wgeoff

First Week in May - Tuesday 5 to Thursday 7 May.

Another week spent looking for seabirds, particularly Short-tailed Shearwaters, and I thought I'd missed out again until ...



very early morning on Thursday. It passed in less than one minute, about 400 yards offshore, typical and good enough for me.

These birds fascinate me since the discovery of their annual spring passage through HK waters in 2006. Why do we see them in Hong Kong in such a focused period, mostly the last week in April and the first two weeks in May, when they should be so far away in the Pacific Ocean somewhere?

The answer can come partly from a paper published in 2014 by CSIRO in Australia, "Trans-equatorial migration of Short-tailed Shearwaters revealed by geolocators". It has long been known that the 20 million birds breeding in southeast Australia migrate across the Pacific to the cold waters north of Japan for their non-breeding season, our summer. But the migration routes and timing were not known, until birds fitted with geolocators in their breeding season in early 2008 were recovered later that year.

20 birds were recovered and their travels during 2008 are given in this diagram



Firstly after breeding, they travel southeast to Antarctic waters south of New Zealand, to fatten up for their long journey. Then they set off, first north and then northwest, to their wintering grounds in the seas off Japan. This journey of 11,000 kms is covered in about 13 days or about 840 km per day, so very quickly. It is unlikely they feed during this migration.
All these movements are very consistent in timing, at least between this 20 birds from one breeding location. Eleven of the twenty arrived in Japan in just two days, on 29 and 30 April.

So how does this compare with what we saw in 2008, and what we consistently see each year for this species?
Firstly, just like the main migration, our birds are very consistent in their timing, more than 40% of HK records occur in the seven days between 10 and 16 May. In 2008 that number was 76%, 25 out of 33 records that year.
But why the delay of about two weeks between our records and the main arrival in Japan? The distance is about the same. But if they are travelling at 840 kms per day, they can travel a long way in that extra two weeks.
Obviously our birds get diverted from the main track somewhere, possibly in the Indonesian islands. Or they may even go the wrong way around Australia, or even up into the Indian Ocean before finding their way back - there are records at this time from the Straits of Malacca between mainland Malaysia and Sumatra. We just don't know the answer to this yet.

Next week should be a good week for this species, and I will be there on Po Toi from Tuesday to Thursday trying to catch the peak passage.   

What else this week? Very few seabirds, a few Black-naped and Bridled Terns from local colonies and one Greater Crested.
On land, the southerly winds and lack of rain meant almost nothing arriving. We have had southerly winds non-stop from 24th April to today, and on for at least the next nine days according to the forecast. And with this, on Po Toi at least, no rainfall. So just some migrating egrets, the White-breasted Waterhen still on the South Peninsular, an Oriental Pratincole, a Dollarbird, several Yellow and eight Grey Wagtails, up to five Brown Shrikes, single Grey-streaked and Asia Brown Flycatchers and Little and Black-faced Bunting - poor fare for early May.

No sign of the Fairy Pitta I was hoping for - but the stream it uses is totally dry this year. The biggest surprise was a Hill Myna which spent five minutes in the tall trees by the school



From today (Friday 8 May) to Tuesday 12 May is the Po Toi Festival Week - Opera, Dragonboat Racing and thousands of people in the main Village area.
Here is the revised Ferry Timetable for that period



[ Last edited by wgeoff at 8/05/2015 09:23 ]

wgeoff

Tuesday 12th to Thursday 14th May.

Having spoken about this being the peak week for Short-tailed Shearwaters, and having stayed on the Island especially to see them, I was very disappointed to see none at all in the three days. This has only happened once before, in 2011. I won't try to explain it.

By way of a small compensation, there was a good passage of terns, eight species including White-winged, Whiskered, Common, Gull-billed, Greater Crested as well as the locally breeding Black-naped, Roseate and Bridled terns, some of which may have been passage birds. White-winged are particularly attractive in flocks, here with a Bridled



The long hours seawatching was also compensated by the arrival of land birds flying in off the sea, always exciting to see. Particularly exciting was a Black-winged Kite which flew in on Wednesday morning and spent the morning on the South Peninsular, and a more regular Striated Heron.  



The Black-winged Kite is only the second Po Toi record.

