Chapter 8: The Phenological World of Guyu (Part Two) — The Cuckoo Flaps Its Wings: The Voice of Heaven's Timing That Urges the Plowing

Section 1: "The Cuckoo Flaps Its Wings" — What Bird$11 What Does It Do$12

Guyu's second pentad is "the cuckoo flaps its wings" (鸣鸠拂其羽). The "Explanation of the Seasonal Instructions" chapter of the Lost Book of Zhou records: "Five more days pass, and the cuckoo flaps its wings." What bird is this "calling cuckoo" (mingjiu)$13 And what does "flapping its wings" mean$14

"Jiu" was, in ancient times, a general term for a category of birds, and the "calling cuckoo" here is mostly interpreted as the common cuckoo (also called shijiu, huogu, or guogong). "Flapping its wings" describes it beating and fluttering its wings—this is the typical posture of the cuckoo when breeding, courting, and active. By the time of Guyu, the cuckoo begins to flap its wings and call frequently, its cry of "cuck-oo—cuck-oo—" ringing out across the fields.

Why did the ancients list "the cuckoo flaps its wings" as a pentad of Guyu$15 Because the cuckoo's cry aligns with the farming season to a striking degree. It is precisely around the time of Guyu—the most crucial season for sowing—that it begins to call loudly. That cry of "cuck-oo, cuck-oo," to the ears of the ancients, sounded like nothing so much as an "envoy sent by Heaven to urge the plowing," as if calling out again and again: "Sow the grain! Sow the grain!" And so this bird came to bear the name "cuckoo" (bugu, literally "spread the grain")—the very name itself expresses its function of urging people to sow.

Section 2: Heaven's Timing Within Sound — Why Did the Ancients Place Such Weight on "Bird Speech"$16

"The cuckoo flaps its wings" is the only one of Guyu's three pentads centered primarily on "sound" (the first pentad, duckweed growing, is visual; the third pentad, the hoopoe descending, is behavioral; only the second highlights "calling"). Behind this lies the ancients' distinctive wisdom of "telling time by sound."

In high antiquity, without clocks or calendars, sound was an extremely important means of "telling time." Different birds called at different seasons; hearing a particular birdcall, one knew that a particular farming season had arrived. The cuckoo calls at Guyu, urging people to sow the grain; the cuckoo (dujuan, a different species also called cuckoo in English) cries deep in spring, its call sounding again and again like "better to return home"; the cicada (han chan) drones as autumn arrives—these "bird speeches" together constitute a living, three-dimensional "sound calendar," resounding throughout Heaven and Earth. The ancients had only to lend an ear, and they knew Heaven's timing.

At a still deeper level, "the cuckoo flaps its wings" was treasured also because it confirmed the belief in "Heaven and humanity moving each other." Why does the cuckoo call precisely at Guyu, of all times$17 In the eyes of the ancients, it was not that the cuckoo "decided on its own" to call, but that the qi of Heaven and Earth, having run its course to the stage of bringing forth the hundred grains, moved the cuckoo, causing it, unable to restrain itself, to flap its wings and cry out. The bird's call is the "spokesperson" of the qi of Heaven and Earth. And so to listen to the cuckoo's cry is to listen to the qi of Heaven and Earth; to hear the bird's speech and thereby know the farming season is to borrow the bird's mouth in order to understand Heaven's instruction.

Section 3: The Cuckoo Urging the Plowing — The Precise Meshing of Phenology and Farm Work

The most moving aspect of "the cuckoo flaps its wings" lies in how seamlessly it meshes "phenology" with "farm work."

Guyu is the crucial period for sowing the hundred grains, when every second counts. And it is precisely at this time that the cuckoo calls without ceasing, like a natural, never-tiring "farming-season alarm clock," reminding the farmers day after day, from high above the fields: do not miss the farming season, sow the seed swiftly. This precise correspondence between phenology and farm work is by no means accidental—it is the result of the ancients' observation, selection, and distillation over thousands of years. Among the countless bird calls of late spring, the ancients singled out precisely "the calling cuckoo" as the marker of Guyu, precisely because its calling period aligns most accurately, most usefully, with the sowing period.

This, once again, confirms the essential nature of solar-term phenology: it is not the romantic musings of literati over wind and moon, but an extremely practical "survival guide" bound up with an entire year's livelihood. That "the cuckoo flaps its wings" was solemnly listed as Guyu's second pentad is, at bottom, because it calls out one of the most practical statements of all—"It is time to sow the grain!"

Section 4: The Cuckoo (Shijiu) in the Book of Songs — From a Bird That Urges the Plowing to a Metaphor for Virtue

The cuckoo (shijiu) is also endowed, in the Book of Songs, with a layer of moral significance worth mentioning here.

The poem "Shijiu" in the "Odes of Cao" opens: "The cuckoo is in the mulberry tree; its young number seven. The good man, the noble person—his bearing is ever one and the same. His bearing is ever one and the same; his heart is as if bound fast." (鸤鸠在桑，其子七兮。淑人君子，其仪一兮。其仪一兮，心如结兮。) The cuckoo perches in the mulberry tree, rearing seven fledglings. That good and noble person—his bearing is constant, ever the same. His bearing is constant because his heart is single-minded and firm, as if tied in a knot.

Why does this poem take the cuckoo as its opening image, using it to liken the noble person's virtue$18 According to the ancient commentators, the cuckoo, in rearing its many fledglings, feeds them "from the top down in the morning, from the bottom up in the evening," treating them all equally, without any partiality—it regards its seven young with perfect impartiality, embodying a virtue of "equal, single-minded evenness." And so the poet, borrowing the cuckoo's "evenness," evokes and likens to it the noble person's "constant bearing" and "heart as if bound fast"—the singleness, fairness, and unshakable firmness of virtuous conduct.

Interestingly, the cuckoo in the poem "Shijiu" is found "in the mulberry"—perched in a mulberry tree—and Guyu's third pentad is precisely "the hoopoe descends upon the mulberry," likewise involving the mulberry tree. The sound of the cuckoo urging the plowing and the matter of mulberry and silk quietly converge upon this image of the mulberry tree. From a bird that urges the plowing, to a virtue of impartial evenness, to an image of perching in the mulberry—a single small cuckoo threads together Guyu's farming season, moral teaching, and sericulture, revealing just how minutely the ancients observed things, and how deeply they embedded meaning within them.