How fast are bee-eaters?

So how fast is a bee-eater? As anyone that monitors our facebook page knows, I am quite fond of bee-eaters and taking pictures of them. For me it is the combination of amazing flying ability, beautiful colouration, social structure and obvious intelligence. From a photographic perspective they are also a real challenge to try to capture. Great fun.

So while thinking about them one evening we started to wonder just how fast they are… They are incredibly acrobatic birds, hawking insects on the wing sometimes milimeters from the water. Apparently they can spot a wasp 100m away. From watching them I can easily believe that. Now I have no idea how to really convey or measure their speed, so this is just a few random ideas jotted down to try to convey just how rapid the example of their action that was captured in the six animated frames above .

Fortunately a camera shutter can move extremely quickly. Stopping motion with a fast bird like this I was using 1/3200ths of a second shutter speed. This is 0.0003125 seconds! Now while that is extremely fast, the action of the shutter, the mirror action of the camera, the autofocus calculations and drive signals to the lens, the processing of the image and writing it to memory going means that the number of these (very short) exposures that can be made in a second is (relatively) not that many. This camera can shoot 10 exposures (frames) per second. That is pretty quick as cameras go. Remember that when you go to the movies you are quite probably watching the movie at 24fps. So the six frames showed here lasted (in terms of actual exposure time) cumulatively for only 1.8 milliseconds. The camera’s ability to keep doing that meant that the actual shooting time for the burst of six shots was a relatively long 600 milliseconds (0.6 secs).

This is the sort of speed of reaction you need if you are going to intercept, dog fight and then eat large, fast insects. Clearly bee-eaters operate in a world with completely different time standards to the one we do. Small animals, insects, even children see the world with a faster frame rate than us adult humans do. Adult humans generally are limited to about 60fps. Birds on the the other hand are able to process their visual world at 90-100 frames per second.

Interestingly this amazing processing speed, ability to see the world in slow motion and reflexes to match seems to result in a confidence in their speed and ability which can be seen. Watching them one day I saw several different large raptors flying over the colony. While the guinea fowl and spur-fowl on the islands were all alarming and diving into cover the bee-eaters just continued hawking and perching. To me it seemed that probably they are so confident in their flying skills and speed that a large, relatively slow moving raptor poses almost no threat at all.  They are truly fascinating birds.

 

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