Following is a day-to-day account of the happenings at the Raptor Migration Watch in Chumporn, written by Dr. Robert DiCandido, a visiting professor from New York and Mr. Chukiat Nulsri, the local Thai coordinator of this event. This post covers Week Five of the event, held at Pencil Hill (Khao Dinsor) and Radar Hill.
Birders interested in participating in the event should contact Khun Chukiat at his e-mail address: bnternstar@gmail.com
All photos and information portrayed in this post are courtesy of Dr. Robert and Khun Chukiat unless otherwise stated and are used with express permission from the authors.
17 September – Saturday – Khao Dinsor, Thailand (Day 25)
75% to 100% cloudy (no rain!)
Winds WSW – approx. 5-18 mph (9-30km/hr)
Japanese Sparrowhawk – 410 – 298 adults (after hatch-year); only 3 hatch-year birds – of the 301 clearly seen.
Chinese Sparrowhawk – 10 (adult males/females and first-year birds)
Oriental Honey-buzzard – 1 (adult male)
Brahminy Kite – 1 (juvenile)
Blue-tailed Bee-eater – 472
Blue-throated Bee-eater – 8
Pacific Swift – 9
Little Egret – 67
Barn Swallow – 1,445 (estimate)
Little Egret – 21
A male Paradise Flycatcher (migrant) is hanging around the shelter we count from. These are fairly common coastal migrants here – and about the fourth we’ve seen since 25 August.
18 September – Sunday – Khao Dinsor, Thailand (Day 26)
50% to 90% cloudy (no rain!)
Winds WSW – approx. 5-12 mph (9-20km/hr)
Japanese Sparrowhawk – 183 – 97 adults (after hatch-year); 0 hatch-year birds – of the 97 clearly seen.
Chinese Sparrowhawk – 10 (adult males/females and first-year birds)
Peregrine Falcon ssp. ernesti – 1 (adult; local resident)
Blue-tailed Bee-eater – 459
Blue-throated Bee-eater – 23
Pacific Swift – 15
Little Egret – 15
Barn Swallow – 2,020 (estimate)
19 September – Monday – Khao Dinsor, Thailand (Day 27)
50% to 90% cloudy (no rain!)
Winds WSW – approx. 5-12 mph (9-20km/hr)
Japanese Sparrowhawk – 224 – 166 adults (after hatch-year); 0 hatch-year birds – of the 166 clearly seen.
Chinese Sparrowhawk – 104 (adult males/females and first-year birds)
Oriental Honey-buzzard – 1 (adult male)
Black Kite – 1 (adult; local resident?)
Crested Goshawk (juvenile female; resident)
Blue-tailed Bee-eater – 211
Blue-throated Bee-eater – 4
Pacific Swift – 84
Little Egret – 63
Barn Swallow – 445 (estimate)
Brown-backed Needletail – 1 (local resident)
20 September – Tuesday – Khao Dinsor, Thailand (Day 28)
90% to 100% cloudy (on and off rain all day)
Winds WSW – approx. 8-16 mph (14-26km/hr)
Japanese Sparrowhawk – 255 – 186 adults (after hatch-year); 0 hatch-year birds – of the 186 clearly seen.
Chinese Sparrowhawk – 137 (adult males/females and first-year birds)
Oriental Honey-buzzard – 1 (adult male)
Blue-tailed Bee-eater – 146
Blue-throated Bee-eater – 10
Pacific Swift – 415
Little Egret – 6
Barn Swallow – 1,165 (estimate)
Brown-backed Needletail – 1 (leading a flock of Pacific Swifts)
Rain held back the migration today…
21 September – Wednesday – Khao Dinsor, Thailand (Day 29)
90% to 100% cloudy/fog (light to heavy rain from 10:30am until dusk)
Winds West – approx. 8-16 mph (14-26km/hr)
Japanese Sparrowhawk – 112 – 112 adults (after hatch-year); 0 hatch-year birds – of the 112 clearly seen.
Chinese Sparrowhawk – 108 (adult males/females and first-year birds)
Blue-tailed Bee-eater – 228
Blue-throated Bee-eater – 28
Pacific Swift – 968
Little Egret – 41
Barn Swallow – 8,165 (estimate)
White-throated Needletail – 3 (one flock)
Steady rain after 10:30am today…but for one hour as barometric pressure dropped and winds increased to 12-18 mph (22-32km/hr), there was significant migration, particularly Barn Swallows and Pacific Swifts. Of more interest is that each day there is a significant pressure drop sometime between 10am to 1pm and these are the hour(s) when most migration occurs. Low pressure is to the east (South China Sea) and high pressure to west (Andaman Sea). As thermals rise and west winds push further east (and combine with a westerly sea breeze), the west winds (and air) rise above the air near the coast. This I believe is what the migrants utilize (wind and lift) – as they move from inland to the coast by late morning.
Rain is forecast for the next several days – sometimes heavy – this will slow migration during some hours but there will be “windows” when birds will come through in large numbers…usually quite low.
22 September – Thursday – Khao Dinsor, Thailand (Day 30)
75% to 100% cloudy/fog (no rain)
Winds West-Southwest – approx. 8-16 mph (14-26km/hr)
Japanese Sparrowhawk – 295 – 209 adults (after hatch-year); 0 hatch-year birds – of the 209 clearly seen.
Chinese Sparrowhawk – 524 (adult males/females and first-year birds)
Oriental Honey-buzzard – 2
Brahminy Kite – 1 (adult)
Pied Harrier – 1 (adult female)
Crested Goshawk – 1 (juvenile female; local resident)
Blue-tailed Bee-eater – 344
Blue-throated Bee-eater – 27
Pacific Swift – 598
Little Egret – 25
Barn Swallow – 285 (estimate)
23 September – Friday – Khao Dinsor, Thailand (Day 31)
98% to 100% cloudy/fog (rain and drizzle almost all day)
Winds West-Southwest – approx. 8-16 mph (14-26km/hr)
Japanese Sparrowhawk – 313 – all adults that we could determine…
Chinese Sparrowhawk – 389 (adult males/females and first-year birds)
Crested Goshawk – 1 (juvenile male; local resident)
Blue-tailed Bee-eater – 50
Blue-throated Bee-eater – 0
Pacific Swift – 1,557
Oriental Pranticole – 4
Little Egret – 6
Barn Swallow – 185 (estimate)
Red-rumped Swallow – 3
Brown-backed Needletail – 2
Silver-backed Needletail – 2
White-throated Needletail – 2
The six Needletails came through in one flock – luckily between what Phil Round and I saw, combined with what Martti Siponen photographed, we were able to determine the ID of all the birds in the small flock.
24 September – Saturday – Khao Dinsor, Thailand (Day 32)
80% to 100% cloudy (rain and drizzle after 4pm)
Winds West-Southwest – approx. 8-16 mph (14-26km/hr)
Oriental Honey-buzzard – 3
Japanese Sparrowhawk – 522 – all adults – except for two juveniles
Chinese Sparrowhawk – 2,564 (adult males/females = 80-90% and first-year birds = 10-20%)
Eastern Marsh Harrier (2nd or 3rd year male)
Brahminy Kite – 1 (adult)
Crested Goshawk – 1 (juvenile male; local resident)
Blue-tailed Bee-eater – 76
Blue-throated Bee-eater – 0
Pacific Swift – 425
Little Egret – 23
Barn Swallow – 125 (estimate)
- To be continued .
Thank you very much for publishing these observations. Both Apus pacificus and Hirundapus caudacutus have experienced a significant decline in recent years throughout Australia and it is interesting to compare the numbers you have flying South at this time.
Cheers & Happy birding
Mike