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|+
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|+ positioned on dam 2: east at blocks, 15 mtr W of y-XCHP, low at dam 2.
- In 2025: n-F|+ moved a few meters, up dam 2 towards Blackberry complex. Was location for nest 63 (nest PAM0-2024), now n-F|+ in 2025.
- ID certain in 2023: male is 4CY n-F|+ and partner is sub-adult female cachinnans.
- ID certain in 2024: male is 5CY n-F|+ and partner is adult female cachinnans.
- ID certain in 2025: male is 6CY n-F|+. Adult female cachinnans is another than in 2024, see pattern on P10. Ringed in 2025, now g-B|+.
| nest | April 21st, 2024: situation at cluster. | April 27 2023: 3 eggs. | April 27 2023: nest at dam 2. |
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| nest | April 21st, 2024: nest n-F|+ now at dam 1. | April 21st, 2024: 3 eggs. | April 21 2025: 3 eggs. |
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| nest | April 21 2025: 3 eggs. | . | . |
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| partner 1 | April 09 2023: n-F|+. | April 09 2023: n-F|+. | March 26 2024: male n-F|+. |
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| partner 1 | March 26 2024: male n-F|+. | April 30 2024: trapped male n-F|+. | April 23 2025: trapped male n-F|+. |
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| partner 2 | May 13 2023: Caspian Gull. | May 13 2023: Caspian Gull. | May 13 2023: Caspian Gull. |
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| partner 2 | April 25 2025: female Caspian Gull. | April 25 2025: female Caspian Gull. | July 09 2025: female Caspian Gull g-B|+. |
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| chicks | May 31 2024: chick g-C|2. | May 31 2024: chick g-C|3. | May 25 2025: chick g-T|+. |
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| chicks | May 25 2025: chick g-R|+. With fatal head injury. | . | . |
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| food | June 04 2024: fish bolus from g-C|2. | . | . |
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Visits and data 2023.
| 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 | n-F|+ 2023 | 69,3 | 46,6 | 75,77 | 67,4 | 47,1 | 75,28 | 67,3 | 47 | 74,85 | 225,91 | new nest |
| ring pulli: May 18 | laying A egg: April 13 | hatch A egg: May 11 | ||||||||||
| n-F|+ 2023 | New nest | |||||||
| dam: | dam 2 east, blacks | |||||||
| location: | 20 mtr SW of nest 55, 15 mtr W of XCHP, low at dam 2. In front of wood. Red spot sprayed. | |||||||
| breeders: | cach x cach | |||||||
| OBSERVATIONS: | ||||||||
| 27-04-2023 | nest: | 3 eggs measured. Water test. | A: 90 - tip bottom | |||||
| adult: | breeding adult cachinnans is n[F|+]. | B: 60 - tip bottom | ||||||
| 30-04-2023 | adult: | partner is also cachinnans. | C: 80 - tip bottom | |||||
| n-F|+ at nest. | ||||||||
| 13-05-2023 | adult: | n-[F|+] & partner are immatures. | ||||||
| 18-05-2023 | nest: | 1 egg hatching, no chicks found | ||||||
| 27-05-2023 | pulli: | 1x chick dead in nest, age 1 day. No other chicks found. Several dead chicks in this section (55, XCHP, n-F|+). | ||||||
| 25-06-2023 | adult: | not present, no birds here. | ||||||
Visits and data 2024.
