After a day of heavy rain and dramatically increased river flow, I returned to the river to check on several Eastern Spot-billed Duck families that I had been monitoring. The previous day, the water level had risen so much that I could not find the duck families at all and was unable to record them.
Fortunately, they had survived.
This unedited wildlife observation documents Eastern Spot-billed Duck (Anas zonorhyncha) ducklings living in a rain-swollen urban river in Japan. Along the way, the young ducks encounter a Grey Heron (Ardea cinerea), a possible large catfish, and the difficult conditions created by high water and strong currents. Several ducklings were also observed without their mothers nearby, making it particularly important to confirm which families and individuals were still present after the flood.
The footage provides a continuous field record of urban wildlife behavior after heavy rainfall, including duckling survival, predator encounters, family separation, vocal communication, and the response of waterbirds to changing river conditions.
Wildlife Species Observed
Eastern Spot-billed Duck
Scientific name: Anas zonorhyncha
Japanese name: Karugamo (カルガモ)
The Eastern Spot-billed Duck is a dabbling duck widely distributed in East Asia and is one of the most familiar wild ducks in Japan. Unlike many migratory duck species, Eastern Spot-billed Ducks can be seen throughout the year in much of Japan and commonly breed along urban rivers, ponds, canals, and other waterways.
Females raise the ducklings without assistance from the male. Newly hatched ducklings are precocial: they can walk, swim, and forage soon after hatching, although they remain dependent on their mother for protection, guidance, and thermoregulation.
Because I monitor many duck families simultaneously, I identify individual mothers primarily by distinctive patterns in their wing feathers and assign each family an observation code.
Grey Heron
Scientific name: Ardea cinerea
Japanese name: Aosagi (アオサギ)
The Grey Heron is a large wading bird found across Europe, Asia, and parts of Africa. It is common along Japanese rivers, ponds, wetlands, and coastal areas.
Grey Herons are opportunistic predators. Their diet includes fish, amphibians, crustaceans, insects, reptiles, small mammals, and occasionally young birds. Because of their large size and predatory behavior, their presence near small ducklings is always noteworthy during field observation.
Possible Catfish
Japanese name: Namazu (ナマズ)
A large fish briefly appeared beneath the water near the ducklings. I could not identify it conclusively from the footage, even in slow motion, but its movement suggested that it may have been a catfish.
This location was especially interesting because two ducklings from another family had previously disappeared here during apparent predation events. I therefore pay close attention to large underwater animals appearing in this section of the river.
The identification in this record should be treated as tentative rather than confirmed.
Swallows
Japanese name: Tsubame (ツバメ)
Many swallows were flying over the river during the rain. Swallows are aerial insectivores and frequently forage above rivers and other open areas where flying insects are abundant. Their increased activity was conspicuous during this observation.
Field Observation Diary
00:00 – Highlights and the River After Heavy Rain
The opening three minutes contain edited highlights from the observation.
Heavy rain had caused the river to rise dramatically the previous day. I searched for the duck families but could not find them, so there was no filming session.
Today I returned to check whether they had survived the high water.
And there they were.
Just as I began filming, however, another large bird appeared near the family.
01:00 – Duck Family and a Grey Heron
A Grey Heron was standing close to the Eastern Spot-billed Duck family.
This immediately caught my attention because a large heron can potentially pose a threat to very small birds. The encounter also provided useful context for understanding the range of animals sharing this urban river habitat after heavy rainfall.
01:08 – Of2-36(31) Is Back in the Usual Area
I found the Of family in its familiar location.
The river had experienced severe flooding only a day earlier, so simply confirming that the family was still here was important.
They had not been swept away by the increased flow.
01:51 – A Possible Catfish Near the Ducklings
Something large moved beneath the surface.
My first impression was that it might be a catfish. Even after reviewing the footage in slow motion, however, I could not identify it with certainty.
The location made the observation particularly interesting. Two ducklings from the Kif family had previously been lost to apparent predation in this same area.
It raised another question: do large predatory fish move into or become more active in this section of the river when the water level rises?
