How Spot-billed Ducklings Recognize Their Own Mother: Weir Crossing, Family Reunion, and Long-Term Behavioral Observations

Can wild ducklings recognize their own mother among many similar-looking ducks?

During this day of continuous field observation, I documented several remarkable behaviors of Eastern Spot-billed Duck (Anas zonorhyncha) families. The footage includes ducklings that had grown strong enough to climb a river weir with ease, as well as another family in which ducklings patiently waited for their mother after being temporarily separated. Even though several unrelated ducks passed nearby, the ducklings showed little interest until their own mother finally returned.

Rather than focusing on a single dramatic moment, this article presents these observations as part of an ongoing day-by-day record. Because every recording is published according to its actual filming date, the videos also serve as chronological evidence that helps reconstruct events occurring over multiple days. Any interpretations presented here are personal observations made by a long-term wildlife enthusiast and should not be regarded as scientific conclusions.

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## Observation Video

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## Main Species Featured

### Eastern Spot-billed Duck

- Japanese: カルガモ

- Scientific name: *Anas zonorhyncha*

- A resident dabbling duck widely distributed across East Asia. Because males and females have very similar plumage, long-term identification often depends on subtle feather patterns, behavior, and family history rather than obvious sexual differences.

### Rock Dove

- Japanese: カワラバト（ドバト）

- Scientific name: *Columba livia*

- Frequently gathers around shallow water to drink and bathe. Their presence often provides an interesting contrast to the behavior of waterfowl sharing the same habitat.

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## Field Observation

This observation day unexpectedly became a reunion with several duck families that I had not expected to encounter again.

Early in the recording, faint duckling calls could be heard coming from dense vegetation. As I searched for the source, another familiar voice became audible—the call of a mother duck. Moments later, I confirmed the reunion of family Of2-23. Judging from both the circumstances and the audio evidence, this appeared to be the same temporary separation that had begun two days earlier. Although the crucial reunion itself occurred behind vegetation, the continuous recording preserved valuable circumstantial evidence linking the sequence of events.

Later, another family (Kf3-18) approached the river weir. Based on previous observations over several weeks, I expected they would attempt the crossing again. This family has repeatedly traveled between upstream and downstream sections of the river every few days. Unlike a previous observation in which the ducklings initiated the climb, this time the mother led the crossing, and all ducklings negotiated the obstacle with remarkable ease. Their rapid improvement highlighted how quickly young Spot-billed Ducks acquire physical ability during the first few weeks after hatching.

One of the most satisfying discoveries came later in the afternoon. Family Lf4-61, which I had not seen together since observation code 0718F, suddenly appeared resting among a large gathering of ducks. I had begun to suspect the family had dispersed permanently after only the mother was seen several days earlier. Fortunately, the mother's distinctive tertial feather pattern made positive identification possible even within a crowded flock, allowing the family to be confirmed once again after the ducklings had passed sixty days of age.

The most emotionally memorable observation involved family Shi6-11.

The six ducklings remained together while their mother was absent, just as they had on the previous day. During the waiting period, several unrelated ducks swam close to the ducklings. Surprisingly, the young birds showed little sign of following them. Instead, they remained together, occasionally calling, seemingly waiting for only one individual.

Eventually the ducklings suddenly reacted.

Although dense vegetation unfortunately blocked the exact reunion point from view, the timing strongly indicated that their own mother had returned by flight, after which the family reunited and continued traveling together. Similar temporary separations have now been documented in multiple families during this breeding season, including Of2 and Shi6. Whether these brief absences are related to feeding, predator avoidance, or another behavioral pattern remains unclear, but repeated documentation may eventually reveal a broader pattern.

The day concluded with observations of family Tf8-53. Only five ducklings remained together with the mother while several additional juveniles were scattered nearby. Based on location and previous observations, I believe these individuals likely belonged to the same family, although the identification cannot be considered fully certain. Recording both confirmed observations and uncertainty is an important part of maintaining an honest long-term field diary.

Throughout this season, one lesson continues to emerge repeatedly.

Even among many nearly identical ducks, the families themselves appear to distinguish one another with remarkable accuracy. Exactly which cues they rely upon—vocalizations, movement, visual recognition, or some combination of these—remains unknown to me. As a non-specialist observer, I can only continue documenting these repeated encounters, allowing future observations to either support or challenge these impressions.

