The assemblage of flowers visited by hummingbirds in the "capoes" of Southern Pantanal, Mato Grosso do Sul, Brazil

Flower species visited by hummingbirds were studied over 13 months in 52 forested patches ("capoes") in the seasonally flooded plains of Southern Pantanal, western Brazil. The size of the surveyed capoes ranged from 0.2 to 3.8 ha and the total sampled area measured 51.6 ha. We recorded 21 plant species, mainly herbs and climbers, whose flowers were visited by hummingbirds. Most of these plant species are regarded as non-ornithophilous (71.4%). The flowering peaks of the hummingbird-visited plants occurred at the end of the dry season and during the rainy season. The density of omithophilous and non-ornithophilous flowers was higher during the rainy season and the dry season, respectively. Helicteres guazumaefolia is the most frequent ornithophilous species, bearing flowers throughout the year. Four hummingbird species were observed in the capoes. Their mean visiting rates for ornithophilous flowers (x = 0.019 +/- 0.01 visits.min(-1).number of flowers(-1)) did not differ (P = 0.09, Kruskal-Wallis) from those for non-ornithophilous flowers (x = 0.025 +/- 0.06 visits.min(-1).number of flowers(-1)). The most frequent visitor, Hylocharis chrysura was the only hummingbird recorded every month. It visited 20 plant species, 75% of which were non-ornithophilous, and seems to be the major pollinating bird in the capoes. The availability of H. guazumaefolia flowers throughout the year may favor the residence of this hummingbird in the study area.