Page formerly titled "Thayer's or Slaty-backed Gull or ???""
Thayer's has been ruled out.
Slaty-backed Gull and hybrid Glaucous-wing X something else have been proposed.

Sparks Marina
Sparks, NV
11/19/13

Photos 1-13 taken 11/19/13.
Photos 14-22 taken 2/26/14.

Unidentified Large White-headed Gull
Unidentified Gull
1: Standing
California Gull in background

Unidentified Gull
2: Standing

Unidentified Gull
3: Standing
California Gull in background

Unidentified Gull
4: From back, standing
California Gull in background

Unidentified Gull
5: From back, standing
California Gull in background

Unidentified Large White-headed Gull
Unidentified Gull
6: Flight

Unidentified Gull
7: Flight

Unidentified Gull
8: Flight, with California Gulls

Herring Gull (left) and unidentified gull
9: Standing

Thayer's Gull (behind) and unidentified gull
10: Standing

Unidentified Large White-headed Gull
Unidentified gull
11: Flight

Unidentified gull
12: Flight

Unidentified gull with California Gull
13: Flight

====================================================================================
The following nine photos are from 2/26/14
====================================================================================

Unidentified Large White-headed Gull

Unidentified Gull
14:Swimming with adult California Gull

Unidentified Gull
15:Perched on float

Unidentified Gull
16:Swimming

Unidentified Gull
17:On shore with adult California Gull and American Coots

Unidentified Gull
18:Swimming with adult and second (or third?) cycle California Gulls

Unidentified Large White-headed Gull

Unidentified Gull
19:Flight

Unidentified Gull
20:Flight

Unidentified Gull
21:Flight, with second-cycle California Gull

Unidentified Gull
22:Flight