Young Eastern Spot-billed Ducks Take Flight: Weir-Climbing Challenges, Maternal Persistence, and Unusual Duckling Behavior

 A group of young Eastern Spot-billed Ducks appeared to cross an important developmental threshold when several individuals used short, uncertain flights to climb a river weir. On the same day, younger ducklings repeatedly struggled with low barriers, became temporarily separated from their mothers, refused proposed routes, and showed possible vigilance responses toward a Grey Heron.

This field record documents more than a single dramatic moment. It follows several individually identified duck families across the same river system and compares ducklings at different stages of development—from eight-day-old chicks still reluctant to climb a weir to approximately 65-day-old juveniles beginning to fly.

The observations were filmed almost continuously with Nikon P1100 and P950 superzoom cameras. The footage is minimally edited, and the recording date is preserved as part of a chronological body of evidence. My interpretations are those of a long-term amateur wildlife observer, not formal scientific conclusions.

Observation Video





Main Species Featured

・カルガモ — Eastern Spot-billed Duck — Anas zonorhyncha  
A resident East Asian dabbling duck. In this record, several individually identified families were observed at different stages of juvenile growth, including climbing, short-distance flight, vigilance, conflict, resting, and maternal guidance.

・ハシボソガラス — Carrion Crow — Corvus corone  
An intelligent and highly adaptable crow. Several adults and juveniles were present around a large piece of bread, and apparent competition occurred between two family groups.

・カワセミ — Common Kingfisher — Alcedo atthis  
A small river bird known for plunge-diving after fish. A male and female were observed together, followed by a brief mating event.

・コサギ — Little Egret — Egretta garzetta  
A small white heron that forages in shallow water. One mother duck displaced other ducks but appeared to respond more cautiously to a nearby Little Egret.

・アオサギ — Grey Heron — Ardea cinerea  
A large heron and a potential threat to small ducklings. Four young ducklings gathered closely and remained unusually still after detecting one nearby.

・コイ — Common Carp — Cyprinus carpio  
A large freshwater fish frequently found in urban rivers. Mother ducks repeatedly pecked at carp that approached their young at close range.

・オイカワ — Pale Chub — Opsariichthys platypus  
A common Japanese river fish that forms spawning aggregations in suitable shallow habitats. A carp was observed entering an area used by Pale Chub for spawning.

・アメンボ類 — Water Striders — Family Gerridae  
Surface-dwelling aquatic insects that move across the water using hydrophobic legs. One was filmed among drifting plant down in a quiet section of the river.


A Juvenile Duck’s Apparent First Flight

One of the most significant observations involved family Gf7, a mother accompanied by seven juveniles estimated to be approximately 65 days old.

At 19:18, the family attempted to move upstream over a river weir. Several juveniles ran up the sloping surface, while others lifted clear of the water and appeared to fly over part of the obstacle. Their movements were still somewhat unsteady, suggesting that sustained flight had only recently become possible.

This was especially valuable because the action combined flight with obstacle negotiation. Rather than simply seeing the birds already airborne at a distance, the footage captured young ducks using their developing wings in a practical movement across the river.

I describe this cautiously as an apparent early-flight event. It cannot be confirmed as the absolute first flight of these individuals, because they may have flown outside the periods when I was present. However, their hesitant technique, the short distance involved, and the mixture of running and flying strongly suggested a transitional stage between wing-assisted climbing and confident flight.

All seven juveniles were still together. At approximately 65 days old, this may be close to the period when the family begins to disperse and becomes increasingly difficult to document as a complete group. Their continued survival and cohesion therefore made the encounter particularly meaningful.

After crossing the weir, Gf7 rested close to family エf5. This created a useful visual comparison between approximately 65-day-old juveniles and 25-day-old ducklings. The older birds had much more developed bodies, longer wings, and increasingly adult-like proportions.


Human Feeding and Sudden Family Separation

Earlier in the observation, human feeding appeared to alter the movements of two mother ducks.

At approximately 03:01, food was thrown near family Xf5. The Xf mother and the mother of family アf became involved in an aggressive encounter and flew away from their young.

The three アf juveniles remained without their mother. They called repeatedly, but she did not return during the period of observation. The Xf mother later came back and reunited with her five young.

The アf mother had originally been present, but she flew before filming began. Visual tracking indicated that she moved toward the feeding location and became involved in the conflict around family Xf5.

This does not demonstrate that feeding always causes parental abandonment. Eastern Spot-billed Duck mothers show different responses depending on the situation. Some ignore food and remain close to their young, some move toward food, and others react aggressively when another family approaches.

