Biological Services Program FWS/OBS-80/03 JANUARY 1980 Beached Marine Birds and Mammals of the North American West Coast: A MANUAL FOR THEIR CENSUS AND IDENTIFICATION Fish and Wildlife Service U.S. Department of the Interior From the collection of The Biological and Wildlife Service key environmental is supporting ecosysterr • To strengthe a primary sc life resourc Impact asses • To gather, a decisionmake problems ass use. • To provide b for Departme as those rel Information dev for use in the planr the impact of develc technical assistance determination of th< and an evaluation ol and to determine pr* the products produci Projects have I and conversion; pow- ment; water resourc water allocation; c ment; and systems 1 habitat classificat The B Services i management and techni studies wi Staff, who certain Fi research s iological n Washing Nationa cal exper th states provide sh and Wi tudies. International Bird Rescue Research Center Cordelia, California in association with 7 ^ ^ m 0 Prelinger I ■ a V !j ibrary p San Francisco, California 2006 the U.S. Fish thodologies on rces and their lows: b1e as wild- ttal aid ►f ter on such is intended or minimize livities and I Issues a iation needs, tion gaps jsure that i I Isl extraction le develop- nd western elf develop- to ry. f Biological il planning and al scientific |1 services rs; Regional and staff at nduct inhouse FWS/OBS-80/03 January 1980 BEACHED MARINE BIRDS AND MAMMALS OF THE NORTH AMERICAN WEST COAST: A MANUAL FOR THEIR CENSUS AND IDENTIFICATION BY David G. Ainley, Gary W. Page, Lisa T. Jones, Lynne E. Stenzel, and Ronald L. LeValley Pt. Reyes Bird Observatory Stinson Beach, California 94970 with drawings by Helen C. Strong Contract No. 14-16-001-77027 Project Officer Jay Watson U.S. Fish and Wildlife Service Lloyd 550 Building Suite 1692 500 NE Multnomah Portland, Oregon 97232 Performed for National Coastal Ecosystems Team Office of Biological Services Fish and Wildlife Service U.S. Department of the Interior Washington, D.C. 20240 For aate by the Superintendent of Documents. U.S. Government Printing Office, Washington. D.C. 20402 S/N 024-010-00541-6 ^^ DISCLAIMER The opinions, findings, conclusions, or recommendations expressed in this report are those of the author and do not necessarily reflect the views of the Office of Biological Services, Fish and Wildlife Service, U.S. Department of the Interior, nor does mention of trade names or commercial products constitute endorsement or recommendation for use by the Federal Government. Digitized by the Internet Archive in 2007 with funding from IVIicrosoft Corporation The correct citation for this report is: Ainley, D.G., et al. 1980. Beached marine birds and mammals of the North American West Coast: A manual for their census and identification. U.S. Fish and Wildlife Service, Biological Services Program, FWS/OBS-80/03. ^°fif!iD://www.archive.org/details/beachedmarinebirOOnatirich ^^^ EXECUTIVE SUMMARY Personnel of the U.S. Fish and Wildlife Service and other agencies often must identify specimens of marine birds and mammals that have washed onto the shoreline. Beach surveys are also conducted routinely along certain beaches to establish baseline information. Identification of beach-cast specimens can be extremely difficult, particularly after disastrous events such as oil spills and major storms. The purpose of this manual is to provide information necessary for the correct identification of beach-cast specimens of marine birds and mammals. Identification keys are supplemented by illustrations, glossaries and narrative accounts of species. Instructions are included for the conduct of beach surveys. This manual includes most species of marine birds and mammals that occur from the Bering Strait, Alaska and along the North American Coast south to Cabo San Lucas at the southern tip of Baja California, Mexico. Table of Contents TABLE OF CONTENTS Page List of Plates v^'- List of Figures vii Introduction I Beached Bi rd and Mammal Surveys I Use of the Manual 2 MARINE BIRDS 4 Measurements of Marine Birds 4 Gl ossary of Terms 7 Key to Bi rd Keys 16 Bird Keys Loons 24 Grebes ......../...,........... 25 Albatrosses ,. 26 Petrels 27 Boobi es 31 Cormorants 32 Waterfowl 33 Shorebi rds 42 Skuas and Jaegers 50 Gulls 51 Terns and Skimmers ] ] 62 Alcids 66 Plates 73 Species Accounts 115 Books and Articles for Additional Information on Aquati c Bi rds 151 MARINE MAMMALS 153 Measurements and Glossary of Marine Mammal Terms I54 Mammal Keys 159 Pinnipeds 160 Sea Otter 1 67 Baleen Whales 168 Toothed Whales and DolplJitjs 170 PI ates 1 76 Species Accounts 1 78 Books and Articles for Additional Information on Marine Mammals 183 Agencies to Notify Concerning Beached Marine Mammals 186 ACKNOWLEDGEMENTS 1 88 INDEX TO SPECIES 1 89 y^ LIST OF PLATES Page s of Large Loons 73 s of Smal 1 Loons and Grebes 74 s of Albatrosses 75 s of Albatrosses, Frigatebirds and Tropicbirds 76 s of Fulmarine Petrels; and A Top View Comparison of Representati ve Petrel Bi 1 1 s 77 s of Shearwaters 78 s of Storm Petrel s 79 s of Boobi es 80 s of Adul t Cormorants 81 s of Juveni le Cormorants 82 s of Swans 83 s of Geese 84 s of Geese 85 s of Dabbling Ducks - top view 86 s of Dabbling Ducks - side view 87 s of Dabbling and Bay Ducks - top view 88 s of Dabbling and Bay Ducks - side view 89 s of Bay Ducks and 01 dsquaws - top view 90 s of Bay Ducks and 01 dsquaws - side view 91 s of Scoters - side view 92 s of Eiders - side view 93 s of Scoters and Eiders - top view 94 s of Mergansers and Coots 95 s of PI overs 96 s of Oystercatchers, Phalaropes, Turnstones and Surfbirds 97 of Medium-sized Sandpipers 98 of Large Sandpi pers 99 of Small Sandpipers 100 of Skuas and Jaegers 101 of Large Gulls 102 of Large Gulls 103 of Medium-sized Gulls 104 of Small Gulls 105 of Large Terns and Skimmers 106 of Small Terns 107 of Large Auks 108 of Puffins 109 of Murrelets and Auklets 110 A large and long webbed foot, in this case, an Arctic Loon Ill 35. Webbed feet; three toes webbed, fourth toe minute: 112 1 . South Polar Skua 2. Northern Fulmar 3. Western Gull 36. Webbed feet: 113 1. & 2. Three toes webbed, fourth toe absent (alcid, in this case. Pigeon Guillemot) 3. Three toes webbed, fourth toe lobed (sea duck, in this case. Surf Scoter) '4. Four toes webbed (in this case, Brandt's Cormorant) Page 37. Incompletely webbed, lobed, or unwebbed feet: 114 1. Oystercatcher - partly webbed 2. Black Tern - partly webbed 3. Shorebird - not webbed 4. Coot - lobed 5. Grebe - lobed 6. Phalarope - lobed 38a . Pi nni ped bacul a 1^° 38b. Pinniped bacula 1'' LIST OF FIGURES 1. Example of a beached bird census form 3 2. Measuring bill or culmen length 5 3. Measuring tarsus and toe length 5 4. Measuring wing length (wing chord) 6 5. Measuring the chord of the nail in a skua / 6 . The morphol ogy of a bi rd ' s body 8 7. Cross-sectional shapes of body parts 9 8. Morphology of the upper and under wing 10 9. Several parts of a bird's bill 9 10. Shapes of primary feathers 11 11 . The mantle 12 12. Different kinds of neck collars 13 13. Scutellate and reticulate tarsus scales 14 14. The speculum 14 15. Subterminal bands 15 16. "Windows" in gull primary feathers 15 17. Comb-like toenail 16 18. Curvatures in partly-folded wings 23 19. The length of upper tail coverts 30 20. Shorebird wings, showing wing stripe and wrist markings . 43 21. Color patterns of shorebird feathers 47 22. Outer three primaries of the Black-headed Gull 51 23. Color patterns in extended wings of three gulls 53 24. Color patterns of outer primaries in terns 65 25. Murre chick old enough to accompany adult at sea 67 26. Murrelets for comparison with Figure 25 68 27. Some baleen whale terms used in the keys 155 28. Some cetacean terms used in the key with a shark for compari son 156 29. Some parts of a pinniped skull 157 30. Dorsal view of a pinniped skull 158 31. Some differences between eared and earless seals 159 32. Some differences between male and female pinnipeds 161 33. Sea lion skull comparisons 162 34. Differences between sea lion skulls and bacula 163 35. Fur seal head comparisons 165 36. Seal skull comparisons 166 37. Some differences between male and female cetaceans 172 INTRODUCTION Much can be learned about the natural history of marine birds and mammals through the systematic study of beach-cast specimens. The first step in such investigations is the correct identification of the carcasses and to that end this manual was prepared. Identifying a dead animal pre- sents problems different from those confronted when identifying a live one. For the latter, many field guides exist but they depend to a great extent on knowledge of behavior and on characteristics observable from a distance. When confronted with a dead animal, close at hand such clues are no longer useful. This manual contains the necessary clues to iden- tify dead marine birds and mammals occurring along the North American west coast. The beach-cast specimen can provide insight into a species' anatomy, physiology, diet, diseases, natural/unatural causes of mortality, and other aspects of its natural history. In cases of rare, endangered or infrequently encountered species, a beach-cast specimen becomes an in- valuable source of information that would otherwise be impossible to collect. In the cases of more abundant species, still more can be learn- ed by accumulating over the long term, carefully tabulated records of beach-case carcasses (see BEACHED BIRD AND MAMMAL SURVEYS). As a start, the seasonal patterns of occurrence are revealed. Taken with environ- mental information, large yearly differences in occurrence patterns help to indicate the factors that affect the distribution of marine species. Similar information can be gathered by direct at-sea observations. This, however, is an extremely expensive and time consuming operation, so much so that only one or two years of direct censuses are usually possible. At-sea observations are also much more difficult to repeat and standardize. The two activities though are complementary because the direct censuses serve to calibrate the beach surveys, both of which after all provide largely an index to a species occurrence and abundance. BEACHED BIRD AND MAMMAL SURVEYS Systematic censuses of carcasses on a beach or beaches can yield sur- prisingly interesting and useful information. To be systematic, censuses need to be made of the same stretch of beach at regular, periodic inter- vals over an extended period. So useful is the information that major projects have been organized in Great Britain, New Zealand and Australia for a number of years, and more recently in the United States and else- where. In some cases, the projects are conducted by government wildlife department personnel and in others by private institutions using volunteer workers. The information gathered is extremely useful in the conservation of marine animals and in just increasing our knowledge about them. Unfor- tunately, the information has also become useful in assessing the mortality of animals due to man's activities, for instance, in the case of oil spills. To conduct a beach census the same stretch of beach should be surveyed each time at regular intervals. Once &\iery three or four weeks is quite satisfactory. In this way one will derive an index of which animals have occurred, when they occur, and in what abundance. To record all animals that wash in one would have to survey constantly, a very impractical alternative. Each animal encountered is identified and then cast into the dunes so as not to be counted on the next census. When surveying, look for carcasses between and in the highest and the lowest tide lines. You will find the fewest specimens at the water's edge. Many museums yery much want to acquire specimens so in some cases removal might entail transport of carcasses to a museum. In the case of any marine mammal and any endangered species removal is unlawful without a permit; one should merely notify the museum of the animals' whereabouts. Enforcement of these laws