Lesser Long-Nosed Bat (Leptonycteris yerbabuenae) Range Expansion into Northern Grant County, New Mexico

Abstract

The lesser long-nosed bat (Leptonycteris yerbabuenae) previously was known only from extreme southwestern New Mexico in southern Hidalgo County. Herein, we documented L. yerbabuenae from northern Grant County along the Gila River on the southern edge of the Mogollon Plateau, which represents a 110-km range expansion to the north. We captured mostly volant young-of-the-year (68.5%) and adult females (25.9%) as well as a few adult males (5.6%) in September 2019. With assistance from local residents, we have evidence that nectar-feeding bats have been using hummingbird feeders in the area at least since 2014 and are a relatively new arrival to the area. In 2019, the latest observation of bats emptying hummingbird feeders at our study site was on 25 October, the latest reported date for the presence of this species in the state. Fur coloration on the back and head of volant young was dull gray compared to the richly orange- and brown-colored adults. Forearm lengths were shorter and body weights lighter in young compared to adults. It is unclear whether this species bears and/or raises its young in the Gila area or whether the documented individuals represent those dispersing from maternity roosts after the young become volant, a common late-season behavior for this species in the northern reaches of its distribution. Our documentation of this nectar-feeding bat adds to the high diversity of bat species associated with the Mogollon Plateau in southwestern New Mexico.