Sources of variation in male mating success and female oviposition rate in a
nonterritorial dragonfly.
Crossbills are highly social and
nonterritorial (see Bailey et al.
However, invading red-backed salamanders were significantly smaller than the original conspecific residents, which supports Mathis' (1990) inference that red-backed salamanders tend to be
nonterritorial floaters until they reach nearly maximum adult size.
The effect of food availability on time and energy expenditures of territorial and
nonterritorial hummingbirds.
In 1952, 1954, and 1955, when several counts were done each spring, many territorial and
nonterritorial birds vanished over short periods as late as May, without dead ones being seen, so Watson (1965) inferred emigration.
Individuals are predicted to delay dispersal when this offers higher inclusive fitness than the alternatives of dispersing to become either an independent reproducer or a
nonterritorial "floater." It is hard to evaluate the lifetime reproductive success for the three options because any particular individual can choose only one at a particular time in its life, but observations of group-living species support the reasoning.
Observation of males was necessarily brief, and I could not rule out the possibility that some were
nonterritorial or that yearlings were more vocal than older males.
Even at population densities above saturation, floaters (e.g.,
nonterritorial individuals) might have no impact on site holders (e.g., Smith 1978, Reichert 1981, Zack and Stutchbury 1992; but see Wauters and Lens 1995).
Other authors have used the maximum number of birds, because point count data represent incomplete counts (Barker and Sauer 1995); in our case, however, this could bias results by exacerbating variation due to multiple observers, and by equally weighting
nonterritorial or transient individuals.
The presence of
nonterritorial males in Willow Warbler, Phylloscopus trochilus populations: a removal study.
Nonterritorial birds initially associate in bands, but eventually they either replace territorial birds that are killed, or are themselves dead by spring.