is strict. Since it is technically unlawful to "collect" or possess any migratory bird specimen without a federal permit, it is best to be associated, if only in a verbal agreement, with an institution that has such a permit. You will, of course, have to turn over specimens to that institution. The knowledge gained from beached bird censuses is thus further increased when the specimens provided to museums become available for future study. Figure 1 gives an example of a form for recording beach census data. Its use makes analysis of data at a later date much easier. USE OF THE MANUAL This manual includes most of the birds and mammals that have occurred in marine waters from the Bering Strait, Alaska, along the North American coast south to Cabo San Lucas, the southern tip of Baja California, Mexico. It even includes most, but not all, of the species known to have occurred only one or two times in this area. It does not include many of the Asian species that have occurred in the central and western Aleutian Islands. The first bird keys and first part of the mammal keys are extremely important, as these identify the major group or family to which an animal belongs. In the "Key to Bird Keys" you will be directed to use another set of keys. There are, however, several species that key out only in the Key to Bird Keys Section. You initially have one of four bird keys to consult depending on the size (wing length) of the specimen. In these keys, in those to which one is then directed, and in the mammal keys, one is always given two choices, for example, 1 and 1'. To decide which choice best fits the animal being identified, aways read both CHOICES ENTIRELY. After each choice will be a number that refers to the next choices to be considered or the species name of the animal, depending on how far along you are. If you have difficulty in deciding which choice fits your animal, follow both through several further choices in the key to see how other characters fit. Then make your initial choice. In some instances, you will only be able to key out an animal to two or more rather similar species. Remarks u a 9) o o 01 0) 3 <1 u T3 c o ■ t: J •H T) H II » lO c o t4^ u >• m !1 ■<: VI o tn T. or x: r n. M c dl >- ifl >- ^ 03 <. o 3 u. T. o o •H 03 < •. m u o o til 01 9 (II •>, o r 1 IV «> 71 X ifl u: n ^ X n) - Li rn 73 t/1 s u m rt -^ u. I' CO 3 «. o 11 > •r^ D. ON O (U II m CT> £ OC >■ ■ H OJ CT-H -* en 1 < 1 1 >- 1 c 1 o 1 1 lU u c: E Oi lU •a c oi tf) , 0) c -H < 6 ■o •r* > o n m j: C c c *-! 3 o 0 iO ■^ u (J .■<: u -n •r-l 11 o T3 11) T) «i n •n ^ fH o fli (V () OQ < en o (_> o- a: u Figure 1. Example of a beach census form. Sometimes in a choice you will encounter two phrases separated by OR. The intended meaning is much stronger than a lower case "or". This means that within the choice, you are being given two or more GROWS of characters, only one group of which will fit the specimen. Both phrases, separated by OR, cannot fit. If they do, something is not correct (perhaps you made a wrong choice earlier). If you find a bird carcass with a head, and this is often the case, a collection of drawings is provided with which you match bill shape and size (Plates 1-33) by holding the bill up to the drawing. A WORD OF CAUTION: Please realize that slight variations in size and shape of bills are to be expected. IN CASES WHERE THERE IS OVERLAP THE DRAWINGS MAY GIVE YOU ONLY A GROUP OF SPECIES, and only a rough idea of the two or three most likely ones. For example. Glaucous and Glaucous-winged Gulls overlap in size to a great extent, and also overlap in size with several other species (Western, Herring, Thayer's Gulls). In many species, we provide small and large examples of each. Please use the keys, too - do not rely entirely on the drawings, especially when dealing with loons, storm-petrels, jaegers, gulls and terns. As another aid to identification a section of "Species Accounts" is given for both birds and mammals. These provide information on the usual timing and locality of occurrence, and in many cases some additional identifying characteristics. MARINE BIRDS In this manual, marine birds include avian species that spend a significant part of their life cycle in contact with the marine environ- ment. In more practical terms, the species included are those likely to occur dead on beaches in the prescribed geographic area. Not in- cluded are wading birds (herons, egrets, flamingoes, storks, etc.), waterfowl that rarely stray from freshwater, and rails (other than the American Coot). These birds do, but very rarely, occur dead on marine beaches, as do almost any species of land bird. One should be especially aware that pigeons (Rock Doves) are, in fact, found dead on beaches more often than many of the rarer marine species included in the key. As will be mentioned later, if you find a footless and headless pigeon specimen, you will likely try to key it out as a tern. MEASUREMENTS OF MARINE BIRDS Many choices require measurements of body parts in metric units. You will thus need a ruler, especially when size differences between two species are small. The ruler presented on the back cover will usually suffice but not always. Sometimes, the measurement is designed only to provide the general difference in size between species; that is, instead of stating in a choice that the carcass is "large" vs. "small" (very relative terms) we quantified the difference using real measure- ments. The measurements are taken as follows: Bill (or culmen) length - the straight line distance from the bill's tip to where it ends at the skin or feathers of the forehead (Fig. 2). Some birds, e.g., cormorants, have bare skin where the bill reaches the forehead. Fig-ure 2. Measuring 1)111 or culmen length. Tarsus (plural - tarsi) length - the length of that bone (tarso- metatarsus) connected to the bird's foot, from the outer edge of one joint (A) to the outer edge of the other (B) in Figure 3. Toe length - the length of a straightened toe, from the tip (C) to the knuckle (B), as in Figure 3. The key will state whether to measure the inner, outer, or middle toe, or maybe just the longest toe. It should also state whether to include the nail in the measurement. Figure 3. Measuring tarsus and toe length. Tardus Le »J«th A^ - ->B Total wing length - the distance from the shoulder or "arm pit" to the tip of the longest primary in the extended wing (see Fig. 8). In conjunction with the width, taken across the wing's upper surface at the wrist (see Fig. 8), a ratio of width to length is derived as an index to wing shape, i.e., long and narrow or short and broad. Wing length - in a relaxed but folded wing, the distance from the wrist's outer edge to the tip of the longest primary feather (Fig. 4). The wing should be flattened against the ruler. Please note if one of the longest (outer) primary feathers is missing or is only partly re- grown. If one of these feathers is missing, then "wing length" will be shorter than it should be in those species where the outermost primary is longest; the same would be true where the 9th primary is missing in a species where that is the longest feather. Figure U. Measuring wing length (wing chord). Top side o? wiivc- UNOER91DE OF WIMG Nail chord - the straight line distance from the point of the bill tip to where the nail's curvature ends (Fig. 5). For birds in which the bill sheath (outer surface of bill that covers internal bone) is divided into distinct sections, such as petrels, cormorants and skuas (see Plates 3-10, 25), the nail is a distinct section. Some birds, such as alcids and terns, have no nail to speak of. GLOSSARY OF TERMS As much as possible, we have avoided use of technical words, but the following may need some explanation: <- a symbol meaning "is less than"; for example: 1 <2 reads, 1 is less than 2. >- a symbol meaning "is greater than". Bill saddle - the bill plate or section, shaped like a saddle, that sits on the culmen or back 2/3 of the bill in adult skuas and jaegers (Fig. 5). Figure 5. Measuring the chord of the nail in a skua, NAIL SADDLE s- (O a. o CO Compressed - refers to the shape of a part when viewed in cross-section (see Fig. 7). Laterally compressed means the sides are flat, as in an oystercatcher's or puffin's bill or a loon's tarsus: (see loon foot illustration). Dorso- ventral ly compressed means the top and bottom are flattened as in a duck's bill . Figure 7. Cross-sectional shapes of "body parts, in this case bills. r\ L(^reRflLI-y COMPRESSED OORSO- VENTRftt-LY CoMPHESSEP (puck (3 ill) Contour feathers - those that cover the bird's body parts other than feathers of the wings and tail and down feathers. Culmen - the uppermost ridge of the bill running from the bill's tip to where it meets the skin or feathers of the forehead. The culmen is thus a specific part of the upper bill (see Fig. 9). Figure 9. Several parts of a bird's bill; see also Figure 5. GONYOEflli ANG-LE or GONYS 10 Figure 8. Morphology of the upper and under wing. WING FE^THER5 IUPPER V lEW (SHOWIMG 60NE STKOCTUREl WRIST ALULfiCFeWTHEPS) — -}_UE5SE-R COVERTS ~~Z rv^cPOuE COVERTS GB£ftTER CPVeRTS LJ '/(TtRTlAL Seco^4pP)f^y FEOTHeRS ■ IPEOTrteRS PRIMA n.y FeRTHe-f?s <^ERTH6R& FLICHT FEATHERS WING F£^THERS'. UNDER SURFACE VVlNG UNJ1N6 — UNDER W(IM6 COVERTS PRIMP^RIES SECONDAR\ES TERTtflL^ 9cAPuCflR II Cut out - refers to the continuity in outline of a primary feather's edge (see Fig. 10). A feather is composed of two webs attached to opposite sides of the shaft. The outer web is on the side away from the bird's body and is usually much narrower than the inner web; the inner web is on the side of the shaft toward the body. Figure 10. Shapes of primary feathers LEADlNiS BViG-E OUTER WE5^r::rC:^ INNER WEB I. NOT CUT OU-r (GULL) 2./1VNER \v;E8 cut our 3.0UTER WEB CUT OUT" cgormorrnt; 4. Both NAi£B5 CUT OUT Decurved - refers to a bill that curves downward, as in the Whimbrel (Plate 23). Down - the small fluffy feathers that lie beneath the covering of contour feathers. Flight feathers - the large wing feathers (primaries, secondaries and tertials) that provide lift during a bird's flight (see Fig. 8). Gonys (or Gonydeal angle) - the ridge where the two sides of the lower mandible meet (Fig. 9). Laterally compressed - see compressed (Fig. 7). Lores - the area between the eye and the bill (see Fig. 6). Mantle - the upper surface of the wings (excluding primary feathers) and the area of the back between the wings (Fig. 11). Marbled - intermixed colors of various shades; variegated. Nares - the external openings of the nasal passages (singular, naris). These are usually on opposite sides of the upper bill (see Figs. 6 and 9). In petrels they are together in a tube on the top of the bill near its base (see Plate 5); in cormorants, boobies and a few other species they may be lacking. Nail - the bill tip; see nail chord under bird measurements (Fig. 5). Figure 11. The mantle. MANTLE 13 Neck collar - refers to coloration in the neck area (Fig. 12). A collar may be dark and complete (see A below), dark and incomplete (B), light and incomplete (C), or light and complete (D). Figure 12. The different kinds of neck collars, Neck collrrs A.OhRKAND CO/v\pLETE C. LIGHT >ANO I M CO/VXPLETE. DftRK BNO IMCO/^PLETE. P. LIGHT AND CoVipLETE Primary (or primaries, plural) - the large "flight" feathers that are attached to wing bones from the wrist joint outward (see Fig. 8). These are numbered from the wrist joint outward. 