Part 2

B. PICARIÆ.[10] Hallux inconsiderable, weak or wanting, not always incumbent, not separately movable by distinction of a special muscle, its claw not longer than that of the middle toe unless of exceptional shape (e. g. _Centropus_). Second or fourth toe frequently versatile; third and fourth frequently with decreased number of joints. Wing-coverts for the most part larger and in more numerous series than in _Passeres_, the greater series reaching beyond the middle of the secondary quills (except in many _Pici_ and some others). Rectrices commonly ten (eight to twelve). Primaries always ten, the first only exceptionally short (as in _Pici_). Musical apparatus wanting, or consisting of a muscular mass, or of not more than three pairs of syringeal muscles. Palate desmognathous or ægithognathous. Sternum of non-passerine character, its posterior border entire or doubly notched or fenestrate. Carotid single or double. Nature completely altricial, but young sometimes hatched with down[11] (e. g. _Caprimulgidæ_).

a. Cypseli. Palate ægithognathous. Wings lengthened in their terminal portions, abbreviated basally, with the first primary not reduced. Tail of ten rectrices. Bill fissirostral or tenuirostral. Feet never zygodactyle nor syndactyle, small, weak, scarcely fitted for locomotion; hallux often elevated or lateral or reversed; front toes usually webbed at base, or with abnormal ratio of phalanges in length and number, or both. Sternum deep-keeled, usually entire or else doubly notched or perforate. Syringeal muscles not more than one pair.

b. Cuculi. Palate desmognathous. Wings not peculiar in brevity of proximal or length of distal portions, and with first primary not reduced. Tail of eight to twelve rectrices. Bill of indeterminate form, never cered; tongue not extensile. Feet variously modified by versatility or reversion of either first, second, or fourth toes, or by cohesion for a great distance of third and fourth, or by absence or rudimentary condition of first or second; often highly scansorial, rarely ambulatorial. Syringeal muscles two pairs at most.

c. Pici. Palate “exhibiting a simplification and degradation of the ægithognathous structure” (Huxley); wings bearing out this passerine affinity in the common reduction of the first primary and the restriction of the greater coverts. Tail of ten perfect rectrices and usually a supplementary pair. Rostrum hard, straight, narrow, subequal to head, with commonly extensile and vermiform but not furcate tongue. Feet highly scansorial. Fourth toe permanently reversed; basal phalanges of toes abbreviated. Sternum doubly notched. Salivary glands highly developed. Hyoidean apparatus peculiar.

C. PSITTACI. Bill enormously thick, short, high, much arched from the base, the upper mandible strongly hooked at the end, cered at base, and freely movable by complete articulation with the forehead, the under mandible with short, broad, truncate symphysis. Feet permanently zygodactyle by reversion of the fourth toe, which articulates by a double facet. Tarsi reticulate. Syrinx peculiarly constructed of three pairs of intrinsic muscles. Tongue short, thick, fleshy. Sternum entire or fenestrate. Clavicles weak, defective, or wanting. Orbit more or less completed by approach or union of postorbital process and lachrymal. Altricial; psilopædic.

D. RAPTORES. Bill usually powerful, adapted for tearing flesh, strongly decurved and hooked at the end, furnished with a cere in which the nostrils open. Feet strongly flexible, with large, sharp, much curved claws gradually narrowed from base to tip, convex on the sides, that of the second toe larger than that of the fourth toe, and the hinder not smaller than the second one. Feet never permanently zygodactyle, though fourth toe often versatile; anterior toes commonly with one basal web; hallux considerable and completely incumbent (except _Cathartidæ_). Legs feathered to the suffrago or beyond. Rectrices twelve (with rare exceptions); primaries sinuate or emarginate (with rare exceptions). Sternum singly or doubly notched or fenestrate. Palate desmognathous. Carotids double. Syrinx wanting or developed with only one pair of muscles. Altricial; the young being weak and helpless, yet ptilopædic, being downy at birth.

