| effects of protective fencing on birds, lizards, and black-tailed hares in the western mojave desert. | / effects of protective fencing on birds, lizards, black-tailed hares (lepus californicus), perennial plant cover, and structural diversity of perennial plants were evaluated from spring 1994 through winter 1995 at the desert tortoise research natural area (dtna), in the mojave desert, california. abundance and species richness of birds were higher inside than outside the dtna, and effects were larger during breeding than wintering seasons and during a high than a low rainfall year. ash-throated ... | 1999 | 9950700 |
| birds and their ticks in northwestern california: minimal contribution to borrelia burgdorferi enzootiology. | birds and their attendant ticks were surveyed for infection with the lyme disease spirochete borrelia burgdorferi, in chaparral and woodland-grass habitats in northwestern california from march to july, 1998 to 1999. in total, 234 birds were captured and recaptured (15%); nearly 2.5 times more birds were captured in chaparral than in woodland-grass. overall, 34 species representing 15 families were collected during this study; of these, 24 species were caught in chaparral, 19 in woodland-grass, ... | 2001 | 11534638 |
| fragmention by agriculture influences reproductive success of birds in a shrubsteppe landscape. | shrubsteppe communities are among the most imperiled ecosystems in north america as a result of conversion to agriculture and other anthropogenic changes. in the intermountain west of the united states, these communities support a unique avifauna, including several species that are declining and numerous others that are of conservation concern. extensive research in the eastern and central united states and in scandinavia suggests that fragmentation of formerly continuous forests and grasslands ... | 2007 | 17494408 |
| a phylogenetic analysis of the emberizid sparrows based on three mitochondrial genes. | previous molecular phylogenetic studies have examined the taxonomic relationships among a number of typical emberizid sparrow genera. to help clarify these relationships, we sequenced a 1673 base pair fragment for the complete sequence of three mitochondrial genes: adenosine triphosphatase (atp8 and atp6) and cytochrome oxidase subunit iii (coiii) for 38 sparrow species, along with passerina amoena (cardinalidae) and piranga ludoviciana (thraupidae) which were selected as the outgroups. our anal ... | 2003 | 12967606 |
| evaluating the impact of gas extraction infrastructure on the occupancy of sagebrush-obligate songbirds. | development associated with natural gas extraction may have negative effects on wildlife. here we assessed the effects of natural gas development on the distributions of three sagebrush-obligate birds (brewer's sparrow, spizella breweri; sagebrush sparrow, amphispiza belli; and sage thrasher, oreoscoptes montanus) at a natural gas extraction site in wyoming, usa. two drivers of habitat disturbance were investigated: natural gas well pads and roadways. disturbances were quantified on a small scal ... | 2015 | 26485947 |
| temporal and spatial variations in the behavior of shrubsteppe birds. | we documented patterns of activity and microhabitat use by breeding male sage sparrows (amphispiza belli) and brewer's sparrows (spizella breweri) in the semiarid shrubsteppe of northwestern u.s.a. to determine how their behavior varies in space and time and how these variations relate to environmental features. in analyses of several sites with multiple plots that were studied for 2-4 yr, the frequencies of activities and substrate use varied significantly with year, plot, and location. the maj ... | 1987 | 28311406 |