Board logo

Subject: Po Toi Seawatch Winter 2021/2022 [Print This Page]
Author: badesc    Time: 6/12/2021 16:55     Subject: Po Toi Seawatch Winter 2021/2022

Here we are with the first survey of the 2021/2022 winter, i.e. December, January and February. As with autumn, there have been very few seawatching surveys in winter, particularly in December. That month is basically completely uncovered. Besides this survey, we plan another one in the second half of the month.

As we’ve entered the winter, let us first have a look at a seasonal forecast. I know, often the weather seemed of little influence to what we’ve seen so far, but we’re still somewhat paying attention to it. Here’s the forecast from the Hong Kong Observatory, issued on 29 November 2021 (source: https://www.hko.gov.hk/en/Whats- ... t-for-winter-202122)

“In the past month or so, sea surface temperatures of the central and eastern equatorial Pacific continued to decrease and became below normal in October 2021. Based on the latest oceanic observations as well as forecasts by a number of climate models around the world, the central and eastern equatorial Pacific are expected to remain colder than normal during winter 2021/22 (December 2021 – February 2022). The situation is likely to develop into a short-lived La Niña event. Statistical analyses indicate that when La Niña occurs during wintertime, winter temperatures in Hong Kong generally tend to be lower than those during the ENSO-neutral state. On the other hand, under the influence of global warming and local urbanization, winter temperatures in Hong Kong show a significant long-term rising trend, partially counteracting the effect of La Niña. Taking all available information into consideration, including prediction from climate models around the world, the temperature in winter 2021/22 in Hong Kong is expected to be normal to above normal.

“Although the average winter temperature in Hong Kong is expected to be normal to above normal, day-to-day fluctuations in weather and temperature can still be quite large with occasional cold weather. It is expected that the number of cold days in winter 2021/22 would be close to that of previous winter. Please refer to the latest local weather forecast and 9-day weather forecast issued by the Hong Kong Observatory. Cold weather refers to temperature falling to 12℃ or below. On average, there are about 14 cold days per winter. During the last winter, there were 14 days of cold weather.

“The impact of La Niña on winter rainfall in Hong Kong is not significant. The majority of climate models predict that the rainfall over southern China is likely to be normal to below normal in winter 2021/22.”

Of course, we were looking for some unusually cold weather, in the hope it would bring a few more ‘arctic’ species down to Hong Kong. But alas, at least according to the above analysis, we’d better have low expectations.

Anyway, February has seen the most records in Hong Kong of birds from the (far) north, so we might have to wait a few more months.

2 to 4 December

To start with, there was yet another cold front:



We didn’t pay too much attention to it regarding our planning and the survey took place after the cold front had arrived.

I started on 2 December, watching from 11h30 until 16h30. The weather was very nice, but not so much for seawatching from Po Toi. It was clear and sunny (yes, bad lighting) and with heat haze. Winds were blowing from the northeast, with force 4. Fairly good numbers of gulls and two species of terns.

Ducks:
9 Northern Shovelers

Gulls:
2 large white-headed gulls
191 Black-headed Gulls

Terns:
1 Common Tern
1 Caspian Tern

Also one gull/tern spec and 1 Barn Swallow. Here’s the checklist: https://ebird.org/checklist/S98350005

3 December was the only full day of this survey, from 07h00 to 16h30. Weather was exactly the same as the previous day. There was good passage of gulls today.

Egrets:
4 white egrets spec.

Ducks:
14 ducks spec.

Raptors:
1 Common Kestrel

Gulls:
18 large white-headed gulls
371 Black-headed Gulls
2 Black-tailed Gulls

Also 1 gull/tern spec. Most of the large white-headed gulls were in one large group of Black-headed Gulls and were most probably all 1st year Black-tailed Gulls. Here’s the checklist: https://ebird.org/checklist/S98393702

And 4 December was already the last (half) day, during which I seawatched from 07h00 to 14h30. The weather was a little different, with a few scattered clouds and force 5 winds, again from the northeast. It was a very quiet day, with only the falcon after 11h00. And surprisingly, compared to the previous day, there weren’t any Black-headed Gulls migrating to the west.

Ducks:
4 Tufted Ducks
2 Northern Pintails

Raptors:
1 Peregrine Falcon

Gulls:
1 large white-headed gull
7 Black-headed Gulls
2 Black-tailed Gulls

Terns:
1 Caspian Tern

Here’s the checklist: https://ebird.org/checklist/S98435301

Remarks:

As most records of (rare) northern species are in February, December would perhaps not be a fantastic month. Of course, we can’t draw much conclusions from just one survey, but it could be that this month will indeed be a rather quiet one. Apart from gulls, there are fewer southbound migrants, winter has just started, and it’s too early for any northbound migrants as well. A month that falls between the two migratory periods – autumn and spring – while perhaps too early for real winter visitors. But we do plan another survey this month, before Christmas, to see what’s out there.

And both bad lighting on sunny days and the heat haze causes us to likely miss some birds and being unable to identify others. Let’s wait for the second survey, but I think December will not be my favorite month for seawatching here.

But still, it was worthwhile:

1/ Tufted Duck was the first record for Po Toi. We’ve now – in autumn and so far in winter – observed no less than four new duck species for the island, the other ones being Northern Pintail, Northern Shoveler and Eurasian Wigeon.

2/ The count of 371 Black-headed Gulls was a record high count for Po Toi and Hong Kong southern waters.

3/ The Common Tern on 2 December was a new late date, the first December record and also the first winter record for Hong Kong.

So, even though we saw not that much, no seabirds and no rarities, we managed to get some fairly satisfying records.

Image Attachment: temperatures.jpg (6/12/2021 16:55, 91.92 KB) / Download count 501
http://hkbws.org.hk/BBS/attachment.php?aid=42529

Author: wcaptain    Time: 6/12/2021 22:44

Author: badesc    Time: 27/12/2021 10:13

21 to 23 December

As planned, I did a second survey in December, before Christmas. Coincidentally, there was typhoon Rai, which moved towards Hong Kong.



