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RELATIONSHIPS OF BIRDS, LIZARDS, AND NOCTURNAL RODENTS TO THEIR HABITAT IN TUCSON, ARIZONA
<br />RESULTS
<br />Land Cover Associations
<br />Native vegetation (combined lower and upper
<br />Sonoran, and mesquite bosque cover types) was
<br />the most common land cover type encountered in
<br />the census plots, and comprised almost 42% of all
<br />land sampled (Table 1). This does not represent
<br />the actual amount of native land cover remaining
<br />in Tucson, because the study area boundary
<br />extended beyond the developed areas. The
<br />amount of native vegetation per plot ranged from
<br />0 to 99.5% of total ground cover. Over 28% of
<br />this land was upper Sonoran habitat, of which 2%
<br />was visibly thinned or degraded by human
<br />activity. Another 12.3% was lower Sonoran
<br />vegetation, with 1% thinned or degraded by
<br />human activity. Less than 0.1% of all native land
<br />cover sampled was classified as visibly thickened
<br />or enhanced by human activity. One percent of
<br />all native vegetation cover sampled was mesquite
<br />bosque. Paved or graded land comprised 18.3% of
<br />all land sampled, and ranged from 0 to 62.2% of
<br />the total ground cover within census plots.
<br />Yards that I classified as urban open were the
<br />most common urban land cover type, comprising
<br />23.8% of all land sampled. The range of values in
<br />the plots for urban open areas was from 0 to
<br />80.0%. Most urban open land was predominantly
<br />non-native vegetation (16.4%), whereas only 3%
<br />was predominantly native, and 4.5% was a
<br />mixture of both native and non-native vegetation.
<br />Both urban treed areas (containing > 60% tree
<br />canopy closure) and urban savannahs (30-60%
<br />canopy closure) were rare, comprising only 0.4%
<br />and 1.3% respectively of the total area sampled.
<br />The average number of houses/ha was 3.3
<br />(1.3/ac), and houses covered an average of 8.0% of
<br />all land within plots. Number of houses ranged
<br />from 0 to 19.8 per ha (7.9/ac) and covered a range
<br />from 0 to 43.7 % of the land within plots.
<br />Apartment buildings and small businesses covered
<br />an average of 1.5% of land in plots, ranging from
<br />0-28.6% of land cover measured. Undisturbed
<br />washes comprised an average of 3.9%, and
<br />disturbed washes comprised an average of 0.3% of
<br />all land cover. The percent of ground covered by
<br />undisturbed washes ranged from 0-65%, disturbed
<br />wash cover ranged from 0-17.9%.
<br />Distance of census plots from mainland areas
<br />ranged from 0-10.7 km and averaged 3.3 km. The
<br />distance from > 1 ha undeveloped patches of land
<br />ranged from 0-2.8 km and averaged only 291 m.
<br />The distance of points from undisturbed riparian
<br />zones averaged 925 m and ranged from 0-5.0 km.
<br />Sampling plots contained an average of 3 distinct
<br />land cover types each, and ranged from only 1
<br />type to 6 distinct types present. Several of the
<br />habitat descriptors were inter-correlated (Table 2).
<br />Wildlife Data Results
<br />Breeding Birds. Fifty-eight species of birds
<br />known to breed within the study area were
<br />detected during spring censuring (Appendix A).
<br />The most abundant species were the house
<br />sparrow (Passer domesticus, n = 2,031), mourning
<br />dove (Zenaida macroura, n = 996), and house
<br />finch (Carpodacus mexicanus, n = 848). The most
<br />wide-spread species were the mourning dove,
<br />house finch, and cactus wren (Campylorhynchus
<br />brunneicapillus), which occurred in 315, 315, and
<br />259 of the 334 total plots, respectively. Species
<br />richness at each census plot ranged from 4-18,
<br />with a mean of 11.8 ± 0.15 (SE). Total number
<br />of individuals per plot ranged from 5.5-68, and
<br />averaged 24.9 ± 0.42. Four species of non-native
<br />birds were detected during censuring, house
<br />sparrow, European starling (Sturnus vulgris), rock
<br />dove (Columba livia), and Inca dove (Columbina
<br />inca). I included the Inca dove in the non-native
<br />bird group because it is a relatively recent arrival
<br />(circa 1870) into the Tucson area, and has a
<br />history of close association with urbanization in
<br />both Arizona and throughout its original range in
<br />Mexico.
<br />Wintering Birds. Forty-two species of birds
<br />were encountered during the winter census period
<br />(Appendix B). Three wintering species were
<br />encountered that were not encountered during
<br />breeding season censuring: black-chinned sparrow
<br />(Spizella atrogularis), ruby-crowned kinglet
<br />(Regulus calendula), and black-throated gray
<br />warbler (Dendroica nigrescens). The most
<br />abundant species encountered were the same as
<br />those in the breeding season censuses; the house
<br />sparrow (n = 1,227), mourning dove (n = 1,217),
<br />and the house finch (n = 385). The same 3
<br />species were also the most wide-spread; mourning
<br />doves were present in 183 plots, house sparrows
<br />were present in 164 plots, and house finches were
<br />present in 123 of the 306 plots that were visited.
<br />Species richness ranged from 0-11, with a mean of
<br />4.5 ± 0.14. Total number of individuals per plot
<br />ranged from 0-132, with a mean of 15.3 ± 1.10.
<br />Four non-native species were detected during
<br />winter censuring, house sparrows, European
<br />starlings, rock doves, and Inca doves.
<br />STEPHEN S. GERMAINE 1995 ARIZONA GAME fr FISH DEPARTMENT, TECH. REP. 20 13
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