Nesting of the Grey-headed Fish Eagles at Little Guilin

Little Gulin Ulf
Little Guilin. Nesting tree is the large one in the Middle.
Contributed by Ulf Remahl. 24 March 2016. All photos by Ulf Remahl.
Until 2008 Little Guilin was for me only on the must see list for overseas visitors to prove that Singapore could indeed be scenic. Even today immediate parkland along Bukit Batok East Avenue 5 is only biologically interesting when the world largest orchid Grammatophyllum speciosum is flowering. For anyone keen on wildlife you instead have to look at far side of the quarry.
Tiger Orchid Ulf
World largest Orchid Grammatophyllum speciosum
 
In July 2008 I spotted a Grey-headed Fish Eagle feeding on a freshly caught 2-foot Malayan Water Monitor. From how the eagle behaved I had a premonition that it could be nesting in the area. Other people confirmed my hunch during coming days when I was already overseas. That year there was one eaglet.
GHFE on Cliff Ulf
Favourite perch of the Grey-headed Fish Eagle at the top of the protruding outcrop.
 
Until mid 2015 I have over the years only been able to see snippets of the breeding cycle for GHFE. Last year it became different. On August 14th I saw an eaglet being fed by an adult. One interesting fact was that both adult and juvenile bird started to feed on the fish from the head. The eagles had this time nested at an alternative site, which I have never managed to find. That the primary nesting tree since 2008 opposite Lianhua primary school had been reduced to a tall barren tree stump sometimes during spring 2015 didn’t matter for this pair of GHFE.
GHFE by nest Ulf
Adult Grey-headed Fish Eagle guarding its nest.
 
In spite of severe haze during autumn 2015 I irregularly continued to visit Little Guilin when the smoke seemed less thick. That was fortunate because on September 23rd I found out the eagles had built a completely new nest at northern end of lake inside the 39 days I had been absent.
GHFE on nest Ulf
Grey-headed Fish Eaglet close to fledgling. 
 
My next visit was on October 11th. My first few fairly thorough scan of the area including nest with a scope 20 – 60 times magnification was discouraging. There was no sign of any eagles anywhere. So I decided to make one final absolutely meticulous search. I hit pay dirt. What a joy! I suddenly spotted the eye of a GHFE between the branches below the rim towards the left side of the nest using 40x magnification.
 
Now and then the bird moved the head. Then I could see beak and part of the head. Once during the 1 ½ hour I stayed the bird stood up in the nest. Although I couldn’t see into the nest from the movement of the head of the bird – only being able to see hind part of it – the behaviour was the familiar one you see for example when a hen is turning her eggs. At least that is the way I interpreted the movements. This activity only lasted a couple of minutes.
GHFE BIF Ulf
Adult Grey-headed Fish Eagle flying off after feeding.
 
Next visit to Little Guilin was on October 29th.  Without knowledge gleaned during previous visit I probably would never have been able to spot the eagle. It was now even better concealed below rim of nest. Considering that GHFE eggs incubate in 28-30 days there ought to be nestling(s) during coming November.
 
A subsequent visit on November 26th became a happy occasion. Then I could for 10 seconds see a tiny head covered in white down pop up above the rim of the nest during the 1-½ hours I was there. Could there be a sibling? It was too early to tell. Considering that a normal clutch is 1-2 eggs there was still that possibility. Without having a high vantage point on slope towards Gombak Stadium I would never have been able to see what I just experienced. As usual two very vocal parents were present the whole time. 
GHFE Perch Ulf
 About a fortnight later or on December 11th it could be confirmed there was only one offspring. It was amazing to find out how fast eaglet had grown. By now the plumage was a mixture of feathers & down. It was even big enough to be able to relieve itself over the rim of the nest.
 
By next visit December 30th eaglet was still in nest. It was now as big as the omnipresent parents. I was never able to see when eaglet fledged, as I couldn’t visit nesting site until January 24th 2016. In spite of that knowing that GHFE fledge after about 10 weeks from having hatched the eaglet should have left its home between 15 – 20th of January. This also fits in with that egg was laid sometimes
around October 10th 2015. (Can you spot the Eagle on the rock face?)
 
When researching a bit about GHFE I found out that even today nobody knows for how long GHFE eaglets are dependent on their parents. Here I make an attempt to figure out what it can be. I try to do this by first working out when eggs are laid by GHFE in Singapore
 
One possible reference point might therefore be when GHFE build or repair a nest. I presume that shortly after that eggs will be laid drawing on the experience with the latest Little Guilin crop. Another option is when there are eaglets in the nest. The optimum one is when they fledge.
 
Myself I have seen nest building activity as follows – August 12th & 29th 2011 Little Guilin, – October 1st and 23rd 2012 Bukit Batok NP,  – Little Guilin between August 14th /September 23rd 2015.
 
Dr Cheong Loong Fah recorded GHFE building nest @MacRitchie October 1997
 
From Raptor Reports Alan OwYong & Lim Kim Keang had 2 adults on nest December 4th 2011 in Choa Chu Kang Cemetery. There is nothing noted about any young ones but I presume something was going on.
 
Then there is a very good record by Tan Chuan Ming at Lentor Avenue where eaglet fledged May 8th 2012. That egg should have been laid during the last days of January 2012.
 
There is nesting recorded at Upper Seletar Reservoir by Doreen Ang & Freda Rickwood November 15th 2014.
 
The only other information to add would be that the latest eaglet in Little Guilin probably fledged during 15th – 20th of January 2016
 
Although materiel is limited it can tentatively be said that in Singapore GHFE commence nesting any time from September to January.
 
Next logical step in my investigation was to find any records about juveniles being fed. To my utter astonishment it seems mine is the only one? Working from that as a template assuming the Little Guilin pair nested as late as the one Tan Chuan Ming recorded 2012 the feeding goes on for just over 3 months or 14 weeks. On the other hand if my pair nested at the same time during 2014 as 2015 the feeding period would be roughly 8 months.
 
So if ornithologist here in Singapore either closely follow the feeding pattern of a pair of GHFE or just record any time they see anything this country could score a world first into settling something unknown until today.
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