Effect of artificial feeders on pollen loads of the hummingbirds of Cerro de la Muerte, Costa Rica

Artificial feeders are commonly used in scientific hummingbird study and for human enjoyment. However, previous to this study very little research had been done on how feeders influence hummingbird behavior and pollination activities, which hold significant ecological importance (especially for specialist hummingbird/flower relationships).  This study examines how the use of feeders and hummingbird behavior, particularly monopolization of a feeder, affected pollen collected by hummingbirds.

Four species of hummingbirds were studied during four sampling periods over two years. The data was collected on Cerro de la Muerte, a region in the Talamanca Mountains of Costa Rica that is dominated by the Oak Forest and Paramo ecosystems. Researchers counted species and number of visits to artificial feeders set out by a local hotel/restaurant (note that a “visit” means when an individual drank from the feeder). They also used mist nets to catch hummingbirds. These individuals were marked and pollen was collected from the beak and throat area using scotch tape.

Feeder usage was dependent on hummingbird species. P. Insignis most frequently monopolized feeder use and was the most frequently recorded visitor to the feeders and in the mist nets. More than 50% of the hummingbirds collected in the nets had little or no pollen on them. Season had a significant impact on pollen collected, but species of hummingbird did not. Pollen from only one species of plant (Centropogon) dominated the pollen collected in this study.

This study shows that artificial feeders have the potential to attract hummingbirds from large distances. This draws them away from flowers, which leads to the potential to decrease of pollination of flowering species in the area. Further, the feeders detract from pollen diversity on hummingbirds, indicating the presence of feeders could reduce plant diversity in the area if some plant species are no longer being pollinated sufficiently by hummingbirds.



Avalos, G., Soto, A., Alfaro, W., (2012). Effect of artificial feeders on pollen loads of the hummingbirds of Cerro de la Muerte, Costa Rica. Revista de Biologia Tropical.