The Barn Owls' Impact on West Coast Ecosystems
Barn Owls are nocturnal predators that keep the rodent and small mammal populations in
balance. These owls are easily recognized by their heart shaped faces, white facial disks and
dark eyes. Barn Owns are found throughout the West Coast of The United States. They live on
all continents excluding Antarctica. Barn Owls are very adaptive to their ever-changing
surroundings and they can live in suburban, urban and rural areas. Although Barn Owls may be
difficult to see, they have a significant impact on our ecosystems. Unfortunately, humans' actions
can have a negative impact on Barn Owls.
Barn Owls have been dying at an increasing rate due to the use of rodenticides. A
primary rodenticide, d-Con, is a blood thinner that is supposed to kill rats and mice in one dose.
Over time, these rodents have become immune to the bait and can take up to five doses without
dying. Barn Owls aren't as adaptive and by consuming a poisoned rodent they will die quickly
from internal bleeding. Organizations such as the Audubon Society are working to ban the use of
rodenticides because they are worried about the declining populations of Barn Owls and other
raptors. Barn Owls are capable of containing the rodent and small animal populations in a natural
and more efficient way. (Your Guide to an NBC Barn Owl Box)
There is a wide variety in a Barn Owl's diet which is comprised of 73 to 100 percent
small mammals. Their diet is not limited to rats and mice; they also feed on voles, gophers,
rabbits, squirrels, and arthropods such as crickets. Barn Owls bring their meal to their nests to
feed to their young and leave no trace outside of their nest. Each Barn Owl has its own hunting
grounds and will contain the populations of "pests" in approximately a four mile area. Barn
Owls do not disrupt human life because they hunt in the dead of the night. (Owls of California
and the West) An owl box built and monitored by the Audubon Society in Walnut Creek counted
the number of rodent skulls that accumulated over a period of one year. They determined that
one Barn Owl consumed 140 pounds of gophers that year not including other small mammals.
(Murphy, Brian)
Even though Barn Owls have a high death rate, they reproduce frequently. Barn Owls are
cavity nesters that often find man-made items such as a hole in a building, a bridge, or a barn owl
box. Female Barn Owls can lay up to seven eggs per season which take 29 to 34 days to hatch.
They start reproducing as soon as they are one year old. In years when prey is plentiful, female
Barn Owls may produce two clutches. Generations of Barn Owls will continue to nest in their
location as long as there are no major disturbances in their habitat. (Birds of Northern California)
Barn Owls play a substantial role in West Coast ecosystems, but if the use of rodenticides
continues they may become endangered. This would completely throw off the food chain where
they live. Man-made substances should not replace the Barn Owls' job. Nature will contain itself
and know what steps each animal in the food chain will need to take in order to survive. This
chain will remain steady with Barn Owls and other raptors in charge of rodent control. People
need to be educated about the dangers of using poison to eliminate one animal and its negative
effect on the ecosystem.