Larus cachinnans
(last update:
Greg Neubauer
Marcin Przymencki
Albert de Jong
Mars Muusse
cachinnans plumages
Larus cachinnans 8CY-9CY male 896P 2006 & 2007, Wörth, Austria & Włocławek Reservoir, Poland. Picture: Wolfgang Schweighofer & Magdalena Zagalska-Neubauer.
8-9th cy male 896P, ringed as chick in 1998. Top May 01 2006, bottom April 28 2007, Wloclawek - Vistula river, Poland. Bird to show variation of wing-tip of adult Caspian Gulls at the mixed colony at Włocławek Reservoir, central Poland. Birds are included only if all characters are within known cachinnans variation, to ensure that influence of argentatus (possible hybrids etc.) is minimal or lacking. All birds were trapped at nests during incubation. If there are photos of the same bird from different years, they are presented side by side.
below: cachinnans 8CY male 896P January 06 2006, Wörth, Austria. Picture: Wolfgang Schweighofer.
above: 8CY male 896P May 01 2006, Włocławek Reservoir, central Poland. Picture: Magdalena Zagalska-Neubauer.
below: 9CY male 896P April 28 2007, Włocławek Reservoir, central Poland. Picture: Magdalena Zagalska-Neubauer.
Below, table 1 is repeated to score this bird. Not all traits can be scored, the partial scores are in italic + bold.
Here, only 5 traits are visible from the image, score so far is 5, with theoretically another 10 points possible.
| 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) | |
| 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 |