Ecology and Ethnobiology of the Slender-billed Grackle Quiscalus palustris

Abstract

A renaissance-era encyclopedia compiled by Fray Bernardino de Sahagun and his research group of elite native scholars from the Royal College of the Holy Cross, Tlatelolco, Valley of Mexico, provides new information on the Slender-billed Grackle (Quiscalus palustris), a bird that disappeared before modern field studies of it could be made. In sixteenth-century Mexico, this grackle nested in emergent aquatic vegetation and in towns. It was abundant, went around in flocks, and did great damage in the maize crop. Although normally not eaten by humans, it was exploited for its feathers and sacrificed to the Aztec fire god. The Slender-billed Grackle inhabited both the Valley of Mexico and the Valley of Toluca. It was found in marshes, but the degree to which it was dependent on marsh habitats is unknown. Edward Alphonso Goldman, who saw living Slender-billed Grackles in the field, declined to call this bird a marsh specialist. Three records exist of Slender-billed Grackles and Great-tailed Grackles (Quiscalus mexicanus) inhabiting the same locality during the same time period. The author recommends that searches for this grackle be expanded to include non-marsh habitats and areas outside its known historical range.

Appendix: Identification of grackle species

Before looking at grackle names, a few remarks need to be made about folk taxonomy. Vernacular bird names, like birds themselves, vary geographically and also change over time. It is therefore a mistake to assume that a bird name used in one area will be used for the same species in another area, or that a name used today will correspond exactly with the name of the same bird species 400 years ago.

Ornithologists living in North America are accustomed to the AOU (1998) designating a single official common name for each bird species. To such people, it may come as a surprise, discomfort and even distress to learn that, in some other cultures, more than one name may be used for the same species of bird. Rea (2007) calls these alternate names folk synonyms and gives many examples from his fieldwork among the northern Pima, a Uto-Aztecan speaking group in Arizona.

Over-differentiated names also occur, where, for example, males and females, different age groups or populations nesting in different habitats may be given separate names (Rea 2007). Under-differentiated names also occur where one or more species are lumped together like a genus. Because one of the purposes of the General History was to collect and preserve Aztec vocabulary (Sahagun [1577] 1982, Edmonson 1974), it is no surprise that the Florentine Codex includes folk synonyms as well as over and under-differentiated names. Fortunately for us, the descriptions in the Aztec and Spanish texts of the Florentine Codex are detailed enough to permit us to determine which grackle species correspond to which names.

In the Spanish text of the Florentine Codex, two species of grackles are mentioned: tzánatl and teotzánatl (Sahagun [1577] 1988, pp. 710–711). We know that these two birds are grackles, rather than other Icterids such as blackbirds, because Sahagun says that the Resplendent Quetzal (Pharomachrus moccinno) has a tail “of the form and composition of the birds called tzánatl or teotzánatl that nest in the towns” (Sahagun [1577] 1988, p. 690). He further describes the tail of the teotzánatl as being “long and sculptured” (Sahagun [1577] 1988, p. 710) and “streaked” i.e. elongated (Sahagun [1577] 1963, p. 50).

The above description of the Quetzal’s tail may at first seem odd to us, because we tend to focus on the spectacular tail-streamers that are such a distinctive feature of this species. However, the General History is not referring to these long feathers, nor even to the other green feathers. It is referring instead to the Quetzal’s black tail feathers, which resemble the grackles’ tail feathers in that they are elongated (Table 1) and black: “The tail of this one [the quetzal] is black, dark…The tail feathers are streaked” (Sahagun [1577] 1963, p. 19).

