The other week, Winterwatch (BBC) had a little segment about the colours of bird feeders (series 5, episode 4, about 42 minutes in, available on iPlayer at the moment). A couple of years ago, an MSc student, Luke, did a similar experiment (ably assisted by two undergraduate project students, Rose and Adam), in collaboration with Westland Horticulture* (who make, amongst other things, bird feeding products). Our paper has just been published in PLoS ONE, if you want to take a look
Luke, Rose and Adam spent lots of time watching birds feeding at our feeders, which we painted eight different colours: red, yellow, green, blue, purple, black, silver and white. Unlike Winterwatch, we only painted the metal bits, so the seed was the same colour in all the feeders. Over the course of the winter, they spent 185 hours watching birds come and go, recorded which colour feeder they landed on, and what species they were. They recorded 7535 individual visits to the feeders from 11 different species.
The most common species they saw were blue tits (Cyanistes caeruleus) accounting for 3263 visits, but we also saw great tits (Parus major), house sparrows (Passer domesticus), coal tits (Periparus ater), robins (Erithacus rubecula) greenfinches (Chloris chloris), marsh tits (Poecile palustris), long tailed tits (Aegithalos caudatus), bullfinches (Pyrrhula pyrrhula) and goldfinches (Carduelis carduelis). So which colour feeder did they like the most? Well, our birds didn’t like red either. Or yellow. And they weren’t particularly fussed about blue. But they definitely liked silver and they also liked green.
There was a tantalising hint that different species might like different colours: blue tits and great tits liked silver and green, but robins liked black, and starlings actually quite liked blue. But we didn’t have big enough sample sizes for the less common visitors to work out whether we could attract particular species with particular colours.
What about the UV idea they mentioned? We wondered whether UV might make a feeder more attractive to birds, since they can see UV, so we did a follow up experiment where we added UV reflectance to both blue and red feeders. Did it make them more attractive to birds? Apparently not – we found no difference in the number of visits to the more- and less- UV reflective feeders. We’ve not written that up yet (publishing non-significant results is hard), but maybe we should!
We (and Westland) were also interested to know whether people liked the same colours of bird feeders as the birds did, so at the University Science Festival, and at a local garden centre, we asked visitors to vote for their favourite by placing counters in nattily decorated sharps bins.
They didn’t agree. People tended to like the bright coloured feeders, the ones least preferred by the birds. The only real agreement was on green, which people liked and which also got the second-most visits from the birds. So perhaps if we make bird feeders green, we can keep everyone happy?
Rothery, L, Scott GS & Morrell LJ. (2017) Colour preferences of UK garden birds at supplementary seed feeders. PLoS ONE 12(2): e0172422
*Westland asked us to do some research into what birds like at bird feeders, with the idea of designing a feeder that attracts more birds. In the interests of transparency, they provided us with some big sacks of bird food, piles of feeders and a small pot of cash for expenses. The School of Biological, Biomedical and Environmental Sciences at the University of Hull provided the fees for Luke’s MSc.