14 Reticulate - refers to the way in which scales of the legs are positioned; in this case, they do not overlap but rather meet each other as in the mesh of a net or as in the lines around the knuckles on a person's hands (Fig. 13). Figure 13. Scutellate (a) compared to reticulate (Td) scales on the tarsus. Scutellate - refers to the way in which scales of the legs are positioned, in this case overlapping as in shingles; see reticulate (Fig. 13). Secondary (or secondaries, plural) - those "flight" feathers that attach to wing bones between the wrist and elbow (see Fig. 8). These are numbered from the wrist inward. Speculum - in some ducks, that part of the wing, usually feathers of the inner secondaries and greater secondary coverts, that in coloration, strikingly contrasts with the remainder of the wing (Fig. 14). Figure lU. The speculum. Subterminal - usually refers to color patterning, in the area immediately adjacent to the tip. The dark colorations in Figure 15 are referred to as "subterminal bands". Figure 15. Subterminal "bands. SuB-TeRfvMNAL BANDS Tertials - those flight feathers attached to wing bones extending from the shoulder to the elbow joint. These are also considered to be the several innermost secondaries (see Fig. 8). In some groups (ducks, shorebirds and terns) the tertials may be yery long and pointed compared to the remaining (outer) secondaries. Underwing - the under surface of the wing; the wing surface that is facing downward in flight or is against the body when the wing is folded (Fig. 8). Upperwing - the upper surface of the wing; the wing surface that is facing upward in flight or is outermost when the wing is folded (Fig. 8). Windows - the large white spots within the black area of a gull's wing tip (Fig. 16). Figure l6. "Windows" in gull primary feathers. 16 KEY TO BIRD KEYS If wings are: use: 1. very large, > 470 mm long Key A. 2. large, 338-467 mm lonq Key B. 3. moderate to small, 162-337 mm long Key C. 4. small, <161 mm long Key D. KEY A. SIZE VERY LARGE, WING >470 mm. 1 Primary 10 decidedly longest feather when wing folded completely in natural position; primaries not cut out on either web (Fig. 10); four toes connected by incomplete webs (Plate 37-1,2) OR if fully webbed then only three toes connected (Plates 35, 36-1,2,3) and scales on fore-edge of tarsi scutellate (Fig. 13). 2 1' Primary 10 not longest wing feather or equal in length to primary 9; primaries 10-8 may be cut out on one or both webs (Fig, 10); four toes connected by complete webs (Plate 36-4) OR if three toes webbed then scales on tarsi reticulate (Fig. 13). 7 2 Wing >600 mm; webbing incomplete, restricted to basal third of toes; nail on middle toes flared and comb-like (Fig. 17). 3 2' Wing <580 mm; three longest toes joined by full webs; no toenails comb- like. 5 Figure 17, A booby's or frlgatebird's comb-like toenail; (about twice natural size). 17 KEY A (Cont.) 3 Belly (and remainder of plumage) black. MAGNIFICENT FRIGATEBIRD, adult male 3' Belly (perhaps head and neck as well) white. 4 Head and neck black. 4' Head and neck white. MAGNIFICENT FRIGATEBIRD, adult female MAGNIFICENT FRIGATEBIRD, immature 5 Tarsi compressed or flattened laterally in cross section (Plate 34); tail feathers very short, 16-20 in number. See LOONS (Page 24) 5' Tarsi rounded in cross section; tail feathers long, 12 in number. 6 6 "^ery large; wing >474 mm; distance from shoulder to wrist much longer than from wrist to tip of primaries; foot longer than tarsus; tarsi >79 mm; more than 25 secondaries. See ALBATROSSES (Page 26) 6' Wing <474 mm; distance from shoulder to wrist not decidedly longer than from wrist to tip of primaries; foot about equal in length to tarsus; tarsi <74 mm; 22 or fewer secondaries. See GULLS (Page 51) 7 Primaries 10, 9, 8 and 7 decidedly cut out on outer web (check at least 2/3 of the feather length), inner web tapering gradually to tip; 4 long toes connected by webs; scales on fore-edge of tarsi scutellate; more than 25 secondaries. 8 7' Primaries 10, 9, 8 and sometimes 7 cut out on inner web, outer web of 9 and sometimes 8 cut out also; only 3 toes of foot connected by webs, 4th toe reduced in size; scales on legs and feet reticulate; 22 or fewer secondaries. See WATERFOWL (Page 33) 8 Wing white with dark primaries, 8' Wing entirely dark. WHITE PELICAN 9 9 Belly white. 9' Belly dark. BROWN PELICAN, immature BROWN PELICAN, adult KEY B. SIZE LARGE, WING .338-469 mm. 1 Primary 10 longest wing feather. 2 r Primary 10 shorter than 9 and usually shorter than 8. 7 2 All 4 toes long and connected by webs (Plate 36-4); middle toenail comb-like (Fig. 17). See BOOBIES (Page 31) 2' Only 3 toes connected by webs, 4th toe reduced in size (Plate 35); middle toenail not comb-like. 3 3 Tarsus flattened laterally in cross section (Plate 34); 16-20 tail feathers. See LOONS (Page 24) 3' Tarsus rounded in cross section; 12 tail feathers. 4 4 Wings entirely black on upper surface. See TERNS (Page 62) 4' Wings not black on upper surface, wings white to gray or brown. 5 5 Wings long and thin in proportion when extended, ratio of width to total length 0.25 or less; tertials and scapulars very long - partic- ularly evident in folded wing; distance from shoulder to wrist less than wrist to wing tip; feet much longer than tarsi; tarsi short (<1/10 wing length); tail deeply forked. See TERNS (Page 62) 5' Wings broader in proportion, ratio of width to total length 0.26 or (usually much) more; tertials and scapulars not unusually long; distance from shoulder to wrist about equal OR slightly more than from wrist to wing tip; feet and tarsi about equal in length; tarsi long (>1/10 wing length). 6 6 Wings very dark brown all over except for white shafts and bases to outer primaries; in some immatures, contour feathers may be spotted with white, giving bird, especially near flanks and rump, a pro- nounced checkered appearance; bill black (bill may be light near nostrils); legs and feet black or legs blue and feet black; claws very long and deeply curved (Plate 35-1). See SKUAS and JAEGERS (Page 50) 19 KEY B (Cont.) 6' Wings gray (charcoal to very light gray) and white OR brown with white flecking throughout OR if entirely brown (immature Heermann's Gull) than remainder of characters do not fit; in immatures, color of contour feathers does not give bird a boldly checkered appearance; legs, feet and bill not black; claws not deeply curved (Plate 35-3). See GULLS (Page 51) 7 Feet with 4 long toes all joined by vvebs; 12 tail feathers. 8 7' Feet with 3 long toes joined by webs, 4th toe reduced in size; 14-24 tail feathers. See GEESE (Page 34) 8 Primary 10 only a few mm shorter than 9, only primary 10 cut out and that very slightly; tail decidedly wedge-shaped; bill serrated, not hooked at tip; middle toenail comb-like. See BOOBIES (Page 31) 8' Primary 10 shorter than 8 or even 7, primaries 10, 9, 8 cut out on inner web; tail fan-shaped; bill deeply hooked at tip, not serrated along cutting edge; middle toenail not comb-like. See CORMORANTS (Page 32) KEY C. SIZE MODERATE TO SMALL, WING 162-337 mm. 1 At least 1 (or all) of the outer 5 primaries with inner, outer OR both webs cut out (Fig. 10). 2 1 ' No webs of any primaries cut out. 7 2 Wings all of one color (black to brown) on upper surface. 3 2' Upper wings with definite contrasting color pattern, if only that some coverts may be white- tipped. 5 3 Extended wing broad and rounded; in folded wing primary 10 shorter than 8 or 7. 4 3' Extended wing more pointed; in folded wing primary 10 longest OR at least longer than 8. See WATERFOWL (Page 33) 20 KEY C (Cont.) 4 Only primary 10 cut out; ratio of wing's width to total wing length is about 0.32 - 0.38; 3 toes connected by webbing, 4th toe lobed (Plate 36-3); 14-24 tail feathers. See WATERFOWL (Page 33) 4' Primaries 10-8 cut out on inner web; wing very broad, ratio of width to total wing length is greater than 0.40; 4 toes connected by webbing (Plate 36-4); 12 tail feathers. See CORMORANTS (Page 32) 5 Extended wing broad and rounded; 12 primaries; outer 3 primaries in folded wing very close in length; webbing of primaries cut out near tip as follows: 10 on inner web, 9 and 8 on both webs; no tail; toes broadly lobed but not joined by webbing (Plate 37-5). See GREBES (Page 25) 5' Wing more pointed, 11 primaries; primary 10 definitely longest OR 10 slightly shorter than or equal to 9; only primaries 10 and 9 cut out OR if 8 included then cut outs subtle and that on 8 confined to outer web; tail present; feet with 3 webbed toes and a 4th toe reduced in size (Plates 34, 35, and 36-1, 2, 3). 6 6 Tips of some wing coverts edged with white - giving flecked appearance - otherwise upper surface of wings dark (almost black); primary 10 longest in folded wing; primaries 10-8 indistinctly cut out, 10 on inner web, 8 on outer and 9 on both; tarsi flattened laterally (Plate 34). See LOONS (Page 24) 6' Definite color pattern to wing, if only a single line of white pro- duced by white tips of a row of feathers; primary 9 usually longest feather; tarsi rounded. See WATERFOWL (Page 33) 7 Primary 10 in folded wing equal in length to 6, primary 9 longest; wing rounded and stubby, the ratio of width to total length about 0.43; wing charcoal gray with white edge of outer primary; toes very long and lobed (Plate 37-4); bill chicken-like (Plate 19-5). AMERICAN COOT 7' Not as in 7. 8 Wings very long and slender when extended, ratio of width to total length 0.23 - 0.25; distance from wrist to tip of primaries 1 1/2 times the distance from wrist to shoulder; tarsi proportionately small, 1/10 the wing length; upper surface of wing silvery gray (with gray or brown edgings to coverts in immatures) OR black, whitish below. See TERNS (Page 62) KEY C (Cont.) 8' Proportions and colors in wings not as above; tarsi not so minute. 9 9 Wing rather stubby - lengths of outer two primaries about equal and not extending much beyond 8th or even 7th; folded wing curved in out- line; body feathers close and compact; only 3 toes, all joined by webs (Plate 36-1,2). See ALCIDS (Page 66) 9' Not as in 9; wings more pointed - if the tips of primaries 10 and 9 are about equal in extent, they extend decidedly beyond 8; folded wing not decidedly curved; 4 toes. 10 10 Tertials very long and pointed; feet webbed, OR only partly webbed, OR not webbed at all (compare Plates 35-37). 11 10' Tertials not projecting beyond other secondaries to any great extent; 3 toes, webbed their entire length. 12 11 Wing narrow, ratio of width to total length is 0.27 - 0.31; 12 tail feathers. See SHOREBIRDS (Page 42) ir Wing broader, ratio of width to length is 0.34 - 0.38; 12-24 tail feathers. See WATERFOWL (Page 33) 12 Bird with distinctive musky odor (not that of rotting flesh!); nostrils together in tube on top of bill (Plates 5 and 6); wings long and narrow, ratio of width to total length 0.22 - 0.29 or less. See PETRELS (Page 27) 12' No distinctive odor; nostrils not as in 12; wing broader. 13 13 Feet with all 4 toes joined by webs (Plate 36-4); bill without nail or hook at tip OR bill not duck-like; white all over except for feather tips on back and several outer primaries being black. RED-BILLED TROPICBIRD 13' Not as in 13. 14 14 Upper surface of wing dark brown (sometimes with buffy edges to coverts) except for white bases and shafts of outer primaries; toes very long and toenails deeply hooked (Plate 35-1); legs blue and feet black. See JAEGERS (Page 50) 14 Not as in 14. 15 22 KEY C (Cont.) 15 Wing entirely black or dark brown, or black or dark brown with several white secondaries; unwebbed 4th toe is lobed (Plate 36-3); outer of 3 webbed toes longest; 12-24 tail feathers. SEE WATERFOWL (Page 33] 15' Wing color not as in 15; 4th toe neither webbed nor lobed (Plate 35-3); middle of 3 webbed toes longest; 12 tail feathers. See GULLS (Page 51] KEY D. SIZE SMALL, WING <161 mm 1 Primaries 10-8 and sometimes 7 cut out on inner, outer or both webs (Fig. 10); 12 primaries; no tail; tarsi flattened laterally (Plate 37); viewed from above the outer edge of folded wing curves decidedly outward, away from body (Fig. 18a). See GREBES (Page 25) r Primaries not cut out or 10 and 9 only slightly so; 11 primaries (outermost often minute); prominent tail; tarsi rounded in cross section; shape of wing not as above. 2 2 Body plumage compact, feathers overlapping tightly; viewed from above, partly folded wings stubby and decidedly curved inward along outer edge (Fig. 18c); wings rather broad, the ratio of width to total length is 0.30 - 0.40; three toes webbed, the fourth either lobed (Plate 36-3) or absent (Plate 36-1). 