However, this incident provides another example of artificial feeding disrupting the normal spacing and movements of wild duck families. Similar temporary separations have been recorded in previous seasons.

Because the アf mother could not be identified among the distant ducks under difficult lighting, the later outcome remains unknown.


Conflict Among Carrion Crow Families

At 11:25, a Carrion Crow carried a large piece of sliced bread. Several crows then gathered, and another individual removed part of it.

At least four adult crows and approximately seven juveniles were seen in the wider area. The red interior of the mouth helped identify some of the younger birds.

The interaction appeared to involve two crow family groups competing over the food. I have often observed crows competing individually, but a dispute involving multiple adults and juveniles from separate family units was less familiar to me.

Because the bread was already present when the event was detected, the origin of the food and the exact relationships between every bird could not be confirmed.


Different Responses to Other Birds

Family エf5, consisting of a mother and five approximately 25-day-old ducklings, provided several examples of selective responses toward other animals.

The mother aggressively displaced nearby ducks on multiple occasions. In contrast, when she encountered a Little Egret, she appeared alert but did not immediately attack it.

This difference may reflect an assessment of species, distance, posture, or immediate risk. It would be too strong to conclude that the mother categorically regarded ducks as territorial rivals and egrets only as potential threats. Nevertheless, her behavior toward the two types of bird was visibly different.


Five Ducklings Struggle to Climb a Low Weir

The most prolonged family challenge involved エf5.

At 46:11, the mother and five ducklings attempted to climb a relatively low weir. Three ducklings initially failed to reach the upper level.

The mother returned toward them, and two succeeded during the next attempt. One duckling remained below.

The remaining duckling then moved away while calling. The mother alternated between the four ducklings above the barrier and the single duckling below it. At times, she climbed toward the upper group; at other times, she returned to the isolated chick.

The separated duckling ran toward the slope and attempted to climb again but failed. It then moved downstream while calling loudly before returning and repeating the behavior.

One possible interpretation is that the duckling was not simply unable to climb, but was communicating distress and influencing the mother’s route choice. This resembles a form of behavioral negotiation between the mother and young, although that interpretation remains speculative.

The mother eventually attempted to lead the four successful climbers back down. She jumped from the weir, and all four followed, reuniting the family below.

The event illustrates that successful route selection is not determined by the mother alone. The physical ability, motivation, fear, and persistence of individual ducklings can change the movement of the entire family.


Why Could a 25-Day-Old Duckling Not Climb?

The barrier was not especially high, making the repeated failure surprising.

Several factors may have contributed:

・The wet surface may have provided poor footing.  
・Water flow may have reduced the duckling’s ability to jump accurately.  
・The successful route may not have been visually obvious from below.  
・The duckling may have been less motivated or more cautious than its siblings.  
・Small individual differences in leg strength, body size, fatigue, or experience may have affected performance.

The footage does not allow one explanation to be selected with certainty. What can be documented is that the mother did not immediately leave the struggling duckling. She repeatedly returned, altered her position, and ultimately abandoned the upstream route so that the family could remain together.


Sliding Down the Weir

Later, the same family descended the barrier they had struggled to climb.

The ducklings slid down the wet surface with much less difficulty than they had shown while moving upward. This contrast demonstrates how strongly the direction of movement affects the challenge presented by an artificial river structure.

The mother briefly returned to forage after descending. This was unusual enough to attract attention, although it is possible that she had noticed a particularly rich feeding patch.


Young Ducklings React to a Grey Heron

Family キf4 consisted of a mother and four ducklings approximately eight days old.

At 1:09:00, the ducklings showed an unusual collective response. They gathered closely and remained almost motionless. A Grey Heron was then identified nearby.

The behavior appeared consistent with vigilance or concealment. Small ducklings can reduce their visibility by remaining still and clustering together, but it is not possible to prove from this single event that the heron directly caused the response.

After the apparent threat had passed, the ducklings gradually resumed normal movement.

The mother later pecked at large carp that approached the family. Similar pecking occurred more than once, suggesting that she was actively maintaining distance between the fish and her young. Carp are not normally regarded as major predators of ducklings, but a large fish moving directly beneath a small chick may still provoke a defensive response.


Repeated Weir Attempts by Eight-Day-Old Ducklings

Family キf4 also attempted to climb a weir.

During the first attempt, some ducklings reached the first level, but the group withdrew. On the second attempt, one duckling climbed higher while the others remained below.

The mother descended, but the successful duckling did not immediately follow. She then returned upward before the duckling finally came down.

The family later approached the weir again, but the ducklings appeared unwilling to climb. Their refusal prevented the mother from continuing along the intended route.

