Larus cachinnans in the Netherlands
(last update: August 16, 2020)
Albert de Jong
Merijn Loeve
Roland-Jan Buijs
Leon Kelder
Mars Muusse
Cachinnans - nest Lelystad PLDP (2020: 005, 2021: 52)
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 005 positioned in dense Blackberry vegetation, in vicinity of Spoonbill nests, on artificial breakwater 1 at T-split.
- Certainty on ID in 2020, breeders are Caspian Gull cachinnans, one partner is ringed yellow PLDP and one unringed partner. Neighbours of yellow PESV (nest 006).
- In 2021: same 2 partners, again Caspian Gulls cachinnans. Bird has moved to nest location of y[PESV]-2020. PESV not present in 2021.
| location | Nest in vegetation: 2020. | Nest: April 16th, 2021. | . |
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| eggs | Eggs April 15th, 2020: 2 eggs clutch. | Eggs April 27th, 2020: 2 eggs clutch. | Eggs April 16th, 2021: 3 eggs clutch. |
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| partner 1 | May 7th, 2020: cachinnans y[PLDP]. | May 7th, 2020: cachinnans y[PLDP]. | April 15th, 2020: cachinnans y[PLDP]. |
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| partner 2 | May 7th, 2020: cachinnans unringed. | May 7th, 2020. | May 6th, 2021. |
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| pulli | June 2nd, 2020 pullus unringed. | May 28th, 2021: pullus b[F|5] probably C-chick. | . |
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Visits and data.
| date: | egg no: | width (mm) | length (mm) | volume (cm3): | ||
| 15-04-2020 | A | 50,4 | 71,9 | 91,96 | 2 eggs in nest. | |
| 15-04-2020 | B | 50,8 | 73,05 | 94,92 | ||
| sum nest: | -- | |||||
| 27-04-2020 | eggs | Controlled: still 2 eggs. | ||||
| 07-05-2020 | pullus | Nest is empty. Small chick next to nest (7 days old). | ||||
| 21-05-2020 | pulli | Empty nest, no pulli found, but lots of shit-traces. | ||||
| 02-06-2020 | pulli | Parent y[PLDP] with 2 chicks close by. | ||||
| date: | ||||||
| 30-03-2021 | PLDP and partner both present at blocks near waterfront. | |||||
| 16-4-2021 | egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 16th, 2021: | |
| A egg | 51,3 | 75,2 | 99,64 | 45 - tip bottom | 3 eggs in nest. 2 partners at nest, one is y[PLDP]. | |
| B egg | 50,6 | 77,2 | 99,52 | 35 - tip bottom | ||
| C egg | 50,5 | 77 | 98,87 | 30 - tip bottom | ||
| sum nest: | -- | |||||
| 24-04-2021 | partner 2 is unringed. Code of nest changed to 52. | |||||
| 26-04-2021 | No visit, Camilla is trapping Spoonbills here. | |||||
| 06-05-2021 | 2 chicks of few days old. 1 egg is hatching. | |||||
| 13-05-2021 | No visit, Camilla is trapping Spoonbills here. | |||||
| 15-05-2021 | mass (gr) | head + bill (mm) | ||||
| pullus | 142 | -- | ||||
| pullus | 221 | 65,5 | measurements Monika Ballmann. | |||
| 28-05-2021 | metal | tibia | mass (gr) | head + bill (mm) | ||
| pullus | .5559418 | b-F|5 | -- | 87 | probably C-chick. | |
| 08-06-2021 | PLDP attacks us. Partner also present. No chick visible. | |||||