It did a lot of damage in the Philippines, but was rather weak when it came close to Hong Kong and only the standby signal 1 was issued. At Po Toi, the weather and wind were not abnormal, but we might have been a day too late to take full advantage (if there was any) of the storm.

Our first seawatching day was on 21 December and it was cloudy, with a little bit of heat haze and temporary some drizzle. Winds were blowing from northeast and then from the north, with force 5 at noon and force 4 in the afternoon. Observation hours were from 11h45 until 17h00.

Raptors:
2 Eastern March Harriers

Gulls:
19 gulls spec.
10 Black-tailed Gulls
9 Black-headed Gulls
2 Mongolian Gulls

Here’s the checklist: https://ebird.org/checklist/S99217491

From now on, our surveys are also published on the well-known migration-records site Trektellen. Many of our sightings are (at least for the time being) omitted by eBird from bare charts and from general sightings-lists (but not from individual checklist). Trektellen will allow analysis of the full range of sightings. This will be clear when we post the 2021 review here. So here’s the count: https://trektellen.nl/count/view/3323/20211221

The only full day of this survey was on 22 December, when I watched from 07h00 to 17h00. (NB: the last hour or so of the day, has always been extremely quiet in December.) Cloudy, so with good lighting. Winds turning from north to northeast with force 3. Mainly gulls on this day, but I had hoped for higher numbers.

Grebes:
3 Great Crested Grebes

Herons and egrets:
3 Grey Heron
1 Little Egret

Waders:
1 Eurasian Curlew

Gulls:
33 gulls spec.
13 Heuglin’s Gulls
10 Black-tailed Gulls
10 Black-headed Gulls
1 Mongolian Gull

Terns:
1 Caspian Tern

Here’s the checklist: https://ebird.org/checklist/S99432682 and the count https://trektellen.nl/count/view/3323/20211222

The last day, 23 December finally saw good numbers of Black-headed Gulls, with either singles or dense groups of 30-80 birds. I watched from 07h00 to 14h00 and it was a cloudy early morning, but turned sunny later. Winds blew from the northeast, force 4 to (mainly) 5.

Ducks:
2 ducks spec.

Gulls:
16 gulls spec.
269 Black-headed Gulls
2 Black-tailed Gulls

Here's the checklist https://ebird.org/checklist/S99432723 and the count https://trektellen.nl/count/view/3323/20211223

Remarks:

Obviously, mainly gulls were seen. Just one (Caspian) tern and also very few ducks, herons and egrets. There is still migration going on, but numbers were low and there were long ‘dead’ periods, during which not a single bird was seen. It has been most birdy from roughly 07h00 to around 10h00 and again from 13h00 to around 15h30.

All Black-tailed Gulls involved 1st calendar year birds.

The 3 Great Crested Grebes – one group – were only the second record for Po Toi. The previous record was a dead bird on the shoreline in the harbour of Po Toi (Geoff Welch in litt.). I believe they could actually migrate in small numbers off Po Toi, but we’ll have to wait for further winter surveys to see if we can confirm this.

[ Last edited by badesc at 27/12/2021 10:20 ]

Image Attachment: Tropical Cyclone Track and Position 2.jpg (27/12/2021 10:13, 119.78 KB) / Download count 490
http://hkbws.org.hk/BBS/attachment.php?aid=42586

Author: badesc    Time: 27/12/2021 10:16

December 2021

Let’s wrap-up December. There were two surveys, with six observation days: two full days and four half days.

Generally, number of birds were rather low. The most numerous species from November, Black-headed Gull and Caspian Tern, were much less numerous in December. Only 288 Black-headed Gulls and 5 Caspian Terns were counted. A late Common Tern on the 2nd was noteworthy.

Also, no seabirds were seen.
Author: badesc    Time: 14/01/2022 11:08

11 to 13 January

Our first survey of the year was planned during these 3 days.

Arriving with the 10 o’clock ferry, I started seawatching on 11 January from 11h45 onwards, until 17h00. The weather was bright and sunny, but with the usual winter heat haze. Winds almost always seems to be blowing from the same direction in winter, so NE winds, force 4 decreasing to 3 in late afternoon.

The first bird of the year was a Caspian Tern. It was flying westwards, but decided to land on the rear end of a container ship and enjoy the ‘ride’. The year started well, with also 2 Ancient Murrelets.

Seabirds:
2 Ancient Murrelets

Gulls:
15 gulls spec.
7 Black-headed Gulls
1 Heuglin’s Gull

Terns:
2 Caspian Terns

Here’s the checklist on eBird https://ebird.org/checklist/S100535631 and the count on Trektellen https://trektellen.nl/count/view/3323/20220111

After a fairly good day, we looked forward to 12 January. However, you can’t really predict what you’re going to see and the birds decide to show up or not, no matter how good or bad the previous day has been, or how good or bad the weather looks like. You have to take it like it is. And, oh boy, this second day was an extraordinary quiet day. Luckily, such days are very exceptional. Apart from an unidentified migrant bird early morning, I saw only two (!) migrants during the whole day.

You could argue I should have quit early and not staring at an empty sea for 9 and a half hours, but of course you don’t know in advance that the day will turn out like this. And noticing that there are days in January with almost no birds is valuable data as well.

Seabirds:
1 Ancient Murrelet

Gulls:
1 Black-tailed Gull

For what it’s worth, here’s the checklist https://ebird.org/checklist/S100687720 and the count https://trektellen.nl/count/view/3323/20220112

It’s regularly the case that a good day is followed by a less good day (bad days don’t exist), but also that a less good day is followed by a good day. So, not giving up hope, we were ready for seawatching on 13 January, from 07h00 until 14h00. A cloudy day, with limited visibility, and similar winds, but less forceful. And more birds; less birds than the day before would be almost impossible anyway.

Seabirds:
7 Ancient Murrelets

Egrets:
2 Great Egrets

Gulls:
1 gull spec.
5 Black-tailed Gulls
5 Black-headed Gulls

Here’s the checklist https://ebird.org/checklist/S100687829 and the count https://trektellen.nl/count/view/3323/20220113

Remarks

Admittedly, very few migrant birds. Caspian Terns and most Black-headed Gulls flew westwards, but all Ancient Murrelets, Great Egrets, most large gulls and all Black-tailed Gulls flew north-eastwards. So soundbound and northbound migration respectively. That indicates that we’re seeing both migrants: the last ones of the autumn season migrating south and the first ones of the spring season migrating north. Interesting will be our next survey(s) and to see if the northbound migrants will now start to increase in numbers. I do expect every subsequent survey to be better than the previous one, with a climax in April (but that remains up to the birds…).

