Many hawk species winter in southern Arizona, some in relatively large numbers, augmenting resident populations. One particularly noteworthy area for drawing these winter visitors is the Santa Cruz Flats in Pinal County. Located along the basin of the Santa Cruz River, which flows northwest across the county towards the Gila River, the area encompasses approximately 325 square miles and has an average elevation of 1,700 feet. It is primarily agricultural, and fields of cotton, alfalfa, and sorghum, laced with irrigation ditches, share the area with two large sod farms, several pecan and pistachio groves, a dairy farm, and a couple of cattle feed lots. Abundant rodents, thousands of wintering sparrows, and a big population of doves offer a ready food supply for raptors. Clumps of tamarisk, Mexican palo verde, palms, and cottonwoods provide roosting sites for owls.

Even though ornithologists no longer consider vultures in the Americas to be related to hawks, we include them in the count. A resident population of Black Vultures is found in the area, although at this point the number is unknown (one group of 71 was reported on 10 January 2005). Turkey Vultures, while common in summer and very numerous during migration, are unusual in the winter. 

Birders often visit this area in the winter to look for raptors as well as nonraptors such as thrashers, Mountain Plovers, and Mountain Bluebirds, but no systematic count of raptors had ever been made before and no part of the area is in a Christmas Bird Count circle. However, annually assessing the number of raptors wintering in this area will be useful for judging population trends and migratory patterns. It’s with this in mind that on 21 January 2006 nine birders, organized into three teams, conducted the first tally of raptors in the area.  On 27 January 2007, thirteen participants, again organized into three teams, joined the count.

The area covered by the survey is bounded on the south by the Pinal County-Pima County line and on the west by Trekell Road. The northern boundary runs along Battaglia Drive from Trekell Road to Wheeler Road then jogs south to run along Baumgartner Road from Wheeler Road though a line extending from Baumgartner to I-10. The eastern boundary is Wheeler Road from Battaglia to Baumgartner and then a diagonal line along I-10 from where it would intersect with Baumgartner if it extended to the Pima County line.

Naturally, such a count can only be approximate; some areas away from roads were not reached, and it’s possible that a few birds were counted twice. But if the count is done consistently each year, a picture of the raptor population will be established.

The survey will become an annual event on the third Saturday of January. For more information, please contact the survey coordinator, Doug Jenness, d_jenness@hotmail.com.