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 014
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 014 positioned at breakwater 2.
- ID certain in 2020, both parents are Caspian Gull cachinnans.
- ID certain in 2021, both parents are the same as previous year, Caspian Gull cachinnans.
- ID certain in 2022, both parents are the same as previous year, Caspian Gull cachinnans.
| location | Nest location on April 15th, 2020. | April 16th, 2021. | April 26th, 2021: female on block. |
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| eggs | Eggs April 15th, 2020: 3 egg clutch. | Eggs April 15th, 2022: 3 egg clutch. | . |
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| partner 1 | April 27th, 2020: cachinnans. | . | . |
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| partner 1 | April 16th, 2021. | April 16th, 2021: P9 with thin band. | . |
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| partner 1 | April 12th, 2022: male is cachinnans. | April 11th, 2022: male is cachinnans. | April 11th, 2022: male is cachinnans. |
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| partner 2 | May 7th, 2020: cachinnans. | May 7th, 2020: cachinnans. | . |
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| partner 2 | April 26th, 2021: female cachinnans. | April 26th, 2021: P9 with broad band. | April 26th, 2021: female cachinnans. |
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| partner 2 | April 29th, 2022: female cachinnans. | April 29th, 2022: female cachinnans. | April 29th, 2022: female cachinnans. |
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| pullus | May 21st, 2020 pullus n[F|=]. | May 21st, 2020 pullus n[F|+]. | |
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| pullus | June 8th, 2021: female with chick. | June 26th, 2021: pullus r[F.L] | . |
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| June 26th, 2021: pullus r[F.M] | June 26th, 2021: pullus r[F.N] | . | |
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| pullus | May 9th, 2022: pullus r[C.T]. | May 9th, 2022: pullus r[C.U]. | May 17th, 2022: pullus r[5.2]. |
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Visits and data.
| datum: | egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 27th: | |
| 15-04-2020 | A | 50,5 | 76,9 | 98,74 | 35 - tip on bottom | 3 eggs in nest. |
| B | 50,4 | 77,2 | 98,74 | 25 - tip on bottom | ||
| C | 50,4 | 71,8 | 91,83 | 15 - tip on bottom | ||
| sum nest: | 289,31 | |||||
| 27-04-2020 | Certainty about parents, cachinnans. | |||||
| 21-05-2020 | pullus | Nest empty, with fish. 2 chicks ringed. n[F|=]. | ||||
| pullus | Nest empty, with fish. 2 chicks ringed. n[F|+]. | |||||
| 02-06-2020 | pulli | n[F|=] together with large juvenile, so nest with 3 juveniles fledged? | ||||
| date: | ||||||
| egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 27th: | ||
| 16-04-2021 | A egg | 52,2 | 73,9 | 101,39 | 40 - tip on bottom | 3 eggs. |
| B egg | 51,2 | 73,7 | 97,28 | 40 - tip on bottom | ||
| C egg | 50,2 | 68,7 | 87,17 | 30 - tip on bottom | ||
| 26-04-2021 | Partner 1 at blocks in front of nest. Seemingly same parents as last year. | |||||
| 15-05-2021 | 3 eggs. (in retrospect: we should have checked for presence of letters on the eggs. Was this the still the same brood as on April 26th?) | |||||
| 28-05-2021 | 2 eggs + 1 chick (1 day old). What has been the breeding period for these eggs??? Was there a rapid 2nd attempt in late April??? | |||||
| Female at nest, but P10 slightly ackward for pure cachinnans? (probably wrong bird?) | ||||||
| 08-06-2021 | Male is cachinnans. | |||||
| Female appears at blocks with one chick. | ||||||
| metal | tibia | mass | head + bill | wing | ||
| 26-06-2021 | .5550684 | r-F.L | 859 | 111,7 | 264 | cachinnans |
| .5550685 | r-F.M | 948 | 112,8 | 252 | cachinnans | |
| .5550686 | r-F.N | 912 | 112,2 | 228 | cachinnans | |
| date: | ||||||
| 11-04-2022 | adult near nest. | |||||
| egg no: | width (mm) | length (mm) | volume (cm3): | water test on April 27th: | ||
| 15-04-2021 | A egg | 51,7 | 70 | -- | 10 - tip on bottom | 3 eggs. |
| B egg | 51,7 | 76,7 | -- | 30 - tip on bottom | ||
| C egg | 51,7 | 72,1 | -- | 20 - tip on bottom | ||
| 19-04-2022 | guarding adfult on block. | |||||
| 29-04-2022 | A egg | float - 1 mm | ||||
| B egg | float - 2 mm | |||||
| C egg | float - 1 mm | |||||
| metal | tibia | mass | head + bill | wing | ||
| 09-05-2022 | 5625068 | r-C.T | cachinnans | |||
| 5625069 | r-C.U | cachinnans | ||||
| 1 egg, hatching soon. | ||||||
| metal | tibia | mass | head + bill | wing | ||
| 17-05-2022 | 5625069 | r-C.U | 363 | -- | cachinnans | |
| 5625136 | r-5.2 | 206 | 69,7 | cachinnans | ||