Noteworthy and an eye-catcher to many, were our daily observations of Ancient Murrelets, all flying straight to northeast. (Two birds landed abruptly on the sea when approached by a Black-tailed Gull, but they were flying to the northeast before that.) It is supposed to be “rare” in winter. So seeing 10, and seeing them every day during our survey, is interesting, to say the least. And with 7 on 13 January, we were close to the highest count, being 9 on 19 February 2006. Normally, the numbers peak in March. Also, they did not appear before 09h40 and the majority was seen between 11h00 and 14h00. We’ll definitely keep an eye on these cool birds in the coming surveys, but I would not be surprised if we’ll see still higher numbers, and eventually a change to their winter status in Hong Kong.
Author: badesc    Time: 17/01/2022 14:26

16 January

During the previous survey this month, the majority of the few migrants appeared during noon. That brought me to the idea to do surveys on Sundays, as the first ferry (from Aberdeen) leaves at 08h15 in the morning and the last one from Po Toi returns at 18h00. That actually provides plenty of time to seawatch. In particular for observing Ancient Murrelets, which – so far – have turned out to be migrating specifically around noon (that is an observation, not yet a conclusion). Hence our first one-day-survey.

So, I could start seawatching from 09h25. As there were no more birds after about 13h00, I watched until 15h50. If gulls or so would have started to appear during the afternoon, I would have prolonged the survey to 17h20.

It was cloudy for most of the time, with winds blowing from the northeast with force 4. It was one of the foggiest days that I have encountered, with visibility limited to roughly 4 km. I couldn’t even see a hint of the Dangan Islands.

Seabirds:
4 Ancient Murrelets

Cormorants:
1 cormorant spec.

Gulls:
1 large gull spec.
2 Black-tailed Gulls

Here’s the checklist https://ebird.org/checklist/S100898449 and the count https://trektellen.nl/count/view/3323/20220116

Remarks:

Not that many remarks for just one day of seawatching, with still very few migrants. But Ancient Murrelet was nevertheless de facto the most numerous species, again.

The cormorant could either have been a Great Cormorant or a Japanese Cormorant. I was unable to see any characters that would strongly suggest one of those species. Great Cormorant is an abundant winter visitor in Hong Kong and is most likely to be seen. Japanese Cormorant is regarded as a rare visitor with only 6 accepted records. The sea area and rocks around Po Toi could potentially be suitable for this species, more so than for Great Cormorant.
Author: badesc    Time: 24/01/2022 16:44

23 January

Another Sunday, another one-day survey. As last week, I watched from 09h25 until 15h50. As usual, northeasterly winds, but only force 3. It was mainly cloudy, with only very little rain. Visibility was excellent, with no (more) heat haze.

It was an enjoyable day, certainly compared to the quiet Sunday a week earlier. Much more gulls on the move this time and birds appearing throughout the day, although the first hour and a half was most busy.

Seabirds:
7 Ancient Murrelets

Ducks:
2 ducks spec.

Gulls:
89 gulls spec.
25 Black-tailed Gulls
6 Heuglin’s Gull
1 Mongolian Gull

Also the first Barn Swallow of the year. Here's the checklist https://ebird.org/checklist/S101333006 and the count https://trektellen.nl/count/view/3323/20220123

Remarks:

This was the best day of the year, as numbers of birds clearly were a lot higher than on any other day in January so for.

We saw the first adult Black-tailed Gulls off Po Toi, 3 in total. Thus far, all were immatures.

On previous days, Ancient Murrelets all flew to the northeast, but this time we saw two flying to the west. And one – on its way to the northeast – landed on the sea.

In general, birds were flying in both directions, indicating that we saw both southbound and northbound migration. However, some birds might just be hanging around in the area and weren’t really migrating (although the majority did fly in a certain direction straight and steadfast). Sometimes we can’t be sure what to make of the behavior and one should wait for more data before jumping to conclusions.

That’s why we’ll do one to two more surveys this month, of which one a 3-day survey.
Author: badesc    Time: 28/01/2022 15:37

25 to 27 January

As planned, here we are with a 3-day survey. And most probably the last survey for this month.

When I was on the ferry, the weather looked not too bad – for what it’s worth: clear views, cloudy and firm easterly winds. And yes, it was worth something because that first day, 25 January, would turn out to be the best one of the three days, even though we missed the first hours.

I could jump as the first passenger off the ferry and had the path free to walk to get prepared for seawatching fast, and I arrived at the seawatch point at 11h25 already. I watched until 17h25. So the weather was cloudy, but it got bright and sunny in the afternoon. Visibility was good with apparently no more heat haze, as we encountered during mainly October-December. Winds were blowing from the east with force 4 (at least). Almost all birds were gulls, most fairly close, and almost all of them flew to the northeast.

Ducks:

1 duck spec.

Gulls:

14 gulls spec. (1 possible Slaty-backed, 1 possible Saunders’s and 1 possible Pallas’s, but too far)
118 Black-tailed Gulls
36 Heuglin’s Gulls
5 Vega Gulls sspec. (mongolicus or vegae)
4 Mongolian Gulls

Here’s the checklist https://ebird.org/checklist/S101566022 and the count https://trektellen.nl/count/view/3323/20220125

With rather similar weather conditions, we were hopeful for the next and full day, 26 January. Winds were unchanged, blowing from the east with force 4. But it stayed cloudy throughout the day, while visibility was limited. I watched for 10 hours, from 07h00 until 17h00. A gull-day again, but alas not as good as yesterday, with especially a very quiet afternoon.

Gulls:

5 gulls spec.
103 Black-tailed Gulls
5 Black-headed Gulls
4 Heuglin’s Gulls
1 Vega Gull sspec.