3 2' Plumage much fluffier, individual feathers overlapping loosely; wings long and slender, ratio of width to total length is 0.22 to 0.31; folded wing straight or curved only slightly inward along outer edge; arrangement of toes not as in 2. 5 3 Wing <138 mm; feet with only 3 toes, all connected by webbing (Plate 36-2). See ALCIDS (Page 66) 3" Wing 138-161 mm. 4 4 Feet with only 3 toes, all connected by webbing; tarsus 15-31 mm; a maximum of 12 tail feathers. See ALCIDS (Page 66) 4' Feet with 4 toes, 3 connected by webbinn and 4th reduced in size (Plate 36-3); tarsus 30-35 mm; 14-24 tail feathers. See WATERFOWL (Page 33) 23 KEY D (Cont.) 5 Primary 10 shorter than 8, sometimes shorter than 7; bird largely same color (gray or brown) all over except rump may be white; tertials not notably longer than other secondaries; distinctive musky smell pervades specimen. See PETRELS (Page 27) 5' Primary 10 longest primary; usually a stripe running outward along upper surface of wing; belly and back OR back, breast or wings checkered; tertials distinctly longer and more pointed than other secondary feathers; no distinctive musky odor. 6 6' Upper surface of wing silver-gray, sometimes with buffy edgings to coverts; exposed portion of outer few primaries darker than rest of wing; tarsi short, <1/10 the wing length. See TERNS (Page 62) Wing color not as in 6; tarsi proportionately longer, >1/10 the wing length. See SHOREBIRDS (Page 42) Figure l8. The ciirvature in the outer edge of the partly folded, wing. 24 KEY TO LOONS 1 Bill length 45-58 mm; wing length <316 mm (260-315); tarsus length 65-79 mm. 2 r Bill 70-98 mm; wing >319 mm (320-395); tarsus usually >79 mm (73-97). 3 2 Bill stiletto-shaped, tip of culmen curved decidedly downward (Plate 2-3). In spring or summer, throat black with green or purple irides- cence; back black, each side of upper mantle with column of rectangular white spots. In fall or winter, throat white; back blackish brown, sometimes a few scapular feathers with each having a pair of dull whitish spots. ARCTIC LOON 2' Bill slender, appearing upturned due to (1) abrupt upward angulation of lower edge, and (2) a straight (perhaps slightly downcurved) or upward curved culmen especially along posterior two-thirds (Plate 2-2). In spring or summer, throat red; back blackish-brown, feathers at shoulder each with a pair of small gray spots at the tip. In fall or winter, throat white; back blackish-brown, but each feather has a pair of white spots at the tip. RED-THROATED LOON 3 Culmen dark along entire (or almost entire) length; bill stiletto- shaped, culmen curved downward (Plate 1-1); central portion of ventral surface of outer 7 primaries light tan, bordered on either side with dark tan; viewed from the front, cross section of bill anterior to nostrils is rounded. COMMON LOON 3' Culmen paler, horn color at tip and darkening toward base; culmen often straight, distal one-third of lower mandible with abrupt upward angle giving bill an upturned appearance (Plate 1-2); central portion of outer primaries on ventral surface creamy, bordered on either side by creamy to pale tan; viewed from the front, cross section of bill anterior to nostrils often flat-sided. YELLOW-BILLED LOON 25 KEY TO GREBES 1 Wings >180 mm (181-215) long; bill longer than the head OR bill >44 mm (45-79) long; tarsus >60 mm. r Wings <155 mm; bill shorter than the head OR bill <30 mm; tarsus <45 mm. 2 Wings with white on inner primaries and outer secondaries; bill length >58 mm; scales on bottom of tarsus smooth; feet olive to yellow. 2' Wings with no white on primaries only on secondaries; bill 45-56 mm; scales on bottom of tarsus pointed; feet dark brown. RED-NECKED GREBE 3 Bill yellow to orange at base; black of cap not extending to lores; dark of back pale in color. WESTERN GREBE, light phase 4 3' Bill yellowish green; black of cap extending below eye to lores; back quite dark. WESTERN GREBE, dark phase 4 4 Bill stiletto-shaped (Plate 2-5), 67-80 mm long and 9.5-13.0 rrni deep at anterior edge of nares; wing length 192-214 mm. WESTERN GREBE, male 4' Bill much more slender and upturned (Plate 2-6), 55-71 mm long and 8-11 mm deep; wing 184-203 mm. WESTERN GREBE, female 5 Only a white spot at tip of inner web of outer secondaries or no white on secondaries; bill chicken-like {wery deep and blunt), hooked at tip (Plate 2-1); feathers on front of crown with bristle- like tips; outer lobes of toes wide, webbing between toes extending more than half the toe length. PIED-BILLED GREBE 5' Broad white areas on both webs of some secondaries; bill slender, not hooked at tip; feathers on crown without bristle-like tips; outer lobes of toes narrow, webbing extending less than half the toe length. 6 6 Bill higher than wide at base; tarsus 44.5-49 mm. In winter, black of cap extending sharply only to level of eye; in breeding plumage, much of neck, upper breast and area along sides chestnut. HORNED GREBE 26 KEY TO GREBES (Cont.) 6' Width and height of bill at base similar, tip may be slightly up- turned; tarsus 38-44.5 mn. In winter, dark of cap extending below eye; in breeding plumage, neck and upper breast black, some chestnut on flanks. EARED GREBE KEY TO ALBATROSSES 1 Body, head and neck white or mottled white and dark brown. 2 1 ' Entirely dark brown. 3 2 Area of back between wings white or mottled white and dark brown; culmen 120-145 mm; bill depth measured at anterior edge of nares, 34-35 mm; tarsus 91-101 rrm; wing length 518-555 mm. SHORT-TAILED ALBATROSS, adult 2' Area of back between wings entirely dark; culmen 99-114 mm; bill depth 24-34 mm; tarsus 78-86 mm; wing 470-510 mm. LAYSAN ALBATROSS, adult and immature 3 Bill and feet light tan or yellow; measurements as in 2 SHORT- TAILED ALBATROSS, immature 3' Bill and feet black or dark brown; culmen 94-113 mm; bill depth 29- 40 mn; tarsus 80-95 mm; wing 485-533 mm. 4 4 Considerable white on face. BLACK-FOOTED ALBATROSS, adult 4' No (or only a very small amount of) white on face. BLACK-FOOTED ALBATROSS, immature sub adult, or young adult 27 KEY TO PETRELS 1 Bill length <18 mm; wing length <180 mm; tarsus <30 mm OR if 33-37 mm then feet with yellow on webs; tarsus decidedly longer than middle toe with claw (STORM PETREL). 2 1' Bill >25 mm; wing >200 mm; tarsus >38 mm OR if 33-37 mm then feet are entirely black; tarsus not longer than middle toe with claw. 10 2 Body, head and neck light to medium bluish-gray; wings with blackish flight feathers but with gray coverts. FORK TAILED STORM-PETREL V Body, head and neck blackish-gray to sooty brown, except for rump which may or may not be white and secondary upper wing coverts which may or may not be distinctly buffy. 3 3 Wing length >165 mm; tarsus 29-33 mm but if close to 33 mm then feet entirely black and no white on rump. BLACK STORM PETREL 3' Wings <162 mm; tarsus 25-33 mm but if close to 33 mm then webs of feet with light (yellow) spots and with white feathers in rump, flanks and under tail coverts. 4 4 At least some white on some rump feathers (upper tail coverts). 5 4' No white on any feathers of rump or flanks. 8 5 Tarsus >30 mm; light (yellow) area on webs of feet; some and usually many under tail coverts white. WILSON'S STORM PETREL 5' Tarsus <26 mm; feet entirely black; under tail coverts not white. 6 6 Upper tail coverts white to the tips including central two (feather shafts dark); tail short, longest tail feather (from skin to tip) 56-57 mm; longest (central) white rump feathers extend about 2/3 the length of the tail (Fig. 19 b); culmen often <12.9 mm (10.6-14.0 mm). GALAPAGOS STORM PETREL 6' Rump extensively white with most of the longer upper tail coverts in center of rump having dark tips except' perhaps the most central ones which may sometimes be entirely white or entirely dark OR only a few feathers on either side of rump have some white (sometimes confined to one white spot on one feather on either side); longest rump feathers extend only about 1/2 the tail length (Fig. 19 a). 7 28 KEY TO PETRELS (Cont.) 7 Two central-most upper tail coverts within the largely white rump patch completely dark or partly dark OR only a few feathers on either side of rump with at least some white; shafts of white rump feathers dark; bases of outermost tail feathers usually dark, but if white, then only for about 1 cm. LEACH'S STORf^ PETREL, light phase 7' The several longest upper tail coverts in center of rump white but with dark tips; shafts of white rump feathers white; lateral tail feathers white at base for 2.5 cm or more. HARCOURT'S STORM PETREL 8 Coloration blackish-gray all over (not brown), particularly on ventral surfaces of wings; upper wing coverts not distinctly buffy (only slightly, if at all). 9 8' Coloration brown, particularly under wing coverts; upper wing coverts very decidedly buffy forming a bar running diagonally from the body to the wrist (not including scapulars); north of Pt. Conception almost all with wings >144 mm {very rarely to 142 mm long). LEACH'S STORM PETREL, dark phase 9 Wing length <130 mm; bill length <12 mm; central tail feathers longer than or as long as outer ones (i.e., tail wedge-shaped or square, not forked); upper tail coverts (rump feathers) extend about 2/3 the length of tail feathers (Fig. 19b). LEAST STORM PETREL 9' Wing 131-142 mm {very rarely to 145 mm); bill 13-15 mm; tail forked; upper tail coverts extend only about 1/2 the length of tail feathers (Fig. 19a). ASHY STORM PETREL 10 Back, mantle of wings, and rump boldly checkered black and white; broad black band at tip of white tail. CAPE PETREL 10' Coloration not as above. 11 11 Underwings white with a broad black bar running from wrist to "armpit"; breast white but belly charcoal gray; bill black, <29 mm long and heavy in proportion (not slender; Plate 5); tarsus <38 mm. SCALED (MOTTLED) PETREL 11' If underwings white then without the broad black bar referred to above; if breast white then belly white also; bill brown, yellow, horn color or pale, >29 mm but if 29-30 mm then especially slender; tarsus >42 mm. 12 29 KEY TO PETRELS (Cont.) 12 Bill large and thick, nasal tube prominent, about 40% of bill length (Plate 5); lower mandible not decidedly hooked at tip; body stocky; tarsus rounded in cross-section. 13 12' Bill slender (especially when viewed from above), nasal tube about 25% of bill length (Plate 6); lower mandible hooked; body slender, torpedo-shaped; tarsus flattened laterally when viewed in cross-section. 15 13 Underparts of body white. 14 13' Underparts of body light gray to dark brown. NORTHERN FULMAR, dark phase 14 Crown, nape and hind neck light gray; underside of head and neck white. NORTHERN FULMAR, intermediate phase 14' Head and neck white. NORTHERN FULMAR, light phase 15 Belly white or partly white. 16 15' Bird entirely dark, except bill and feet may not be dark. 19 16 Wing length 270-300 mm; tail decidedly wedge-shaped; under tail coverts white; inner webs of primaries largely white; in fresh plumage, back light to medium gray; a prominent dark "W" pattern visible when both wings are extended (not evident in worn plumage). BULLER'S SHEARWATER 16' Wing <270 mm OR greater than 300 mm; tail not decidedly wedge- shaped; under tail coverts dark; inner webs of primaries dark; back brown, never a "W" pattern over wings and mantle. 17 17 Wing <270 mm; bill black along top and at tip, remainder bluish- gray; legs and feet light (flesh-colored) but with outer side of tarsus and outer toe black. COMMON SHEARWATER (See Species Accounts) 17' Wing >300 mm; bill largely straw-colored except darker along top and at tip; legs and feet entirely light (flesh-colored) but tending toward brown along outer toe. 1^ 30 KEY TO PETRELS (Cont.) 18 Under tail coverts white; feathers of forehead, face and sides of neck white each with a central dark streak running along the shaft giving a streaked appearance to these areas; coloration of bill warm tan. STREAKED SHEARWATER 18' Under tail coverts dark; feathers of forehead, face and sides of neck usually dark but sometimes whitish and broadly tipped with dark coloration imparting a speckled appearance to these areas; straw- colored bill lighter than 18. PINK-FOOTED SHEARWATER 19 Bill straw-colored; feet and legs light-colored (pinkish in fresh specimens); wing length 298-333 mm. FLESH-FOOTED SHEARWATER 19' Bill and feet dark (black to brownish or bluish); wing 263-320 mm. 20 20 Wing linings (under wing coverts) generally brown; small (wing 263-290 mm, culmen 29-35 mm). SHORT-TAILED SHEARWATER 20' Wing linings usually light gray, in some cases almost white; larger (wing 280-320 mm; culmen 38-48 mm). SOOTY SHEARWATER Figure 19. The length of upper tail coverts (riamp feathers) relative to the length of the tail: tail coverts (a) about 1/2 the tail length and (b) about 2/3 the tail length. 