Fortunately, the ducklings observed today were already considerably larger than newly hatched chicks.
02:50 – Mother Duck Shows Little Concern About the Grey Heron
The Of mother remained surprisingly calm despite the Grey Heron being nearby.
At this distance I would normally expect more obvious vigilance, avoidance, or defensive behavior, so her apparent lack of concern was interesting.
Wild animals do not respond to every potential predator in the same way. Distance, previous experience, the age of the ducklings, the predator's behavior, and immediate environmental conditions may all influence their response.
05:34 – Many Swallows in the Rain, Then a Duckling Appears
Numerous swallows were flying over the river in the rainy conditions.
Then I noticed a duckling.
At approximately 05:39, it appeared to be one of the Shif ducklings, around 24 days old.
But I could hear additional duckling calls nearby.
06:07 – Possible Suf Ducklings
Another group appeared.
These seemed to be the Suf ducklings, approximately 15 days old. There should have been three of them, but initially I could not confirm all three.
Distinguishing the Shif and Suf ducklings is not particularly easy from the video alone. While filming in the field, however, differences in their calls, positions, apparent body size and overall appearance made them easier to separate.
07:18 – Was That the Mother?
For a moment, I thought I heard the call of an adult female.
I could not confirm it.
Vocalizations are extremely useful when tracking duck families in vegetation or poor visibility, but sounds can be difficult to localize accurately around a river, especially with rain, flowing water, and multiple birds calling simultaneously.
08:44 – All Three Suf Ducklings Appear to Be Present
I was finally able to confirm what appeared to be all three Suf ducklings.
The adult-like call I thought I had heard earlier was probably a mistake. I still could not locate their mother.
09:03 – Shif Ducklings Upstream
Slightly upstream from the three Suf ducklings, I could intermittently see ducklings that appeared to belong to the Shif family.
However, they never gathered together clearly enough for me to confirm the entire family at once.
After a flood, confirming survival is not simply a matter of seeing "some ducklings." When individual families are being monitored over time, the number of surviving young and their association with a particular mother are important parts of the record.
10:35 – An Adult Duck Approaches
An adult Eastern Spot-billed Duck appeared.
At first I wondered whether this could be one of the missing mothers, but its behavior did not provide a clear answer.
The three Suf ducklings had separated into groups of one and two.
Initially, one of the Suf ducklings appeared to threaten or drive the adult away. The other two seemed less concerned when the adult approached them.
Because the rain made observation difficult and the adult's behavior was unusual enough to interest me, I continued following it.
12:10 – One Shif Duckling
I located one Shif duckling.
This at least confirmed that members of this family were still present in the area following the heavy rain.
12:41 – Shif Duckling Meets the Adult Duck
The Shif duckling and the adult duck seen earlier approached each other.
Their interaction was difficult to interpret. I could not confidently determine from this brief encounter whether the adult had any family relationship with the duckling.
End of the Observation
I remained in the area for some time after the recorded sequence.
Eventually I stopped hearing the ducklings, and I could no longer locate either the Suf or Shif groups, so I ended the observation.
I had definitely confirmed all three Suf ducklings. Although I could not capture all of the Shif ducklings clearly on video, I personally observed at least two individuals.
The previous day's heavy rain and flooding had been a major concern, but the most important result of today's survey was encouraging: the Of, Suf, and Shif families had all been confirmed in their usual general area after the flood.
I could not locate the mothers of the Suf and Shif families, and I was unable to confirm all six Shif ducklings together. Nevertheless, simply establishing that the ducklings were still present was valuable.
I would continue searching for them on subsequent days.
Why I Preserve Long, Unedited Wildlife Footage
My YouTube Shorts primarily feature Eastern Spot-billed Duck families and other remarkable moments of urban wildlife behavior.
Short-form wildlife videos, however, are necessarily selective. They may contain music, sound effects, cuts, slow motion, captions, and other forms of editing. These techniques make important moments easier to understand and enjoyable to watch, but they also remove much of the continuous context surrounding an animal's behavior.
