The role of size and dominance in the feeding behaviour of coexisting hummingbirds

Abstract

Interspecific competition can strongly influence community structure and limit the distribution and abundance of species. One of the main factors that determine hummingbird community structure is competition for food. The temporal and spatial distribution of nectar has a strong impact on hummingbird assemblages, shaping foraging niches according to hummingbird dominance and foraging strategy. We investigated whether body size and the degree of aggressive dominance influence feeding behaviour of hummingbirds in a temperate forest in northwestern Mexico (El Palmito, Mexico) when winter migrant hummingbirds are present in the community. First, we determined the dominance status of hummingbirds and evaluated the relationship between dominance and body mass, wing disc loading and migratory status. Secondly, we determined how hummingbird species used plant species differently. Thirdly, we examined whether the most dominant hummingbird species defended floral patches with more energy and/or with a larger number of flowers. At each flower patch, hummingbird species, number of hummingbird interactions, feeding time and number of flowers present were recorded. The total number of calories available within each floral patch was also determined. Our results demonstrate that the dominance hierarchy of 13 hummingbird species (migratory and resident) was correlated with body size but not wing disc loading, and that members of the hummingbird community showed a clear separation in resource use (by plant species). Hummingbirds at the top of the dominance hierarchy defended and fed on the best flower patches, defined by the quantity of calories available. Hence, the feeding behaviour of hummingbirds at El Palmito depends on the abundance of plant species used by hummingbirds and on the amount of energy available from each flower patch. Thus, hummingbird body size, aggressive dominance and defence of quality flower patches determines niche partitioning among species.

Functional diversity mediates macroecological variation in plant–hummingbird interaction networks

“…For all hummingbird species, we compiled information on three morphological traits that influence their interactions with flowers and interspecific competition for nectar: bill length, bill curvature and body mass (Dalsgaard et al, ; Feinsinger & Colwell, ; López‐Segoviano et al, ; Maglianesi et al, ; Maglianesi, Blüthgen, et al, ; Maruyama et al, ; Snow & Snow, ; Stiles, ; Vizentin‐Bugoni et al, ). Bill length and curvature were measured by inspecting an average of 10 adult specimens, both males and females, deposited in museums (Zanata, Dalsgaard, Rahbek, & Varassin, ; see details in Supporting Information Appendix S6); body mass data were gathered from the literature (Supporting Information Appendix S2).…”

“…Our aim was to elucidate whether functional trait diversity mediates the effects of environmental factors on network structure at a macroecological scale. We focused on hummingbird body mass, bill length and shape, because these traits are known to influence their interactions with their nectar plants (Dalsgaard et al, ; Feinsinger & Colwell, ; López‐Segoviano, Bribiesca, & Arizmendi, ; Maglianesi, Blüthgen, Böhning‐Gaese, & Schleuning, ; Maglianesi, Böhning‐Gaese, et al, ). Given that hummingbirds depend on floral nectar for energy intake and partition floral resources according to their morphology, we expected that hummingbird communities with higher degrees of functional diversity should form specialized interaction networks with higher degrees of niche partitioning (Feinsinger & Colwell, ; Inouye, ; MacArthur & Levins, ; Maglianesi, Blüthgen, et al, ; Stiles, ).…”

Hummingbird migration and flowering synchrony in the temperate forests of northwestern Mexico

“…Des Ganges (1979) stated that A. beryllina is an opportunistic species that follows the blooming of feeding plants; this species may also be more sensitive than resident species to variations in the availability of nectar. A. beryllina are larger and heavier than S. rufus and migrate to the upper ranges of mountains in the study region during fall/winter ( López-Segoviano, Bribiesca & Arizmendi, 2018 ). In addition, A. beryllina exhibits an intermediate level of aggressive dominance, while S. rufus has a low level of dominance at the study site ( López-Segoviano, Bribiesca & Arizmendi, 2018 ).…”

Body mass as a supertrait linked to abundance and behavioral dominance in hummingbirds: A phylogenetic approach

“…However, Bee hummingbirds represent the only clade present at the northernmost limit of the global hummingbird geographic distribution, with species living in the USA and Canada conducting latitudinal migratory movements (Carpenter, Hixon, Russell, Paton, & Temeles, 1993;Kodric-Brown & Brown, 1978;López-Segoviano, Bribiesca, & Arizmendi, 2018). Furthermore, members of this clade are not acting as plentiful or behaviorally dominant species in more complex communities located in Mexico and Central America, where they are winter migrants (Lara et al, 2009;López-Segoviano et al, 2018;Schondube, 2012). This could be caused by the fact that a trade-off appears to limit the ability of species to be good at both migration and their ability to win in aggressive interactions, allowing resident species to be dominant over migrant species (DesGranges & Grant, 1980;Freshwater, Ghalambor, & Martin, 2014; Lara, Corcuera, and Valverde (2018) who propose that in order to win aggressive interactions independently of differences in body mass, species should be genetically distant so that the "disadvantage of being small in aggressive interactions could be overcome over evolutionary time through the accumulation of novel traits that can counteract the advantages of being large" .…”