October 12, 2017
By Gemara Gifford, MS Cornell Department of Natural Resources Class of 2015
Many of us put out nectar feeders in our gardens hoping to see the most whimsical feeder birds of all—hummingbirds! Arizonans are likely to see Anna’s, Costa’s, and Black-chinned hummingbirds at their feeders, to name a few. Have you ever wondered why some feeders seem to host lots of hummingbirds while other similar feeders host far fewer? Researchers at the University of Arizona and the Hummingbird Monitoring Network found that fewer hummingbirds at your feeder may actually be a good thing.
Power to the Flower
Researchers Rachael McCaffrey and Susan Wethington (2008) set up several feeders in Tohono Chul Botanical Park. Each feeder was located in a different “micro-habitat,” with different types and amounts of hummingbird plants, such as the Baja fairy duster and Mexican bush sage. Volunteers counted the number of times they saw hummingbirds visit feeders versus the number of times they visited flowering plants at each site. Knowing that hummingbird species composition and flower abundance change seasonally, the research took place over the span of a year. The observations showed that hummingbirds visit feeders less frequently when there are more flowers in the area.
What about our feeders?
Hummingbird feeders should contain a 1:4 sugar solution, which amounts to a 20% sugar concentration. The sugar concentrations in the nectar of plants that hummingbirds tend to visit averages as much as 22-26%. While hummingbirds may spend more time foraging for and extracting nectar from flowers, the caloric payoff is higher. This difference does not mean we should add another cup of sugar to our nectar solution! Adding too much sugar runs the risk of dehydrating our feathered friends. (Read more about the ideal nectar solution.)
Hummingbirds help with plant reproduction by pollinating a variety of plants. Some plants, such as native ocotillo are highly dependent on hummingbirds. Ocotillo blooms during peak hummingbird migration, helping hummingbirds along their journey while encouraging high pollination rates.
If you have a lack of hummers at your feeders, it may indicate a healthy ecosystem. So plant native flowers, hang nectar feeders, and enjoy the show!
McCaffrey, R.E. and Wethington, S.M. 2008. How the presence of feeders affects the use of local floral resources by hummingbirds: A case study from southern Arizona. The Condor. 110(4): 786-791.