31 KEY TO BOOBIES 1 Belly entirely white or very light gray (almost white). 2 1' Belly not white but rather mottled or dark. 8 2 Breast very dark brown; demarcation between breast and belly straight and abrupt. 3 2' Breast white or light brown; if brown, coloration grading gradually into belly or boundary not straight. 4 3 Forehead white or lighter than crown; feet green. BROWN BOOBY, adult male 3' Forehead and crown same dark color; feet more yellow. BROWN BOOBY, adult female 4 Throat entirely white. 5 4' Throat with some brown. 6 5 Tarsus 34-43 mm; bill length 77-90 mm; bill depth 28-34 mm; feet and legs red. RED-FOOTED BOOBY 5' Tarsus 53-62 mm; bill 98-106 mm; bill depth 35-38 mm; feet and legs blue-gray. BLUE-FACED BOOBY, adult 6 Feathers on head and neck light centrally with outer parts dark giving these areas a streaked appearance; feet light blue. BLUE-FOOTED BOOBY 6' Head and neck not streaked. 7 7 Head and neck dark brown, sometimes speckled; measurements as in 5'; feet light blue, occasionally tending toward pinkish. BLUE-FACED BOOBY, immature 7' Non-white color of neck, head or shoulders very light; measurements and foot color as in 5. RED-FOOTED BOOBY 32 KEY TO BOOBIES (Cont.) 8 Belly mottled dark and white; dark breast clearly defined in con- trast to mottled belly - demarcation line straight. BROWN BOOBY, immature 8' Belly all one color or dark with light feather tips giving delicate scaled effect. 9 9 Dark belly feathers with fine, light edgings; feet green to yellow; bill length 90-101 mm; tarsus 41-51 mm. BROWN BOOBY, immature 9' Feathers without light edges; feet reddish; bill 77-90 mm; tarsus 34-43 mm. RED-FOOTED BOOBY KEY TO CORMORANTS 1 General body coloration yery dark with green or purple iridescence, 1' Body all brown or mostly brown (except sometimes belly like 1 above); brown of belly and neck may be a very light sandy color or almost white. 2 Lower mandible yellow, culmen black. 3 2' Bill dark brown all over. 4 3 Bill short and deep (length only 2.7 - 3.4 times greater than depth at base) with wery prominent and sharp hook, curving far below tip of lower mandible (Plate 9-1); throat skin yellow or orange; back feathers bronze with black edges giving a scaly appearance; long white or black plumes may or may not extend up and back from above each eye. DOUBLE-CRESTED CORMORANT, adult 3' Bill thinner (length 3.7 - 4.1 times greater than depth at base), hook barely reaching below lower mandible (Plate 9-4); face and throat skin red; back feathers dark iridescent green, not scaly; flank feathers may or may not be white; two crests on head, one extending back from forehead and the other projecting from back of head. RED- FACED CORMORANT, adult 33 KEY TO CORMORANTS (Cont.) 4 Bill length 64-80 mm; tarsus 59-72 mm; bill 3.8 - 4.3 times longer than deep at base (Plate 9-3); feathers of chin tan; throat pouch may be blue; long, thin white plumes may extend backward from sides of head and back. BRANDT'S CORMORANT, adult 4' Bill 42-57 mm; tarsus 47-59 mm; bill very thin, 4.4 - 6.0 times longer than deep at base (Plate 9-5); feathers of chin same color as head and throat; face and throat pouch red; flanks may or may not be white. PELAGIC CORMORANT, adult 5 Lower mandible entirely chrome yellow or yellow only at base. 6 5' Upper and lower mandible brown. 7 6 Face and throat yellow; feathers of back tan with thick, dark brown edges giving a scaly appearance; belly and throat sometimes very light, almost white; bill as in 3 above (Plate 10-1). DOUBLE-CRESTED CORMORANT, immature 6' Face and throat not yellow; back feathers brown with purple iridescence, not prominently scaly; bill as in 3'. RED-FACED CORMORANT, immature 7 Measurements as in 4. BRANDT' S CORMORANT, immature 7' Measurements as in 4'. i PELAGIC CORMORANT, immature KEY TO WATERFOWL 1 Body, head and neck white or very light gray; wings white or white with black primaries; three or four outermost primaries with one or both webs cut out (see Fig. 10). 2 r Coloration largely brown or gray with a little white here or there; no primaries or only outer two decidedly and the third outermost sometimes slightly cut out (see Fig. 10). ^ 2 Wings entirely white or very light gray; primaries 10-7 have one or both webs cut out; area between eye and bill (the lores) unfeathered; very large bird, wing length 500-680 mm. 3 34 KEY TO WATERFOWL (Cont.) 2' Wings largely white except for black primaries; primaries 10-8 have one or both webs cut out; medium large bird, wing 318-402 mm. 4 3 Tail of 20 feathers; usually, but not always, a yellow spot in front of eye; distance from tip of bill to anterior edge of nostril <48 mm; wing length 500-575 mm. WHISTLING SWAN, adult (all white) or immature (gray wash to some feathers) 3' Tail of 24 feathers; never a yellow spot in front of eye; distance from tip of bill to anterior edge of nostril > 50 mm; wing 544-680 mm. TRUMPETER SWAN, adult (all white) or immature (gray wash to some feathers) 4 Bill length 50-63 mm; sides of bill open in a "grin" as in Plate 12a-2, where "grin" is >l/3 the bill depth; wing length 380-470 mm. SNOW GOOSE 4' Bill 34-46 mm; not as open on sides, "grin" 220 mm. ' ^ 34 33' No white on outer web of the 5 inner primaries and wing length <208 mm (birds not fitting 33 or 33' should be compared with specimens for identification). 35 34 Head mostly glossy greenish. GREATER SCAUP, male 34' Head brown but forehead and front of face may be white. GREATER SCAUP, female and immature 35 Head glossy mostly purple. LESSER SCAUP, male 35' As in 34'. LESSER SCAUP, female and immature 36 Inner secondaries and inner greater secondary coverts white; outer secondaries and outer greater secondary coverts green; bill long and slender with serrate edges (Plate 19-1). (MERGANSER) 37 36' Wing pattern not as above; bill more duck-like (broad and flat). 40 37 Nostril near middle of bill; feathering on bill near gape (corner of mouth) extends forward as far as that on lower mandible (Plate 19-1); in dorsal view, forehead feathering extends farther on bill toward bill tip than does feathering on side of upper mandible; wing length 246-285 mm. 38 39 KEY TO WATERFOWL (Cont.) 37' Nostril near base of bill; feathering on side of upper mandible near gape extends forward of that on lower mandible (Plate 19-2); feathering of forehead and on sides of upper mandible extends an equal distance toward bill tip; wing 213-257 mm. 39 38 Head, neck and back green; breast, belly and sides white to faintly salmon. COMMON MERGANSER, male 38' Head and neck chestnut; distinct demarcation between neck color and whitish of breast. COMMON MERGANSER, female and immature 39 Head green, throat largely white; sides grayish. RED-BREASTED MERGANSER, male 39' As in 37' but neck color grading gradually into whitish breast. RED-BREASTED MERGANSER, female and immature 40 Wing length >255 mm; wing entirely dark except for white of inner and middle secondaries and coverts. 41 40' Wing <246 mm. 42 41 Body black dorsally; yellow-orange on bill; feet orange with black webs; greater secondary coverts tipped with white. WHITE-WINGED SCOTER, male f 41' Body brown dorsally; feet brown with black webs; greater secondary coverts entirely dark. WHITE-WINGED SCOTER, female and immature 42 Feet yellow with dark webs. 43 42' Feet pink or gray. 45 43 Breast entirely white. 44 43' Breast white with gray collar. BARROW'S and COMMON GOLDENEYE, female and immature 44 Greater coverts black, center ones tipped with white; crescent- shaped white spot between eye and bill. BARROW'S GOLDENEYE, male 40 KEY TO WATERFOWL (Cont.) 44' Greater coverts white (though black at bases); round white spot between eye and bill. COMMON 60LDENEYE, male 45 Feet pink; triangular white patch on crown of head extending to cheeks; all coverts mainly white. BUFFLEHEAD, male 45' Feet gray; head dark except for large white spot behind eye; wing coverts dark. BUFFLEHEAD, female and immature 46 Speculum black and white with some greater coverts chestnut. 47 46' Speculum containing bright metallic color: blue, green or blue- green. 48 47 Chestnut on coverts extensive, forming large patch on wing; rump black. GADWALL, male 47' Chestnut on coverts very faint; rump brown. GADWALL, female 48 Upper wing coverts light blue forming large blue wing patch. 49 48' Upper wing coverts not blue. 53 49 Wing length >215 mm; bill spoon-shaped, widest at tip and > 56 mm long; feet red-orange. 50 49' Wing <200 mm; bill not spoon-shaped, <50 mm long; feet yellow. . 51, 50 Rump, head and neck green; belly and sides cinnamon; breast white. NORTHERN SHOVELER, male 50' Generally brown all over. NORTHERN SHOVELER, female 51 Generally brown all over, except in wings. BLUE-WINGED and CINNAMON TEAL, female 51' Belly cinnamon, either wery pale or very dark, rich color. 52 52 Belly pale cinnamon (to buffy) with dark spots; head gray, with large white crescent in front of eye. BLUE-WIN^-ED TEAL, male 41 KEY TO WATERFOWL (Cont.) 52' Rich cinnamon red over much of body and head. CINNAT^ON TEAL, male 53 Speculum purplish-blue with upper and lower white borders; feet orange. 54 53' Speculum with no purple; feet bluish-gray. 55 54 Generally brown all over (except speculum and whitish belly). MALLARD, female 54' Sides and belly white; breast cinnamon; rump, head and neck green OR with flecks of these colors in the latter 3 areas. MALLARD, male NOTE: In a wing specimen without accompanying feet, Steller's Eider (choice 20) and Harlequin Duck (choice 21) might key out to here; check choices 19-21 to be sure. 55 Speculum violet, bronze and green. 56 55' Speculum green or green and black. 57 56 Speculum glossy, bordered behind with black and white bars and in front by cinnamon-buff bar. PINTAIL, male 56' Speculum dull without black bar. PINTAIL, female 57 Speculum green and black, edged in front by cinnamon-buff bar; no shoulder patch; wing length <210 mm. 58 57' Speculum mostly green, edged in front by black; large white or gray shoulder patch; wing >230 mm. 59 58 Upper tail coverts black with ashy edges; under tail coverts black and yellow; sides gray. GREEN-WINGED TEAL, male 58' Body brownish all over. GREEN-WINGED TEAL, female 59 Middle and greater wing coverts white, forming large white wing patch; green speculum shades to black towards tips of feathers. AMERICAN WIGEON, male 59' Middle and greater wing coverts gray; green speculum feathers tipped with white. AMERICAN WIGEON, female 42 KEY TO SHOREBIRDS 1 Wing length >200 mm. 2 1 ' Wing length <200 mm. 13 2 Upper wing with a distinct, single, longitudinal white stripe that extends well into the outer half of the wing (Fig. 20a). 3 2' Upper wing without a white stripe extending into the outer half of the wina (Fia. 20b). 5 3 Shaft of outermost primary dark brown; dorsal body feathers blackish- brown; bill flattened laterally. AMERICAN OYSTERCATCHER 3' Shaft of outermost primary partially white; dorsal body feathering mottled or uniformly gray. 4 4 Front half of underwing mostly black; most secondaries mottled above; tail brownish gray mottled with darker gray; bill 50-65 mm long and not swollen dorsal ly near tip (Plate 22-1). WILLET 4' Underwing mostly white and medium gray with some black feathers where it meets the body; tail white, irregularly barred with blackish-brown; bill 25-35 mm long and swollen dorsally near tip (Plate 20-7). BLACK-BELLIED PLOVER 5 Upper wing without barring, spots or mottling and completely or nearly completely black or black-brown. 