Here’s the checklist https://ebird.org/checklist/S101566083 and the count https://trektellen.nl/count/view/3323/20220126

And the last day of the survey, 27 January, was the weakest of the three. Winds blew from the northeast, force 3. It was partly cloudy, partly sunny, but with the same limited visibility. Exclusively gulls, all to northeast.

Gulls:

1 gull spec. (possibly Saunder’s)
49 Black-tailed Gulls
9 Heuglin’s Gulls
1 Mongolian Gull

Here’s the checklist https://ebird.org/checklist/S101566119 and the count https://trektellen.nl/count/view/3323/20220127

Remarks:

Gulls were obviously the majority during this survey. And all but one migrated to the northeast. They appeared around a quarter past seven and usually continued flying-by throughout the day. A small dip in numbers could be observed around lunch, and then again more gulls appeared between roughly 13h00 and 15h00. Late afternoon was most quiet.

Concerning Black-tailed Gull, almost all were young birds, in their 2nd calendar year. Only a couple of adults.
Author: badesc    Time: 28/01/2022 15:40

January 2022

Let’s wrap-up January. We did 4 surveys, two 3-day surveys and two Sunday surveys, resulting in 8 (half or full) days of seawatching, which is a bit more than usual.

I feel it was an interesting month. Firstly, we encountered Ancient Murrelets on every survey-day and in relatively good numbers. But by the end of the month, they were suddenly gone, at least none were seen.

According to Lehman (1994) Ancient Murrelets are irruptive in south California, with some years in which large numbers appear. So we might have to be careful when dealing with the occurrence in Hong Kong: Are they wintering around here (they are small birds that are easily overlooked when sitting on the sea)? Are they regular or are they irruptive? Do they winter further south and we only encounter them close to Po Toi while they’re migrating northwards? We’ll see how it goes in the coming months and we might mention this subject again if we have more data.

Secondly, we encountered very few birds and migrants during surveys in the first three weeks of the month. We even had a day (12 January) with just two birds! Only from 25th onwards did we observe obvious northbound migrating of almost only gulls. It seems that the spring migration season kicks-off here in late January.

Lastly, let’s hope the heat haze is a thing of the past for now, as it reduced the ability to identify birds. But the annoying tiny ants we had to endure at the watch points for most of the summer and autumn, were replaced by equally annoying mosquitoes…

References:
Lehman, P.E. 1994. The Birds of Santa Barbara County, California. University of California, Santa Barbara Vertebrate Museum, Santa Barbara, CA, USA.
Author: badesc    Time: 10/02/2022 14:10

6 to 8 February

Time flies, we’re already in February, the last month of our winter period.

I did plan to go for a one-day survey on 2 February, as it was a public holiday. Alas, the ferry company decided otherwise and there was no ferry at 08h15. (I later learned they sailed from 10h00 on that day, but that’s too late for a one-day survey). It’s the second time that the ferry let me down, illustrating one of the disadvantages of seawatching from an island.

Anyway, I started seawatching on day one, 6 February, at 09h50, as this was a Sunday with an early ferry (08h15). The sea was rather rough, with winds blowing from the northeast with force 5. Nice cloudy conditions, meaning good lighting, but limited visibility of about 5000 m. It turned out to be a calm day, but a good one for Ancient Murrelets.

Seabirds:

10 Ancient Murrelets

Gulls:

13 Black-tailed Gulls
2 Heuglin’s Gulls

Here’s the count https://trektellen.nl/count/view/3323/20220206 and the checklist https://ebird.org/checklist/S102313341

7 February was a full day. We looked forward to this day, as there would be strong easterly winds and I was already thinking of something like a Sooty Shearwater or a Sabine’s Gull… (spoiler alert: I did not see any of these). It was a rather odd day. During the first period, from 07h00 to 14h00, I encountered misty circumstances with visibility limited to 1000-1500 m. Due to the mist, it was also wet. Winds were indeed blowing from the east, with force 6 and waves were high. Due to the limited visibility, my best option was scanning the sea with my binoculars. I encountered very very few birds: 2 Black-tailed Gulls and 1 Pacific Swift.

The second period, from 14h00 to 17h00, was very different, after a shower made the mist disappear. Winds turned northeast and were reduced to force 3. Visibility was a lot better and birds appeared instantly after the rain stopped and the mist was gone.

Seabirds:

17 Red-necked Phalaropes

Gulls:

25 Black-tailed Gulls (1 group of 22 right after the rain/mist)
4 Heuglin’s Gulls

Swift(lets), swallows & martins:

2 Barn Swallows
1 Pacific Swift

Here’s the count https://trektellen.nl/count/view/3323/20220207 and the checklist https://ebird.org/checklist/S102313495

On 8 February the mist was still gone and winds were still blowing from the northeast, with force 5.

Seabirds:

4 Red-necked Phalaropes
2 Ancient Murrelets

Egrets & herons:

1 Little Egret

Gulls:

120 Black-tailed Gulls
4 Heuglin’s Gulls
1 Mongolian Gull

Swift(lets), swallows & martins:

8 Barn Swallows

Here’s the count https://trektellen.nl/count/view/3323/20220208 and the checklist https://ebird.org/checklist/S102313568

Remarks

Yes, quite a few remarks I like to make this time.

In general, and what we expected, the survey was better than the ones before, with higher counts of some species and also a few more species: the first Little Egret of the year, the first Pacific Swift of the year, the highest number of Black-tailed Gulls, the highest number of Barn Swallows so far, and the appearance of Red-necked Phalaropes. It can and will only get (much) better from here on, but of course with the usual ups & downs.

During mornings, migration starts slow. In contrast to other periods, like September when lots of terns appeared even before sunrise, I saw the first birds somewhere between 07h15 and 07h30, and just a few. It builds up from there to until about 09h00 to 10h00 and slows a bit down after that. But it clearly doesn’t stop at 10h00; birds continue to migrate.

Ancient Murrelets were back, after being absent in late January. I’d like to wait for February and winter to be over to make some more remarks, but we’ve counted up to 33 in January and February so far. I think that’s already more than in most winters, maybe even the highest number in any winter pre-2021/2022. And note, as was to be expected, the 10 individuals on 6 February were a new record high count for Hong Kong. I still believe this record will be broken in the near future, but it’s of course up to the birds.