| NEST code | parent 1 | parent 2 | A_length | A_width | A_volume | B_length | B_width | B_volume | C_length | C_width | C_volume | TOTAL NEST: | |
| n-F|+ 2024 | cach | cach | 74,6 | 48,6 | 88,72 | 72,1 | 50 | 90,76 | 70,7 | 47 | 78,63 | 258,11 | |
| # eggs | A-egg | hatch | # ringed chicks | # all chicks | # fledged chicks | comments | |||||||
| 3 | 16-4-2024 | 14-5-2024 | |||||||||||
| dam: | dam 1 south | ||||||||||||
| location: | dam 1 south, near cluster nest 60, but 5 mtr S, at Blackberry edge. | ||||||||||||
| parents? | n-F|+-2023 was at dam 2. Now new breeder at dam 1. | ||||||||||||
| ring pulli: | 18-May | ||||||||||||
| date | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale | 30-04-2024 | n-F|+ | .5552921 | Dam 1 | PONT | M | 5CY | 464 | 1180 | 135 | 60,3 | 71 | 19,6 | 5 |
| 31-05-2024 | g-C|2 | .5631128 | N-F|+ | PONT | 1CY | ||||||||
| 31-05-2024 | g-C|3 | .5631129 | N-F|+ | PONT | 1CY | ||||||||
| 04-06-2024 | g-C|2 | .5631128 | N-F|+ | PONT | 1CY | 127 | 91,9 | ||||||
| 04-06-2024 | g-C|3 | .5631129 | N-F|+ | PONT | 1CY | 220 | 809 | 108,7 | |||||
| OBSERVATIONS: | |||||||||||||
| 12-04-2024 | eggs: | no nest found. | |||||||||||
| 21-04-2024 | eggs: | 3 eggs, measured. | |||||||||||
| nest: | cluster again: 60, 69, PAM0, n-F|+, and 2 Herrings to follow soon. | ||||||||||||
| 30-04-2024 | adults: | trapped n-F|+. | |||||||||||
| 02-05-2024 | eggs: | 3 eggs. | |||||||||||
| 05-05-2024 | nest: | 3 eggs, not measured. | |||||||||||
| 14-05-2024 | nest: | 2 eggs, no chick found in dense vegetation. | |||||||||||
| 31-05-2024 | chicks: | 2x ringed. | |||||||||||
| 04-06-2024 | chick: | g-C|2 & C|3 present. measured. | |||||||||||
| food: | fish bolus. | ||||||||||||
Visits and data 2025.
| NEST code | parent 1 | parent 2 | A_length | A_width | A_volume | B_length | B_width | B_volume | C_length | C_width | C_volume | TOTAL NEST:
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| n-F|+ & g-B|+ | cach | cach | 75,2 | 50,2 | 73,6 | 50,4 | 71,8 | 49,2 | 3 | |||||
| dam: | dam 1 nest 60 cluster
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| location: | was nest 63, nest PAM0-2024, now n-F|+ in 2025
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| parents: | new: n-F|+ moved a few meters, up dam 2 towards Blackberry complex,
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| ringed: | darvic | metal | location / nest# | species | sexe | age | wing | mass | head+ bill | bill | tarsus | gonys | greyscale | |
| 23-04-2025 | n-F|+ | 5,552,921 | Nest n-F|+ | cach | M | 6CY | 465 | 1144 | 137,3 | 67,7 | 72,3 | 19,7 | 6 | |
| 01-05-2025 | g-B|+ | 5641025 | Nest n-F|+ | PONT | F | >4CY | 446 | 880 | 127 | 56,9 | 71,1 | 17,8 | 6 | |
| 25-05-2025 | g-T|+ | 5641859 | n-F|+ & g-B|+ | PONT | pullus | 380 | ||||||||
| 31-05-2025 | g-R|+ | 5641922 | n-F|+ & g-B|+ | PONT | pullus | 437 | FOUND DEAD, RING NOT REUSED | |||||||
OBSERVATIONS:
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| 20-03-2025 | nest | n-F|+ again near nest 60 cluster
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| 04-04 | nest | n-F|+ again near nest 60 cluster
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| 21-04 | eggs | 3x eggs measured,
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| nest | old PAM0 nest is now for n-F|+,
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| 23-04 | adult | CONTROL: trapped male n-F|+, incubating 3 eggs, We aimed for the partner,
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| 28-04 | nest | 3 eggs, n-F|+ incubating
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| 01-05 | eggs | 3 eggs | ||||||||||||
| adult | Thijs's Chinaloop for trapping female, 2 times, 1x successful,
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| 08-05 | adult | F|+ present
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| 25-05 | NEST | 1 chick ringed, 1 rotten egg, 3rd chick?
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| Food | 2x roach, 2x duckling
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| 31-05 | chicks | g-R|+ ringed, not 100% sure if it belongs to this nest,
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| 09-06 | chicks | g-R|+ found dead
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