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 021
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 021 positioned at breakwater 1 at T-split corner near Spoonbills. In 2021 position of nest is exactly the same, marked with "the grey jerrycan" from flotsam. Nest close to Spoonbill nests, therefore limited visits. Instead: observed from distance with binoculars or telescope.
- ID in 2020 certain, Caspian Gull cachinnans; one partner with sub-adult patterns.
- ID in 2021: 2 partners are adult Caspian gull cachinnans. Ringed chicks 2021 quickly after fledging reported from abroad (click links on pulli thumbnails below).
- ID in 2022 uncertain. One parent is Caspian Gull, other parent not photgraphed. Location is exactly the same as in 2021 & 2020.
- ID in 2023 certain: both parents are Caspian Gull. Male same as in 2022 (P8 mirror left wing). Location is exactly the same as 21-2020 / 2022.
below: Caspian Gull cachinnans adult, April 27 2020, Lelystad, the Netherlands. Picture: Albert de Jong.
Albatrossing to the partner flying overhead. On the right: adult Lesser Black-backed Gull breeder on nest 22, and some Spoonbills in the background.
| location | April 27th, 2020: nest location. | May 7th, 2020: nest location. | April 27th, 2020: 3 eggs clutch. |
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| location | April 16th, 2021: 2 eggs clutch. | April 27th, 2022: 3 eggs clutch. | April 27th, 2022: 3 eggs clutch. |
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| location | April 9th, 2023: 1 egg. | April 26th, 2023: 3 eggs clutch. | April 26th, 2023: nest location. |
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| partner 1 | May 7th, 2020: male cachinnans 4CY? | May 7th, 2020: male cachinnans 4CY? | May 7th, 2020: male cachinnans 4CY? |
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| partner 1 | April 16th, 2021: male cachinnans. | April 16th, 2021: male cachinnans. | May 9th, 2022: male cachinnans. |
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| partner 1 | May 9th, 2022: male cachinnans. | May 9th, 2022: male cachinnans. | July 8th, 2023: male cachinnans. P8 mirror in left wing. |
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| partner 2 | May 7th, 2020: female cachinnans. | May 7th, 2020: female cachinnans. | May 13th, 2023: female cachinnans. |
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| partner 2 | May 13th, 2023: female cachinnans. | . | . |
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| pulli | May 21st, 2020: pullus n[F|2]. | May 21st, 2020: pullus n[F|4]. | May 17th, 2022: pullus r[5.J]. |
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| pulli | May 17th, 2022: pullus r[5.K]. | July 8th, 2023: r[8.D]. | July 18th, 2023: r[8.E]. |
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| pulli | May 11th, 2023: pullus r[8.Y]. | . | . |
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Visits and data 2022:
Estimation egg laying: A-egg = April 13 2022. Estimating hatching = May 11 2022.
| date: | ||||||
| egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 15th: | ||
| 27-04-2020 | A | 49,6 | 68,9 | 85,35 | 30 - angled, tip on bottom | 3 eggs in the nest. Male with sub-adult pattern. |
| 27-04-2020 | B | 49,8 | 70 | 87,41 | 60 - angled, tip on bottom | |
| 27-04-2020 | C | 50,1 | 66,6 | 84,17 | 35 - angled, tip on bottom | |
| sum nest: | 256,92 | |||||
| 21-05-2020 | pulli | Two chicks, ringed n[F|2] & n[F|4]. C-egg is unfertile, taken from nest. | ||||
| 02-06-2020 | pulli | Two partners at nest. | ||||
| date 2021: | ||||||
| 16-04-2021 | egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 16th: | |
| A | 50,5 | 70,9 | 91,04 | 20 - flat on bottom | 2 eggs in the nest and 1 adult. Eggs just laid. | |
| B | 49,5 | 74,5 | 91,91 | 15 - flat on bottom | ||
| 24-04-2021 | 2 partners, 3 eggs in nest but accidentally no measurements taken. | |||||
| 26-04-2021 | No visit, Camilla is trapping a Spoonbill. | |||||
| 06-05-2021 | egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 16th: | |
| A | - | - | - | 6 mm - floating. | ||
| B | - | - | - | 6 mm - floating. | ||
| C | 48,4 | 66,1 | 77,96 | 2 mm - floating. | ||
| sum nest: | 260,91 | |||||
| 13-05-2021 | No visit, Camilla is trapping a Spoonbill. | |||||
| 15-05-2021 | B egg & C egg present, and 1 chick (99 gr). | |||||
| 28-05-2021 | Empty nest. Searched for chicks in vegetation, but not found. | |||||
| 02-06-2021 | Guarding female near nest. | |||||
Visits and data 2022:
Estimation egg laying: A-egg = April 6 2022??? Estimating hatching = May 4 2022.
