Owls bring surprise nest egg to Casa Grande Ruins

CASA GRANDE, Ariz. (AP) - Visitors are always welcome at the Casa Grande Ruins National Monument and their enjoyment and experience is always the staff's No. 1 priority. But what happens when they decide they like it so much that they move in?

Believe it or not, it isn't an uncommon thing for the Ruins - but it's not the kind of visitors one would expect. A family of great horned owls has taken refuge atop the west wall of the ``Great House.''

Currently, the couple is awaiting two eggs to hatch and can be seen on any given day in the rafters of the ``Great House's'' cover.

``We want to keep them here, but we want them in a place we can manage,'' said James Dawson, a biologist with the Arizona-Sonora Desert Museum in Tucson.

The feathery guests are more than welcome at the Ruins and actually a benefit, as they assist with vermin control and pose only a small threat to the Ruins' preservation. They are preferred over some other birds.

``The presence of owls in Compound A has been historically documented as a benefit to Ruins preservation because owls eat many of the smaller animals that cause damage to the Ruins, do not have the same tendency to nest in structural cracks, and do not have the same issues with acidic, white washing of walls with their feces,'' noted Rebecca Carr, park ranger at the monument.

Great horned owls don't construct what is commonly known as a bird's nest. These owls lay and tend to their eggs on a flat surface, and because of this, lose control of their eggs on occasion, which has been the case at the Ruins.

``Since 2005, we have also lost at least five owls in the same time period (including at least three eggs that have rolled off that same wall nested now),'' Carr said. ``In 2006, we installed a nesting box at the southwest corner of the Ruins shelter. The purpose of this nesting box is to provide a safer and more secure location for the owls to nest, which will also prevent them from damaging the Great House and still encourage them to live at and hunt rodents within Compound A.''

The old approach, according to Dawson, was to just get rid of the animals but ``We're using a new approach these days,'' he said. ``We don't want to just get rid of them, we want to find a way for the animals and humans to coexist.''

The safety haven for the owls was installed several years ago for the same purpose and will house the family in the southwest corner of the Great House shortly after the eggs have hatched.

``It takes 21 days for an egg to hatch,'' Dawson said. But currently, there isn't any way to distinguish exactly how old the eggs are, so for now it's a waiting game.

Great horned owls are also commonly known as the stereotypical ``hoot owls'' and, according to Dawson, cannot carry away your kitten or puppy.

``They can't carry much,'' he said. ``Maybe 2 or 3 pounds.''

From this point, Carr and Dawson, along with the rest of the Ruins staff, will wait for the newborn owlets to arrive before they can be moved.

Once the babies have hatched and become stable, the plan is to transport them to the prefabricated ``nest,'' where they will be out of harm's way and safe from falling off the ``Great House's'' wall.

The man-made nest has a lip that borders its edge, preventing the babies from accidentally falling off, in addition to the same happening to future eggs.

After the transfer, the mother and father owls will return to their young in approximately an hour, according to Dawson. The new spot will also increase survivability and reproduction, as the owls will continue to use the platform after the young have grown.

After 21 days in the shell, the babies will stay perched in the ``nest'' for the following 70 days, until mom decides it's time for them to ``fly the coop.''

The family of owls is currently visible to Ruins visitors and staff and will be very easily noticed after the move has occurred. The family has become an added bonus for visitors and, if all goes well, will continue to be present as they expand their family.