Here are some excerpts from the Wikipedia article on the house sparrow or Passer Domesticus:
The plumage of the House Sparrow is mostly different shades of grey and brown. The sexes differ, with females and juveniles mostly buff, and the male marked with bold colours. In breeding plumage, the male’s crown is grey, and it is marked with black on its throat and beneath its crown. The cheeks and underparts are pale grey. The mantle and upper back are a warm brown, broadly streaked with black, while the lower back, rump and uppertail coverts are a greyish-brown. The female has no black on head or throat, nor a grey crown and its upperparts are streaked with brown.
There is some variation in the twelve subspecies of House Sparrow. The subspecies are divided into two groups, the Oriental indicus group, and the Palaearctic domesticus group. Birds of the domesticus group have grey cheeks, while indicus group birds have white cheeks, as well as bright colouration on the crown, a smaller bill, and a longer black bib. The subspecies Passer domesticus tingitanus differs little from the nominate subspecies, except in the worn breeding plumage of the male, in which the head is speckled with black and underparts are paler. P. d. balearoibericus is slightly paler than the nominate but darker than P. d. bibilicus. P. d. bibilicus is paler than most subspecies, but has the grey cheeks of domesticus group birds. The similar P. d. persicus is paler and smaller, and P. d. niloticus is nearly identical but smaller. Of the less wide ranging indicus group subspecies, P. d. hyrcanus is larger than P. d. indicus, P. d. bactrianus is larger and paler, P. d. parkini is larger and darker with more black on the breast than any other subspecies, and P. d. hufufae is paler.
I challenge you to find anything like this level of detail regarding human beings on Wikipedia. Granted, all humans are considered to belong to the same subspecies Homo Sapiens Sapiens, whereas the groups of house sparrow are separate subspecies, but it is unclear how crucial this distinction is as the different kinds do intergrade where their habitats meet. The article on humans remarks
There is no scientific consensus of a list of the human races, and few anthropologists endorse the notion of human “race”. For example, a color terminology for race includes the following in a classification of human races: Black (e.g. Sub-Saharan Africa), Red (e.g. Native Americans), Yellow (e.g. East Asians) and White (e.g. Europeans).
Referring to natural species, in general, the term “race” is obsolete, particularly if a species is uniformly distributed on a territory. In its modern scientific connotation, the term is not applicable to a species as genetically homogeneous as the human one, as stated in the declaration on race (UNESCO 1950). Genetic studies have substantiated the absence of clear biological borders, thus the term “race” is rarely used in scientific terminology, both in biological anthropology and in human genetics. What in the past had been defined as “races”—e.g., whites, blacks, or Asians—are now defined as “ethnic groups” or “populations”, in correlation with the field (sociology, anthropology, genetics) in which they are considered.
This is very salient, but no discussion of the “ethnic groups” or “populations” follows. There are separate articles for ethnic group and race (classification of human beings), but they are mostly devoted to a general overview of measures of genetic differences and a historical discussion of how these concepts have been viewed, and detailing what proportion of the representatives of various scientific disciplines or nationalities disagree with statements like “There are biological races in the species Homo sapiens.” It is elaborated at length that any genetic division of human groups is necessarily “fuzzy” – something that was taken for granted in the case of house sparrows, which naturally have the same property. The only forays into the actual substance of the matter occur in the section “Political and practical uses”, where a caption states “From left to right, the FBI assigns the above individuals to the following races: White, Black, White (Hispanic), Asian.” There is no verbal guide to how this classification is arrived at.
By way of comparison, in the article on house sparrows “plumage” is descriptively used five times, “beak” twice and “tail” thrice. In the articles on human subdivisions, “nose”, “jaw” and “forehead” were not mentioned in any context, and “height” only as an element in a list of features law enforcement might use to describe a person.
In comparison to other species well known to biology, practically no distinguishing information is available about humans. This is not just about ethnic groups: differences between the sexes are also very hard to pin down. I did find information about what changes happen during adolescence, so from that you can back-reason what children and adults comparatively look like, but with nothing like the convenience I had with the house sparrow.
One exception to this is the resources produced by visual artists for other visual artists: both visual and verbal descriptions of all kinds of human subtypes are available in this context. An excellent example is Drawing People by Joumana Medlej. Summary of Asians, summary of Caucasians, summary of Africans.