The Long-toed Stint seen in the lagoon area over the weekend is a first record for Po Toi and was still there on Tuesday but left on Wednesday night.



Other more regular species for mid-May were four Red Turtle Doves in the tall trees on Tuesday (two only in the photo), a few Brown Shrikes, Arctic Warblers and at least seven Grey-streaked Flycatchers on Tuesday. Late species for May included a very late Swinhoe's Minivet on Tuesday, photo by Peter Ho with thanks, a Yellow-browed Warbler and a White-shouldered Starling on Wednesday.



I won't be staying on Po Toi again this spring, or maybe at all - it's a young man's game, very exhausting. Just going for days from now on.

PS my thanks to all the Po Toi supporters who sent their comments in to the Town Planning Board. Let's hope it makes them think.

[ Last edited by wgeoff at 15/05/2015 17:22 ]

wgeoff

Thanks Ivan.

Yes, I had a note of your record in 2012.
I didn't look carefully enough, there have actually been at least three previous records of Black-winged Kite

25 March 2008
24 September 2009
22 April 2012 - yours

Geoff

wgeoff

Hi Alan

The waders are Curlew. At least one tern on the rocks (third from right) looks like a Roseate or Common Tern

Geoff

[ Last edited by wgeoff at 17/05/2015 19:21 ]

wgeoff

Not much to see on Tuesday, except for terns.

The number of terns around Po Toi Rock (Castle Rock) seems more than I have seen before. My estimates based on photos taken were
Black-naped - 100+
Bridled - 40+
Roseate - 20+



These numbers may be related to the ban on trawler fishing around Hong Kong - there are certainly many more small fish to be seen around the Island.
I'm not sure if all the terns will breed on the Rock - it will be very crowded if they do.

On the Island, just a single Red Turtle Dove



This species is a frequent late May migrant on Po Toi.

Two very different kinds of boats seen on the way over and back. Firstly, the largest Oil Rig I have seen in HK waters. Secondly a new type of sailing boat, raised up on a narrow platform, the only thing in the water. Otherwise, it would be flying - and it certainly was very fast

wgeoff

At last a change of weather.
After heavy rain on Wednesday night, the wind turned to strong easterly by Thursday morning - the first non-southerly wind since late April.
Too late for most land bird migrants, but good conditions for late seabird migrants.

Unfortunately, I did not stay on the Island this week as this wind change was not predicted by HKO. I went straight to the South Peninsular from the Ferry but it was too late for any seabirds. I was compensated by a Himalayan Swiftlet feeding on the small insects using the protected side of the cliff face there. I had some very close views over the hour it was there, unfortunately too close for my camera which anyway insisted on focusing on the sea or the rocks.



This species is a fairly regular late May and September migrant on Po Toi, suggesting a breeding ground somewhere close in Guangdong.




The three breeding species of Tern, Black-naped, Roseate and Bridled, could all be seen feeding off the South Peninsular although Bridled feed much further out than the other two.
Here three Roseates together with a smaller first summer White-winged Tern (I guess)



On land, a Brown Shrike and a quite late Grey-streaked Flycatcher in the tall trees by the lower school.

In earlier years I would have stayed on Po Toi this week whatever the weather forecast and almost certainly seen some small Bittern species as well as possibly an interesting seabird. But I can't do that any more.

That's my last visit this spring, I'm off to UK at the end of next week.

wgeoff

A good set of records Alan.

Apart from the Yellow and Schrenck's Bitterns (and possible Black Bittern), which are all regular after bad weather in late May, I'm particularly interested in the Frigatebird, the Common Myna and the Yellow-fronted Canary.

May is the peak month for Lesser Frigatebird. The bird was seen again on Po Toi on Monday and may be the same as one photographed off Tai O two weeks ago.

The Common Myna is only the second record I have for Po Toi, the other being also in May but in 2007.

Yellow-fronted Canary is an annual May and September species for Po Toi, as the following chart shows



I believe these birds come to Po Toi each year to breed (I have once seen a juvenile being fed). From where? - I guess somewhere in Hong Kong or the surrounding area.
There is evidence of similar breeding migration for the species in Taiwan. I think the species should probably be on the main HK List, in Cat IIB.