Larus cachinnans

(last update: February 16, 2013)

Coordinator:
Greg Neubauer
Marcin Przymencki
Albert de Jong
Mars Muusse

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cachinnans plumages

Larus cachinnans adult, January 06 2006, Wörth, Austria. Picture: Wolfgang Schweighofer.

Much white in wingtip, with a broken band on P9.

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