Birds and glass windows - 1

On 27th February 2006, Philip Tatham wrote: “During the last three months, one, and now a pair of, Red-whiskered Bulbuls (Pycnonotus jocosus) visited our apartment block on Jalan Hang Jebat (off Portsdown Road) and spent hour upon hour, almost every day, pecking at our windows. There are six flats in the block and as far as I can tell, the bulbuls peck at all the windows of all the flats. At first we were very worried the birds were trying to get in so we had to switch off the ceiling fans but it seems the birds were only interested in their reflections and ignored the wide-open windows (unlike the mynas, who nest above the windows and perch on the window frames and windowsill all day long). Is this a territorial thing or a breeding matter? And are the Red-whiskered Bulbuls feral, escapees or lost?”

This posting attracted much attention from readers. Jeremy Lee reported seeing Yellow-vented Bulbuls (P. goiavier) attacking the side view mirror of a car. “Some years back a whole flight of starlings crashed into my window pane" he added. "It was a whole series of bangs that I had initially thought was thunder. When I saw the trail of saliva/blood on the window, I checked the flower pots outside the window and there were about eight birds lying on the ground. Only two were still alive and a bit dazed. The rest probably died on impact. Our windows are quite large and it is not difficult for the bird to mistake the reflected image for the real thing.

“The funny thing is that these birds get 'tunneled' when they are distracted. Especially for birds with their eyeballs on the side of the head (as in most non-predatory birds). In aviation terms...we call it CFIT...Controlled Flight Into Terrain. This is a situation when a perfectly flyable aircraft gets flown into the ground because the pilots are disorientated or distracted by some other issues in the cockpit.

“In a place like Shenton Way, the birds are probably out in the open and have a big view of what's ahead. So they are more able to distinguish the glass from the overall picture of the environment ahead. In an environment where greenery is closely meshed with man-made stuff like large windows, things can be quite different.

“Imagine a bird dashing through familiar territory and is suddenly chased by a raptor or some other silly bird cuts into their path and they take evasive action, and then suddenly lock onto a nearby reflection for a safe flight path, they may just make a mistake that will cost them their lives.”

Patricia Thong wrote: “It is perceivable that birds mistake the reflection of the blue sky on windows and fly straight into them. I have observed Collared Kingfishers (Todiramphus chloris) flying into my neighbours' windows on bright sunny days. Eventually, my neighbours had to place an "X" on their window using tape to prevent that.

“However, I have also observed an inexplicable behaviour by Collared Kingfishers that dived into the trunk of large trees at the MacRitchie Reservoir Park. Surely there is no confusion with reflection, whether of sky or self here. Has anyone else observed this behaviour or would like to suggest an explanation?”

[R Subaraj has this explanation: "As for the diving kingfishers at MacRitchie that crash into trees, I think that they are hunting for lizards or big bugs on the tree trunks and those that crash get it all wrong or more likely, get blinded by the sun before crashing."]

Angie Ng has this to say: “I have witnessed this fascination by the male Scarlet-backed Flowerpecker (Dicaeum cruentatum) with its own reflection on my window panes too. It was just a month before I moved house. The FP kept flying at its reflection and wouldn’t go away. At times it stood at the bottom edge of the glass pane and 'peered' into our room; it often stayed for more than an hour each time! When I opened the window to invite it in, it hopped onto the sui mei (Wrightia religiosa) and then away. I did wonder if it knew we were leaving the place.

“My SBFP wasn't crashing into the glass; it was flying/trying to get through. When it couldn't, it stood waiting patiently and looking in. It could have been a dozen times trying since it was there when I woke up and still there when I had to leave to run my errands.

“Some years ago, I was entertained by a peacock apparently enjoying itself jumping up and attacking its reflection on a highly polished car. The parked car sustained some serious scratches from its claws; wonder if the driver knew who did it!”

Watch out for Part 2 where others join in the discussion.

Thanks to Philip Tatham for bringing up the subject and to Jeremy Lee, Patricia Thong and Angie Ng for participating in the discussion. Images by YC.