Date: 16/11/2009, Monday
Start time: 6.50 am
End time: 10.00 am
Location: NUS (Kent Ridge), site 1
Surveyors: HW & NWQ
Weather: Cloudy, later on sunny. Light to moderate downpour from 9.35 am to 10.00 am
Comments: Compared to the previous two days, the activity today was rather subdued
*Pictures of the Simpoh Air fruits taken by NWQ
Waking up early for three consecutive days whilst sleeping late is no fun, especially when you know mozzies will be feasting on your blood. Free blood donation…
Staring the little terror in the eyes.
Today was when we had a proper encounter with the off-colour seeds (and I’m encountering even more while doing observations in January). Anyway, here are the lines of data:
6.50 am - 20+15+15+02+26+06+06+24+03+03+09
Only 2 ovules became seeds (number highlighted in yellow). Half of the seeds in fruit (number highlighted in green) had seeds that were off-colour – white to orange – that were of the typical size of the usual red seeds.
Only 2 seeds here.
What happened here? The red arrow indicates seeds? that are larger than the ovules. What are they?
7.01 am – Calls of the White-crested Laughingthrushes (WLCTs) were heard.
7.25 am – First calls of the Yellow-vented Bulbuls (YVBs) heard. Compared to the past two days, the bulbuls appeared to stir later.
7.27 am - YVBs start flying from their roost to the large Dillenia patch opposite.
7.30 am - Evidence of sharing one fruit among two bulbuls ie. 2 birds feeding at the same time. Lasted for approximately 2 seconds.
7.37 am – Evidence of YVBs feeding on fruits of Muntingia calabura.
A YVB looking rounder than usual.
7.40 am -
19+00+00+02+00+05+06+24+03+02+00
8.00 am -
19+00+00+02+00+05+06+24+03+02+00
8.30 am -
03+00+00+02+00+05+06+24+03+02+00
9.00 am (became very sunny – could the YVBs have gone to hide?) -
03+00+00+02+00+05+06+24+03+02+00
9.25 am – Back to being cloudy.
9.30 am - 03+00+00+02+00+05+06+24+03+02+00
9.35 am – Commencement of light to moderate downpour.
Between 9.36 to 10.00 am - Several YVBs were seen flying to the large Dillenia patch in the rain.
9.45 am – Distant rumbles of thunder heard.
10.00 am – Downpour became a light drizzle that quickly ceased.
5.15 pm (came back to check on the seeds) – 03+00+00+02+00+00+00+24+03+02+00
For fruit number 6 (highlighted in red), the remaining seeds did not appear to be ripe (and were thus left uneaten?).
This photo was taken earlier in the day. Off-colour seeds were left out of the count.
I would have liked to continue observing the patch for another day, but had to put a stop to it to study for the exams. The next time I’d be back at site 1 would be in January 2010, after returning from an overseas study programme.
Further observations/questions:
Do birds wake up at differing times depending on what time sunrise is? According to http://www.timeanddate.com/worldclock/astronomy.html?n=236&month=11&year=2009&obj=sun&afl=-11&day=1, sunrise times for the 14th to 16th November was at 6.48 am. Hmm. Why do the YVBs wake up/become more active at different times then?
Do some fruits of D. suffruticosa open in the afternoon (as a supplement, maybe? From the point of the plant, this would mean that seed dispersal is not limited to the morning. From the birds’ perspective, this would mean that their supply of Dillenia seeds in the morning are not all exhausted. I have observed that partially opened fruits in the morning do split open sometime in the afternoon.
From today’s data, it appears that seeds in some of the opened fruits were ignored though they were right at the edge (and tags were tied sufficiently away from the fruit). Could it be that YVBs have enough food such that they can be picky about what they eat? Or did they just not see the open fruit/aim for better positioned one ie. easy for them to perch and reach the seeds?
