Sunbirds on the balcony

A friend recently gave me a sunbird feeder. It’s a relatively simple design, with an upturned bottle in a metal wire ‘nest’, the open end of the bottle resting in a small pyrex dish. The physics of why all the water doesn’t run out is quite something. All to do with equal and opposite forces, or at least that’s what I’ve concluded in my attempts to dredge up my A-level physics! Initially I included some red food colouring in the sugar solution in order to attract the birds. It took them a week or so to figure out that this hanging object that had appeared on my balcony was something good. The downside was sticky patches over my balcony and plants, where the sweet syrup had either been splashed, or alternatively where a mob of sunbirds had upset the balance on the suspended bottle. (I initially thought I had an infestation of some sort, until I realised what it actually was!) By the time I came back from Togo, the bottle was empty. Since then, I’ve refilled a couple of times, though now I use a glucose solution which is clear. It is delightful to watch the birds, such as the variable sunbird in the photo, come and feed.