Tag Archives: wildlife habitat

Promise of summer 2014

We have seen 4 of the sterile Grass Carp trying to keep up with the growth of water weed in Sovaco Lake. There are small bass and bluegill right at the “beach” so there must be big fish in deeper   water.

The Mineral or Sovaco Lake has now filled to capacity and is flowing south to the Gold Boulder Dam.

The Town Lake is in process to become a riparian area as the empty years have allowed willows to arrange themselves along the length and provide more habitat for birds.  This will be a site to observe as it transforms.  Right now there is a lot of water, drowning the grasses and will probably have many migrating ducks soon.  We have had some fish transplanted but might need winter rains to sustain them.

Habitat of Ruby

Ruby has worked with the Arizona Game and Fish Department and the U.S. Fish and Wildlife Service to better understand and protect the area’s wildlife. A big-game fence was constructed around the perimeter to allow access for wildlife and help protect the property’s ecosystem.

Several film companies have expressed interest in documenting the biodiversity of Ruby, and one group, Oxford Scientific Films from the U.K., produced a video, “The Ghosts Of Ruby” which airs regularly on PBS and Discovery channels. Others use it for filming drama and photogenic properties.

Plans are being developed to survey and document the wide variety of plants and animals of the area and for the next several years, we will be working with biologists from several agencies and conservation groups to understand in greater detail Ruby’s potential as a wildlife refuge.

A colony of Mexican Free Tail Bats inhabits Ruby’s abandoned mine shafts from May to September each year. Estimates of the colony range from 90,000 to as high as 150,000 animals , representing a nightly appetite for up to 1/2 ton of insects.  This is considered a maternal colony and they produce their young in June and leave for parts south in late August.  Their nocturnal schedule varies with storm, wind and insect life.

Montana Mine Bat Habitat

The largest number of bats appears to be the Mexican Free-Tailed Bat (Tadarida brasiliensis)…family:  Molossidae.


Montana Mine underground shaft is one of the most species diverse roosts in southern Arizona.
~Brian Corbett, BCI





These medium-sized bats have a wingspan about 12 inches and weigh 10-12 grams.  They have short grayish fur with long and slender wings, round ears and wrinkled upper lips.  These bats are migratory, spending summers in N. Mexico and the US and wintering in Mexico and very south US.  They breed in late February and early March.  One or two young/female are born in mid-June to early July.  Young develop rapidly and begin flying in 4-5 weeks.  When emerging at sunset they are predated upon by raptors, owl and snakes. (they sometimes fall to the ground at Ruby).Photography by David Bygott

The Mexican free-tail bats emerge from a roost around sunset to forage and drink.  They are fast and efficient fliers and usually hunt within a 50 mi. radius, but could forage up to 150 miles.  These feed primarily on moths but numerous other insects as well.  Nursing females require large quantities of insects that are high in fat, such as egg-laden moths.  The Mexican free-tail bats are adept aerial hunters who eat their prey in flight and often forage in groups.Photography by David Bygott

Mexican free-tail bats roost in tight clusters in caves, mines, tunnels, crevices in bridges, buildings, attics and hollow trees.  Many roosts are used in spring and fall during migration.  At Ruby we have the bats mainly April until late August.  Their arrival and departure varies with drought and insect availability seemingly.  Ruby probably has a maternal colony.  Most of the very large maternity colonies are in Texas and Mexico although the Ruby colony has been estimated by biologists at 70,000 to 200,000.  It fluctuates year to year.

Threats to Mexican free-tailed bats include pesticides and destruction or disturbance to roost sites.  Suitable sites for large maternity colonies are extremely limited.

Bats found in the underground shafts of Montana Mine:

  1. Tadarida brasiliensis – Mexican free-tailed bat
  2. Eptesicus fuscus – Big brown bat
  3. Corynorhinus townsendii – Townsend’s bit-eared bat
  4. Choeronycteris Mexicana – Mexican long-tongue bat
  5. Myotis thysanodes – Fringed myotis
  6. Myotis velifer – Cave myotis
  7. Myotis californicus – California myotis
  8. Myotis ciliolabrum – Small-footed myotis