Monthly Apprehensions on the U.S-Mexico Border January 2000 to April 2007
Striking seasonal fluctuations are apparent in the apprehension data (Figure 11). The highest numbers of apprehensions are recorded from February to May as migrants move north for the construction and harvesting seasons. Meanwhile the lowest numbers of apprehensions are registered in November and December when many unauthorized migrants travel south for the holidays. That seasonal pattern has remained consistent for many years, regardless of whether the total number of apprehensions for the entire year is up or down. Looking back to the start of the decade, for example, the highest number of apprehensions has occurred in March of every year.
From 2004 to 2006, monthly apprehensions during the peak months leveled off at about 150,000. The latest data, for March 2007, shows the number of apprehensions declined to about 114,000. That represents a 30% decrease from March 2006, when apprehensions exceeded 160,000.
Apprehensions Figure 11  | Monthly Apprehensions on the U.S-Mexico Border  | January 2000 to April 2007  | March  | 250 Thousands  | 220  | 200  | 161  | 55  | 150  | 100  | 50  | a  | 2000  | 2001  | 2002  | 2003  | 2004  | 2005  | 2006  | 2007  | Source: U.S Department of Homeland Security, Customs and Border Protection, unpublished data 