greenshanks & a murder @ SBWR - Nov2017 from SgBeachBum on Vimeo.
Monday, November 13, 2017
greenshanks & a murder @ SBWR - Nov2017
The crows had a few moments ago ganged up against the visiting whimbrels successfully causing them to flee for fear of being clawed at. This time it was the greenshanks' turn (and a hapless common sandpiper who thought the greenies were safe to hang around with).
With the crows being repeatedly concentrated within the safe refuge of the wetland reserve due to the crow-culling team shooters regularly lingering outside the boundary of the protected wetland reserve, their numbers have increased to such a level that any species even remotely competitive would eventually be harassed away by the relentless murders of crows. This change in the avian dynamics within Singapore's only wetland reserve seems inevitable given the persistent crow culling just outside.
The crows have also begun their taste experiments with organisms within the muddy mangrove substrate. No doubt they had plenty of opportunity to watch and learn from their shorebird cousins. This puts them in direct competition with the shorebirds which unfortunately have a much less aggressive disposition as compared to the average marauding murder of house crows. This perhaps explains why the crows harass the shorebirds.
Saturday, September 23, 2017
Bar-Tailed Godwit & Whimbrels @ Pulau Sekudu
Ventured to Chek Jawa on 23Sep2017 a bit too late as the tide was fast rising. Some shorebirds had flown to Pulau Sekudu to roost on the granite boulders. There were a handful of about 15 whimbrels and a lone bar-tailed godwit along with some common sandpipers and what could be a grey plover. The video clip shows the bar-tailed godwit amongst the whimbrels as the wind picked up before a sudden downpour. The birds moved to another part of the island to avoid the worst of the strong winds which preceded the rain.
Thursday, August 10, 2017
Yishun Dam shorebird primer @ 9Aug2017 PM
The Yishun Dam sees quite a number of shorebirds throughout the July to April months. Hearing that there were lesser sand plovers and whimbrels reported at the dam, i paid the dam a visit in the evening of 9Aug2017. It was a moderate low tide of about 1.0m at about 6.15pm and there was a bit of the mudflat exposed.
An average of two counts gave a number of 65 lesser sand plovers and 1 little egret on the mudflat near the dam. There were no whimbrels though. The presence of fishermen wading about at the shore area to the left of the mudflat was enough for some of the LSPs to take flight towards the right at first and then across the bay.
Looking beyond the bay towards the eastern tip of the military training area, there is a sandbar with eastern part of Pulau Seletar in the background. This is about 1250m away (measured via Google Earth) and one can just about make out some birds on the sandbar with a scope.
At this distance, any positive ID of the smaller shorebirds is purely a guess. I'm guessing there were about 70 to 90 LSPs (it was easy to lose count due to the distance and the birds flying about in small groups) at the sandbar. I also saw 3 whimbrels with their distinctive curved bills. I could not make out any redshanks or greenshanks. There were also two great-billed herons walking about looking for food. Discounting what most likely were mynahs, the sandbar seemed to house a rather large number of shorebirds. A conservative LSPs count alone for both the mudflat and sandbar should be between at least 135 to 155.
It is possible that the mangroves and shore area closer to the western tip of Pulau Seletar may also house a good many shorebirds. It is a pity this area is difficult to access....anyone got a boat?
Given the number of fishermen at the mudflat in front of the dam that evening, it looked like the birds were mostly avoiding the mudflat and preferring instead to stay at the faraway (and pretty isolated) sandbar.
Assuming that there would have been a much lower number of fishermen in the morning, perhaps a weekday low tide visit would see more of the shorebirds on the mudflat instead of on the faraway mudflat.
Given the lack of sandbars, mudflats and mangrove areas on both the eastern and western shores of mainland Singapore, the Yishun Dam mudflat and adjacent sandbars serve a very important role in feeding these yearly avian visitors much like how the Mandai mudflat (beside the Causeway) is on the western shore.
One has to ask why the shorebirds frequent these shores? What do these shores have that other shore areas do not have?
Yishun Dam primer @ 9Aug2017 PM from SgBeachBum on Vimeo.
An average of two counts gave a number of 65 lesser sand plovers and 1 little egret on the mudflat near the dam. There were no whimbrels though. The presence of fishermen wading about at the shore area to the left of the mudflat was enough for some of the LSPs to take flight towards the right at first and then across the bay.
Looking beyond the bay towards the eastern tip of the military training area, there is a sandbar with eastern part of Pulau Seletar in the background. This is about 1250m away (measured via Google Earth) and one can just about make out some birds on the sandbar with a scope.
