Common Name: Cardinal, Northern cardinal, Redbird, Common cardinal, Cardinal grosbeak – The eye-catching red color of the male plumage is almost identical to the color that distinguishes the echelon of ecclesiastical prelates that rank just below the pope in the Roman Catholic Church. While officially named the Northern cardinal to distinguish it from other members of the genus that predominate in Central and South America, its range from Maine to Florida and west to Texas leads to the more common use of cardinal throughout the United States.
Scientific Name: Cardinalis cardinalis – The genus and species names are the original Latin form of the word cardinal, derived from cardo, meaning “hinge.” The implication is that it is something of central importance, like the cardinals of Rome, the cardinal (N,S,E.W) directions, and the cardinal (1,2,3 …) numbers. The double genus-species designation connotes that the northern cardinal is the type species for the genus, which in a way does stress centrality.
Potpourri: The male northern cardinal is arguably the most recognizable and popular bird in North America. It was chosen as the official bird by seven states, foregoing uniqueness for panache. It is the only team name shared by two professional teams―baseball in Saint Louis and football in Arizona. It is one of the official color of colleges ranging from MIT in Massachusetts to Stanford in California. The cardinal was chosen for its eye-catching, strident redness and not for any particular avian vitality, ubiquity, or the singularity of song. The cardinal is not especially notable, just one of the many so-called songbirds of the order Passeriformes that flit from tree to tree in search of food, nest-building materials, or each other. And all the while, the female cardinal is swathed in the brown feathers to match the colors of the trees and soils. [1] Why then, is the male cardinal cloaked in cardinal red?
There is also a Sacred College of Cardinals, the source of both the name and the color of the bird. The first use of the term cardinal to indicate a person of pivotal importance (literally on which things hinged from the Larin word cardo) was the deacons that presided over the seven regions of Rome in the 6th century. These prelates eventually became a privileged class as Roman magistrates and adopted the red that had long been used in Roman society to indicate rank and importance. [2] Red has been a key color in almost every society in human history, from the red ochres used in cave drawings to the war paint of Native Americans. The red that later became the robes of royalty throughout Europe was a rare and expensive commodity, ranking just behind royal purple in prominence. Red that was symbolic of power and wealth in the Roman Empire was sourced from miniscule, sap-sucking insects of the genus Kermes that fed on oak trees in the Mediterranean basin that were collected, crushed, and strained. A great deal of painstaking labor went into making just a few drams of dye. The red bug goo color that passed from Roman centurion to cardinal in antiquity was and still is scarlet and not cardinal red.
So why are North American red birds called cardinals and not scarlets? The bird cannot have been seen by Europeans before the 15th century, when the mainland of North America was first colonized. The striking red bird was almost certainly noticed by the French moving their bateaux up the Saint Lawrence River to lay claim to the region as New France. Suffering a dearth of settlers, the French government, directed by Cardinal Richelieu, chief minister to King Louis XIII, encouraged emigration starting in the middle of the 17th century. The new settlers who expanded along the Saint Lawrence River from Quebec City to Montreal were in a sense his agents, eventually renaming a tributary the Richelieu River. A bird named cardinal as Richelieu’s signature color would be equally apt. The cardinal bird name probably carried south with commerce and cultural contact to reach English colonists moving inland from Boston. No friends of persecuting papists, they may have favored the cardinal name in mockery. This is not outside the guardrails of the bawdy humor of the age. When Mark Twain was presented a scarlet robe on his receipt of an honorary doctorate at Oxford, he remarked “There is no such red as outside the arteries of an archangel.” [3] The bird is cardinal in both French and English with only a change in pronunciation as distinctive.
