Date: 18/01/2010, Monday
Start time: 6.50 am
End time: 10.15 am
Location: NUS (Kent Ridge), site 1
Surveyors: HW
Weather: Cloudy to sunny
Comments: Low number of fruits in visible range; fruit quality poor, with around half the seeds in each fruit either unpollinated (is there such a word?) or off-colour.
It has been almost two months since I last did any observations. Freshly back from abroad, I knew the coming weeks were the REAL crunch time. And so the mad rush to collect data begins…
BUT, rusty as I was, I had not yet quite forgotten just how formidable those winged, six-legged mobile blood donation vehicles were. And so, I unleashed my secret weapon!
Mozzies, you won’t get me this time! Above: insect repellent from Australia that actually smells good and is effective against the Singapore blood-suckers. Muahahahaha.
On a more serious note, I neglected to do a recce the day before and took my chances. There were 5 ripened fruits in total in the patch. Unfortunately, quantity does not equal to quality for each fruit only had a few red seeds with the rest either unpollinated or off-colour. Bad news indeed. What would this mean for the birds?
One of the five fruits. See the numerous white ‘seeds’?
6.50 am - 16+11+18+8+8
Sky still dark. All fruits only partially split open.
6.55 am – Disturbance: engine noise.
7.10 am - First sign of activity pertaining to patch; one bird (probably a YVB) entered the patch.
Thoughts: after looking at the data for the day, this observation set me thinking about bird behaviour. Do they have scouts that are first to fly out and report findings back to the flock??? Or was that this particular YVB that did not know any better?
7.20 am – Sighted a White-breasted Waterhen (Amaurornis phoenicurus) poking around at the far right of the patch.
7.25 am – Human disturbance.
7.40 am – Brahminy Kite (Haliastur indus) circling overhead.
7.52 am – One person walked past.
Okay, further observations pertaining to passers-by shall be omitted.
7.55 am - One YVB flew into patch.
8.00 am – 16+11+18+8+8
Some YVBs in Jamaican Cherry Tree (Muntingia calabura).
One individual is seen here.
8.30 am - Sighted a Banded Woodpecker (Picus mineaceus).
8.35 am - 3 Javan Mynas (Acridotheres javanicus) seen feeding on leaves? of a legume (?)
ID, anyone?
9.00 am - 16+11+11+8+8
9.10 am – Sighted a Black Baza (Aviceda leuphotes).
10.00 am - 16+11+11+8+8
Tagged an additional fruit that appeared to be in the process of splitting open.
4.35 pm - 00+05+11+4+8
Additional tagged fruit: appeared to be in the same state of partial opening.
Further observations/questions:
Out of the whole patch of Dillenia today, there were only 5 ripe fruits. All were partially split open at 6.50 am but later opened fully, except for fruit number 1. It was evident that the quality of today’s fruits was rather poor, for around half of the seeds in each fruit were unpollinated (?). Also, not all the seeds had the bright red colour; some tended towards orange. As expected, there was no feeding frenzy observed at the expected time of 7 am in the patch, not even behind it (on other days, when there was a higher yield, it was observed that YVBs would also fly behind the patch to feed). There was also little activity in the Jamaican Cherry Tree behind. This raises some questions:
- Are the YVBs able to determine when the fruits will open? If so, do they change their roost the night before/early in the morning to a location where there is a good yield of fruits (can rule out the possibility of them predicting the quality of the fruits since they do not have X-ray vision)?
- In the scenario where the patch has a good yield, but the fruits are removed before the birds wake up, what would happen? Would they still fly down to the patch searching for the fruits? If the birds were allowed to feed for one round but the fruits are removed subsequently, how would they react?
To do: search for papers on Dillenia suffruticosa pollination. Do fruits still form when the flower is not pollinated? If not, what are the white seeds?
Noticed something rather peculiar: a butterfly got on to the cone-shaped pollination organs just like a carpenter bee. Could it have mistaken the flower for a mate? According to Endress (1996), “[i]n all species observed the flowers are nectarless multistaminate pollen-flowers”, though “the spectrum of flower visitors is high, (but) only Xylocopa sp. bees were efficient pollinators”.
References:
Endress, P. K. (1996). Relationships between floral organization, architecture, and pollination mode in Dillenia (Dilleniaceae). Plant Systematics and Evolution, 206(1-4), 99-118.