Red-necked Phalaropes are a rare sighting in winter in Hong Kong. The peak occurs around April. Outside this period, I’ve experienced that they occur with strong onshore winds and often when other oceanic birds appear, like shearwaters or a booby. After the rain and mist subsided on 7th, they suddenly appeared in different groups, flying in different directions. There were almost certainly more around, as I saw small birds appearing to be landing on the sea but (too) far out. But anyway, Red-necked Phalaropes outside their normal spring occurrence could signal the appearance of other oceanic birds. Of course, there is no guarantee and none were seen on 7th. A reason could well be that it’s simply too early for tubenoses and jaegers.

Some interesting stuff concerning Black-tailed Gulls.

Firstly, on 7th, with strong easterly winds, I saw them flying to the north to northwest, not to the northeast, as if they wanted to avoid flying against strong winds (but they are capable of doing that, if they want to). Their flight behavior also was rather lackluster, as if they were in no mood to migrate. I concluded early that the morning would not produce much, until the mist would subside and the wind to be reduced.

Secondly, on 8th, and with less wind and no mist, the migration clearly picked up, which makes sense. But besides that, I’ve experienced that migrants in autumn fly further out than in spring. This is logical to some extent, if you’d look at a map: southbound birds in autumn would divert from the coast, while northbound birds in spring bump on to the coast, so to speak. Yet it is very intriguing that we did see shearwaters, petrels, storm petrels and jaegers in autumn as well.

But back to the Black-tailed Gulls on 8th. Of the 120 birds, 52 flew westwards (southbound) and 67 northeastwards (northbound) (and 1 to the north). Very noticeably, the vast majority of northbound gulls flew rather close, while all the southbound gulls flew much further out.

It is a bit strange that this happens in the Lema Channel and Southern Hong Kong waters, as if the area is a dual carriageway. It is the first time I noticed this with the same species on the same day.

[ Last edited by badesc at 10/02/2022 14:39 ]
Author: badesc    Time: 22/02/2022 06:23

15 to 19 February

Time for a longer survey: five days. What was interesting, was the forecast for strong winds blowing from the east and southeast during this survey. Hence, we were of course on the lookout for some oceanic birds. Eventually, we got only easterly winds, not south-easterly, but did get the oceanic birds.

I started seawatching on 15 February a bit later than usually after arriving with a weekday ferry, at 12h00, until 17h30. A White’s Thrush along the way to the seawatch point was a nice one, although not a seabird ;-). The weather was cloudy, but turned sunny rather soon, and the sea became a glistering mirror (read: bad lighting conditions). Luckily, there weren’t that many birds. Winds were blowing from the northeast with force 3 to 4, and there was some fog, which was lifted during the day when it turned sunny.

Seabirds:
1 Ancient Murrelet

Gulls:
23 Heuglin’s Gulls
1 Black-headed Gull

Swift(lets), swallows and martins:
2 Barn Swallows

Checklist on eBird: https://ebird.org/checklist/S102674427
Count on Trektellen: https://trektellen.nl/count/view/3323/20220215

16 February was a day with strong winds – force 6 – from the east, which in theory could be good for seabirds. It was, but not with high numbers. I started at 07h00 and seawatched until 17h00. At least it was cloudy, but visibility was limited due to fog. Things would only get better from this day on. Very noteworthy was the absence of any gulls, but a good count of Ancient Murrelets.

Seabirds:
8 Ancient Murrelets
2 jaegers spec.
2 Pomarine Jaegers
1 Long-tailed Jaeger
1 Red-necked Phalarope

Swift(lets), swallows and martins:
3 Barn Swallows

Checklist on eBird: https://ebird.org/checklist/S102726959
Count on Trektellen: https://trektellen.nl/count/view/3323/20220216

Winds continued to blow from the east, with force 6, on 17 February. Still cloudy, with some rain, and limited visibility. It was clearly a rough sea, good for seabirds, apparently. I watched from 07h00 until 17h15.

Seabirds:
33 Streaked Shearwaters
1 jaeger spec.
1 Pomarine Jaeger
1 Long-tailed Jaeger
4 Red-necked Phalarope

Gulls:
6 Black-tailed Gulls

Raptors:
1 Peregrine Falcon

Swift(lets), swallows and martins:
2 Barn Swallows

Checklist on eBird: https://ebird.org/checklist/S103144787
Count on Trektellen: https://trektellen.nl/count/view/3323/20220217

The fourth day, 18 February, turned out to be very good. Still the same winds and cloud-cover, but better visibility and dry. Again, I watched from 07h00 until 17h15.

Seabirds:
204 Streaked Shearwaters
3 Ancient Murrelets
2 jaegers spec.
23 Pomarine Jaegers

Ducks:
3 Eurasian Teals

Gulls:
5 gulls spec.
33 Heuglin’s Gulls
1 Black-tailed Gulls

Waders:
1 Common Redshank
1 Pacific Golden Plover

Swift(lets), swallows and martins:
8 Barn Swallows

Checklist on eBird: https://ebird.org/checklist/S103145009
Count on Trektellen: https://trektellen.nl/count/view/3323/20220218

The last day of this survey, 19 February, was good as well, although winds turned to north-northeast and dropped to force 5, at most. Visibility was good, especially when dry, but it did rain quite a bit. It turned noticeably cold. I started at 07h00, but finished at 12h30. Several other seawatchers were still present when I left and their results are included below.

Seabirds:
139 Streaked Shearwaters
2 Ancient Murrelets
1 jaeger spec.
1 Pomarine Jaeger

Egrets and herons:
2 white egrets spec.

Gulls:
128 Black-tailed Gulls
7 Heuglin’s Gulls
1 Mongolian Gull

Swift(lets), swallows and martins:
8 Barn Swallows

Checklist on eBird: https://ebird.org/checklist/S103158625
Count on Trektellen: https://trektellen.nl/count/view/3323/20220219 These are the counts of both others and me.

