||||
| 17-06-2022 | Cachinnans-type n-F|N at nest. | ||||||
| 21-06-2022 | Nest empty, Chick r-7.B not found in vegetation. | ||||||
| 12-07-2022 | Photographed r-7.B. | ||||||
| In 2022 one chick ringed in this nest: r-7.B. | |||||||
| 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 | nFN & r7N | 0 | 0 | 0,00 | 0 | 0 | 0,00 | 0 | 0 | 0,00 | 0,00 | same as 2022 |
| ring pulli: -- | laying A egg: -- | hatch A egg: -- | ||||||||||
| catch: | date: | metal: | darvic: | mass: | wing: | head+bill: | bill: | gonys: | greytone: | |||
| adult | 03-05-2023 | 6.214.906 | R-7.N | -- | 433 | 123,7 | 52,6 | 18,4 | 6 | female cach | ||
| pullus: | 18-05-2023 | 5.556.488 | R-8.F | 256 | -- | 65,4 | -- | -- | -- | |||
| pullus: | 18-05-2023 | 5.556.489 | R-8.J | 224 | -- | 70 | -- | -- | -- | |||
| pullus: | 27-05-2023 | 5.556.488 | R-8.F | 643 | -- | -- | -- | -- | -- | |||
| pullus: | 18-06-2023 | 5.556.489 | r-8.J | 1020 | 341 | 126,8 | -- | -- | -- | with sibling | ||
| n-F|N & r-7.N | |||
| dam: | dam 1 west | ||
| location: | Is nest n-F|N-2022. Nest 2023 is 3 mtr further N now, closer to Herring Gull w-8Z. | ||
| breeders: | cach x cach | ||
| OBSERVATIONS: | |||
| 04-04-2023 | adult: | n-F|N at nest location. | |
| 09-04-2023 | nest: | no eggs, but nest ready. | |
| adult: | Male is n-F|N, female is cach unringed. | ||
| 27-04-2023 | adult: | Male is n-F|N, female is cach unringed. | |
| 03-05-2023 | adult: | Trapped unringed female at nest: r-7N. | |
| 13-05-2023 | adult: | Both parents present. | |
| 18-05-2023 | pulli: | 2 chicks ringed, 3rd one not found. | |
| 27-05-2023 | pulli: | 1x control chick. | |
| 18-06-2023 | pulli: | r-8J & r-8F present. Probably no 3rd chick. Fledged: 2 juveniles. | |
| 25-06-2023 | pulli: | r-8J & r-8F present. Both parents as well. | |