E. COLUMBÆ. Bill straight, compressed, horny at the vaulted tip, which is separated by a constriction from the soft membranous basal portion. Nostrils beneath a soft, tumid valve. Tomia of the mandibles mutually apposed. Frontal feathers sweeping in strongly convex outline across base of upper mandible. Legs feathered to the tarsus or beyond. Hallux incumbent (with few exceptions), and front toes rarely webbed at base. Tarsus with small scutella in front, or oftener reticulate, the envelope rather membranous than corneous. Head very small. Plumage without after-shafts. One pair of syringeal muscles. Sternum doubly notched, or notched and fenestrate on each side. Carotids double. Palate schizognathous. Monogamous, and highly altricial and psilopædic.

F. GALLINÆ. Bill generally short, stout, convex, with an obtuse vaulted tip, corneous except in the nasal fossa, and without constriction in its continuity. Nostrils scaled or feathered. Tomia of upper mandible overlapping. Frontal feathers forming re-entrant outline at the base of upper mandible. Legs usually feathered to the tarsus or beyond. Hallux elevated, with few exceptions (e. g. _Cracidæ_ and _Megapodidæ_), smaller than the anterior toes, occasionally wanting (as in the Hemipods). Tarsus, when not feathered, generally broadly scutellate. Front toes commonly webbed at base. Claws blunt, little curved. Wings strong, short, and concavo-convex. Rectrices commonly more than twelve. Head small. Plumage usually after-shafted. Carotids double (except _Turnicidæ_ and _Megapodidæ_). No intrinsic syringeal muscles. Sternum very deeply, generally doubly, notched. Palate schizognathous. Chiefly polygamous. Præcocial and ptilopædic.

G. LIMICOLÆ. Tibiæ bare of feathers for a variable (sometimes very slight) distance above the suffrago. Legs commonly lengthened, sometimes excessively so, and neck usually produced in corresponding ratio. Tarsi scutellate or reticulate. Toes never coherent at base; cleft, or united for a short distance by one or two small movable basal webs (palmate only in _Recurvirostra_, lobate only in _Phalaropodidæ_). Hallux always reduced, obviously elevated and free, or wanting; giving a foot of cursorial character. Wings, with few exceptions, lengthened, pointed, and flat; the inner primaries and outer secondaries very short, forming a strong re-entrance on the posterior border of the wing. Tail shorter than the wing, of simple form, and of few feathers, except in certain Snipes. Head globose, sloping rapidly down to the contracted base of the bill, completely feathered (except _Philomachus_ ♂). Gape of bill short and constricted; tip usually obtuse; bill weak and flexible. Rostrum commonly lengthened, and more or less terete and slender; membranous wholly or in great part, without hard cutting edges. Nostrils narrow, placed low down, entirely surrounded with soft skin; nasal fossæ extensive. Palate schizognathous. Sternum usually doubly, sometimes singly, notched. Carotids double. Pterylosis of a particular pattern. Nature præcocial and ptilopædic. Comprising the “Plover-Snipe” group; species of medium and small size, with never extremely compressed or depressed body; more or less aquatic, living on plains and in open places, usually near water, nesting on the ground, where the young run freely at birth.

H. HERODIONES. Tibiæ naked below. Legs and neck much lengthened in corresponding ratio. Toes long, slender, never coherent at base, where cleft, or with movable basal webbing. Hallux (as compared with that of the preceding and following group) lengthened, free, and either perfectly incumbent or but little elevated, with a large claw, giving a foot of insessorial character. Wings commonly obtuse, but broad and ample, without marked re-entrance on posterior border, the intermediate remiges not being much abbreviated. Tail short and few-feathered. Head narrow, conico-elongated, gradually contracting to the large, stout base of the bill; the loral and orbital region, or the whole head, naked. Gape of the bill deeply fissured; tip usually acute; tomia hard and cutting. Bill conico-elongate, always longer than the head, stout and firm. Nostrils small, placed high up, with entirely bony and horny, or only slightly membranous, surroundings. Pterylosis nearly peculiar in the presence, almost throughout the group, of powder-down tracts, rarely found elsewhere; pterylæ very narrow. Palate desmognathous. Carotids double. Altricial. Comprising the Herons, Storks, Ibises, etc. (not Cranes). Species usually of large stature, with compressed body and very long S-bent neck; perching and nesting usually in trees, bushes, or other high places near water; young hatching weak, scarcely feathered, and reared in the nest.

