DOI: 10.6073/pasta/e12ec9719c0cd7c7f85a645072742959
title: Point-count bird censusing: long-term monitoring of bird abundance and diversity in central Arizona-Phoenix, ongoing since 2000

description: project overview
         Over the past half-century, the greater Phoenix metropolitan area (GPMA) has been one
          of the fastest growing regions in the US, experiencing rapid urban expansion in addition
          to urban intensification. This backdrop provides an ideal setting to monitor biodiversity
          changes in response to urbanization, and the CAP LTER has been using a standardized
          point-count protocol to monitor the bird community in the GPMA and surrounding Sonoran
          desert region since 2000. 
         The bird survey locations in this CAP LTER core monitoring program include six
          general site groupings: 
        
          
            
               ESCA. Forty bird survey locations were selected from a subset of the CAP LTER's
                Ecological Survey of Central Arizona (ESCA; formerly named Survey200) long-term
                monitoring sites. ESCA sites were located using a tessellation-stratified
                dual-density sampling design, and, as such, span a diversity of habitats including
                urban, suburban, rural, commercial areas, parks, agricultural fields, and native
                Sonoran desert. Earlier versions of this data package included data from the ESCA
                project that was intended to complement the bird data. However, while positioned in
                close proximity, the bird survey locations do not necessarily overlap with the 30m x
                30m plot that constitutes an ESCA sampling location, and leveraging data from these
                two monitoring programs should be addressed carefully. ESCA data have corresponding
                survey location names, and those data are available through the CAP LTER and LTER
                network data portals. At the conclusion of the 2016 spring survey, fifteen of the
                ESCA-correlated sites were discontinued as the core monitoring program refocused its
                efforts on desert parks and PASS neighborhoods. Among the deleted locations were all
                agricultural and commercial sites, as well as sites where access had become
                restrictive. 
            
            
               North Desert Village (NDV). Additional bird survey locations were positioned in
                treatment areas of the North Desert Village (NDV). This was a site of intense study
                on the Arizona State University Polytechnic Campus in which the CAP LTER converted
                the landscaping of small neighborhoods to reflect the dominant landscaping
                preferences employed throughout the GPMA. NDV landscape types include: oasis
                (NDV-O), xeric (NDV-X), mesic (NDV-M), control (NDV-C), and native (NDV-N).
                Monitoring at NDV was discontinued after the spring 2016 season as research efforts
                at this site came to an end. 
            
            
               Riparian. While the forty bird survey locations that were selected to coincide
                with ESCA sampling locations span a wide diversity of habitats throughout the GPMA,
                because of the generally random nature of selecting those sites, they did not
                reflect riparian habitats. Riparian areas are important bird habitat but constitute
                a very small area of the GPMA. To address this deficiency, bird survey locations
                were established specifically in twelve riparian habitats. Riparian habitat
                sub-types include: (1) ephemeral-engineered (EE, n=4), (2) ephemeral-natural (EN,
                n=2), (3) perennial-engineered (PE, n=3), and (4) perennial-natural (PN, n=3). This
                research was successfully concluded and these sites were discontinued after the
                spring 2016 season. 
            
            
               Salt River. Seven study sites along the Salt River as it runs through the GPMA
                that were selected as part of a related study (Salt River Biodiversity Project
                (SRBP)) were ultimately included in the CAP LTER's core bird monitoring programs.
                These sites reflect continued monitoring of riparian habitat. 
            
            
               Desert Fertilization. Beginning with the 2016-2017 winter survey, six sites at
                desert parks were added to core monitoring to coincide with the CAP LTER Desert
                Fertilization (DesFert) experiment sites. 
            
            
               PASS. Beginning with the 2016-2017 winter survey, what used to be a separate
                bird-monitoring effort (monitoring in Phoenix Area Social Survey (PASS)
                neighborhoods) was incorporated into this core bird-monitoring program. Eight points
                were carried over from prior PASS monitoring, and 28 new points established,
                resulting in three bird monitoring locations in each of the twelve PASS
                neighborhoods. Visiting these locations each year, versus only in years surrounding
                the PASS survey as done previously, provides more data on bird populations found in
                the neighborhoods of the CAP LTER study area. 
            
          
        
      
      
        method overview
         In a given season, each bird survey location is visited independently by three
          birders who count all birds seen or heard within a 15-minute window. The frequency of
          surveys has varied through the life of the project. The first year of the project (2000)
          was generally a pilot year in which each site was visited approximately twice by a varying
          number of birders. The monitoring became more formalized beginning in 2001, and each site
          was visited in each of four seasons by three birders. The frequency of visits was reduced
          to three seasons in 2005, and to two season (spring, winter) beginning in 2006.