Sunbirds are important pollinators in South Africa, feeding on nectar and carrying pollen away from flowers. So what happens when you start feeding them in your garden? Are you competing with the flowers? Asekho Mantintsilili and colleagues studied how artificial sugar-water feeders affect bird behaviour in a nature reserve’s recovering vegetation after fires. Their findings are important in helping manage populations of the 300 plant species that rely on the birds to reproduce.
The ecologists conducted their experiment at Grootbos Private Nature Reserve in South Africa, where they set up 8 sugar-water feeders and watched bird behavior before, during and after installing feeders. Here they counted bird visits to both feeders and flowers in winter (July/August) and spring (September/October)
Happily, the results are good news. The team found that birds made 679 visits to feeders in winter when flowers were scarce, but only 90 visits in spring when flowers were abundant. They also found that it was only specialist nectivorous birds that used the feeders, rather than opportunistic nectar feeders. They also found that adding feeders didn’t reduce how often birds visited wild flowers.
The results seem at odds with previous studies in suburban areas that found feeders could reduce bird visits to wild flowers. Why the difference? Well, the birds in the reserve had no history of supplementary feeding, so maybe they stuck to natural sources from suspicion of novelty. So, for the reserve, it is possible that the feeders could be helping sustain a population of pollinators when food is scarce. This puzzle raises a new question of how birds react to feeders over time. The authors suggest follow-up studies looking at sites with varying histories of feeder presence.
Mantintsilili, A., Geerts, S., Seymour, C.L., & Coetzee, A. (2024). Impacts of Supplemental Feeding on Sunbird-Pollination Systems in Young Fynbos Varies with Floral Abundance. Environmental Management. https://doi.org/10.1007/s00267-024-02089-8
Cross-posted to Bluesky, Mastodon & Threads.
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