At this distance, any positive ID of the smaller shorebirds is purely a guess. I'm guessing there were about 70 to 90 LSPs (it was easy to lose count due to the distance and the birds flying about in small groups) at the sandbar. I also saw 3 whimbrels with their distinctive curved bills. I could not make out any redshanks or greenshanks. There were also two great-billed herons walking about looking for food. Discounting what most likely were mynahs, the sandbar seemed to house a rather large number of shorebirds. A conservative LSPs count alone for both the mudflat and sandbar should be between at least 135 to 155.
It is possible that the mangroves and shore area closer to the western tip of Pulau Seletar may also house a good many shorebirds. It is a pity this area is difficult to access....anyone got a boat?
Given the number of fishermen at the mudflat in front of the dam that evening, it looked like the birds were mostly avoiding the mudflat and preferring instead to stay at the faraway (and pretty isolated) sandbar.
Assuming that there would have been a much lower number of fishermen in the morning, perhaps a weekday low tide visit would see more of the shorebirds on the mudflat instead of on the faraway mudflat.
Given the lack of sandbars, mudflats and mangrove areas on both the eastern and western shores of mainland Singapore, the Yishun Dam mudflat and adjacent sandbars serve a very important role in feeding these yearly avian visitors much like how the Mandai mudflat (beside the Causeway) is on the western shore.
One has to ask why the shorebirds frequent these shores? What do these shores have that other shore areas do not have?
Yishun Dam primer @ 9Aug2017 PM from SgBeachBum on Vimeo.
Sunday, July 30, 2017
Redshanks @ SBWR-30July2017
The morning low tide was, as usual, dominated by the resident crocodiles (and there were 5 today) including a rather small one just over a metre long.
Then there was a flash of white and red that flew past the main bridge towards the sand bar. Could this be a redshank? One of the over-summering ones or a returning adult?
My first thought was that the two birds seen were over-summering juveniles. This is now some doubt as to whether the two birds in the videoclip are over-summering redshanks which did not return north with the larger group of shore birds in late April. After the main group had left in late April, there were about 7 redshanks seen in the weeks after at SBWR throughout the better part of May, occasionally being seen at the sand bar south of the bridge in the main river.
Given that one of the two birds has a geolocater in addition to the green-white tags, this means that the geolocater bird is not a juvenile and likely did return North (likely to the summer grounds in the Tibetan plateau) in April-May.
About two weeks ago, I had seen one redshank zoom past the main bridge but this was identified solely by a guess after momentarily seeing a very noticeable pair of red legs. This had been my first sighting of a redshank after even the over-summering redshanks had disappeared around mid-May. Perhaps this lone bird has been part of the over-summering group which had found another better place to roost.
Towards the end of the clip, a resident collared kingfisher greets the returning redshanks by dive-bombing one of the redshanks. Looks like SBWR is gearing up for the return of the migratory shore birds in August. It has begun.
Then there was a flash of white and red that flew past the main bridge towards the sand bar. Could this be a redshank? One of the over-summering ones or a returning adult?
My first thought was that the two birds seen were over-summering juveniles. This is now some doubt as to whether the two birds in the videoclip are over-summering redshanks which did not return north with the larger group of shore birds in late April. After the main group had left in late April, there were about 7 redshanks seen in the weeks after at SBWR throughout the better part of May, occasionally being seen at the sand bar south of the bridge in the main river.
Given that one of the two birds has a geolocater in addition to the green-white tags, this means that the geolocater bird is not a juvenile and likely did return North (likely to the summer grounds in the Tibetan plateau) in April-May.
About two weeks ago, I had seen one redshank zoom past the main bridge but this was identified solely by a guess after momentarily seeing a very noticeable pair of red legs. This had been my first sighting of a redshank after even the over-summering redshanks had disappeared around mid-May. Perhaps this lone bird has been part of the over-summering group which had found another better place to roost.
Towards the end of the clip, a resident collared kingfisher greets the returning redshanks by dive-bombing one of the redshanks. Looks like SBWR is gearing up for the return of the migratory shore birds in August. It has begun.
Saturday, April 22, 2017
Flight of the Whimbrels @ Sungei Buloh Wetland Reserve - 16Apr2017
April is when the visiting shorebirds fly up North back to their summer breeding grounds. They will not be back until September-October as part of their annual cycle. In the videoclip, the birds appear to be rather plump as they fly past. Looks like they had a successful Winter stayover at SBWR.