I. ALECTORIDES.[12] Tibiæ naked below. Neck, legs, and feet much as in the last group, but hallux reduced and obviously elevated, with small claw, the resulting foot cursorial (natatorial and lobate in _Fulica_). Wings and tail commonly as in _Herodiones_. Head less narrowed and conic than in the last, fully feathered or with extensive baldness (not with definite nakedness of loral and orbital regions). Bill of various shape, usually lengthened and obtuse, never extensively membranous. Rictus moderate. Nostrils lower than in _Herodiones_. Pterylosis not peculiar. Palate schizognathous. Carotids double. Nature præcocial and ptilopædic. Comprising the Cranes and Rails and their allies; the former agreeing with the _Herodiones_ superficially in stature, etc., but highly diverse in the schizognathous palate, præcocial nature, etc.

J. LAMELLIROSTRES. Feet palmate; tibiæ feathered (except _Phœnicopterus_). Legs near centre of equilibrium of the body, its axis horizontal in walking; not lengthened except in _Phœnicopterus_. Knee-joint rarely exserted beyond general skin of the body. Wings moderate, reaching when folded to, but not beyond, the usually short and rounded (exceptionally long and cuneate) tail. Feet tetradactyle (except sometimes in _Phœnicopterus_); hallux reduced, elevated and free, often independently lobate. Bill lamellate, i. e., furnished along each commissural edge with a regular series of mutually adapted laminæ or tooth-like processes, with which correspond certain laciniate processes of the fleshy tongue, which ends in a horny tip. Bill large, thick, high at base, depressed towards the end, membranous to the broad obtuse tip, which is occupied by a horny “nail” of various shape. Nostrils patent, never tubular; nasal fossæ slight. No gular pouch. Plumage dense, to resist water. Eyes very small. Head high, compressed, with lengthened, sloping frontal region. Palate desmognathous. Reproduction præcocial; young ptilopædic. Eggs numerous. Carotids double. Sternum single-notched. Comprising Flamingoes and all the Anserine birds.

K. STEGANOPODES. Feet totipalmate; hallux lengthened, nearly incumbent, semilateral, completely united with the second toe by a full web. Tibiæ feathered; position of legs with reference to axis of body variable, but generally far posterior; knee-joint not free. Wings and tail variable. Bill of very variable shape, never lamellate, wholly corneous; its tomia often serrate; external nares very small or finally abortive. A prominent naked gular pouch. Tarsi reticulate. Sternum entire or nearly so; furculum confluent with its keel. Carotids double. Palate highly desmognathous. Reproduction altricial; young psilopædic or ptilopædic. Eggs three or fewer.

L. LONGIPENNES. (To most of the characters of the group here given the genus _Halodroma_ is a signal exception, though unquestionably belonging here.) Feet palmate. Tibiæ feathered. Legs at or near centre of equilibrium, affording horizontal position of axis of body in walking. Knee scarcely buried in common integument; tibia sometimes with a long apophysis. Hallux elevated, free, functionless; very small, rudimentary, or wanting. Rostrum of variable shape, usually compressed and straight to the hooked end, sometimes entirely straight and acute, commonly lengthened, always corneous, without serration or true lamellæ. Nostrils of various forms, tubular or simply fissured, never abortive. No gular pouch. Wings very long and pointed, surpassing the base and often the end of the large, well-formed, few-feathered tail. Carotids double. Palate schizognathous. Reproduction altricial; young ptilopædic. Eggs three or fewer. Habit highly volucral.

M. PYGOPODES. Feet palmate or lobate. Tibiæ feathered, often with a long apophysis, always buried in common integument nearly to the heel-joint, necessitating a more or less erect posture of the body on land, where progression is difficult. Hallux small, elevated or wanting; feet lobate or palmate. Bill of indeterminate shape, wholly corneous, never lamellate or serrate, nor with gular pouch. Nostrils not abortive. Wings very short, reaching scarcely or not to the base, never to the tip, of the short, sometimes rudimentary, tail. Palate schizognathous. Carotid usually double, sometimes single (in _Podiceps_ and _Mergulus_). Nature altricial or præcocial; young ptilopædic. Highly natatorial.

