Larus cachinnans
(last update:
Greg Neubauer
Marcin Przymencki
Albert de Jong
Mars Muusse
cachinnans plumages
Larus cachinnans hybrid 6CY-7CY female PLG DN-19343 January 2010 & February 2011, Deponie Pohlsche Heide - Minden, Germany (52°23'05N, 08°46'45E).
Picture: Armin Deutsch.
6CY hybrid Caspian x Herring Gull, Pohlsche Heide, Germany, January 21 2010. Mother known as Herring and father as Caspian. Ringed as a chick in Wisla reservoir - Wloclawek, Poland (52°39'N, 19°08'E) on May 14 2005. This hybrid is strikingly Caspian-like, particularly the elegant structure and slim bill, pure white head, and P10 with less black than white and a virtually pure white tip. However, the P10 tongue was grey and the eyes pale and unspotted. Its overall score was 9, and most UK birders would probably identify this bird as a Caspian Gull.
To discuss such birds, its good to first classify it on the 'hybrid scale' according Gibbins et al, see table below pictures.
below: cachinnans hybrid 6CY female PLG DN-19343 January 21 2010, Deponie Pohlsche Heide - Minden, Germany (52°23'05N, 08°46'45E).
Picture: Armin Deutsch.
below: cachinnans hybrid 7CY female PLG DN-19343 February 18 2011, Deponie Pohlsche Heide - Minden, Germany (52°23'05N, 08°46'45E).
Picture: Armin Deutsch.
Much recalling cachinnans.
Below, table 1 is repeated to score this bird. Not all traits can be scored, the partial scores are in italic + bold.
Total score is 9 (both by authors and by Mars Muusse), but open for discussion.
| Trait | Score | Description |
| P10 overall pattern: white to black ratio | 0 | less black than white |
| 1 | approximately equal black and white | |
| 2 | more black than white | |
| P10: white tip | 0 | clear white, no signs of black |
| 1 | small dark spots on one or both webs | |
| 2 | incomplete subterminal bar (two large black spots, one on each web or an unconnected bar, broken in the middle) | |
| 3 | complete subterminal bar | |
| P10: tongue | 0 | white or whitish |
| 1 | paler than mantle | |
| 2 | same shade as mantle | |
| P5: extent of black | 0 | black on both webs connected, forming band, black of equal depth on each web |
| 1 | black on both webs connected, forming band, black on outer web deeper than inner | |
| 2 | black on both webs, but isolated spots (= incomplete bar) | |
| 3 | black on outer web only | |
| 4 | no black | |
| P4: extent of black | 0 | black on both webs |
| 1 | black on one web only | |
| 2 | no black | |
| Iris peppering | 0 | dark-looking, >50% covered by dark spotting/peppering |
| 1 | moderately dark, with 10-50% of the area spotted | |
| 2 | single or very few dark spots (area < 10%) | |
| 3 | no dark spotting on iris | |
| Eye-ring colour | 0 | dark/deep orange to red |
| 1 | pale to moderately orange | |
| 2 | yellow | |
| Bill shape | 0 | very long and slim, with little/no visible gonydeal angle (L:D ratio >2.8) |
| 1 | slim, slight gonydeal angle (ratio 2.4-2.79) measured 2,49 Mars Muusse from picture | |
| 2 | intermediate (ratio 2.0-2.39) | |
| 3 | short and deep, well-marked gonydeal angle (ratio <2.0) | |
| Leg length | 0 | long |
| 1 | moderately long | |
| 2 | short |