Species are arranged in decreasing order of size (weight). Each set of measurements is expressed in millimeters, with mean length of males followed by range of males and females. Sample sizes (6-15) are small, and the ranges given may be exceeded in most if not all species. Note the substantial overlap in many species of similar size, especially because females are distinctly smaller than males. All measurements are taken from The gulls (Laridae) of the World, by Jonathan Dwight, Bull. Amer. Mus. Nat. Hist. 25, 1925.
* Very rare to accidental species are asterisked.
Measurements of Pacific Northwest Gulls
| Species | Wing Length | Bill Length | Bill Depth | Bill Depth/Length |
|---|---|---|---|---|
| Species Great Black-backed Gull* | Wing Length 481 (454-498) |
Bill Length 64.8 (57-72) |
Bill Depth 25.0 (22-27) |
Bill Depth/Length 0.386 |
| Species Glaucous Gull | Wing Length 459 (430-477) |
Bill Length 62.6 (56-67) |
Bill Depth 22.4 (18-25) |
Bill Depth/Length 0.358 |
| Species Glaucous-winged Gull | Wing Length 423 (385-445) |
Bill Length 57.6 (49-64) |
Bill Depth 20.6 (18-22) |
Bill Depth/Length 0.358 |
| Species Western Gull | Wing Length 412 (384-420) |
Bill Length 55.6 (49-58) |
Bill Depth 21.2 (17-22) |
Bill Depth/Length 0.381 |
| Species Slaty-backed Gull* | Wing Length 440 (405-447) |
Bill Length 58.7 (49-60) |
Bill Depth 20.6 (18-22) |
Bill Depth/Length 0.351 |
| Species Herring Gull | Wing Length 434 (397-460) |
Bill Length 57.0 (47-62) |
Bill Depth 20.3 (17-22) |
Bill Depth/Length 0.356 |
| Species Lesser Black-backed Gull* | Wing Length 412 (382-428) |
Bill Length 53.1 (44-56) |
Bill Depth 17.8 (15-19) |
Bill Depth/Length 0.335 |
| Species Thayer’s Gull | Wing Length 418 (380-430) |
Bill Length 52.2 (43-57) |
Bill Depth 18.1 (15-20) |
Bill Depth/Length 0.347 |
| Species Iceland Gull* | Wing Length 412 (378-433) |
Bill Length 42.6 (39-45) |
Bill Depth 15.6 (14-17) |
Bill Depth/Length 0.366 |
| Species California Gull | Wing Length 399 (368-415) |
Bill Length 50.0 (42-56) |
Bill Depth 16.9 (14-20) |
Bill Depth/Length 0.338 |
| Species Ring-billed Gull | Wing Length 377 (335-392) |
Bill Length 42.4 (36-46) |
Bill Depth 14.0 (12-16) |
Bill Depth/Length 0.330 |
| Species Heermann’s Gull | Wing Length 347 (329-368) |
Bill Length 43.7 (37-48) |
Bill Depth 14.1 (12-15) |
Bill Depth/Length 0.323 |
| Species Ivory Gull* | Wing Length 338 (320-346) |
Bill Length 35.9 (32-38) |
Bill Depth 12.1 (10-13) |
Bill Depth/Length 0.337 |
| Species Mew Gull | Wing Length 351 (328-366) |
Bill Length 35.4 (30-38) |
Bill Depth 10.8 (9-12) |
Bill Depth/Length 0.305 |
| Species Black-legged Kittiwake | Wing Length 310 (295-320) |
Bill Length 37.9 (34-40) |
Bill Depth 11.0 (10-12) |
Bill Depth/Length 0.290 |
| Species Red-legged Kittiwake* | Wing Length 305 (290-310) |
Bill Length 28.6 (26-30) |
Bill Depth 10.7 (10-11) |
Bill Depth/Length 0.374 |
| Species Laughing Gull* | Wing Length 321 (295-330) |
Bill Length 40.2 (35-44) |
Bill Depth 11.3 (10-12) |
Bill Depth/Length 0.281 |
| Species Franklin’s Gull | Wing Length 277 (262-286) |
Bill Length 30.7 (27-34) |
Bill Depth 9.0 (8-10) |
Bill Depth/Length 0.293 |
| Species Black-headed Gull* | Wing Length 312 (280-325) |
Bill Length 36.8 (32-39) |
Bill Depth 9.3 (8-10) |
Bill Depth/Length 0.253 |
| Species Bonaparte’s Gull | Wing Length 263 (246-271) |
Bill Length 29.9 (27-32) |
Bill Depth 7.0 (6-8) |
Bill Depth/Length 0.234 |
| Species Sabine’s Gull | Wing Length 267 (245-284) |
Bill Length 25.5 (22-28) |
Bill Depth 7.6 (6-8) |
Bill Depth/Length 0.298 |
| Species Ross’ Gull* | Wing Length 255 (248-265) |
Bill Length 19.3 (18-20) |
Bill Depth 6.1 (5-7) |
Bill Depth/Length 0.316 |
| Species Little Gull | Wing Length 221 (210-230) |
Bill Length 23.2 (21-25) |
Bill Depth 5.5 (5-6) |
Bill Depth/Length 0.237 |
Although wing length is correlated with body size, it is also correlated with other attributes of the bird such as long-distance flying (both foraging and migration). Similarly, bill size is correlated with feeding mode. Thus the birds are not exactly in order of decreasing wing or bill length. The larger the figure in the bill depth/bill length column, the relatively deeper the bill.