For me, preserving these everyday moments without excessive editing is just as important as recording rare or dramatic events.

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## Understanding the Observation Codes

The family identification codes (such as Of2-23 or Lf4-61) and date recording codes (such as 0729F) are part of my long-term observation system developed to document individual duck families across multiple breeding seasons.

A detailed explanation of these codes, together with the purpose of this ongoing project, is available here:

https://okasinaikimono.blogspot.com/p/welcome-to-wild-duck-diaries.html

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This article is based on continuous day-by-day field observations collected over multiple years. The publication date of each video matches the actual recording date, allowing the archive itself to function as chronological evidence. Behavioral interpretations presented here reflect the observations of a dedicated wildlife enthusiast and should not be interpreted as formal scientific conclusions. I hope that by preserving these records as faithfully as possible, they may become useful references for anyone interested in the natural history and behavior of Eastern Spot-billed Ducks.

00:00 Highlights (unordered) 03:01 Duckling calls from the bushes… just as a mother duck appeared! 03:28 It’s オf母! Where are the ducklings!? There they are! オf2-23 * The situation seemed almost identical to the “left behind” case from two days ago. When the ducklings started calling, I heard a mother-like call too, and in the footage you can hear the ducklings until the mother enters the bushes—so the circumstantial evidence is there. 05:24 オf2 swimming with ducklings 08:57 Oh, another family… キf3-18 09:30 Ducklings fascinated by the bushes * Based on past behavior, if キf3 has come this far, they’ll likely climb the weir. (They move between the weir top and downstream every few days; it’s been a while since they came here.) 14:13 キf3 climbing the weir! Cleared it easily! * Last time the ducklings went first; this time the mother led ★ 19:48 Many ducks sleeping together. * Couldn’t tell if they were families, but—wait! Those feathers!? Did a clear double take lol. 20:21 Lf4-61 – Lf母! And 4 juveniles! Congrats on passing 60 days!! * Lf4 disappeared after 0718F, with only the mother seen on 0723. I thought we’d never meet again—what a surprise, so happy. * I usually give up distinguishing this group among large flocks, but Lf母 has very distinctive feathers, so unlikely I ever missed her. 21:11 Lf母 moved into the shade. Other ducks already there were pushed out. 22:48 Of2-58 was sleeping nearby * Of母’s feathers are getting worn and the pattern fading. Normally I might not have noticed this—spotting Lf first helped. 23:14 Flock of pigeons gathering at the water 24:14 シf6-11 – Only the ducklings… same as yesterday, no sign the mother flew off… * All 6 ducklings together for now—that’s a relief. * I kept waiting, but it was blazing hot Yesterday and today, the シf ducklings seemed so cool and comfy—I was jealous. 26:15 Another duck approached, but just an unrelated one 27:44 Another different duck… the ducklings seemed to know it wasn’t their mother 29:07 Ducklings started calling, but still no mother 32:40 Duckling pile—when the middle one faces this way it looks like an older sibling 34:22 ★ Ducklings reacted! Mother flew in! * Yesterday and today… so frustrating that the reunion spot is hidden in bushes 36:09 Mother had to take a detour because she couldn’t pass through directly 37:39 Confirmed シf母’s left wing. Ducklings disappeared into the bushes. 38:17 A solo duck swimming (thought it was シf but wasn’t) 38:41 Tf8-53 – only the mother and 5 ducklings. * Tf8 ducklings are starting to scatter lately. Saw 7 yesterday and really want to confirm all 8… 39:51 Found 3 nearby—probably Tf ducklings ▲▲▲ End of timestamps * So… シf6 safe! And not only that, I managed to see オf2 and キf3, and even Lf4, who I’d given up on, showed up after a long absence! At the end, I debated going to check キf2 one more time, but after yesterday’s long ordeal with シf, I was a bit traumatized and went home. Interesting that both シf母 and オf母 were found in “left behind” situations two times in a row. * To keep track of the many duck families, I use the mother duck’s wing (tertial feather) patterns and code system. [List here ↓] https://okasinaikimono.blogspot.com/2025/07/0729f.html