Table 1 Black-colored Icteridae from the area formerly known as New Spain

Why would the Aztecs focus on the black tail feathers instead of the green feathers that cover them and hide most of the black from view? Perhaps the answer is that the Aztecs regularly plucked the green feathers of captive Quetzals (Diaz del Castillo [1570] 1956). This plucking was probably still being done when Sahagun’s research group collected data for the General History, for we are told that the Aztecs at that time still did featherwork with quetzal plumes (Sahagun [1577] 1959, p. 92). Consequently, on the Quetzals plucked for feathers, more of the black tail feathers and less of the green feathers may have been visible. One can also imagine that the Quetzal’s long green tail-streamers were less frequently seen at their full-length, since they were plucked.

The tzánatl is described as being the same size as the Resplendent Quetzal (Sahagun [1577] 1963, p. 19), while the teotzánatl is the size of the Plain Chachalaca (Ortalis vetula) (Sahagun [1577] 1963, p. 53). See Tables 1 and 2.

Table 2 Wing and tail measurements (in millimeters) with means in parentheses for male Plain Chachalacas (Ortalis vetula vetula) and male grackles (Quiscalus mexicanus and Q. palustris)

The fact that the tzánatl is significantly smaller than the teotzánatl means that these two grackles are either different species or different sexes of the same species. With regards to the latter idea, one finds in some parts of Mesoamerica today that male and female Great-tailed Grackles are called different names. For example, in Guatemala male Great-tailed Grackles are called “clarineros” and females “sanates” (Skutch 1954), while in Campeche, the male is called “zocao” and the female “cahuix” (Santamaria 1992). The Aztec text of the Florentine Codex specifically says that the teotzánatl is the male, but includes a description of the female with it: “The very black one, very curved of bill, glistening, is the cockerel and is called teotzánatl. The one that is not very black, but a little sooty, is the hen” (Sahagun [1577] 1963, p. 50).

I conclude that the tzánatl of the General History is not the female of the teotzánatl because the colors and morphology described for these two birds are different. The tzánatl is “black,” while the female of the teotzánatl is “not very black, but a little sooty” (Sahagun [1577] 1963, p. 50). In addition, as mentioned above, the tzánatl, like the teotzánatl, is said to have an elongated tail. Female grackles do not possess the long tails of male grackles (Ridgway 1902), so it is hard to imagine how the female by itself could fit the description of the Tzánatl.

One other clue is provided by the Florentine Codex: The bill of the teotzánatl is described as being more curved than that of the tzánatl (Sahagun [1577] 1963, p. 50).

Martin del Campo (1940) identified the tzánatl as Quiscalus palustris, and the teotzánatl as Quiscalus mexicanus. I agree with Martin del Campo’s identifications of these two species. To me, the identification of the teotzánatl as Quiscalus mexicanus seems indisputable, since an extensive description of the teotzánatl is given in the Florentine Codex which matches mexicanus in every way including color, size (see Tables 1 and 2), elongated tail, more curved bill and habits (Sahagun [1577] 1963, p. 50). In addition, this bird is said to have been introduced from Cuextlan and Totonacapan, and the same race of mexicanus that occurs there today (Q. m. mexicanus) is also found in the Valley of Mexico (Haemig 1978).

The identification of the tzánatl as Q. palustris also seems right to me. As mentioned above, the tzánatl was said to be the same size as a resplendant quetzal. The tzánatl was thus too large to be one of the other blackbirds of the Valley of Mexico, yet too small to be a Great-tailed Grackle (Table 1). Its elongated tail, less-curved bill and well-textured black color of males confirm its identification as Quiscalus palustris.

Christensen (2000) claims that the tzánatl of the Florentine Codex could be Brewer’s Blackbird (Euphagus cyanocephalus). However the latter species is too small (Table 1), lacks an elongated tail and did not breed in the towns of New Spain as the tzánatl was said to do” (Sahagun [1577] 1988, p. 690).

Christensen has also argued that the word tzánatl may have been used by the Aztecs as a generic term for “blackbirds” in general. However, as can been seen in Table 1, the other “blackbirds” do not have elongated tails and are too small to fit the description of the tzánatl, except for the Giant Cowbird (Scaphidura oryzivora) and Wagler’s Oropendola (Psarocolius wagleri) whose length measurements come close to the Resplendent Quetzal. However, these latter two icterids, like all the other “blackbirds” of the region (Table 1), lack the elongated quetzal-like tail of the tzánatl and teotzánatl, which both grackle species possess (Table 1).

