Competition Between Hummingbirds and Insects for Nectar

Preliminary data are provided suggesting that hummingbirds competewith bees and hawkmoths for flower nectar while on southwardmigration through the Sierra Nevada of California during thesummer. Evidence is given that removal of hummingbirds enhancesforaging in bees and hawkmoths on plants shared with the birds.The birds were aggressive against moths but not usually againstbees. Competition between these taxa leads to temporal and spatialpartitioning of the resource that is apparently behaviorallymediated. It is speculated that for hummingbirds competitionwith insects is less predictable and more difficult to contendwith than is competition with other hummingbirds.