My recent experiences with the hummingbirds of Costa Rica led me to ponder the why and how of the dazzling phenomena of Iridescence. As a recap, look at the two pictures of the Fiery-throated Hummingbird above. From sideways on this Hummingbird appears emerald green but front on it is truly transformed into a veritable artists pallet of colours. To see the Fiery throat you have to be essentially face on, a few degrees either side and the fiery iridescence disappears. You would certainly be forgiven for thinking these were two entirely different birds. I guess it’s fairly obvious that the colouration is not your run of the mill pigment colouration. In fact Hummingbirds are coloured by what’s known as structural colouration. This is a similar effect to how a prism splits light into its constituent colours. The Hummingbirds feathers have specialised pancake microscopic structures called melanosomes. These contain little air bubbles that refract the light...
Fiery-throated Hummingbird Now if you asked me when I was, say 18, if I would make it to three score years and ten on the 17 th of November 2025 I would probably have laughed in your face and said of course not. But here I was celebrating hitting the milestone in some style at the end of my wonderful Costa Rican adventure. We had planned a leisurely departure from the Savegre complex before a day’s birding on the way back to the capital for our flight home on the next day. Our plans, however, were thrown into the air when we discovered that the only long winding road out of the complex was going to be shut for the day for road works! We hence had a hurried breakfast and departure before we were trapped for the day the wrong side of the road works. After passing the road works we all relaxed a little and looked forward to our final full days birding in paradise. We stopped at the lovely Miriam’s Café where we enjoyed the hummingbird feeders whi...