The difficulty in obtaining the requisite material for such a study makes it likely that novel techniques, such as extracting DNA from preserved specimens, will be needed to address this problem.

In the United States, B. rosaliae is known from only one road-killed specimen, CSDSNH 644161 taken 26 May 1984 on Interstate Highway 8, 3.84 km (2 mi) east of Mountain Spring (Imperial County), California.

The habitat components critical to this snake have not been identified precisely, but it may require some kind of shrub or tree with a moderately dense crown in which to take refuge because it has been taken in native fan palms (Washingtonia spp.

It notes that the snake is an infrequently observed species avidly sought after by amateur, scientific, and professional collectors alike.

Because of the uncertain status of the single record from California, it believes that it should remain protected until further information regarding its distribution within the state becomes available.

The California Department of Fish and Game Habitat Conservation Planning Branch recommends that intensive surveys of habitats with shrubs or trees having a moderately significant crown in Imperial and San Diego counties are needed to determine whether this snake is really part of the herpetofauna of California.

If populations are discovered, the Planning Branch states that the local habitat needs to be protected from modification and potential collecting, and some kind of monitoring for this taxon should be initiated.