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 r-C.S (108)
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).
- In 2022 nest s108 positioned on dam 1 at T split; 10 meters from nest 21.
- ID certain in 2022: both immature (4CY) cachinnans, one trapped at the nest and ringed r[C.S].
- ID cetrain in 2023: both are cachinnans, but partner 1 is not r[C.S].
| location | April 27th, 2022: location of nest. | April 15th, 2022: location of nest. | April 15th, 2022: 1 egg. |
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| nest | April 9th, 2023: 2 eggs. | April 26th, 2023: 3 eggs. | April 26th, 2023: 3 eggs. |
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| partner 1 | May 9th, 2022 4CY cachinnans r-C.S. | May 9th, 2022 4CY cachinnans r-C.S. | May 9th, 2022 4CY cachinnans r-C.S. |
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| partner 2 | May 4th, 2022 4CY cachinnans. | May 4th, 2022 4CY cachinnans. | . |
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| partner 2 | April 27th, 2023: 5CY male cachinnans. | April 27th, 2023: 5CY male cachinnans. | April 27th, 2023: 5CY male cachinnans. |
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| pullus | May 17th, 2022 pullus r[5.G]. | May 17th, 2022 pullus r[5.H]. | June 18th, 2023: juvenile r[8.P] & r[8.4]. |
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| pullus | May 11th, 2023: pullus r[8.V]. | July 8th, 2023: pullus r[8.P]. | July 8th, 2023: pullus r[8.4]. |
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| prey | May 17th, 2022 prey is Eel (50 cm). | May 17th, 2022 prey is Roach (in mm). | . |
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Visits and data 2022:
Estimation egg laying: A-egg = April 15 2022. Estimating hatching = May 13 2022.
| date: | |||||||
| 11-04-2022 | nest ready. Still empty. | ||||||
| 12-04-2022 | 2 birds at nest site. | ||||||
| egg no: | width (mm): | length (mm): | volume (cm3): | water test | |||
| 15-04-2022 | A | 48,1 | 70,9 | -- | -- | ||
| 27-04-2022 | A | float - 1 mm | |||||
| 27-04-2022 | B | 67,9 | 47,7 | -- | 80 - tip on bottom | ||
| sum nest: | -- | ||||||
| 04-05-2022 | 4CY at nest. | ||||||
| 09-05-2022 | 4CY trapped at nest. Ring metal = NLA 5.625.067. | ||||||
| darvic | gonys | wing | tarsus | head+bill | bill | mass | |
| r[C.S] | 18,0 | 446 | 69,2 | 127,2 | 59,1 | 1025 gr. | |
| 17-05-2022 | metal | darvic | mass | ||||
| pullus | NLA 5.625.106 | r[5.G] | 151 | ||||
| pullus | NLA 5.625.107 | r[5.H] | 89 | ||||
| prey | Roach & Eel (50 cm). | ||||||
| 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 | nest 108 | 74 | 49,7 | 92,03 | 68,2 | 49,8 | 85,16 | 69,7 | 48,6 | 82,89 | 260,08 | same as 2022 |
| ring pulli: 12-mei | laying A egg: 7-april | hatch A egg: 5-mei | ||||||||||
| catch: | date: | metal: | darvic: | |||||||||
| pull | 11-05-2023 | NLA 5.556.472 | r 8.P | |||||||||
| pull | 11-05-2023 | NLA 5.556.473 | r 8.V | |||||||||
| pull | 11-05-2023 | NLA 5.556.474 | r 8.4 | |||||||||
| pull | 18-06-2023 | NLA 5.556.472 | r-8.P | |||||||||
| pull | 18-06-2023 | NLA 5.556.474 | r-8.4 | |||||||||
| nest 108 | ||
| dam: | dam 1 T-split | |
| location: | on W-part, border bitumen - blocks. Top of dam. Coded. Exact spot as in 2022, then r[C.S] (which was at almere dump + partner, on 23/4). | |
| breeders: | cach x cach | |
| OBSERVATIONS: | ||
| 09-04-2023 | nest: | 2 eggs measured. No watertest. |
| adult: | 1x cachinnans unringed. Still not sure if r-CS is partner this season. | |
| 26-04-2023 | adult: | legs not visible. |
| nest: | 1,5 m NW is another nest, 2 eggs. LBBG? (on 27/4: yes, this is LBBG). | |
| eggs: | 3x egg, measured. No water test, ringing date known. | |
| 27-04-2023 | adult: | 5CY male cach. Unringed. |
| 11-05-2023 | pulli: | 3 chicks ringed. |
| 13-05-2023 | adult | partner 1 present. |
| 18-06-2023 | pulli: | r-8P and r-84 present. Large chicks. 2x juveniles fledged. |
| 25-06-2023 | pulli: | r-8P present, other ring unreadable, probably r-8.4. |