Remarks

On the one hand, we’ve seen good seabirds (and good numbers) before, without strong winds from the east, and on the other hand – and pointed out by Geoff before – easterly winds do often produce good results. I think we can say this was indeed the case during this survey. I believe it does not exclusively depends on wind direction and strength, but also on the time of the year and on the weather system over a much larger area, not just off Po Toi. It’s the right combination of several factors that might increase the chance for seeing many seabirds in Hong Kong. But of conditions are right, it’s awesome.

Furthermore, and weather related, the appearance of a pretty robust cold front on 19 February did seem to have a very clear impact on some birds. Remember that we failed to see such a clear pattern in November and December. But on 19th, with temperatures dropping to 11°C, all gulls were returning and flying to the west. Even Ancient Murrelets were seen flying in that direction.

Regarding the jaegers, the number we encountered – 35 in total – is pretty decent. Usually, Pomarine Jaeger is the earliest jaeger in late winter/spring, and we counted 27, with 23 on one day, which is rather high. Thank the easterly winds for that. Much more ‘unusual’ were the two Long-tailed Jaegers. The first one being an older individual, but not an adult in full breeding plumage, and the second one a very close-by 2nd calendar year bird. Both stood out very clearly from the Pomarine Jaegers seen on the same days and they were also surely not Parasitic Jaegers. The earliest day for the latter is 21 March, but there were a few that I could not identify as certain Pomarine or Parasitic, hence ‘jaeger spec.’. The previous early date for Long-tailed Jaeger was 12 March.

Again some interesting remarks about Black-tailed Gulls. Namely on 18th, with many shearwaters and jaegers, I recorded only one individual. But Roman Lo, who was seawatching from Cape D’Aquilar, counted 81. It seems that they fly closer to land to avoid strong headwinds that appear in the Lema Channel. But above all, we obviously don’t record every coastal migrant from Po Toi!

Again, good numbers of Ancient Murrelets, with a nice count of 8 on 16th. I made this video: https://youtu.be/u5WUMBx8An0. Please do change the quality manually to 2160p 4K.

Of course, the most prominent seabird encountered, was Streaked Shearwater. It started with just 3 in the morning of 17th and the highest counts were 204 on the morning of 18th and 158 during just 50 minutes in the afternoon on the same day. The shearwaters were counted flying to the northeast, but later many flew to the west, and back. Some stayed around for a long time, some rested on the sea. Especially on 18th they were everywhere. We’ll never know the exact number, but it’s by far the highest count for Hong Kong and also the first record in February and during winter.

As many already know, this is only part of the story… I’m leaving it for the end of these remarks, as it is a bit of an additional story, but one that I think is useful to share.

In brackets I put the number of mistakes and errors I made and will discuss them later in the text.

On 17th, I saw 1 shearwater flying to the west. Actually two, and followed by a third one. My first idea was early Streaked Shearwater, evidently. But when I looked at the birds’ head, I noticed it was not whitish. I should say face, rather than head, as Streaked is darker towards its neck. The birds appeared small-headed, with a noticeably dark cap. The tail was rather long. The photo below was taken on another day, but perfectly illustrates this brief description (more photos are on eBird and a video is posted here: https://youtu.be/u5WUMBx8An0; please do change the quality manually to 2160p 4K).



“These must be pale morph Wedge-tailed Shearwaters!”, I thought (1). A rare vagrant to Hong Kong, with only two previous records of dark morph singles in autumn. 20 minutes later, I encountered – presumably the same – three shearwaters flying northeast. Then one slowed down, turned a bit and showed a long, clearly wedge-shaped tail. I also noted a scaly appearance on the mantle and scapulars and an indistinctive pale diagonal bar on the upperwings. But with that wedge-shaped tail, these must indeed be Wedge-tailed Shearwaters! (2) I immediately shared the news with the birding community (3).

That afternoon, 33 shearwaters flew west again. And again I thought I must be looking at Wedge-tailed. There was nothing else on my mind.

The next day, they appeared even before I started the count. And that resulted in an unbelievable high number of 204 (4).

It attracted quite a few birders on Saturday and most of them saw the shearwaters (5).

Finally, when I did examine the 800+ photos at home, I realized very quickly that they were all Streaked Shearwaters. I immediately shared this conclusion with the birding community. I’m glad I at least recognized my own mistake.

Mistakes and errors:

(1) With Wedge-tailed, I was dealing with a vagrant seabird, but A/ did not went over all the characters I should be seeing and B/ did not check my photos clearly, or better yet, simply waited until the evening to check on my laptop and sort it out thoroughly.

(2) After the first thought, I was completely biased towards Wedge-tailed an was only looking at anything that matched that species, without considering anything else any longer. This is actually odd, as I usually challenge myself not only to confirm an ID, but also to look for anything that could prove my first idea wrong. E.g., when seeing a dark-rumped storm petrel off Po Toi, the first thought is Swinhoe’s, but then you should be looking not only why it’s this species, but also why it is not a Matsudaira’s. Same with the Bulwer’s Petrels I saw: clearly Bulwer’s, but in the field, I went over almost everything else, from noddies, jaegers, dark morph Wedge-tailed Shearwaters, dark storm petrels to even nightjars, but failed to see any characters that would point to any of these species, but Bulwer’s.

I obviously should have followed the same procedure here, and not just having only Wedge-tailed in my mind.

It's partly maybe also a matter of ego. I think everyone has that to some extent. You don’t want to report “shearwaters spec.” which you will identify when you’re at home. You want to identify them without any doubt on the spot, although there is actually nothing wrong with having a much more prudent approach. After all, it’s better to be approximately right than exactly wrong…

(3) Sharing the observation of a rarity with the birding community is in itself normal and correct, but you do make a statement. You do pound in what you’ve just pounded out and it leaves actually even less room to go back and think it over. I did not copy any of the photos to my laptop to look at them clearly that evening, I just thought I could do that at home, later, and show everybody good shots of Wedge-tailed Shearwater.

It’s strange. I’ve been trying to improve the seawatching in all possible ways: looking and finding new watch points to better cope with the wind, staying full days seawatching, replace pen and paper with a voice recorder, trying different cameras with different lenses or with digiscoping to improve photographic recording, bringing a laptop to work on the survey results,… But just copying the photos to examine them was something I completely neglected. I sure will be doing this in the future!

