Nesting of the Grey-headed Fish Eagles at Little Guilin

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.

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.

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 14^th 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.

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 23^rd I found out the eagles had built a completely new nest at northern end of lake inside the 39 days I had been absent.

Grey-headed Fish Eaglet close to fledgling. 

 

My next visit was on October 11^th. 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.

Adult Grey-headed Fish Eagle flying off after feeding.

 

Next visit to Little Guilin was on October 29^th.  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 26^th 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. 

 About a fortnight later or on December 11^th 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 30^th 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 24^th 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 – 20^th of January. This also fits in with that egg was laid sometimes

around October 10^th 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 12^th & 29^th 2011 Little Guilin, – October 1^st and 23^rd 2012 Bukit Batok NP,  – Little Guilin between August 14^th /September 23^rd 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 4^th 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 8^th 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 15^th 2014.

 

The only other information to add would be that the latest eaglet in Little Guilin probably fledged during 15^th – 20^th 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.