Cardinals have some characteristics that distinguish them as unusual when compared to the other perching birds of the Order Passeriformes more commonly called songbirds. Their most obvious is the pronounced color difference between the male and the female, a trait called sexual dimorphism. While there are subtle differences in the hue of plumage between the sexes of many birds, none take it to the extreme of a scarlet red male and a forest brown female. One hackneyed rationale is that the male would draw predators away from the nest so that the female could remain hidden with the brood. More chicks would then survive to retain the color dichotomy in perpetuity. The female, as procreator, would therefore choose a more cardinal red mate to enhance the survival of her genes. This doesn’t make much sense, since mammal egg snatchers like foxes and ferrets cannot see red. While demonstrably true physiologically and experimentally, the reason mammals cannot see red (including bulls charging at capes) can only be a matter of conjecture. The operative theory is that mammalian origins in the shadows of the dominant dinosaurs was literally devoid of much light but movement mattered; smell and hearing were paramount. Over evolutionary time, mammals retained only blue and green cones for rudimentary color vision, with a surfeit of rod cells for dim light peripheral movement perception. (Red cones were regained by primates like us as a consequence of taking to the trees to facilitate locating the bright colored fruits that became their mainstay diet). [4] The consequence is that the red male cardinal might as well be brown since its movement is all that would matter for a predator mammal. There are other cardinal predators such as owls, hawks, and snakes that do see red, but there is no correlation between the degree of male redness, which is referred to as “ornamentation,” and predator avoidance behavior in field studies. In fact, female cardinals have been observed fighting back against predation with no reliance on male participation. [5]
Mate choice is a more compelling reason for cardinal red. The selection of the most desirable male by a female has been well established in some species of birds. In New Guinea, there are male birds of paradise that put on elaborate feathered displays to impress females and male bowerbirds that build extravagant nests with colorful decorations that range from red fruits to green fungi as proffered bridal suites. [6] The elaborate tail of the peacock can have no other function than to impress the pea hen. Mate choice, however, is not just for the birds. To a greater or lesser extent, it is pervasive throughout the animal kingdom from fruit flies to fruit bats and especially humans. Our very identity depends on a random sequence of mate choices that were made by parents and grandparents that extends through hundreds of generations. Mate choice can be defined as “any pattern of behavior, shown by members of one sex, that leads to their being more likely to mate with certain members of the opposite sex than with others.” In biological jargon, these are called the courter and the chooser. While there is no serious scientific disagreement about the existence of mate choice as an essential component of the birds and the bees doctrine, there is neither consensus about its actual mechanisms nor understanding of the way it evolved. [7] It is complex, inclusive of combinations of sight, smell, sound, and perhaps touch (but rarely, if ever, taste). For female chooser cardinals, some combination of sight for color and sound for birdsong are the most likely factors.
The unusual characteristics of birds were not lost on Charles Darwin, whose evolution epiphany was inspired at least in part by the different beak sizes and shapes of Galapagos Island finches. The importance of what have come to be known as Darwin’s finches on his ultimate conclusions concerning survival of the fittest has been oversubscribed. In visiting the islands of the archipelago, Darwin was struck by the similarities of a Galapagos mocking-bird to one called Thenca that he had recently seen in South America. On traveling to a second island and finding a third type of mocking-bird and observing that the indigenous giant tortoises were equally varied, he first posited that there must be something about isolated islands that promotes variations. In his field notes, he wrote that “such facts would undermine the stability of species.” It was only on his return to England with his collected finch specimens that an ornithologist named John Gould reached the conclusion that the finches were “so peculiar as to form an entire new group containing twelve new species.” [8] In the seminal work Darwin published about twenty years later, his thoughts on birds were much more nuanced. In a chapter entitled “Difficulties with the Theory,” he observes that “beautiful colours” and “musical sounds” must be due to sexual selection since “natural selection acts by life and death.” He concluded that structures created “for the sake of beauty” would be “absolutely fatal to my theory.” [9]
Darwin’s radical theory of evolution was in direct contradiction to the Bible’s origin story of the Great Flood and Noah’s Ark, an issue that resonates to this day despite overwhelming DNA evidence of evolution’s veracity. He purposely excluded any discussion of mankind’s origins so as to mitigate shock and backlash from the ecclesiastical establishment of the Victorian Era. A decade later, he elected to take on Adam and Eve directly in a second book, The Descent of Man, with the almost forgotten subtitle and Selection in Relation to Sex. Here then is Darwin’s full blown retraction: “If female birds had been incapable of appreciating the beautiful colors, the ornaments and voices of their male partners, all the labor and anxiety exhibited by the latter in displaying their charms before the females would have been thrown away; and this it is impossible to admit.” He even alludes to the use of bird feathers in women’s fashion that was popular at that time to assert that “the beauty of such ornaments cannot be disputed.” [10] There must then exist a sexual selection based on perceived beauty that operates hand in hand with natural selection based of fitness that combine to produce the tree of life. The dating game of young adult humans only differs from the pairings of birds such as cardinals in range and scope.
Sexual color dimorphism in cardinals must have something to do with mate choice, but it may not be the only factor. The intricacy, variation and tonal quality of song is also considered to be one of the primary means by which male courters seek the attention of the female choosers among passerines. In most species, only the male sings, lending some credence to this behavior as mate related. However, cardinals are unusual in that both the male and the female sing. In fact, the songs are so similar between the two that to the human ear they are indistinguishable. However, when the male and female cardinal songs are separately analyzed by frequency and amplitude, the two songs are shown to be distinct.[10] Since bird songs are learned and, in some cases, embellished by practice, the question would be whether males learned their version of the song from other males and females likewise learned if from other females. A third intriguing possibility is that the female learned from the male and then modified the sounds ever so slightly as a way to respond. The reverse, with the male learning from the female is also possible but unlikely. This would suggest that the male and female cardinal share in a more or less egalitarian fashion.
