Priorities for Future Research

Vocalizations of this species are poorly represented in collections of natural sounds; only flight calls are adequately recorded.

Spacing in this species has been reported as a response to both mutual avoidance and aggressive interactions. What parameters—for example of resource abundance, plover density, or habitat type—might determine which habit is followed? It is common for a feeding bird to run right past another to display aggressively to a third; what determines the recipient of this behavior?

Dominance relationships, if any, between adults and juveniles should be worked out; this is easiest during Aug–Oct, but first-year birds are recognizable into spring. Because birds in full Alternate plumage can be sexed, observers, especially in spring, could monitor sexual differences in migration schedules; sufficient Prebasic molt occurs on breeding grounds to complicate this in fall. Why do females vary in brightness? Is it only a proximate factor involving their relative abilities to replace feathers during Prealternate molt, or is there an ultimate factor that involves honest signaling? Wing molt can be quantified easily by photographing flocks of Black-bellied Plovers in flight throughout the autumn. What determines where an individual undergoes wing molt?

Nocturnal feeding has not been documented in the Americas. Does it occur with the same frequency as at similar latitudes in Europe? Is this adaptation what allows Black-bellied Plovers and some other shorebirds to winter so far north? How does the abundance of birds at different times and places correlate with resource abundance?

This species roosts with its head out, facing the wind, or with its bill tucked in its scapulars, an easy study to determine conditions that favor one alternative.

Geographic variation in size needs to be described more thoroughly, so wintering and migrant populations can be associated with breeding ones. A hypothesis to test is that birds that migrate farther (e.g., e. versus w. Siberia) might have longer wings. What percentage of the population can breed at 1 yr of age? In the aggregate many birds summer south of the breeding range, but they seem to total fewer than the expected number of yearlings. Why is dorsal coloration so different between Alternate-plumaged Black-bellied Plovers and golden-plovers, as they seem to nest in about the same habitat? Could it be related to their different habitats in migration?

An interesting aspect of Pluvialis is that members of the genus are convergent with some sandpipers in their substantial seasonal plumage change and the complexity of markings in juveniles; these similarities are dramatic, as plovers and sandpipers otherwise are colored very differently. Dark underparts are probably an adaptation to aerial display, as in sandpipers dark underparts are more likely in larger species. Juvenile markings are especially similar to comparable markings in juvenile sandpipers of the genus Tringa, and one would presume convergence; however, juvenile Pluvialis and juvenile Tringa are not typically found in the same habitats.