(4) Friends called it “crazy”, “unreal”, “unbelievable” and “ridiculous”. All very well meant, of course, but they were right. I should have gone through the ID process again; 200 Wedge-tailed Shearwaters is unreal for Hong Kong. “Sure they weren’t Streaked?” That thought never appeared to me. I was submerged in the believe that they were Wedge-tailed. The more you repeat that thought and the more you mention it to others, the less likely you’re going to change your mind. Even when I noted in the field that, flying head-on, they all seem to have whitish faces. “So what, they’re Wedgies and nothing else”, I must have been thinking.

(5) As far as I know, nobody doubted the ID of the birds (although some might quietly have wondered if there were Wedge-tailed for sure). We all are subject to confirmation bias and when we’re twitching species XYZ, that’s what we will be looking for. I felt rather honoured that people trusted my identification process and also did not doubt it, but confirmed it. But seeing Streaked Shearwaters on the photos, feelings turned into shame and embarrassment. All these people came over for the wrong reason.

Identification points:

The separation of pale morph Wedge-tailed Shearwater and Streaked Shearwater is not always that easy. And certainly in Hong Kong, we should be very careful with it. We now know that it is indeed a rarity and a single one or at most a few is what we can expect, not hundreds. And maybe only dark morphs and only in summer-autumn.

Shun, from Japan (Twitter: @morgan930_m), was so kind to let me share some of his photos of both species side-by-side.







He also mentioned his video's of both species: https://youtu.be/edfpmbwpGcI and https://youtu.be/plqNtREmhzA. Thank you Shun!

Jemi Holmes reminded us of this website from the well-known seabirders Hiroyuki and Shoko Tanoi, also from Japan, with good photos of Wedge-tailed Shearwaters and this species side-by-side with Streaked on fig. 21 and fig. 22: http://seabirding-japan.com/wedge-tailed-shearwater/

At a distance, when seawatching from land, even when the birds are relatively close (500-750m), many obvious differences start to fade away. But I do believe that the rear-end has some good clues. Wedge-tailed has a fairly clearly and dark undertail, while dark is rather limited to the tip of the tail in Streaked. And Wedge-tailed lacks any white on the uppertail and rump, whereas Streaked shows more or less white feathers. Tail shape and scaling on the upperparts are actually quite similar. And details on the head are not that clear from a distance.

Yann Muzika also stressed the difficulty of separating pale morph Wedge-tailed from Streaked “at a distance and without direct comparison, as flight style and structure are very similar”. He further added, based on his experience, that Wedge-tailed is quite variable in size and that larger birds are only slightly smaller than Streaked, making ID based on size very tricky. Unless given good views at close range, the pattern of the head and the undertail coverts can easily lead to mistakes. I can confirm that, yes ;-).

Congratulations if you’ve read until the end! Hope you enjoyed this story and it is at least something we can learn from. I sure did, obviously never too old to learn.

[ Last edited by badesc at 22/02/2022 06:48 ]

Image Attachment: _6__0387.jpg (22/02/2022 06:23, 203.83 KB) / Download count 443
http://hkbws.org.hk/BBS/attachment.php?aid=42804



Image Attachment: 1.jpg (22/02/2022 06:48, 264.02 KB) / Download count 407
http://hkbws.org.hk/BBS/attachment.php?aid=42821



Image Attachment: 2.jpg (22/02/2022 06:48, 286.61 KB) / Download count 418
http://hkbws.org.hk/BBS/attachment.php?aid=42822



Image Attachment: 3.jpg (22/02/2022 06:48, 271.83 KB) / Download count 437
http://hkbws.org.hk/BBS/attachment.php?aid=42823



Image Attachment: 4.jpg (22/02/2022 06:48, 302.33 KB) / Download count 429
http://hkbws.org.hk/BBS/attachment.php?aid=42824



Image Attachment: 5.jpg (22/02/2022 06:48, 206.62 KB) / Download count 416
http://hkbws.org.hk/BBS/attachment.php?aid=42825

Author: John Holmes    Time: 26/02/2022 05:16     Subject: Shear Bliss

Great write-up, Bart !

I think the important thing is that keen birders who weren’t afraid of the bad weather (including yourself) saw dozens of shearwaters from Po Toi, - what an experience it must have been.

Streaked Shearwater would still be a “HK Tick” for many, and a spectacular species by any standards.

Anyway, I’m looking forward to more Po Toi seawatching accounts, now that spring migration is getting started.
Author: badesc    Time: 1/03/2022 15:19

Quote:
Original posted by John Holmes at 26/02/2022 05:16
Great write-up, Bart !

I think the important thing is that keen birders who weren’t afraid of the bad weather (including yourself) saw dozens of shearwaters from Po Toi, - what an experience it must ...
Thanks, John. Yes, shearwaters and petrels are spectacular - certainly with strong winds - and so is indeed Streaked Shearwater.
Author: badesc    Time: 1/03/2022 15:24

27 February

There was room for one more Sunday survey, to finish the month and the winter season.

So, we were present on 27 February from 09h25 until 17h20. The weather was bright and sunny, with only some clouds in late afternoon. To cope better with the bad lighting, I watched from point 2, the most south-westerly watch point, as this provides a very broad panoramic view. Winds blew from the northeast, with force 3 to 4. Visibility was limited, due to fog. A group of 6 Red-necked Phalaropes from the ferry was actually a good start.

Seabirds:
1 Streaked Shearwater
3 Ancient Murrelets
4 Red-necked Phalaropes

Gulls:
39 gulls spec.
41 Heuglin’s Gulls
13 Mongolian Gulls
7 Black-tailed Gulls
1 Vega Gull subspec.

Terns:
8 Caspian Terns

Waders:
2 Pied Avocets

Swift(lets), swallows and martins:
8 Barn Swallows

Checklist on eBird: https://ebird.org/checklist/S103945058 The one Vega Gull is missing here, because eBird only lets me chose between ssp. vegae or ssp. mongolicus and does not provide the choice for Vega Gull (vegae or mongolicus).
Count on Trektellen https://trektellen.nl/count/view/3323/20220227 If you want to look at our records and analyse them in many different ways, visit Trektellen!