All that feeding on the Mandai mudflats at low tides has paid off to restore the energy stores on these long range birds. They have to make the flight back up North. This is no easy task. This last weekend may be their last or rather our last opportunity to see the flock of whimbrels (numbering about 165 at the highest count this year) fly to, fro and about the Sungei Buloh Wetland Reserve along with about 60 greenshanks and up to about 250 redshanks for companionship. The counts vary every few days from September through April as the birds may alternate between roost sites.
Their reliance on the coastal mudflats is absolutely crucial and the birds' flight out from SBWR to the Mandai mudflats everyday in expectation of the best low tide window to feed is indicative of the importance of the mudflats for the birds. Without the rich feeding grounds presented by the mudflats and the safe open roosting sites nearby at SBWR, these birds would have disappeared from our skies in search of the right combination of feeding and roosting grounds elsewhere. Indeed, the numbers of shorebirds at SBWR ten years ago were in the thousands. In recent years, the number has reduced to just a few hundred and with a reduction in the number of species also. The reduction could be explained by the shorebirds preferring alternative roosting sites instead of SBWR.
Given that most of the shorebirds prefer open roosting grounds, it is possible that recent (within the last 4 years) mangrove land development across the Johor Straits has made open grounds temporarily available and the birds have flocked there instead. When the builders move in on that cleared land, the birds may choose to roost back at SBWR's open controlled water level ponds. It takes about 4 minutes for the birds to fly between SBWR and the Mandai mudflats and this short flight enables the birds to burn only a small amount of calories allowing them to stock up on their reserves without expending too much energy each day flying to and fro. Each day, they may get about 5 to 6 hours of feeding at the mudflats or more depending on how low or high the tides for the day were. The moon's effects on the tides nevertheless plays an intrinsic part as to how much the birds can feed each day. They even feed throughout the dark of night at Mandai if suitable low tides present themselves overnight.
Given that the SBWR birds often roost within the controlled ponds and do not have sight of the receding tides, the birds must have an innate sense for knowing when to fly out for the low tides. Generally, they fly out about 2 to 3 hours before the lowest tide and they fly back in about 3 hours after the lowest tide. The timing depends on how fast or slow the tides move. Sometimes, the birds are a little delayed in their departure out from the controlled water level ponds (where the water level does not change with the tides). This could be due to the 'leader' birds themselves losing track of tides and delaying their flights out.
Flying back is necessarily dictated by the rising coastal waters and the average length of the whimbrel's legs. Usually, the smaller plovers (eg. mongolian, pacific golden) take off first with the rising tide followed by the redshanks, then greenshanks. The whimbrels leave last. The whimbrels and greenshanks were not seen on 22 April 2017. It is possible they finally flew North sometime during the week. There were still about 30 redshanks and handful of pacific golden plovers seen at SBWR on 22 April 2017. Last chance to see them before they too fly North this year.
Flight of the Whimbrels @ Sungei Buloh Wetland Reserve - 16Apr2017 from SgBeachBum on Vimeo.
Interesting links :
https://www.facebook.com/AWSG.sat.tag/?hc_ref=PAGES_TIMELINE&fref=nf
https://www.youtube.com/watch?v=W95SJ6BLdG0 - An Interview with a Bar-tailed Godwit.
https://www.youtube.com/watch?v=MRPZYjsMUZ0 - Oh My Godwit, The longest bird migration in the world.
https://www.youtube.com/watch?v=Q-mMMpl_T80 - TedEd - Bird Migration, A Perilous Journey
https://www.youtube.com/watch?v=Ahm9x8QTQJk - the physics of bird migration
https://www.youtube.com/watch?v=4JUYyMHOHb8 - how do birds know where to go when they migrate?
https://www.youtube.com/watch?v=CwIT9pv4kh
https://www.youtube.com/watch?v=WhwBDjfWr_M
https://www.youtube.com/watch?v=8FcCJIpsH0U
http://www.worldmigratorybirdday.org/news/2017/stopping-habitat-loss-china-proposes-yellow-sea-be-added-world-heritage-tentative-list-0
http://www.birdlife.org/worldwide/news/chasing-ghosts-how-technology-helping-track-bird-mysteriously-disappeared
All that feeding on the Mandai mudflats at low tides has paid off to restore the energy stores on these long range birds. They have to make the flight back up North. This is no easy task. This last weekend may be their last or rather our last opportunity to see the flock of whimbrels (numbering about 165 at the highest count this year) fly to, fro and about the Sungei Buloh Wetland Reserve along with about 60 greenshanks and up to about 250 redshanks for companionship. The counts vary every few days from September through April as the birds may alternate between roost sites.
