The Border Patrol's Tucson sector reported 132 migrant deaths for the 10 months ending July 31, down from 212 a year before, The Arizona Republic reported.
Migrant deaths in the Tucson sector are on a pace to decline to their lowest level in years for the fiscal year ending Sept. 30, the Republic said.
At the same time, the border patrol said its apprehensions of illegal immigrants decreased 44 percent, from 194,065 to 108,900.
The Republic said deaths are typically caused by dehydration, exposure to heat or cold, motor vehicle accidents or train accidents.
The declines reflect what is widely seen as a sign fewer migrants are crossing illegally through the Arizona desert, the newspaper said.
But border patrol officials said it's hard to make a direct link between the decline in migrant deaths and the decline in apprehensions.
From Oct. 1, 2009, to Sept. 30, 2010, the agency said immigrant apprehensions dropped but migrant deaths rose to a record 249.
Agent Andy Adame, a spokesman for the Tucson Sector, said tighter border enforcement has kept more migrants from crossing illegally.
Under a program that started in January, the Tucson sector prosecutes almost all migrants entering illegally, with migrants deported by immigration judges instead of being allow to voluntarily return to their country. Deported migrants face criminal charges if caught trying to re-enter illegally, the Republic said.
And a Border Patrol publicity campaign with journalists in Mexico warned of the dangers of crossing illegally through the desert, Adame said.