6 5' Upper wing not as in 5. 7 6 Upper wing nearly or completely black with green iridescent sheen; tail gray; bill slender, straight to very slightly upturned and not compressed laterally; belly white. BLACK-NECKED STILT 6' Upper wing nearly or completely blackish-brown without irridescence; tail dark brown; bill stout and compressed laterally (Fig. 7); belly brown-black. BLACK OYSTERCATCHER 43 Figure 20. Shorebird wings, showing the (a) presence (Ruddy Turnstone) or (b) absence (Pectoral Sandpiper) of a wing stripe. (c) shows underside of a Dunlin wing with wrist markings. 44 KEY TO SHOREBIRDS (Cont.) 7 Inner half of upper wing with extensive white trailing and leading edges; tail grayish-white or \iery pale gray; bill slender and markedly upturned (Plate 23-6). AMERICAN AVOCET 7' Inner half of upper wing without extensive white areas; tail with barring; ventral body feathering never uniform white or blackish. 8 8 Lighter portion of underwings pink, buff or cinnamon; tail brown and barred. 9 8' Lighter portion of underwings whitish; tail white to pale buff with dark brown barring. 12 9 Underwing more cinnamon or buff than dusky; bill curved downwards or upwards. 10 9' Underwing more dusky than pink or buff; bill curved downwards and almost always <100 mm long. 11 10 Underside of primaries cinnamon with a variable amount of gray speckling; bill curved upwards (Plate 23-4). MARBLED GODWIT 10' Underside of primaries cinnamon with dusky bars; bill curved downward (Plate 23-1). LONG-BILLED CURLEW 11 Tail pale rufous or orange-brown, heavily barred with dusky brown. BRISTLE-THIGHED CURLEW 11 ' Tail olive or buffy olive with heavy, dusky brown barring. WHIMBREL 12 Wing length >215 mm; upper surface of primary shafts 9 and 10 white; bill length >70 mm. BAR-TAILED GODWIT 12' Wing < 21 5 mm; upper surface of shaft of primary 9 much browner than that of primary 10; bill < 70 mm. GREATER YELLOWLEGS 13 Upper wing with distinct longitudinal white stripe (Fig. 20a). 22 13' Upper wing without distinct longitudinal white stripe (Fig. 20b). 14 45 KEY TO SHOREBIRDS (Cont.) 14 Shaft of outermost primary light brown on upper surface, outer web of outermost primary whitish in contrast to much darker inner web; tail with much orangish coloration; bill length 50-80 mm. COMMON SNIPE 14' Shaft of outermost primary usually whitish over much of its length; outer web of outermost primary dark as in inner web; tail not ex- tensively orange. 15 15 Inner half of upper wing with white or golden spots. 16 15' Inner half of upper wing not spotted. 18 16 Front half of underwings (underwing coverts) brownish-gray; upper wing often with yellow or golden spots; tail dusky, irregularly barred with grayish-white or gray and yellowish; bill swollen dorsally near tip (Plate 20-6). AMERICAN GOLDEN PLOVER 16' Front half of underwings white with gray and brown barring; much of tail whitish with dusky barring; bill not swollen dorsally near tip. 17 17 Wing length >175 mm; bill length >47 mm. GREATER YELLOWLEGS 17' Wing <175 mm; bill <47 mm. ^ LESSER YELLOWLEGS 18 Wing 160-190 mm; gray or white-tipped gray feathers dominate front half of underwing; tail and rump uniformly slate-gray. WANDERING TATTLER 18' Wing < 160 mm; white feathering conspicuous in some areas on front half of underwing; tail and rump not as in 18. 19 19 Inner secondaries with conspicuous white zig-zagging bars; bill length >50 mm; tail barred white and black. LONG-BILLED or SHORT-BILLED DOWITCHER 19' Wings and bill not as above. 20 20 Central tail feathers mouse gray, outer tail feathers irregularly barred on inner web; toes lobed, margined laterally with conspicuous membrane (Plate 37-6); breast never streaked, spotted or barred but occasionally washed with gray or brown. WILSON'S PHALAROPE 46 KEY TO SHOREBIRDS (Cont.) 20' Central tail feathers black; toes not lobed, without lateral mem- branes (Plate 37-3); breast with some spotting, streaking or barring at least on sides. 21 21 Outermost tail feather distinctly shorter than adjacent ones; shaft of outermost primary usually partially brown dorsal ly. SHARP-TAILED SANDPIPER 21' Outermost tail feather equal to or slightly longer than adjacent one; shaft of outermost primary usually entirely white. PECTORAL SANDPIPER 22 Inner half of extended upperwing has a white patch where wing attaches to body (Fig. 20a); tail feathers white with broad black band on outer half. 23 22' Upperwing without white patch where wing attaches to body. 24 23 Upperwing blackish brown and white without gray-brown, buff or rufous coloration, (except in juveniles where some feathers may be finely buffy-tipped) ; throat gray-brown to brown-black. BLACK TURNSTONE 23' Upperwing coverts with considerable gray-brown, buff or rufous; throat mostly white. RUDDY TURNSTONE 24 Wing length >180 mm; front half of underwing mostly black; tail brownish gray mottled with darker gray. WILLET 24' Wing not as in 24. 25 25 Wing >170 mm; underwing white and gray with some sharply contrasting black feathers where it meets the body; tail white and irregularly barred with blackish-brown; bill 25-35 mm long and swollen dorsally near tip (Plate 20-7). BLACK-BELLIED PLOVER 25' Wing not as in 25. 26 26 Wing length <115 mm; many upperwing coverts gray-brown with a dark bar near the tip; underwing shows distinct longitudinal white stripe; tail grayish-brown with lateral feathers broadly barred white; body white ventrally or white with heavy black spotting. «;pnTTFn ^anhptpfr 47 KEY TO SHOREBIRDS (Cont.) 26' Wing not as in 26. 27 27 Wing length >140 mm, shaft of outermost primary markedly bicolored, white and dark brown on upper surface; bill shorter than head and swollen dorsally near tip (Plate 20-5); rump orange-brown; two dark breast bands. KILLDEER 27' Wing not as in 27. 28 28 White on upper surface of outer web of two or more of inner 6 primaries restricted to a patch adjacent to shaft and not extending to leading edge of feather (Fig. 21-5); wing length 110-130 mm; bill swollen dorsally near tip, 9-15 mm long; one dark neck band. SEMIPALMATED PLOVER 28' Wing does not fit both the above conditions, 29 Figure 21. Color patterns of shorebird feathers, FIFTH PRimRlES - NATURAL SIZE! northern phal^rope: SANDE1RUN6 DUNLIN PhALAROPE SE/vNi-pAL/^ATED PLOVLFk 4. 48 KEY TO SHOREBIRDS (Cont.) 29 Underwings light and lacking conspicuous dark markings on leading edge; bill swollen dorsally near tip; hind toe lacking. 30 29' Underwings mostly dark or if light then with conspicuous dark 31 markings on the leading edge (Fig, 20c). 30 Wing length 135-160 mm; bill length 18-24 mm; dark shoulder patch absent; tail gray-brown basal ly, dark toward tip. MOUNTAIN PLOVER 30' Wing 90-115 mm; bill 12-17 mm; shoulder patch present; outer portion of tail whitish with central portion grayish-brown and darker toward tip. SNOWY PLOVER 31 White on upper surface of outer web of the 5th primary runs from the feather margin to shaft (Fig. 21-1,2 and 4). 32 31' White on upper surface of outer web of the 5th primary does not 35 reach shaft (Fig. 21-3). 32 Wing length 160-190 mm; tail white basal ly, dusky near tip. SURFBIRD 32' Wing <160 mm. 33 33 Black on outer web of 5th primary meets shaft at obtuse angle (Fig. 21-2); toes not lobed. SANDERLING 33' Black on outer web of 5th primary meets shaft at acute angle (Fig. 21-1,4); toes lobed. 34 34 Wing length 100-118 mm; bill tapering gradually toward sharp tip (Plate 21-3). NORTHERN PHALAROPE 34' Wing 120-140 mm; bill swells noticeably laterally near tip before tapering to a point (Plate 21-2). RED PHALAROPE 35 Wing length 145-180 mm; secondaries all dark; tail pale brownish- gray, not conspicuously darker centrally. RED KNOT 35' Wing <145 mm. 36 49 KEY TO SHOREBIRDS (Cont.) 36 Wing length 109-144 mm. 37 36' Wing 80*108 mm. 42 37 Shafts of secondaries lack any brown coloration on upper surface; hind toe absent; bill swollen dorsally near tip (Plate 20-3); breast never spotted or streaked. WILSON'S PLOVER 37' Shafts of some secondaries have brown on upper surface, ranging from entirely brown to having merely a thin, longitudinal brown streak. 38 38 One to four of the inner secondaries predominantly (90% or more) wh i te . 39 38' No secondaries predominantly white. 40 39 One to two inner secondaries predominantly white; bill black; legs black. DUNLIN 39' Three to four inner secondaries predominantly white; ridge on dorsal surface of upper mandible and base of lower mandible brownish; legs yellow or greenish. ROCK SANDPIPER 40 No conspicuous white rump patch. BAIRD'S SANDPIPER 40' Conspicuous white rump patch (white rump feathers may have some dark brown markings) . 41 41 Central tail feathers gray; bill noticeably curved downwards, >30 mm long (Plate 24-8). CURLEW SANDPIPER 41' Central tail feathers brown-black; bill straight, <30 mm long. WHITE-RUMPED SANDPIPER 42 Anterior toes with no trace of webbing (as in Plate 37-3). 43 42' Distinct partial web between outer and middle and inner and middle toes (somewhat like Plate 37-2). 44 50 KEY TO SHOREBIRDS (Cont.) 43 Legs and feet yellowish; throat white, with or without brownish streaking; breast always with brownish streaking; bill width at nail <1.4 mm; wing length 81-96 mm. LEAST SANDPIPER 43' Legs and feet black; throat white and breast with gray or buffy- gray wash OR throat rufous and breast with dusky streaking or spotting; bill width at nail >1.4 mm; wing 93-108 mm. RUFOUS-NECKED SANDPIPER 44 Bill length usually <20.0 mm; bill length <10 times bill width at nail. SEMIPALMATED SANDPIPER 44' Bill usually >20.0 mm; length >10 times bill width at nail. WESTERN SANDPIPER KEY TO SKUAS AND JAEGERS 1 Large and stout birds; wing length >380 nm; tarsus shorter than middle toe with claw. SKUA, probably SOUTH POLAR SKUA 1' Smaller and slightly built; wing <375 mm; tarsus longer than middle toe. 2 2 Bill deeper than wide at base, 38-44 mm long; wing length 349-374 mm; tarsus 48-55 mm. POMARINE JAEGER 2' Bill wider than deep at base, 27-35 mm long; wing 295-341 mm; tarsus 38-46 mm. 3 3 Humerus (wing bone from shoulder to elbow) 94-105 mm long; tarsi and feet almost always black (occasionally bluish in juveniles); bill saddle along culmen usually longer than chord of nail (see Fig. 5). PARASITIC JAEGER 3' Humerus 83-88 mm; legs and basal half of toes and webs bluish, re- mainder of feet black; bill saddle along culmen usually shorter than chord of nail. LONG-TAILED JAEGER 51 KEY TO GULLS 1 Outer 5 primaries wholly white, r Outer 5 primaries not wholly white. 23 2 2 Outer 5 primaries white with black tips; body plumage white with black spots. IVORY GULL, first year 2' Outer 5 primaries not white with black tips. 3 3 Wing length <325 mm, 3' Wing >325 mm. 4 24 4 Wing >295 mm. 4' Wing <295 mm. 5 Outer three primaries uniformly blackish (check inner webs carefully). 5' Outer three primaries with white or gray areas. 15 6 6 Outer three primaries extensively white, with black tips and dark (gray to black) trailing edges (Fig. 22). 17 6' Primaries not as above, (KITTIWAKE) 7 Figure 22. Outer three primaries of the Black-headed Gull. 52 KEY TO GULLS (cont.) 7 Mantle (see Fig. 11) dark gray; culmen length 20 mm or less; tarsus red, and yery brightly so in fresh specimens. 18 7' Mantle pale gray; culmen 31 mn or more; tarsus black or grayish. 19 8 Wing length <230 mm. 20 8' Wing >230 mm. 9 9 Upper wing surface with three bold triangles of more or less solid color: outer primaries forming black triangle, inner primaries and secondaries forming white triangle, wing coverts and back forming gray or brown triangle (Fig. 23c); tail slightly forked. 21 9' Upper wing surface not displaying triangles of solid color. 10 10 Wing mostly uniform gray above and below, except black leading edge to outer primary; central tail feathers longer than outer tail feathers; pink cast to underparts. ROSS' GULL, adult 10' Not as above. 