One might think that while this lack of scientific information is regrettable, we are at least in a better position than the naïve human classifications of the past, which were tinged with racist/imperialist attitudes and eugenic goals. I was actually a little surprised to find the following rather mature discussion in the 1911 Britannica article on anthropology:
Were the race-characters constant in degree or even in kind, the classification of races would be easy; but this is not so. Every division of mankind presents in every character wide deviations from a standard. Thus the Negro race, well marked as it may seem at the first glance, proves on closer examination to include several shades of complexion and features, in some districts varying far from the accepted Negro type; while the examination of a series of native American tribes shows that, notwithstanding their asserted uniformity of type, they differ in stature, colour, features and proportions of skull. (See Prichard, Nat. Hist. of Man; Waitz, Anthropology, part i. sec. 5.) Detailed anthropological research, indeed, more and more justifies Blumenbach’s words, that ” innumerable varieties of mankind run into one another by insensible degrees.” This state of things, due partly to mixture and crossing of races, and partly to independent variation of types, makes the attempt to arrange the whole human species within exactly bounded divisions an apparently hopeless task. It does not follow, however, that the attempt to distinguish special races should be given up, for there at least exist several definable types, each of which so far prevails in a certain population as to be taken as its standard.
In determining whether the races of mankind are to be classed as varieties of one species, it is important to decide whether every two races can unite to produce fertile offspring. It is settled by experience that the most numerous and well-known crossed races, such as the Mulattos, descended from Europeans and Negroes – the Mestizos, from Europeans and American indigenes – the Zambos, from these American indigenes and Negroes, &c., are permanently fertile. They practically constitute sub-races, with a general blending of the characters of the two parents, and only differing from fully-established races in more or less tendency to revert to one or other of the original types. It has been argued, on the other hand, that not all such mixed breeds are permanent, and especially that the cross between Europeans and Australian indigenes is almost sterile; but this assertion, when examined with the care demanded by its bearing on the general question of hybridity, has distinctly broken down. On the whole, the general evidence favours the opinion that any two races may combine to produce a new sub-race, which again may combine with any other variety. Thus, if the existence of a small number of distinct races of mankind be taken as a starting-point, it is obvious that their crossing would produce an indefinite number of secondary varieties, such as the population of the world actually presents.
(from earlier in the article)
Stature is by no means a general criterion of race, and it would not, for instance, be difficult to choose groups of Englishmen, Kaffirs, and North American Indians, whose mean height should hardly differ. Yet in many cases it is a valuable means of distinction, as between the tall Patagonians and the stunted Fuegians, and even as a help in minuter problems, such as separating the Teutonic and Celtic ancestry in the population of England (see Beddoe, ” Stature and Bulk of Man in the British Isles,” in Mem. Anthrop. Soc. London, vol. iii.). Proportions of the limbs, compared in length with the trunk, have been claimed as constituting peculiarities of African and American races; and other anatomical points, such as the conformation of the pelvis, have speciality. But inferences of this class have hardly attained to sufficient certainty and generality to be set down in the form of rules. The conformation of the skull is second only to the colour of the skin as a criterion for the distinction of race; and the position of the jaws is recognized as important, races being described as prognathous when the jaws project far, as in the Australian or Negro, in contradistinction to the orthognathous type, which is that of the ordinary well-shaped European skull. On this distinction in great measure depends the celebrated ” facial angle,” measured by Camper as a test of low and high races; but this angle is objectionable as resulting partly from the development of the forehead and partly from the position of the jaws. […] The general contour of the face, in part dependent on the form of the skull, varies much in different races, among whom it is loosely defined as oval, lozenge-shaped, pentagonal, &c. Of particular features, some of the most marked contrasts to European types are seen in the oblique Chinese eyes, the broad-set Kamchadale cheeks, the pointed Arab chin, the snub Kirghiz nose, the fleshy protuberant Negro lips, and the broad Kalmuck ear. Taken altogether, the features have a typical character which popular observation seizes with some degree of correctness, as in the recognition of the Jewish countenance in a European city.
Going further into articles on eg. “negro”, there is a wealth of descriptions of different subtypes – many seem inaccurate or exaggerated, and especially the social sciences side is very flawed, but this is 1911 science (there are also numerous passages that make the modern reader blush, eg. “The capacity of the cranium is estimated in cubic measure by filling it with sand, &c., with the general result that the civilized white man is found to have a larger brain than the barbarian or savage.”) There is no article of general relativity because it hadn’t been developed yet. In 2011, the Wikipedia article on black people intimates only that black people often have dark skin, and that they commonly have a thick hair type.
These preoccupations with the nitty-gritty of appearance are perhaps trivial, but they seem to me to point to the root of a general lack of understanding in the human sciences. We still have no idea why different cultures, composed of different groups of humans, have had such different historical outcomes (by “we” I don’t mean the scientific best, but the general well-educated Wikipedia reader, say). We know in almost no detail why the performance of men and women in most areas is as different as it is. We don’t know very much about why and how personality types, patterns of behaviour and occupational specialisations recur in families. In short, there is so much more to know about humans – and we seem to be moving backwards! How can this be?