Two New Duck Families After Rain: Newly Hatched Ducklings, Carp, and Older Juveniles in an Urban River

 

On June 26, 2025, I recorded another long field observation of Eastern Spot-billed Duck families in an urban river environment. The main purpose of this survey was to check the effects of the previous day’s rain and increased water flow, and also to search for two newly observed families from the day before: アf3 and イf4.

However, the day brought an unexpected result. Instead of finding those two families, I encountered two more newly hatched duck families. This made them the 30th duck family group observed in the 2025 season.

This article is based on my own daily video records and timestamps. I am not a professional ornithologist, but I have continued observing and recording wild duck families almost every day. Because the footage is published with minimal editing, it also works as time-stamped field evidence that can be compared across different dates.

Observed Species

- カルガモ / Eastern Spot-billed Duck / Anas zonorhyncha  

  A resident duck species commonly seen in Japan. This observation focuses mainly on family movement, duckling survival, territorial behavior, and differences in growth stage.

- コイ / Common Carp / Cyprinus carpio  

  Large freshwater fish often seen in urban rivers. In this footage, carp appeared close to newly hatched ducklings, creating a tense moment.

- ツバメ / Barn Swallow / Hirundo rustica  

  Aerial insectivorous bird often seen around rivers and bridges. A young bird was observed near the road toward the end of the recording.

- カワセミ / Common Kingfisher / Alcedo atthis  

  A small river bird often seen near clean water and fish-rich areas. Briefly observed, though the camera had difficulty focusing.

Field Observation Summary

The first major discovery was ウf9-2, a new family with nine very small ducklings, probably around two days old. I had expected to find families that may have been pushed downstream by the rain, but the river was strangely quiet at first. Then, near vegetation where another family had been seen the previous day, this new group suddenly appeared.

The mother seemed cautious and uncertain about the route. At one point, carp followed the family closely, and the newly hatched ducklings looked extremely vulnerable in the water. The family moved downstream, then turned back upstream, repeatedly using the same vegetated area. This suggested that the mother may have been searching for a safe path to reach the upper bank.

A territorial encounter occurred when another adult duck, likely Lf mother, flew in. ウf mother reacted strongly and drove her away. This kind of defensive behavior is important to record, because newly hatched ducklings are at high risk not only from predators and water flow, but also from conflicts with other ducks.

Later, I found Lf4-27 feeding on land farther downstream than usual. This raised the possibility that the previous day’s rain had affected the positions of several families, although later observations suggested that not all families had been displaced.

Another interesting moment involved Zf1, a lone calling duckling, and Bf捨1, a separated or abandoned duckling. Their reactions to ウf9 showed how complex the river environment becomes when multiple families, lone ducklings, and older juveniles share the same area.

The second new family was エf4-2, another group of very small ducklings. At first I was unsure because the mother’s wing markings resembled another mother observed the previous day, but the size of the ducklings confirmed that this was a different and newly hatched family.

One of the most striking scenes was the encounter between エf4-2 and Gf7-42. The difference between two-day-old ducklings and 42-day-old juveniles was dramatic. This size comparison clearly showed how rapidly ducklings grow, and how different their survival challenges become within only a few weeks.

Other Families Observed

Mf1-28 appeared in its usual area.

Cf3-45 was also present above the weir. Nearby, Df捨4 was partially confirmed, with three individuals seen.

Af13 was found above the weir. This was notable because this family had previously been observed going downstream after rain, but by the following day they were already back upstream. This may suggest that some families move back very early in the morning or possibly during the night.

Tf8-20 was observed in a temporary separation event. Two ducklings failed to notice the family’s movement at first, and later one final duckling also remained behind. I continued watching until the last duckling noticed the separation and returned to the family.

Uf1-16, Df5, Ef6-39, Ff6-39, Xf5-16, and Gf7-42 were also confirmed. Many of the regular families appeared to be safe after the rain.

Behavioral Notes and Interpretation

This observation showed several important patterns.

First, heavy rain and increased river flow may change the positions of duck families, but the effect is not always simple. Some families may be displaced, while others remain in familiar areas or return quickly.

Second, newly hatched ducklings often use vegetated edges repeatedly. These areas may provide shelter, but they can also become dangerous if the family is trapped, separated, or forced into strong current.

Third, territorial behavior between mother ducks can occur even when very young ducklings are present. The mother’s ability to repel another adult may be important for protecting her family’s space.

Fourth, the comparison between newly hatched ducklings and older juveniles was visually powerful. A two-day-old duckling and a 42-day-old juvenile belong to the same breeding season, but their body size, mobility, and risk level are completely different.

Finally, small gestures such as hesitation, route changes, ducklings reacting late, or mothers choosing detours can reveal a great deal when observed across many days. These are not controlled scientific experiments, but repeated daily records can still provide valuable situational evidence.

Conclusion

The June 26, 2025 observation began as a search for families affected by rain, but it became a record of two newly discovered duck families and many overlapping family movements in the same urban river.

The most important findings were the discovery of ウf9-2 and エf4-2, the carp-related tension around very small ducklings, territorial interaction between mother ducks, and the dramatic size difference between newly hatched ducklings and older juveniles.

This kind of daily field recording helps preserve small but meaningful details of urban wildlife behavior. Even ordinary river scenes can contain important evidence when they are documented continuously across dates.