11 11 Outer primaries with conspicuous white areas. 22 ir Outer primaries uniformly dark, or with very small white areas at tips; tail white with black band not extending to two outermost tail feathers. FRANKLIN'S GULL, first year 12 Wing length >275 mm; underside of wing grayish. 17 12' Wing <275 mm. 13 13 Upper wing surface with brown or black bar at base of secondaries (Fig. 23b). 14 13' Upper wing surface without brown or black bar at base of secondaries. BONAPARTE'S GULL, adult 53 KEY TO GULLS (cont.) Figure 23. Color patterning in the extended wings of (a) immature Black-legged Kittiwake and ("b) immature Bonaparte's Gull, and (c) immature Sabine's Gull, 14 Wing bar at base of secondaries black; tail distinctly wedge- shaped (central tail feathers longer than outer tail feathers). ROSS' GULL, first year 14' Wing bar at base of secondaries brown; tail not as above. BONAPARTE'S GULL, first year 15 Tail white with black band; top of head, neck and back uniformly brown; wings with brownish cast. LAUGHING GULL, first year 15' Tail white or nearly so; top of head, neck and back not uniformly brown. '^ 16 Head white with dusky spotting on nape usually extending down neck; wings with brownish cast. LAUGHING GULL, second year 16' Head hooded with black (summer) OR white with dusky spotting on upper nape (winter); wings without brownish cast. LAUGHING GULL, adult 54 KEY TO GULLS (Cont.) 17 Upper surface of wing with brown bar at base of secondaries (as in Fig. 23a); tail white, banded with black; head with a dark spot behind eye. BLACK-HEADED GULL, first year 17' Upper surface of wing without brown bar at base of secondaries; tail white; head black (summer) OR white with dark spot behind eye (winter). BLACK-HEADED GULL, adult 18 Outer primary coverts with black; back of neck spotted with black; in outer three primaries, leading edge as dark as tips. RED-LEGGED KITTIWAKE, first year 18' Outer primary coverts pure gray; back of neck white; in outer three primaries, only outermost as in 18, the other two are dark only at tips. RED-LEGGED KITTIWAKE, adult 19 Upper surface of wing with dark bar at base of secondaries (Fig. 23a); hind neck (nape) with blackish collar; tail white with black band; in outer three primaries, leading edge as dark as tips. BLACK-LEGGED KITTIWAKE, first year 19' Upper surface of wing gray without dark bar at base of secondaries; tail pure white; head white (summer) OR smudged with gray on hind neck (winter); in outer three primaries, only outermost as in 19, the other two are dark only at tips. BLACK-LEGGED KITTIWAKE, adult 20 Upper surface of wing with bold black bar at base of secondaries (as in Fig. 23a); back feathers dull black with broad white edgings; tail white with black band. LITTLE GULL, first year 20' Upper surface of wing and back uniform gray; tail white; head black (summer) OR white with gray smudge on hind neck and black spot behind eye (winter). LITTLE GULL, adult 21 Top of head, back and adjacent wing surfaces brownish-gray; tail white, banded with black. SABINE'S GULL, first year 21' Back and adjacent wing surfaces uniform gray; head black (summer) OR white with black spot behind eye (winter); tail white. SABINE'S GULL, adult 22 Secondaries and tertials gray with conspicuous white tips. FRANKLIN'S GULL, adult 55 KEY TO GULLS (Cont.) 22' Secondaries and tertials not gray with conspicuous white tips. 12 NOTE: Albino gulls of many species may key out to this step. Iden- tification of albino gulls usually requires comparison with known material by someone \/ery knowledgeable about gulls. Interesting specimens should be saved. Pure white birds or birds with ex- cessively worn and bleached feathers should be treated cautiously. 23 Wing length <360 mm; plumage all white; legs black; bill black with yellow tip. IVORY GULL, adult 23' Wing >425 mm; plumage usually with some buffy or gray. 61 24 Tail nearly all white (dark smudge may be present on a few tail feathers). 25 24' Tail not all white. 34 25 Head entirely white OR head and neck with dusky streaks; wing length usually >330 mm. 26 25' Head black, brown or gray OR head white with a blackish smudging on top extending down back of the neck; wing usually <330 mm. 15 26 Wing tips without black. ' GLAUCOUS-WINGED GULL, adult NOTE: Glaucous-winged Gulls interbreed with Western and Herring Gulls. The progeny often have very dark wing tips and may be confused with Western, Herring or Thayer's Gulls. Beach walkers in northern California, Oregon, Washington and British Col- umbia should be cautious of this problem. 26' Wing-tips with black (sometimes dark gray). 27 27 Outer three primaries not distinctly darker than inner primaries and secondaries; mantle dark, slate gray. 27' Outer three primaries distinctly darker than inner primaries and secondaries; mantle pearly to silver-gray. 30 28 Wing length >420 mm; two white spots (mirrors; see Fig. 16) or much terminal white in outer primaries; Bering Sea and Aleutians. SLATY-BACKED GULL, adult 56 KEY TO GULLS (Cont.) 28' Wing <420 mm; one white spot in outer primaries; Mexico to British Columbia. 29 29 Legs and feet bright yellow; Gulf of California and Salton Sea. YELLOW-FOOTED WESTERN GULL, adult 29' Legs and feet pink; Pacific Coast of Baja California north to British Columbia. WESTERN GULL, adult NOTE: These two forms are usually indistinguishable without the leg color. 30 Bill plain yellow-green, sometimes with dusky subterminal mottling or dusky tip; outermost two primaries with large white spots near the tips; culmen usually <37 mm; eye dark. MEW GULL, adult 30' Lower mandible with red and/or black at gonydeal angle; culmen usually >37 mm. 31 31 Bill banded (both mandibles) with black (as in Fig. 15), no red at gonydeal angle; gray of back and wings yery pale; eye and legs yellow. RING-BILLED GULL, adult 31' Lower mandible with red spot at angle. 32 32 Bill almost always with both black band and red at gonys or rarely with only red spot; eye dark brown; legs bluish to greenish; gray of back and wings relatively dark. CALIFORNIA GULL, adult 32' Bill without black band; legs pink. 33 33 Upper surface of wing tips dark gray to black, under surface light gray; eye brownish often with dark flecks. THAYER'S GULL, adult 33' Upper surface of wing tip black, under surface dark gray to black; eye yellow without flecks. HERRING GULL, adult 34 Underparts uniform dark gray or brown; no mottling. 59 34' Underparts mostly white OR mottled with brown or gray. 35 57 KEY TO GULLS (Cont.) 35 Tail with distinct dark subterminal band (see Fig. 15). 36 35' Tail not distinctly banded (usually with areas of dark and light mottling). 39 36 Band along wing at base of secondaries (greater secondary coverts) gray; culmen usually >37 mm. 37 36' Band along wing at base of secondaries (greater secondary coverts) brownish; culmen usually <37 mm. 38 37 Upper wing (lesser and middle) coverts brownish, tipped with white; primaries more or less pointed. RING-BILLED GULL, first year 37' Upper wing (lesser and middle) coverts gray; primaries more or less rounded. RING-BILLED GULL, second year 38 Secondaries browner than mantle; primaries more or less pointed. MEW GULL, first year 38' Secondaries gray like mantle; primaries more or less rounded. MEW GULL, second year 39 Tail with gray or buffy, no dark brown. 40 39' Tail with dark brown or black, sometimes largely white or largely brown. 45 40 Back between wings brown or gray-brown, much mottled; underparts clouded and flecked with gray-brown; bill black. 41 40' Back between wings primarily "gull -gray"; underparts more or less white; tail with much white basally; bill with some paleness basally. 42 41 Bill rather large and heavy, gonys prominent (Plate 26a-4); primaries gray on both upper and under surfaces. GLAUCOUS-WINGED GULL, first year 41' Bill more slender, gonys slight (Plate 26b-2); primaries usually dark gray-brown to black on upper surface and light gray on under surface with distinct paler borders at the tips. THAYER'S GULL, first year 58 KEY TO GULLS (Cont.) 42 Back between wings "gull-gray"; wing coverts brown; bill pale at base but dark towards tip, lacking red or orange at gonydeal angle. 43 42' Back between wings and wing coverts mostly "gull -gray"; bill yellowish, usually with a trace of orange at angle and dusky towards tip; underparts nearly all white. 44 43 Bill rather large and heavy (Plate 26a-4); primaries gray on both upper and under surfaces. GLAUCOUS-WINGED GULL, second year 43' Bill more slender (less pronounced gonydeal angle; Plate 26b-2); primaries usually dark gray-brown to black on upper surface with distinct paler borders, pale gray on under surface. THAYER'S GULL, second year 44 Bill rather large and heavy (Plate 26a-4) ; primaries gray on both upper and under surfaces. GLAUCOUS-WINGED GULL, third year 44' Bill more slender (less pronounced gonydeal angle; Plate 26b-2); primaries usually dark gray-brown to black on upper surface, pale gray on under surface. THAYER'S GULL, third year 45 Back between wings light to dark brown, mottled. 46 45' Back between wings light to dark "gull -gray", not mottled. 51 46 Bill all black (maybe some pale areas basal ly in late spring). 47 46' Bill with pale area basal ly. 50 47 Body plumage very dark brown; outer primaries not distinctly darker than inner primaries and secondaries; tail nearly solid dark brown; bill large with a prominent gonydeal angle. 48 47' Plumage generally paler; outer primaries distinctly darker than inner primaries and secondaries. 49 48 Wing length >410 mm; body barred or finely speckled, the dusky areas usually exceeding the white; unusual north of British Columbia. WESTERN GULL, first year 59 KEY TO GULLS (Cont.) 48' Wing <410 mm; body coarsely spotted, the white areas usually ex- ceeding the dark; not to be expected outside of the Bering Sea and Aleutian area in the eastern Pacific Ocean. SLATY-BACKED GULL, first year 49 Bill rather slender (less pronounced gonydeal angle; Plate 26b-2); primaries dark brown to black on upper surface, usually with distinct pale edgings, pale gray to brown on under surface. THAYER'S GULL, first year 49' Bill large with prominent gonydeal angle (Plate 26a); primaries yery dark brown on both upper and under surfaces. YELLOW-FOOTED WESTERN GULL, first year 50 Bill pink in basal half with clearly defined blackish tip. CALIFORNIA GULL, first year 50' Bill with pink base gradually fusing into blackish tip. HERRING GULL, first year 51 Back between wings "gull-gray"; wing coverts and secondaries brown; tail usually largely dark brown. 52 51' Back between wings, wing coverts and secondaries more or less uniform "gull -gray", sometimes with a brownish cast; tail usually with some white at the base and at yery tip of the feathers. 55 52 Back between wings dark gray; outer three primaries not distinctly darker than inner primaries and secondaries. WESTERN GULL, second year 52' Back between wings light gray; outer three primaries distinctly darker than inner primaries. 53 53 Legs dull bluish; eye dark brown; primaries "^ery dark brown without conspicuous edgings. CALIFORNIA GULL, second year 53' Legs pink; eye pale brown or yellow. 54 54 Primaries dark brown on both upper and under surfaces, without conspicuous pale edgings; eye pale yellow. HERRING GULL, second year 60 KEY TO GULLS (Cont.) 54' Primaries dark brown with conspicuous pale edgings; underside of primaries pale brown; eye brown. THAYER'S GULL, second year 55 Tail nearly all dark. YELLOW-FOOTED WESTERN GULL, second year 55' Tail mostly white, with dark spots on all or som.e tail feathers. 56 56 Outer three primaries not distinctly darker than inner primaries and secondaries; bill with prominent gonydeal angle (Plate 26a-2). WESTERN GULL, third year 56' Outer three primaries distinctly darker than inner primaries and secondaries; gonydeal angle not as prominent (Plate 26b). 57 57 Legs bluish-gray to greenish; iris dark brown. CALIFORNIA GULL, third year 57' Legs bright pink; iris yellow or brownish. 