| 11-04-2022 | Nest is ready, still no eggs. | ||||||
| 12-04-2022 | From distance: adult guarding nest. | ||||||
| egg no: | width (mm): | length (mm): | volume (cm3): | water test | |||
| 15-04-2022 | A-egg | 50,7 | 70,1 | -- | 20 - tip on bottom | ||
| B-egg | 51,4 | 67,9 | 10 - tip on bottom | ||||
| sum nest: | -- | ||||||
| White jerrycan placed next to nest. | |||||||
| egg no: | width (mm): | length (mm): | volume (cm3): | water test | |||
| 27-04-2022 | A-egg | -- | -- | 3 mm - floating | |||
| B-egg | -- | -- | 2 mm - floating | ||||
| C-egg | 49,3 | 65,3 | 80 - tip on bottom | ||||
| 09-05-2022 | From distance: adult at nest. Picture: bird has extra mirror, on P8. | ||||||
| 17-05-2022 | metal | darvic | mass | wing | H+B | ||
| pullus | NLA 5.625.108 | r-5.K | 118 | ||||
| pullus | NLA 5.625.109 | r-5.J | 189 | ||||
| 17-06-2022 | From distance: several larger chicks between blocks at this locations. No rings read, unfortunately. | ||||||
| 21-06-2022 | From distance: no activities at nest. No rings read, unfortunately. | ||||||
| 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 | 21-2023 | 69,5 | 53,1 | 98,67 | 67,8 | 52,9 | 95,53 | 66,4 | 51,4 | 88,33 | 282,52 | same as 2022 |
| ring pulli: 14-mei | laying A egg: 9-apr | hatch A egg: 7-mei | ||||||||||
| catch: | date: | metal: | darvic: | |||||||||
| Pullus | 11-05-2023 | NLA 5556475 | r-8.D | |||||||||
| Pullus | 11-05-2023 | NLA 5556476 | r-8.Y | |||||||||
| Pullus | 11-05-2023 | NLA 5556477 | r-8.E | |||||||||
| Pullus | 18-06-2023 | NLA 5556477 | r-8.E | |||||||||
| Pullus | 18-06-2023 | NLA 5556475 | r-8.D | |||||||||
| 21-2023 | ||
| dam: | dam 1 T-split | |
| location: | Nest "white jerrycan in de oksel". Same as 21-2020/2022. | |
| breeders: | cach x cach | |
| OBSERVATIONS: | ||
| 09-04-2023 | adult: | adult cachinnans at nest. |
| nest: | 1 egg measured. No watertest. | |
| 26-04-2023 | adult: | 1x adult at nest. |
| eggs: | 3x egg, measured. No water test, as ringing date known from A-egg date April 9th. | |
| 11-05-2023 | pulli: | 3 chicks ringed. |
| 13-05-2023 | adult | both parents photographed: cach. Partner 1 with extra P8 mirror is same as 2022. |
| 18-06-2023 | pulli: | large chicks r-8D and r-8E at nest site. |
| 25-06-2023 | pulli: | r-8D and r-8E present. 2 chicks fledged. |