Seasonal distribution of northwestern populations of the long-nosed bats, Leptonycteris sanborni family Phyllostomidae

Abstract

AN ANALYSIS OF THE RATHER LIMITED CURRENTLY AVAILABLE RECORDS OF SEASONAL AND GEOGRAPHICAL OCURRENCE OF LONG - NOSED BATS, LEPTONYCTERIS SANBORNI HOFFMEISTER, SUGGEST THAT THE GRAVID ADULT FEMALES ENTER THE NORTHERN PART OF THE RANGE IN LATE APRIL AND EARLY MAY AND CONGREGATE IN TRADITIONAL MATERNITY ROOSTS AT LOWER ELEVATIONS WITHIN THE AREA OF DISTRIBUTION OF THE SAGUARO (CEREUS) AND ORGAN PIPE CACTI (LEMAIREOCEREUS). ADULT MALES, AND APPARENTLY SOME NON - GRAVID FEMALES, REMAIN IN MORE SOUTHERN AREAS MIGRATE INTO THE AREA. THESE MOVEMENTS, RESULTING IN AN EXPANDED RANGE, MAY BE THE COMBINED RESULTS OF A LARGER POPULATION NEEDING MORE FOOD AND A REDUCTION OF AVAILABLE SUITABLE FOODS (NECTAR AND RIPE FRUIT OF COLUMNAR CACTI) AT THE LOWER ELEVATIONS WHERE AGAVE NECTAR IS AVAILABLE. BY THIS TIME, MANY FAMALES AND GOUNG HAVE LEFT THE MATERNITY ROOST, AND INDIVIDUALS OF BOTH SEXES THAT HAVE EARLIER BEEN IN MORE SOUTHER AREAS MIGRATE INTO THE AREA. THESE MOVEMENTS, RESULTING IN AN EXPANDED RANGE, MAY BE THE COMBINED RESULT OF A LARGE POPULATION NEEDING MORE FOOD AND REDUCTION OF AVAILABLE SUITABLE FOODS (NECTAR AND RIPE FRUIT OF COLUMNAR CACTI) AT THE LOWE ELEVATIONS. BY LATE SEPTEMBER OR EARLY OCTOBER ALL BATS, ADULTS, YOUNGS, MALES, FEMALES, MIGRATE SOUTH. THE RELATIVE SEASONAL AND GEOGRAPHICA IMPORTANCE OF THE NECTAR AND RIPE FRUIT OF COLUMNAR CATI, THE NECTAR OF AGAVES AND OF INSECTS IN THE DIET NEEDS TO BE DETERMINED.