This was another example of family movement emerging from repeated communication between the mother and her young rather than from simple one-way following.


An Unusual Climbing Route Used by Of2

Family Of2 consisted of a mother and two juveniles approximately 48 days old.

The mother began climbing a weir, but the young initially appeared reluctant to follow. One was carried downstream by the current while the mother continued upward.

The first juvenile later found an unusual route through a water-filled depression or opening in the structure. The second eventually followed using the same technique.

Although this family had often been observed above the weir, previous attempts to record their ascent had usually ended with hesitation or failure. This occasion finally documented the route used by both juveniles.

It was a reminder that seeing a family regularly at a destination does not reveal how they reached it. Continuous observation is necessary to document the actual route and the physical techniques used.


Common Kingfisher Pair Behavior

At 1:03:30, a female Common Kingfisher called from one side of the river while a male was positioned nearby.

A brief mating event followed at 1:04:08.

The pair may have been the same individuals previously observed during courtship feeding, although this could not be confirmed through markings alone. Their behavior may indicate preparation for another nesting attempt.

The event also highlighted a recurring fieldwork problem. Moving to obtain a clearer angle can cause the observer to miss a behavior that lasts only a few seconds. Remaining in place preserved the event, although the female was partly obscured.


Age-Related Changes in Of2

At approximately 48 days old, the Of2 juveniles showed visible pale or white developing feathers around the wings and body. These feathers gave them a noticeably more adult-like appearance than younger ducklings.

Changes in plumage can occur rapidly during this stage. Comparing identified families across consecutive dates helps distinguish genuine growth from differences caused by lighting, posture, wet feathers, or viewing distance.


Other Juvenile Groups

Several older juvenile groups were detected but could not always be identified with certainty.

A group of five was probably Df5, and a group of six was probably Ff6. Both were seen without an obvious mother nearby. Poor lighting, dense vegetation, and overlapping resting groups prevented confident identification.

Later, approximately seven young ducks appeared near the Df mother, even though Df was expected to have five juveniles. Multiple families or unrelated juveniles may have been sharing the same shaded resting site.

These uncertain records are intentionally retained. In long-term field observation, it is important to distinguish between what was seen, what was inferred, and what could not be confirmed.


The Importance of Recording Uncertainty

Several identifications in this record remain provisional.

A distant group was probably イf4-47, but the mother’s identifying tertial feather pattern was not clearly visible. Other nearby ducks further complicated the observation.

Likewise, the apparent flight by Gf7 was strongly suggestive of newly acquired flight ability, but it cannot be proven to have been their first-ever flight.

Rather than removing uncertain observations, I preserve them with explicit qualifications. This allows later footage, changes in family size, movement between areas, and comparisons across dates to support or contradict the initial interpretation.


Daily Video Records as Chronological Evidence

This blog is part of a continuing field record built from daily wildlife observations.

Whenever possible, I record all known duck families, changes in duckling numbers, movements between upstream and downstream areas, interactions with predators, responses to river structures, and changes in juvenile development.

The videos are published according to their recording dates and are kept largely unedited. This creates a chronological sequence that can be checked across multiple days.

For some wildlife species, public release is delayed because advance disclosure of a location may attract large numbers of photographers. Early footage may therefore be shown to channel members before general publication. The original recording date remains preserved in the observation code and video archive.

These records should not be treated as controlled scientific research. They are field observations by a non-specialist who has repeatedly followed the same animals and locations over many years. My interpretations may change when later footage provides better evidence.

The strength of the project lies not in claiming certainty, but in preserving the visible sequence of events—including failed searches, incomplete identifications, unexpected disappearances, and observations that only become meaningful when compared with another day.


Observation Codes

Recording date code: 0719F

The date code uses the format MMDD followed by a letter representing the year.

・07 = July  
・19 = the nineteenth day of the month  
・F = 2025

Duck family codes identify the mother, the observation year, the number of young, and their estimated age.

Examples from this record:

・Gf7-65 — Mother Gf with seven juveniles, estimated at 65 days old  
・エf5-25 — Mother エf with five ducklings, estimated at 25 days old  
・キf4-8 — Mother キf with four ducklings, estimated at eight days old  
・Of2-48 — Mother Of with two juveniles, estimated at 48 days old

The katakana characters used in codes such as エf and キf are distinct identification symbols and must not be converted into English alphabet letters.

A detailed explanation of the date codes, duck family identification system, chronological evidence, and the purpose of the Wild Duck Diaries project is available here:

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

A reference table showing the mother ducks’ identifying tertial feather patterns and family codes is available here:

https://okasinaikimono.blogspot.com/2025/07/0719f.html