Friday, August 13, 2010

11th August 2010: Think like a wader!

It's the return migration season again, and the first urgent task of a dedicated wader-watcher is to locate the main roosting sites. This may be quite simple in many countries where the coastline stays more or less the same from year to year, and where known roost sites are well-protected. Here, it's a bit more complicated.

For a start, the whole west coast of the Peninsula is in a constant state of ebb and flux, with currents eroding the mudflats in some areas and depositing silt in others. Then, as soon as mud starts to appear, mangroves follow, increasing the richness of the mud, but also, eventually, eating up the open areas which the waders need to feed in. So every year, or every few years, favourite wader feeding areas shift.

Then there are the high tide roost sites. There are very few natural areas left where birds can roost safely. So they are forced to improvise, using temporarily exposed open areas in construction sites, prawn ponds, paddyfields, etc. These may only be available for one or two seasons, and then they have to find alternatives.

Today and the next few days are the highest tides of the year - king tides - which means there'll be a long period in the day when the birds have to find somewhere away from the tidal zone to roost - which gives me the best chance of finding the roost.

To find it, I need to think like a wader!

1. I need to know where the best feeding area is. From past experience I know that the mudflats north of the port usually hold higher numbers than areas south of it.

2. I need to find suitable roost areas within a few kilometers of the main feeding area. A suitable roost area needs:

i) Good all-round visibility so the birds can see potential predators approaching. This means no or little ground vegetation, and the larger the wide-open space the better.
ii)Low disturbance.
iii)Freshwater or brackish water, where the birds can bathe and drink.

First of all I checked areas where birds had roosted in the past. The construction site where I found the birds last year was, surprisingly, still there, though smaller and more surrounded by new houses. I asked one of the workmen if birds still came there and he said they did, though he estimated fewer than a hundred. I checked the area thoroughly and found a small area where there were wader footprints and feathers - a good sign of a roost. Nevertheless, it didn't seem large - probably only a small flock. By now the tide was high, and I felt that if the birds were using this site, they should be here by now. So I guessed they probably only use it when the labourers are not working.

Searching for these temporary roost sites is labour-intensive, as they don't normally exist for long enough to appear on Google Earth. I drove many kilometers down narrow roads behind the mangroves in the hope of finding something.

Eventually, on my last throw of the dice, I was driving along a narrow road through a small Malay fishing village when suddenly, a cloud of waders rose from an area to my left. The jackpot!

I discovered that the birds were roosting in an empty prawn-pond, and that they had serendipitously been flushed by a man driving round the pond on his motorbike. Ten minutes before or after, I would probably have driven right past without knowing they were there!

My elation was somewhat tempered by finding that the ponds were being guarded by a polite but zealous watchman, who, despite my best efforts, refused to allow me entry! In the end I was forced to retreat to a spot where I could, by standing on the roof of my car, peer over the top of the surrounding fence!

Even then, I could only see the birds roosting on the far side of the pond. Those in the middle or on the near side were hidden by the bank. Later, when the birds went up again, I discovered that I could probably see fewer than half the birds.

My first scan revealed a few Black-tailed Godwits. As soon as I see this species I start hoping for Asian Dowitchers, as they often seem to migrate together. Sure enough, I counted 6 adult dowitchers, still sporting the remains of breeding plumage. There are four in this photo.

Some slightly better views!

A navy helicopter was doing some kind of exercise which involved repeatedly flushing the birds - bad news for them but quite helpful for me!

The Eurasian Curlews were all in wing moult and looked very skinny - most likely newly arrived from a long migratory flight.

Among the Common Redshanks I was really thrilled to find this orange-and-black leg-flagged bird - it's the first time I've seen a Sumatran-flagged wader in Malaysia. By the way, if you are luicky enough to spot a leg-flagged wader, you can report it here:

The only chance I got to see the smaller waders was when the helicopter disturbed them.

Later, when I was checking my photos of the flock, I came across this bird, which looks suspiciously like a Red-necked Phalarope. However, I couldn't find any other more conclusive image than this, and it would be extremely early for a phalarope here, so I will have to put it down as only a possible. Now... if only I can talk that guard round to letting me in! Watch this space!

1 comment:

terence said...

Well Dave, Your wader are here. Well not so for raptors. Still too early