wgeoff

1440 Chinese Goshawks flew through Po Toi this morning between 9.30am and 11.30am, a spectacular sight.

Unlike the previous high count of 780 on 16th April 2006, which could only be seen from the highest point of Po Toi, this movement took place right through the harbour, the birds passing at heights mostly below 200 feet in a steady steam with more than one thousand birds between 10.30 and 11.30am.
This meant that those birdwatchers on the Ferry could witness the spectacle - in fact, they landed right in the middle of it.  

My photos cannot do it justice, but Neil took some video shots and I am hoping the video will give you a better impression



These birds will have been migrating north across the South China Sea between the Philippines and East China/Taiwan when they came up against the cold front which passed through Hong Kong on Tuesday afternoon and were driven west by the strong NE winds towards the coast of South China. They probably made landfall on the Dangan Islands late yesterday and overnight, then resumed their migration this morning to reach Po Toi in the late morning. See the HKO weather chart for yesterday



An amazing sight for all those lucky enough to witness it

[ Last edited by wgeoff at 15/04/2010 17:28 ]

wgeoff

Thanks Gary, it was an amazing two hours. Thanks also to Neil for the video.

I think all the spring high counts of Chinese Goshawk (and Grey-faced Buzzard) in Hong Kong are related to cold fronts - certainly all the ones I have had on Po Toi are. Otherwise we just get a few birds, I think most birds will make landfall well to the east of Hong Kong when the weather is good, in Fujian and Taiwan. Here is a map with the regular route of a satellite-tracked Grey-faced Buzzard (I think)



Hong Kong spring counts for these species are tiny by comparison with some places in Taiwan. Kao Shiung averages about 30,000 Chinese Goshawks every spring with regular daily counts of 5000 and a maximum of 33,000 on a single day in 2004. Grey-faced Buzzard counts in a place called Chung Hwa average 15,000 every spring with a daily count of 4000 quite common.

All these figures are recorded in the Asian Raptor Network website http://www5b.biglobe.ne.jp/~raptor/index.htm

[ Last edited by wgeoff at 16/04/2010 07:00 ]

wgeoff

Just to add to my previous posting.

In Spring 2009, Taiwan Raptor Group satellite tracked 5 Grey-faced Buzzards on their spring migration from Philippines to North Korea. Four of them took the route via Taiwan. The fifth one (the green line in the map below) went via south China, to the west of Hong Kong.
See this map



Why did it go via south China?
The detailed maps showed this bird arrived in south China on 15th April 2009. Here is the HKO Weather Map for 14th April 2009, the date when it must have been making the sea crossing.
It ran into the cold front when crossing the South China Sea, which pushed it westwards.



It still made it to North Korea for the breeding season, as you can see from the first map.

We only get these raptors in large numbers when adverse weather conditions push them west into south China. This is probably true also for most of our spring Philippine migrants, in particular flycatchers, but also Brown Hawk Owl, Brown Shrike, Yellow Wagtail (simillima). Large numbers for them also tend to coincide with adverse weather. Other migrants coming around the south China coastline such as buntings can also be affected by bad weather, but not as seriously because they are flying close to or over land.

[ Last edited by wgeoff at 16/04/2010 18:12 ]