Listed in Ainley (2) are several efforts that would help to better understand the populations of the Ashy Storm-Petrel (Oceanodroma homochroa), particularly a constant-effort mist-netting program. The same would apply to Black Storm-Petrel. Although Carter et al. (45) made a start toward fulfilling these goals for Ashy Storm-Petrels nesting in the Channel Islands, much remains to be done. Mist-netting, and well-planned capture-recapture protocols, remain practically the only tools available to better understand population dynamics of the complex of storm-petrel species that inhabit islands off southern California (United States) and Baja California (Mexico). Most of these species nest in talus and rocky habitat, which allows little access, unlike the situation of the burrowing species that occur farther north, such as Leach's Storm-Petrel (O. leucorhoa).
Through mist-netting and banding, it is more likely that we can understand the metapopulation dynamics of storm-petrels. Genetic studies would be helpful. Particularly interesting would be work to define what actually constitutes a colony when storm-petrels are nesting among adjacent rocks or islands. For example, do Santa Barbara Island and adjacent Sutil Island together make up one colony?; see Carter et al. (45). Ultimately, from this work a better understanding would result of interchange of individuals among breeding sites, and the factors that might affect population viability of peripheral populations (e.g., the Channel Islands).
The need for additional research on Mexican islands is particularly acute, as it is likely that far less than one percent of the population breeds on islands off the United States west coast. Many breeding sites in the Gulf of California need documentation.
Since the early 1990s there have been many eradications of exotic predators from numerous islands around Baja California (83, 104). These islands should be investigated on a regular basis to see if predators (e.g. rats [Rattus spp.], cats [Felis catus], mice [Mus, Peromyscus] have re-established island populations.
Finally, the isolating mechanisms among the complex of 7 distinct storm-petrel taxa that inhabit waters and islands off the southwest coast of North America remain a very interesting problem of study. Included in the complex are the 4 all-dark forms of the region (see Appearance; 16). Certainly, segregation of nesting cavities by body size plays a role (see Habitat: Breeding Range), but so, too, must segregation of marine habitat and food resources. Genetic study, again, would be helpful.
Conservation efforts might be aided if it proved valuable to use playback recordings of calls to re-establish populations on islands from which mammalian predators have been eradicated. Although difficult to accomplish, monitoring of the rate of recolonizations would help managers and agencies to quantify expectations of recovery.