Cardinals are very aggressive―males and females in almost equal measure. This is especially notable in the late spring and early summer when adequate and suitable territory for nesting is established. Any intruder cardinal that attempts to penetrate the guarded perimeter of a mate pair’s domain will be subject to assault by the male, the female, or both. With lowered crest and eyes fixed on the aggressor, defending cardinals have been observed lunging after the intruder, using their feet and beak as weapons to force expulsion. The physical onslaught is often augmented by vocalizations described as chips and pee-toos. Intruder bird chases can go on as long as thirty minutes. This pronounced defensive posture is the cause of one of the more notable cardinal behaviors. Since birds are not self-conscious like humans and a few other animals, they do not recognize themselves in reflective surfaces like window glass. Cardinals are therefore frequently given to aggressively attacking their image in a window or even a shiny car bumper, pecking at the imagined intruder that will never go away until they themselves do. Sapience as its benefits. They eventually cease in fatigue and probably frustration.
Cardinal appearance goes beyond the red color of the male plumage to the broader category of ornamentation, inclusive of the length of the crest, bill coloration, and face mask contrast. Many attempts have been made to correlate variations in cardinal ornamentation to variations in body size and condition, feather growth, parental care, territorial defense, and mating choices. In general, the results have failed to establish any definitive relationship between any ornamentation trait including male redness and any other aspect of cardinal behavior or physiology. For example, in a trial in a rural area of New York found that males with brighter colors were positively correlated with reproductive success but those in an urban area in Ohio were not. In a more controlled experiment called a captive mate trial, females showed no preference for colorful males. [12] The only variable that can be directly attributed to a cardinal’s relative redness is the availability of fruit during the molting period when feathers are renewed. Fruits are colored by the chemicals called carotenoids that are found in many plants to augment chlorophyll by absorbing light energy from additional frequency bands. When cardinals are fed a diet devoid of carotenoids, they vary in color from pale red to yellow. [13]
Why are male cardinals red and female cardinals brown? There is clearly a mate choice of some sort in operation, but it is not a choice favoring redness. Cardinals have elaborate courting behaviors that demonstrate evolutionary development of sex related activities. Sex matters. Many if not most birds are monogamous, retaining the same mate for life. Cardinals are a bit less stoical, changing mates not regularly but on occasion. So there must be come choosing going on and that would be under the purview of the female chooser. This is an evolutionary result related to the lack of an external male sexual organ in most birds. Sex therefore requires the consent of the female since copulation involves contact of the male and female cloacae, known euphemistically as the cloacal kiss. This could not happen without mutual consent. (Cloaca once meant sewer, the name given to the opening in birds, reptiles, amphibians, and fish that serves for both excretion and conception). One hypothesis is that the female cardinal chooses a male for a mate due to his compatibility. Female and male cardinals have very similar behaviors that range from having almost identical songs to being equally aggressive. The hypothesis is that this similarity was the result of female cardinal mate choice. The complexities of human mate choice are equally qualitative. If this is the case, then the red color of the male cardinal is more likely a genetic coincidence incident to female selection of a companionable mate. This is not without precedent. Dogs bred for friendliness by humans develop rounded snouts and drooping ears.
References:
1. Alderer, J. editor, Complete Birds of North America, National Geographic Society, Washington, DC, pp 597-606.
2. “Cardinal” Encyclopedia Brittanica Micropedia, William Benton, Chicago, Illinois 1972.Volume 11, p. 560.
3. Rossi, M. The Republic of Color, University of Chicago Press, Chicago, 2019, p 132.
4. Drew, L. I, Mammal, Bloomsbury Sigma, London, 2017, pp 254-256.
5. Jawor, J. and Breitwisch, R.. Multiple ornaments in male Northern Cardinals, Cardinalis cardinalis, as indicators of condition. Ethology 2004, Volume 110 Number 2 pp 113–126.
6. Prum, R. The Evolution of Beauty, Doubleday, New York, 2017, pp 184-205
7. Rosenthal, G. Mate Choice, Princeton University Press, Princeton, 2017, pp 3-30.
8. http://darwin-online.org.uk/EditorialIntroductions/Chancellor_Keynes_Galapagos.html
9. Darwin, C. On the Origin of the Species, The Easton Press, Norwalk, Connecticut, 1976, pp 164-166, 360-366.
10. Darwin, C. The Descent of Man, The Easton Press, Norwalk, Connecticut, 1976, pp 79-80.
11. Yamaguchi, A. “A sexually dimorphic learned birdsong in the northern cardinal”. The Condor. 1 August 1998, Volume 100 Issue 3, pp 504–511.
12. Cornell Lab of Ornithology. “Cardinalis cardinalis” at https://www.allaboutbirds.org/news/ and https://birdsoftheworld.org/bow/species/norcar/cur/behavior#sex
13. McGraw, K. et al “The Influence of Carotenoid Acquisition and Utilization on the Maintenance of Species-Typical Plumage Pigmentation in Male American Goldfinches (Carduelis tristis) and Northern Cardinals (Cardinalis cardinalis)”. Physiological and Biochemical Zoology. University of Chicago Press. November, 2001 Volume 74 Number 6 pp 843–852.
Hiker's Notebook 