Location Matters: Drivers of Individual Variation in the Courtship Displays of a Territorial Hummingbird

Abstract

Courtship displays are some of the most spectacular signals in the animal kingdom. In territorial species, courtship displays can signal territory resource holding potential to prospective mates. Broad-tailed hummingbird (Selasphorus platycercus) males perform U-dive courtship displays of varying frequency and intensity, but the drivers of this variation remain unclear. I examined how territorial characteristics predict courtship behavior in territory-holding males at the Rocky Mountain Biological Laboratory in Gothic, Colorado, using behavioral observation and quantification of territorial characteristics such as size, floral diversity, and proximity to rivers and feeders. Contrary to predictions, floral diversity, territory size, and proximity to feeders did not significantly predict display behavior. Instead, proximity to river was the strongest predictor, with males farther from rivers spending more time U-diving later in the breeding season. Additionally, territories increased in size and in floral diversity later in the season. These results suggest that resource abundance on territories may not strongly predict courtship behavior, but distance to river may represent abiotic factors not represented in this study. Furthermore, display behavior likely increases later in the breeding season due to seasonal phenology and the mating status of females. Male investment in courtship behavior is likely shaped by environmental factors, whether biotic or abiotic, that are associated with the location of their individual territories and the time of year.