I am personally cautious about interpreting heavily edited wildlife footage without seeing what happened before and after a dramatic moment.
That is why my short videos originate from a very different kind of archive.
For more than 1,000 days, I have repeatedly visited local waterways and recorded wild animals for long periods of time. Much of this material is preserved with minimal or no editing, retaining natural sounds, uneventful periods, unsuccessful searches, ambiguous encounters, changes in weather, and the ordinary behavior surrounding the moments that eventually become short videos.
These recordings are not intended to be polished wildlife documentaries. They are chronological field records.
A single day's footage may seem mundane, but when observations accumulate across hundreds or thousands of days, they can document seasonal changes, individual animals, breeding success, duckling survival, predator encounters, flood events, habitat use, family movements, and changes in animal behavior over time.
I therefore preserve these videos as observational evidence as well as wildlife footage.
I recognize that long, largely unedited recordings are less convenient to watch. However, I hope this growing archive can serve as useful reference material for birdwatchers, wildlife enthusiasts, researchers, educators, and anyone interested in the real behavior of animals living alongside people in urban environments.
🦆 Raw Bird & Wildlife Footage | No BGM 🌍️
https://www.youtube.com/playlist?list=PLL7dTQKKqrPzZpmfSA98tn9tXWfkp1jBB
Timestamps / Notes
00:00 Highlights (out of order)
*Yesterday, heavy rain caused the river to rise significantly. I didn’t see any of the duck families, so I didn’t film. Today... there they are! Just as I was about to start filming...
01:00 Duck family... and a Grey Heron 
01:08 オf2-36(31) — They’re in their usual spot!
*Despite yesterday’s major flooding, they weren’t swept away!
01:51 Catfish!? Looks like one... I’m glad the ducklings are bigger now
*Probably a catfish. I couldn’t confirm it even in slow motion, but judging by the way it moved, that’s what it seemed like. This is the same spot where two キf ducklings were taken one after another. Maybe catfish come here when the river rises...
02:50 オf mother doesn’t seem wary of the Grey Heron. Unusual at this distance
05:34 Lots of swallows because of the rain... Ah! A duckling!
05:39 Looks like a シf duckling, around 24 days old... but I can hear other ducklings calling too
06:07 There! This looks like a スf duckling, around 15 days old... but there should be three...
*シf and スf ducklings... It’s not very easy to tell them apart in the footage, but while filming, I felt I could distinguish them by differences in their calls, locations, and overall appearance.
07:18 I thought I heard what sounded like the mother’s call... but I’m not sure
08:44 Looks like all three スf ducklings are here! I guess I was mistaken about hearing the mother
09:03 A little upstream from the three スf ducklings, I can occasionally see シf ducklings... but they’re not all together
10:35 Mother!? Apparently not. The three スf ducklings split into groups of 1 and 2
*At first, a スf duckling threatened and chased this adult away. The two upstream didn’t seem too bothered when it approached them? It’s hard to tell because of the rain, but this adult duck is behaving in a way that caught my attention, so I decided to follow it.
12:10 Found one シf duckling
12:41 The シf duckling and the adult duck from earlier approached each other... but I’m not sure what to make of the reaction
▲▲▲ End of timestamps
*After this, I waited for a while, but I stopped hearing the ducklings’ calls and could no longer find either スf or シf, so I decided to leave.
*There were definitely three スf ducklings. I couldn’t get them all on camera, but I definitely saw at least two シf ducklings.
So... I was worried about the effects of the rain since yesterday, but for now, オf, スf, and シf had all survived the flooding and were still in their usual areas. I couldn’t find the スf or シf mothers, and I wasn’t able to see all six シf ducklings together... but at least I was lucky enough to confirm where they were. I’ll look for them again tomorrow and over the next few days.
*There are too many duck families to keep track of individually, so I identify the mothers by the patterns on their tertial feathers and assign each one a code. 【Identification chart ↓】
https://okasinaikimono.blogspot.com/2025/08/0811f.html
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