N. SPHENISCI. With general characters of the last group, but distinguished by unique ptilosis and wing-structure, etc. Plumage without apteria, of singularly modified scale-like feathers on most parts; no developed remiges. Wings unfit for flight, insusceptible of perfect flexion or extension, very short, with peculiarly flattened bones and stable articulations. Skeleton non-pneumatic. Many bones, terete in ordinary birds, here flattened. Metatarsal bone flattened transversely, doubly fenestrate. Hallux elevated, lateral, minute, free. No free pollex. Two anconal sesamoids; patella from double centres; tibia without apophysis; a free tarsal ossicle. Sternum with long lateral apophyses. Pelvic connections unstable. Carotids double. Comprising only the Penguins. Confined to the Southern Hemisphere.

Having thus presented and defined an arrangement of the higher groups into which recent Carinate birds are susceptible of division, I next proceed to the consideration of the North American Families of birds which the authors of the present work have provisionally adopted as suitable to the end they had in view. Professor Baird urges the caution that the scheme is intended merely for the convenient determination of the North American species, aware that in many instances diagnoses or antitheses of entire pertinence in such application would fail or be negatived by consideration of the exotic forms. The arrangement of the families here adopted is essentially that presented in 1858 in Professor Baird’s “Birds of North America,” modified somewhat in accordance with more recent views of Professor Sundevall and others. But before proceeding to the analysis of the families, I will introduce an artificial clew to the preceding higher groups as adopted, so far as they are represented by North American species.

ARTIFICIAL KEY TO THE FOREGOING HIGHER GROUPS,

_By means of which any North American bird may be readily referred to that group to which it is held to belong._

I. Toes 3; 2 in front, 1 behind (_Pici_) PICARIÆ.

II. Toes 3; all in front. Toes cleft or semipalmate LIMICOLÆ. Toes palmate. Nostrils tubular LONGIPENNES. Nostrils not tubular PYGOPODES.

III. Toes 4; 2 in front, 2 behind. Bill cered and hooked ITTACI. Bill neither cered nor hooked. (_Cuculi_ or _Pici_) PICARIÆ.

IV. Toes 4; 3 in front, 1 behind. 1. Toes syndactyle (_Cuculi_) PICARIÆ. 2. Toes totipalmate (all four full-webbed) STEGANOPODES. 3. Toes palmate. Bill curved up LIMICOLÆ. Bill not curved up; lamellate LAMELLIROSTRES. not lamellate; hallux lobate PYGOPODES. hallux not lobate LONGIPENNES. 4. Toes lobate. Tail rudimentary PYGOPODES. Tail perfect. A horny frontal shield ALECTORIDES. No horny frontal shield LIMICOLÆ. 5. Toes semipalmate; joined by evident movable basal web (A). 6. Toes cleft to the base, or there immovably coherent (B).

A. Hind toe elevated above the level of the rest. Tibiæ naked below. Nostrils perforate ALECTORIDES. Nostrils imperforate. Tarsi reticulate. Head bald HERODIONES. Head feathered LIMICOLÆ. Tarsi scutellate in front LIMICOLÆ. Tibiæ feathered below. Nostrils perforate RAPTORES. Nostrils imperforate. Gape reaching below eye. (_Cypseli_) PICARIÆ. Gape not reaching below eye GALLINÆ.

AA. Hind toe inserted on the level of the rest. Tibiæ naked below HERODIONES. Tibiæ feathered below. Bill cered and hooked RAPTORES. Bill not cered. Nasal membrane soft and tumid COLUMBÆ. Nasal scale hard and flat GALLINÆ.

B. Hind toe elevated above the level of the rest. Gape reaching below eye (_Cypseli_) PICARIÆ. Gape not below eye. First primary emarginate or about equal to 2d LIMICOLÆ. First primary not emarginate and much shorter than 2d ALECTORIDES.

