Effect of Food Reductions on Territorial Behavior of Purple-throated Caribs

We experimentally reduced the number of flowers of two species of Heliconia (H. caribaea and H. bihai) by 50% on territories defended by male Purple-throated Caribs (Eulampis jugularis). Following reductions, males decreased the amount of time they spent feeding on their territories and lost a significant amount of weight, but increased their time feeding and regained weight to premanipulation levels following restoration of flower abundance. Territorial males also spent less time in defense following flower reductions, in part by reducing the durations of chases of female intruders. Significantly fewer females intruded onto male territories following reductions in only 1 of 3 years; in all 3 years, significantly more females intruded onto the more rewarding H. caribaea territories, which offered a greater number of flowers per inflorescence than H. bihai territories.