In the Aztec Text of the Florentine Codex, a third grackle name is used: acatzánatl, which translated means “reed grackle.” The acatzánatl is reported to dwell and hatch among the reeds (Sahagun [1577] 1963, p. 50). It is dimorphic: “Some are quite black, some only smoky” (Sahagun [1577] 1963, p. 50), suggesting that this name could not refer to only females or only males.

The Spanish text of the Florentine Codex substitutes the name tzánatl for acatzánatl, explaining that the latter are “other forms of these birds called tzánatl (Sahagun [1577] 1988, p. 711).” Thus, acatzánatl is either a name for other plumages of the Slender-billed Grackle (e.g., immature males, juveniles, females), or a name that overdifferentiates the species on another basis such as habitat. For example, acatzánatl could be used to differentiate marsh-nesting from town-nesting Slender-billed Grackles, or to separate the shorter-tailed plumages of the species from the longer-tailed adult males.

Still another possibility is that acatzánatl and tzánatl are folk synonyms. Before the reign of Auitzotl, the Slender-bill may have been called only tzánatl. After the Great-tailed Grackle was introduced into the Valley of Mexico by Auitzotl (Haemig 1978), the name acatzánatl may have been coined to distinguish the Slender-bill from its congener. However, some people may have continued to call the Slender-billed Grackle tzánatl because of tradition.

Christensen (2000) claims that the acatzánatl could be the Red-winged Blackbird (Agelaius phoeniceus). I do not agree that the acatzánatl of the Florentine Codex could be the Red-winged Blackbird for the following reasons: First, the physical description does not fit. For example, there is no mention of red on the wings in the description of the acatzánatl. Instead, the plumage description simply reads, “some are quite black, some only smoky;” (Sahagun [1577] 1963, p. 50). Second, another bird listed in the Florentine Codex, the coyoltototl (bell bird, i.e., tinkling type of bell), seems to fit more closely the physical descriptions of both the Red-winged Blackbird and the Yellow-headed Blackbird (Xanthocephalus xanthocephalus) than does the acatzánatl (This lumping is understandable since the Yellow-headed Blackbird did not nest in New Spain, but wintered there with locally nesting Red-wings). Rea (2007) reports that many northern Pimas similarly lump Red-winged Blackbirds, Yellow-headed Blackbirds and other small blackbirds under the same folk taxon. Third, the description of the song of the coyoltototl: “like a cascabel” matches the Red-winged Blackbird (Sahagun [1577] 1963, p. 50, Sahagun [1577] 1988, p. 711). Fourth, Sahagun substituted the name tzánatl for acatzánatl when he wrote the Spanish text, thus indicating that the acatzánatl is a grackle. “Sahagun is after all the ultimate authority on the Florentine Codex!”

It also does not seem likely that the acatzánatl could be Brewer’s Blackbird because the acatzánatl nested in New Spain (Sahagun [1577] 1963, p. 50). Brewer’s Blackbird has not been reported to breed south of Baja California, so it was not known to nest in the region covered by the General History (i.e., New Spain).

A Spanish colonial name for grackle was urraca (Sahagun [1577] 1988, pp. 710–711, Barcena 1872). This name may have been applied to both species of grackles during the sixteenth century. However, since we know that the Great-tailed Grackle was not present in the Valley of Mexico until introduced there by Auitzotl during the years 1486–1502 (Haemig 1978), I have made the following assumption: in Spanish language translations of indigenous histories of the marshlands of the Valley of Mexico before the reign of Auitzotl, any urracas mentioned are Slender-billed Grackles (e.g., Duran [1581] 1990, p. 150).