Lesser Long-nosed Bats: Do They Follow the Nectar Trail?
Contributed by Dr. Ginny Dalton, Bat Biologist

U.S. & Mexico Desert Region

Leptos (lesser long-nosed bats) are nectivorous and frugivorous, meaning they eat nectar and fruit. While they sometimes eat insects, like most of the bats you probably know, in the spring time they feed primarily on the nectar found in flowers. This means they must always find flowers that are in bloom. Since flowers bloom at different times of the year in different locations, the bats' food sources can change with the seasons. The blooming calendar below shows some of the most important nectar sources available to bats at different locations.

  • Look at the blooming calendar along with your range map to see how you'll answer this question: Does there seem to be a nectar pathway across the bats' range that they could follow to Arizona and New Mexico each spring?"

  • After you compare the blooming calendar with the range map you made, state your conclusion. THEN see the Traveling Bats facts at the bottom of this page to see if they support your conculsion.

Blooming Calendar: Food Sources for Lesser Long-nosed Bats
At Selected Portions of Their Range

November through January:
There is a frost-free zone south of Sinaloa and Durango, Mexico. Tree morning glories and wild tequila century plants bloom in the foothills of the Sierra Madres as well as from nearby fields where the plants are cultivated as a cash crop. Localities for these plants in bloom include Chapala, Jalisco and Infiernillo, Michoacan. Peak blooming of these plants at these locations is over by the end of April.

February through March:
In Sinaloa and in the "barrancas" of central and southern Sonoran, nectar is available from flowers of the northern-most tree morning glories and bacanora century plants. (The "barrancas" are similar to the Grand Canyon. The local people make bootleg mescal, a local form of tequila, from these century plants.) Localities for these plants in bloom include Pericos and Concordia, Sinaloa.

Giant columnar cacti that Leptos are known to feed upon are in bloom in western Mexico from the northern part of Sinaloa (Pericos) southward through the southern part of Nayarit (Nayar). By early May, peak blooming in those areas for those cacti is over. Agaves do not begin to flower in those areas until late May/early June.

The majority of the saguaro cacti are in bloom from southern Sonora, Mexico northward into southern Arizona. Early May to late June is during the peak of cactus flowering. Localities for these plants include Guaymas and Carbo in Sonora and Ajo in Arizona. These cacti are not located in Portal, Arizona.

The fruit of the giant columnar cacti begin to ripen in the same locations as are mentioned in May. In addition, Palmer and Parry's agaves begin to bloom in southeastern Arizona (Portal and Sierra vista) and southern New Mexico (Animas). Each flowering stalk, or "panicle", of these agaves produces as much as a cup of nectar! (These wild century plants were
historically a major food source for Mescalero Apaches.)

July and August:
In mid to late July, in the U.S., century plants are in bloom in the mountainous regions of southwest Arizona (e.g. Portal and Sierra Vista); namely the Chiricahua Mountains, Huachuca Mountains and the Santa Rita mountains. Near Ajo, Arizona, the peak flowering and fruiting is past, although some are still produced. Agaves are more scarce in this region. In Mexico, agaves that bats feed upon bloom from July through late September/early October in the state of Sonora.

September and October:
Agaves in Arizona, New Mexico and northern Sonora have passed the peak flowering. More agaves are now blooming in
southern Sonora, western Chihuahua, Durango and Jalisco (e.g. Chapala).

Traveling Bats: Facts About Arrivals
Does the following information support the idea that the lesser long-nosed bats do indeed migrate northward as their food resources begin to bloom? Explain.

  • Bats have been found in the roosts (or captured nearby) in Chapala, Jalisco and Infiernillo, Michoacan in November and December. They are usually gone from those roosts by March.
  • Roosts located at Pericos and Concordia, Sinaloa do not have bats arrive until late February through early March.
  • By April, bats have arrived at in Alamos and Guaymas, Sonora.
  • By late April and early May, bats have arrived at the Bania Kino and Carbo, Sonora roosts, plus the roosts near Ajo, Arizona.
  • In August, bats are found in the western part of Arizona (Portal) and eastern New Mexico (Animas).
  • In September, bats are gone from the U.S. and have been seen in the vicinity of Pericos, Sinaloa.