PASS Birds

We surveyed birds at a single point in each of the 40 neighborhoods addressed by the CAP LTER Phoenix Area Social Survey (PASS; 2006). Bird survey locations were located at or near the CAP LTER Survey 200 long-term monitoring sites in each of these neighborhoods. The observer stood at the bird monitoring site and recorded all birds seen and heard within a 15 minute count period, and within a 40-m radius. We conducted the bird surveys over two years, encompassing two seasons of sampling per year: December 2006 and 2007 (winter season) and March 2007 and 2008 (spring season). For all analyses we only included birds seen within 40 meters of plot center and omitted all birds flying through the plot. We combined the bird community data and calculated the maximum number of each species recorded per site over the 12 visits to accurately portray the year-round bird community. We then classified the bird community into three major distribution categories. Global species include nonnative or alien invasive species introduced by humans, predominantly urban specialists (invasives). National species include wide-spread generalist species found in a variety of land-use types throughout the United States and Canada (generalists). Regional species include predominantly native Sonoran desert species (desert).

Habitat

At each bird monitoring site, we conducted three 100 m * 40 m habitat transects; one transect encompassed the bird monitoring site with the point count at transect center, and the remaining two transects were selected randomly within a 300 m radius from the bird monitoring location. We measured vegetation along transects parallel to the road and quantified ground cover, trees, and shrubs in front yards using observational measurements.

For each transect we calculated the percent of the yards with crushed gravel as a ground cover (xeric), turf ground cover (mesic), yards with mixed crushed gravel and turf (oasis), yards with bare soil as ground cover (bare), yards with cement ground cover (cement), and yards with natural desert ground cover (desert). We categorized the trees into five different leaf structures: conifers, broad-leaf evergreen, broad-leaf deciduous, monocots, and thin-leaf evergreen. Thin-leaf evergreen trees are predominantly native or drought tolerant trees typical of xeric designs, while trees in the other categories are generally water-dependent exotic trees typical of mesic designs. We then binned the trees into three height classes (0 – 10 m, 10 – 20 m, > 20 m). Native and drought tolerant trees are predominantly < 10 m while the taller trees (e.g. monocots and conifers) tend to be exotic. We counted the total number of shrubs in two height classes (< 1 m and > 1 m) and cacti taller than 1.5 m.

LandCover

We measured the amount of impervious surface, vegetation, and soil around the CAP LTER Survey200 site that corresponded to each bird monitoring location using Quickbird and Imagine Software. We measured the distance from the Survey200 site to desert tracts (3.2 ha), in ArcMap 9.2.

Socioeconomic variables

We used the census block group as our unit to describe ethnicity, socioeconomic status, and lifestyle stages of the residents from each neighborhood. We included the following socioeconomic variables from the 2000 U.S. Census: percent Hispanic, median household income, highest education degree obtained, percent owner occupied, and percent of residents age 0 - 18, 19 - 64, and 65 and older. We also included the age of the neighborhood.

Phoenix Area Social Survey (PASS; 2006)

Survey respondents were asked to rate the variety of birds in their existing neighborhood (satisfaction with bird variety in the neighborhood) and the variety of birds in their ideal neighborhood (desire for bird variety in the neighborhood). Ratings ranged from highly satisfied / desirable to highly unsatisfied / undesirable (respectively). We summarized ratings for each neighborhood by calculating the percent of respondents who rated their actual and ideal bird variety as either "highly" or "moderately" satisfactory or desirable (respectively).