Circular migrants, both internal and external, were classified as absentee population in the 1981 census. The major difference between the two groups was that the internal absentee population generally consisted of short-term or seasonal migrants. Such migrants left the hills in search of temporary jobs in nearby towns or at construction sites and generally returned to their villages after the winter season to resume farming. On the other hand, the external absentee population was largely composed of long-term migrants. In the cases of both types, most migrants were adult males although some husbands periodically took their wives with them after they were well established in their jobs.

The volume of circular migration, or absentee population, has been rising. In the mid-1950s, such migration totaled almost 217,000 persons, most coming from the hills. More than 90 percent, or more than 198,000 people, were external migrants the vast majority went to India. In 1981 the absentee population totaled almost 591,000 people. Of these, 188,000 people, or 32 percent, were internal migrants, and approximately 403,000 people, or 68 percent, were external migrants. Even though the percentage of external migrants in the total absentee population had declined from 90 percent in the mid-1950s to 68 percent in 1981, their absolute number had increased by 205,000 people. Whereas the increasing number of absentee population from the hills was an unmistakable indicator of the region's deteriorating economic and environmental conditions, the decreasing percentage of external migration in the total volume was largely the result of the emergence of the Tarai as an alternative, internal destination.

The vast majority of migrants came from the Hill and Mountain regions. Together, they made up 141,200 (85 percent) of the total of internal migrants and about 365,000 (91 percent) of total external migrants. Unlike in the Hill and Mountain regions, the majority of the Tarai's 82,650 absentees were found within the country.

An analysis of reasons for absence from home revealed quite a contrast between lifetime internal migration and circular migration. Service, which included a variety of jobs, surfaced as the most dominant reason for being absent from home in both internal and external cases of circular migration. On the average, 64 percent of external migrants mentioned service as their reason for migration, the highest rate being posted by the Hill migrants 28 percent gave no reasons, or other reasons (see table 6, Appendix).

Data as of September 1991