58 58 Iris clear yellow; under surface of primary tips black. HERRING GULL, third year 58' Iris brown, often flecked with dark brown; under surface of primary tips pale gray. THAYER'S GULL, third year 59 Bill red with black tip; mantle and adjacent wing surface dark slate-gray; tail black, tipped with white. HEERMANN'S GULL, adult 59' Bill pale pink at base with black tip; mantle and adjacent wing surfaces dark gray washed with brown OR these areas dark brown; tail dark blackish-brown, lacking white tip. 60 60 Mantle is pure dark gray; adjacent wing surfaces with some dark brown; head and underparts medium gray. HEERMANN'S GULL, second year 60' Plumage wholly dark chocolate brown, somewhat paler on upper wing surface. HEERMANN'S GULL, first year 61 KEY TO GULLS (Cont.) 61 Plumage marbled with pinkish-buff feather edgings; bill pink basal ly, with clearly defined black tip; primaries more or less pointed, tail feathers rounded at tips. GLAUCOUS GULL, first year 61' Plumage paler, nearly all white, sometimes with pale gray on back; primaries more rounded, tail feathers more squarish at tips. 62 62 Pale gray feathers present on back. 63 62' No pale gray on back, some individuals may approach pure white. GLAUCOUS GULL, second year 63 Tail pure white; bill yellow with red spot at gonydeal angle. GLAUCOUS GULL, adult 63' Tail often freckled with dusky or smudged terminally; bill usually with a dusky band near tip. GLAUCOUS GULL, third year 62 KEY TO TERNS AND SKIMMERS 1 Basic color of upper surface of wings, back and hind neck dark brown, black or dark charcoal -gray (tips of secondaries may be white) - close in color to back of head, but sometimes with buffy feather edgings. 2 r Basic color of upper wings, back and hind neck light gray, or pearly to silver-gray; sometimes neck almost white, otherwise much lighter than cap or back of head; sometimes with buffy feather edgings. 7 2 Wing length <225 mm; webbing extending only half way to end of toes (Plate 37-2). 3 2' Wing >270 mm; toes fully webbed. 4 3 Brown edgings on wing coverts; belly white. BLACK TERN, immature 3' Wing coverts entirely charcoal-gray; belly black or white. BLACK TERN, adult 4 Wing length 270-300 mm; upper surface of wing entirely black or dark brown except that coverts may have buffy tips; tarsus 20-25 mm. 5 4' Wing 338-412 mm; secondaries broadly tipped with white; tarsus 28-37 mm. 6 5 Upper surface of wings entirely jet black; belly white. SOOTY TERN, adult 5' Wing coverts with buffy tips; belly charcoal-gray. SOOTY TERN, immature 6 Upper wing jet black except for white in secondaries (sometimes on inner primaries). BLACK SKIMMER, adult 6' Upper wing coverts with light tips, otherwise upper wing dark brown. BLACK SKIMMER, immature 7 Wing length >295 mm; tarsus >27 mm. 8 7' Wing < 290 mm; tarsus < 24 mm. 15 63 KEY TO TERNS AND SKIMMERS (Cont. Both webs of outer 4 primaries entirely dark; wing length 400-423 mm; tarsus 40-46 mm. 9 Outer web of outer 4 primaries dark, inner web white except for broad dark stripe next to shaft (Fig. 24a); wing <395 mm; tarsus <36 mm. 10 9 Wing coverts each with dark brown V bordered by white. CASPIAN TERN, immature 9' Wing coverts pearly gray (primaries darker) CASPIAN TERN, adult 10 Wing length 357-393 mm. 10' Wing <330 mm. 11 12 11 Some wing coverts with dark outer portions, 11 ' Wing coverts pearly gray. ROYAL TERN, immature ROYAL TERN, adult 12 Dark coloration in webbing of outer primaries very light, in primaries 7-9 white of inner web grading gradually to dark area near shaft (Fig. 24b). 13 12' Dark coloration in primary webbing very dark, forming a dark stripe near shaft yery distinct from outer portion of inner web (Fig. 24a). 14 13 Brown or buffy edgings to feathers of back and wing coverts. GULL-BILLED TERN, immature 13' No buffy edgings on any feathers. GULL-BILLED TERN, adult 14 Buffy edgings to feathers on back and wing coverts, 14' No buffy edgings on any feathers. ELEGANT TERN, immature ELEGANT TERN, adult 15 Very small; wing length <180 mm. 15' Wing 230-290 mm. 16 17 64 KEY TO TERNS AND SKIMMERS (Cont.) 16 Tips of upper wing coverts buffy, each with a dark center within buffy area. LEAST TERN, immature 16' Coverts pearly gray. LEAST TERN, adult 17 Dark stripe along shaft on inner web (contrasting with white along outer edge) distinct only in primaries 10 and 9; inner primaries largely dusky throughout. 18 17' Dark stripe referred to in 17 very distinct on at least the outer 6 primaries. 19 18 Upper wing coverts with buffy edges. FORSTER'S TERN, immature 18' Upper wing coverts entirely pearly gray. FORSTER'S TERN, adult 19 Inner web of primary 10 colored like 9, having both a dark stripe along shaft and a dark border along outer edge from tip inward about 1/3 the way toward wing bone (Fig. 24c). 20 19' Inner web of primary 10 without dark border referred to in 19, OR border extending for only a few mm (Fig. 24d). 21 20 Greater upper wing coverts broadly tipped with white. ALEUTIAN TERN, immature 20' Greater wing coverts dark. ALEUTIAN TERN, adult 21 Viewed from above, outer web of primary 10 usually about as dark (almost black) as stripe along shaft on inner web (as in Fig. 24a); primary 10 completely dark along outer 20-33 mm of tip; tarsus 17-21 mm, longer than middle toe without claw. 22 21' Outer web of primary 10 usually decidedly darker than stripe on inner web (as in Fig. 24b); primary 10 dark along outer 15-25 mm; tarsus 13-16 mm, shorter than middle toe without claw. 23 22 Feathers of back and wing coverts with buffy tips. COMMON TERN, immature 22' No buffy edges on any feathers. COMMON TERN, adult 65 KEY TO TERNS AND SKIMMERS (cont.) 23 Feathers of back and wing coverts with buffy tips. 23' No buffy edges on any feathers. ARCTIC TERN, immature ARCTIC TERN, adult Figijre 2U. Color patterns of outer primaries in terns, a. d. 66 KEY TO ALCIDS 1 Large: exposed culmen >25 mm; wing length >162 mm; tarsus usually >30 mm. 2 1' Small: exposed culmen <25 mm; wing <160 mm; tarsus usually <30 mm. 16 2 Underwing linings mostly white. 3 2' Underwing linings mostly dark. 8 3 A great deal of white in wing coverts of upper surface of wing; secondaries dark; feet may be pink to intense red. 4 3' Upper surface of wing dark except that secondaries are broadly tipped with white; feet black or brown. (MURRE) 5 4 Scapulars and back feathers checkered with black and white; upper wing coverts mottled black and white. BLACK GUILLEMOT, immature 4' Scapulars and back black; upper wing coverts extensively white. BLACK GUILLEMOT, adult 5 Throat and entire head dark. 6 5' Throat and lower cheeks white. 7 6 Cutting edge of bill at base white or yellow (giving appearance of a light mustache); depth of bill at gonydeal angle >l/3 the exposed culmen. THICK-BILLED MURRE, breeding plumage 6' Bill entirely dark; depth of bill at gonydeal angle 105 mm; tips of secondaries dark. 19 18 Dark collar completely encircling upper breast, separating throat from belly (Fig. 12a). LEAST AUKLET, breeding plumage 18' Collar around breast incomplete (Fig. 12b). LEAST AUKLET, winter adult or immature 19 Bill yellow to ivory (upper edge dark); culmen 12-16 mm; throat almost always entirely or partly dark (Fig. 26); wing length 122-141 mm. 20 19' Bill entirely dark, culmen 15-22 mm; throat entirely white (Fig. 26); wing 111-128 mm. XANTUS' MURRELET 20 Throat dark all the way to breast; long, thin white feathers prev- alent above and behind eyes (an eyebrow) and on shoulders. ANCIENT MURRELET, breeding plumage 20' Throat mostly white except near base of bill (Fig. 26); long white feathers above eyes and on shoulder very sparse. ANCIENT MURRELET, winter adult or immature 21 Underwing linings mottled, white and gray. 22 21' Underwing linings entirely dark. 24 22 Feathers of throat and around anus gray. CASEIN'S AUKLET 22' Feathers of throat and around anus white (under down is gray). 23 23 Tail and flight feathers absent or tiny (Fig. 25); length of middle toe >32 mm. THICK-BILLED or COMMON MURRE, juvenile 71 KEY TO ALCIDS (Cont.) 23' Tail and flight feathers present (as in Fig. 26); length of middle toe <26 mm. CRAVERI'S MURRELET 24 Wing length <90 mm; primaries absent or tiny (Fig. 25). THICK-BILLED OR COMMON MURRE, juvenile 24' Wing >95 mm; primaries present. 25 25 Wing length 97-105 mm. 26 25' Wing >115 mm. 11 26 Bill red with white tip; long curved feathers form crest on fore- head; white facial plumes m^t^j prominent. WHISKERED AUKLET, adult 26' Bill yellowish at base, dark at tip; no crest; white facial plumes present but not prominent. WHISKERED AUKLET, immature 27 Secondaries and tail feathers broadly (2-3 mm wide) tipped with white. 28 27' Wing and tail feathers dark except some coverts on upper surface of wing may be m^t)j narrowly edged with white. 29 28 Belly and breast white except many feathers tipped with dark brown, giving undersurfaces a speckled appearance; remainder of head and body plumage brown, streaked with white and buffy. KITTLITZ'S MURRELET, breeding plumage 28' Sides of head and all undersurfaces completely white except for a dark incomplete breast collar (Fig. 12b) and a ^^vy occasional feather with a dark tip; scapular and shoulder feathers white. KITTLITZ'S MURRELET, winter or immature 29 Scapulars cinnamon OR white. 30 29' Scapulars gray, same color as remainder of wing. 31 30 Scapulars cinnamon; undersurfaces of body with white feathers tipped with brown giving spotted appearance; upper surfaces dark. MARBLED MURRELET, breeding plumage 72 KEY TO ALCIDS (Cont.) 30' Scapulars white; undersurfaces of body largely white except for occasional dark tipped feathers; lower face white. MARBLED MURRELET, winter and immature 31 Bird entirely gray except often some elongated white feathers on face. 32 31' White on belly and breast; remainder of plumage gray except often some elongated white feathers on face. 33 32 No elongated, curved feathers on forehead forming a crest; no white plumes on face. CRESTED AUKLET, immature 32' Elongated feathers forming a crest on forehead; white plumes ex- tending backward from face. CRESTED AUKLET, adult 33 Throat dark; bill red; elongated white plumes extending backward from behind eye. PARAKEET AUKLET, breeding plumage 33' Throat light; bill dark; no elongated white plumes on face. PARAKEET AUKLET, winter adult and immature Plate 1 1. Common Loon 2. Yellow-billed Loon 0 74 o 0 Plate 2 1. Pied-billed Grebe 2. Red-throated Loon 3. Arctic Loon h. Red-necked Grebe 5. Western Grebe cf 6. Western Grebe ? 7. Eared Grebe 8. Horned Grebe 8, 0 Plate 3 1. Short-tailed Albatross 2. Black- footed Albatross <^ 3. Black- footed Albatross ? 75 Plate h 1. Frigatebird 2. TropiclDird 3. Laysan Albatross ? U. Laysan Albatross ^ Plate 5 1. Northern Fulmar Cook's Petrel Mottled Petrel Cape Petrel (or Pigeon) Fork- tailed Storm-Petrel Short- tailed Shearwater Northern Fulmar Black- footed Albatross^ S Plate 6 Light-bellied: 1. Pink- footed Shearwater 2. Buller's (New Zealand) Shearwater 3. Common (Manx) Shearwater Dark-bellied: h. Sooty Shearwater 5. Short-tailed Shearwater 6. Wedge-tailed Shearwater 7. Flesh- footed Shearwater Plate 7 1. Black Storm Petrel Least Storm Petrel Leach's Storm Petrel Ashy Storm Petrel Fork-tailed Storm Petrel 6. Harcoiirt's Stoinoti Petrel 7. Galapagos Storm Petrel 8. Wilson's Storm Petrel o . 7 80 > Plate 25 1. Fulmar (for comparison) 2. South Polar Skua 3. Pomarine Jaeger h. Parasitic Jaeger 5. Long-tailed Jaeger > > V Plate 26a 1. Western Gull cf 2. Western Gull ? 3. Glaucous-winged Gull cf k. Glaucous-winged Gull ? 5. Glaucous Gull cf 6. Glaucous Gull ? Plate 26b 1. Herring Gull ^ 2 . Thayer ' s Gull ^ 3. Herring Gull ? U. California Gull ^r 5. California Gull ? 6. Heermann's Gull ? 7. Heermann's Gull cf c Plate 27 1. Ring-billed Gull cf,; 2. Ring-billed Gull ? 3. Red-legged Kittiwake h. Black-legged Kittiwake Black-legged Kittiwake Mew Gull cT Mew Gull ? . _ ■ , 8. Ivory Gull ? ' • - 9. Ivory Gull d- 5. 6. 7. 0 ^ Plate 28 1. Black-headed Gull 2. Laughing Gull 3. Franklin's Gull h. Sabine's Gull 5. Ross' Gull 6. Little Gull 7. Bonaparte's Gull 106