Their reliance on the coastal mudflats is absolutely crucial and the birds' flight out from SBWR to the Mandai mudflats everyday in expectation of the best low tide window to feed is indicative of the importance of the mudflats for the birds. Without the rich feeding grounds presented by the mudflats and the safe open roosting sites nearby at SBWR, these birds would have disappeared from our skies in search of the right combination of feeding and roosting grounds elsewhere. Indeed, the numbers of shorebirds at SBWR ten years ago were in the thousands. In recent years, the number has reduced to just a few hundred and with a reduction in the number of species also. The reduction could be explained by the shorebirds preferring alternative roosting sites instead of SBWR.
Given that most of the shorebirds prefer open roosting grounds, it is possible that recent (within the last 4 years) mangrove land development across the Johor Straits has made open grounds temporarily available and the birds have flocked there instead. When the builders move in on that cleared land, the birds may choose to roost back at SBWR's open controlled water level ponds. It takes about 4 minutes for the birds to fly between SBWR and the Mandai mudflats and this short flight enables the birds to burn only a small amount of calories allowing them to stock up on their reserves without expending too much energy each day flying to and fro. Each day, they may get about 5 to 6 hours of feeding at the mudflats or more depending on how low or high the tides for the day were. The moon's effects on the tides nevertheless plays an intrinsic part as to how much the birds can feed each day. They even feed throughout the dark of night at Mandai if suitable low tides present themselves overnight.
Given that the SBWR birds often roost within the controlled ponds and do not have sight of the receding tides, the birds must have an innate sense for knowing when to fly out for the low tides. Generally, they fly out about 2 to 3 hours before the lowest tide and they fly back in about 3 hours after the lowest tide. The timing depends on how fast or slow the tides move. Sometimes, the birds are a little delayed in their departure out from the controlled water level ponds (where the water level does not change with the tides). This could be due to the 'leader' birds themselves losing track of tides and delaying their flights out.
Flying back is necessarily dictated by the rising coastal waters and the average length of the whimbrel's legs. Usually, the smaller plovers (eg. mongolian, pacific golden) take off first with the rising tide followed by the redshanks, then greenshanks. The whimbrels leave last. The whimbrels and greenshanks were not seen on 22 April 2017. It is possible they finally flew North sometime during the week. There were still about 30 redshanks and handful of pacific golden plovers seen at SBWR on 22 April 2017. Last chance to see them before they too fly North this year.
Flight of the Whimbrels @ Sungei Buloh Wetland Reserve - 16Apr2017 from SgBeachBum on Vimeo.
Interesting links :
https://www.facebook.com/AWSG.sat.tag/?hc_ref=PAGES_TIMELINE&fref=nf
https://www.youtube.com/watch?v=W95SJ6BLdG0 - An Interview with a Bar-tailed Godwit.
https://www.youtube.com/watch?v=MRPZYjsMUZ0 - Oh My Godwit, The longest bird migration in the world.
https://www.youtube.com/watch?v=Q-mMMpl_T80 - TedEd - Bird Migration, A Perilous Journey
https://www.youtube.com/watch?v=Ahm9x8QTQJk - the physics of bird migration
https://www.youtube.com/watch?v=4JUYyMHOHb8 - how do birds know where to go when they migrate?
https://www.youtube.com/watch?v=CwIT9pv4kh
https://www.youtube.com/watch?v=WhwBDjfWr_M
https://www.youtube.com/watch?v=8FcCJIpsH0U
http://www.worldmigratorybirdday.org/news/2017/stopping-habitat-loss-china-proposes-yellow-sea-be-added-world-heritage-tentative-list-0
http://www.birdlife.org/worldwide/news/chasing-ghosts-how-technology-helping-track-bird-mysteriously-disappeared
Monday, February 20, 2017
crows vs eagle @ SBWR - Feb 2017
This clip shows the ubiquitous house crows harassing a juvenile white-bellied sea eagle. The crows are certainly persistent and each brave enough to mess with the much larger eagle.
The eagle tried its best to maintain its balance but lost it and had to take to the air although it was clearly unprepared to do so and seemingly forgot to tell its legs that it was no longer on the tree.
Tuesday, February 7, 2017
Subscribe to:
Comments (Atom)