Thayer's Gull (thayeri)
(last update: January 22, 2013)
Thayer's Gull - Table 2.
From: Identification and Variation of Winter Adult Thayer’s Gulls with Comments on Taxonomy, by Steve N.G. Howell & Martin T. Elliott, IN: Alula 4/2001.
| Table 2. Iris colour variation in 283 adult Thayer's Gulls in central California (see Methods). | ||||||||
| Score | 0.0 | 0.5 | 1.0 | 1.5 | 2.0 | 2.5 | 3.0 | |
| N = | 2 | 7 | 19 | 27 | 21 | 23 | 5 | (King and Howell 1999, N = 104) |
| N = | 1 | 5 | 12 | 15 | 5 | 5 | 1 | (This study, 44 presumed males) |
| N = | 0 | 4 | 9 | 7 | 7 | 2 | 1 | (This study, 30 presumed females) |
| N = | 2 | 19 | 23 | 25 | 16 | 14 | 6 | (This study, 105 sex not determined) |
| Aggreg sample % | 2% | 12% | 23% | 26% | 17% | 16% | 5% | 100 % (n = 283) |
| Totals | 5 | 35 | 63 | 74 | 49 | 44 | 13 | n = 283 |
For comparison with Kumlien's Gulls sampled in Newfoundland, see HERE.
For the sake of consistency, the same scores were used for eye colour as King and Howell (1999):
0.0 iris uniformly dark brown;
0.5 medium brown;
1.0 pale brown or honey-coloured;
1.5 dusky, greenish, dark yellow, or amber, extensively mottled brown;
2.0 pale greenish or yellowish, moderately marked with brown;
2.5 pale greenish or yellowish with little or no brown mottling visible;
3.0 apparently unmarked pale yellowish (like an adult Herring Gull); in a few cases, eye colour differed between left and right eyes, in which cases we gave a mean score.