Remarks

Northbound movement of large gulls was obvious. As demonstrated by Geoff’s extensive work on Nam Kok Tsui in the past, March is the peak month for gulls and we saw the start of that by the end of February. We also noted the first Caspian Terns migrating to the northeast.

Although there were no real onshore winds, seabirds were observed, with the shearwater, murrelets and phalaropes.

[ Last edited by badesc at 4/03/2022 17:58 ]
Author: badesc    Time: 1/03/2022 15:28

February 2022

Let’s wrap-up February. We did 3 surveys, covering 9 days. One 3-day survey (2 half days, 1 full day), one 5-day survey (2 half days, 3 full days) and 1 full Sunday. Total seawatching time during the month was 76 hours and 10 minutes, much more than in January (57 hours and 50 minutes).

It seems the month in which spring migration took off and was clearly visible, although there were indications that we witnessed the start of that – to a lesser degree – already by late January. The number of species flying northbound certainly increased in February and so were the numbers of individuals. Interesting though, was the southbound migration of gulls and Ancient Murrelets when a cold front arrived on 19th. We can most probably assume that the next survey, in March, will see birds flying mostly northbound again, as real cold weather should subside and spring will be in the air.

The two species in February with the highest counts were Streaked Shearwater (377) and Black-tailed Gull (300). Certainly for the shearwaters, there were most probably double counts on different days during the period when the majority were seen (17th to 19th). But it is fair to say that more than 200 passed Po Toi or stayed around in the area.

The first migrating waders were noted as well: Common Redshank (1), Pacific Golden Plover (1) and Pied Avocet (2). The latter should be the first record for Po Toi.

30 Red-necked Phalaropes is a good count for a winter month, or maybe it’s just normal that they start to appear in February. So are 27 Pomarine Jaegers and especially 29 Ancient Murrelets. The appearance of shearwaters, jaegers and phalaropes was most likely helped by strong easterly winds. We also noted the first two Long-tailed Jaegers for winter in Hong Kong. February was a good month.
Author: badesc    Time: 1/03/2022 15:34

Summary of winter 2021/2022

This is an overview of all seabirds, grebes, terns and gulls seen during the winter (i.e. December, January and February) of 2021/2022. Below are the totals for the whole season. We mostly encountered winds from the northeast and from the north and the east as well.



Good birds and numbers have been seen over the past year or so, yet there’s usually just a single seawatcher present, who can’t see everything and who only visits the spot on limited occasions. In other words, usually there’s nobody there. My point is that I feel most people still vastly underestimate the full potential of the Lema Channel or the true abundance of migrants in the area. I still believe that I don’t witness much unusual stuff – the area is just that good in Hong Kong, and actually even much better than what we can observe, which is only a small part.

But back to our winter review. There were 23 survey-days, exactly the same as in autumn.

Not a bad season either, although – based on our limited data – the first half of January seems to be the quietest period. But both December and February saw satisfying number of birds. The highlights of this winter season were:

200+ Streaked Shearwaters
30 Red-necked Phalaropes
27 Pomarine Jaegers
2 Long-tailed Jaegers
629 Black-tailed Gulls
875 Black-headed Gulls
16 Caspian Terns
1 Common Tern
50 Ancient Murrelets

Yes, double counts could always be possible, as we counted birds flying in both directions. A few noteworthy points.

(1) We never thought we’d be counting a record number of Streaked Shearwaters in a winter month. Highest numbers should occur in spring, yet only one of our high counts was in this season:

204 on 18 February 2022
149 on 22 July 2021
139 on 19 February 2022
129 on 16 April 2021

So, how many are we going to count in the coming spring? Below are the high counts since 2005, based on data from the Hong Kong Bird Report up to 2018 and our own counts in 2021 and (so far) in 2022:



(2) Species like Red-necked Phalarope, Pomarine Jaeger and Long-tailed Jaeger seem to occur before spring starts, already in February. Same thought here: these numbers should increase in the coming months.

(3) The peak in Black-tailed Gulls should occur in March. Yet, January was the busiest month for this species in the past winter. High counts during January and February were 128, 120, 118 and 103 when it was much more common than in autumn and December. The graph below, from Trektellen, shows our counts during 2021 and 2022.



(4) Noteworthy points regarding Black-headed Gulls: 1/ The total winter count was of 875, making it the commonest bird in the season; 2/ most individuals were seen in December (but we counted 651 last autumn, mainly November); 3/ they have been absent since January – will they occur in March? The graph below shows the opposite pattern from Black-tailed Gull.



(5) 50 Ancient Murrelets were counted during the winter season, but none in December. During January and February, they were seen on 70% of our surveys, making it a pretty regular bird. The highest count, and a new high count for Hong Kong, was 10 on 6 February. We could encounter even more in the traditional high season for them, March. But I do think that they are a regular winter visitor to southern waters, not a rarity in this season. They could be irruptive, as mentioned earlier, but that might mean we then would see even more individuals. Only future winter seawatch surveys from Nam Kok Tsui would make any conclusion more definite.

Spring has been mentioned a few times in this review, as a season that should be even better. Together with autumn, it’s the busiest season for migrant birds, of course. We, too, look forward with great optimism to an awesomely good spring.

[ Last edited by badesc at 1/03/2022 15:39 ]

Image Attachment: count.jpg (1/03/2022 15:34, 186.55 KB) / Download count 432
http://hkbws.org.hk/BBS/attachment.php?aid=42846



Image Attachment: streaked shearwater.jpg (1/03/2022 15:34, 19.66 KB) / Download count 425
http://hkbws.org.hk/BBS/attachment.php?aid=42847



Image Attachment: black-tailed gull.jpg (1/03/2022 15:34, 36.34 KB) / Download count 429
http://hkbws.org.hk/BBS/attachment.php?aid=42848



Image Attachment: black-headed gull.jpg (1/03/2022 15:34, 39.32 KB) / Download count 424
http://hkbws.org.hk/BBS/attachment.php?aid=42849





Welcome to HKBWS Forum 香港觀鳥會討論區 (http://hkbws.org.hk/BBS/) Powered by Discuz! 6.0.0