BB. Hind toe inserted on the level of the rest. Nostrils opening beneath soft swollen membrane COLUMBÆ. Nostrils otherwise. Bill cered and hooked RAPTORES. Bill otherwise. Secondaries only six (_Cypseli_) PICARIÆ. Secondaries more than six (_a_) PASSERES. (_a_) Primaries 10; the 1st more than 2/3 as long as the longest. (_Clamatores_) PASSERES. Primaries 10; the 1st not 2/3 as long as the longest. (_Oscines_) PASSERES. Primaries 9. (_Oscines_) PASSERES.

Recurring now to consideration of the North American _Families_ of the foregoing higher groups, I take up the latter in the natural order in which they have been presented, giving under head of each such group an analysis of the North American families by which it is represented, reiterating the caution that the characters are drawn up only with reference to the North American genera, and are, consequently, not necessarily or always applicable upon wider considerations. These analyses are made as nearly natural as the state of the case permits, but I seize upon any obvious external characters which may be afforded, without regard to their morphological significance or taxonomic value.

ANALYSIS OF THE FAMILIES OF PASSERES.

A. Oscines. Musical apparatus highly developed. Back of tarsus undivided, or formed of a few scutella distinct from those lapping over the front. First primary wanting, spurious, or at most not over two thirds the length of the longest.

_a._ Each side of tarsus covered with a plate undivided in most or all of its length, and meeting its fellow in a sharp ridge behind.

_b._ Primaries only nine.

_c._ Bill triangular, depressed, about as wide at base as long; the gape twice as long as the culmen, reaching to about opposite the eyes; tomia straight or gently curved. No obvious rictal bristles. Tarsi not longer than the lateral toe and claw. Wings long and pointed, the first primary equal to or longer than the second. Central tail-feathers not half as long as the wing … _Hirundinidæ_.

_cc._ Bill variously conico-elongate or slender, or, if depressed, with long rictal bristles; gape not nearly twice as long as culmen; tomia straight or gently curved. Nostrils not obviously nearer culmen than tomia. Tarsus longer than lateral toe and claw.

Bill very slender, acute; culmen rather concave at base. Longest secondary acuminate, nearly or quite equal to the primaries in the closed wing. Hind claw little curved, about twice as long as the middle claw. Hind toe and claw longer than middle toe and claw … _Motacillidæ_.

Bill variously conico-elongate and acute; culmen not concave at base. Longest secondary not acuminate, falling far short of primaries in the closed wing. Hind claw well curved, not nearly twice as long as middle claw; hind toe and claw not longer than middle toe and claw. Gape ample; tongue slightly bifid or brushy, if at all … _Sylvicolidæ_.

Bill lengthened, very acute, even decurved. Wings and feet as in the last. Gape constricted; tongue generally deeply bifid or brushy … _Cærebidæ_.

_ccc._ Bill more or less truly conic, usually short, thick; commissure usually more or less evidently abruptly angulated near the base, or with lobe or tooth further forward. Nostrils obviously nearer culmen than tomia. Tarsus longer than lateral toe and claw.[13]

Bill stout, tumid, convex in nearly all its outlines; tomia not angulated, but with one or more lobes or nicks in advance of the base. Nostrils placed very high. Other characters much as in _Sylvicolidæ_. Colors chiefly red and yellow. One genus of … _Tanagridæ_.

Bill truly conic, much shorter than head, usually with the angulation evident; no lobe along middle of tomia, but usually a notch at end. Nostrils placed very high. Rictal bristles usually obvious … _Fringillidæ_.

Bill conic, but lengthened, little if any shorter than head; the angulation of the tomia evident; no notch at end. Nostrils high. No rictal bristles … _Icteridæ_.

_bb._ Primaries ten.

Otherwise with characters much as in _Icteridæ_ … _Sturnidæ_.

_d._ Nostrils concealed with antrorse bristly feathers (except in _Psilorhinus_ and _Gymnokitta_).[14]

Base of bill sheathed with antrorse bristly feathers, having lateral branches to their very ends; its tip mostly notched. Basal joint of middle toe united only half-way to the lateral. Sides of tarsus occupied by a lateral groove, mostly filled in with small plates. First primary more than half as long as second. Large,—over seven inches … _Corvidæ_.