Comparisons of foraging time and energy cost budgets for male (circles) and female (traingles) purple-throated caribs at flowers of green H. bihai (A and B), red-green H. bihai (C and D), and H. caribaea (E and F). Foraging times are presented as percentages of 7.5 h during which birds were on territories during daytime (0630-1400 h) and were computed using the equation for balanced costs and benefits from Gill and Wolf (1975) Ecology, modified for purple-throated caribs. For these equations, males were assumed to weigh 10 g and females were assumed to weigh 8 g. Both sexes were assumed to spend 23.87 s per flower at green H. bihai, 15 s per flower at red-green H. bihai, and 10.8 s per flower at H. caribaea. Arrow indicates that calculated foraging time exceeds the time available. Foraging time and energy bidges for males and females at flowers of green H. bihai at nectar volumes of 5 microliters per flower greatly exceeded time available and are not illustrated in graphs (A) and (B). See Temeles et al. 2005 Auk.

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