USGS Science⌕ Search

Geology topics

M.K. Skoruppa

Publications and source records attributed to M.K. Skoruppa.

6 recordsLinked to original sources
USGS2009

Species richness, relative abundance, and habitat associations of nocturnal birds along the rio grande in Southern texas

The segment of the Rio Grande between International Falcon Reservoir and Del Rio, Texas (distance ca. 350 km), remains largely unexplored ornithologically. We surveyed nocturnal birds monthly during February-June 1998 at 19 stations along the Rio Grande (n = 6) and at upland stock ponds (n = 13) in Webb County, Texas. We conducted 10-min point counts (n = 89) after sunset and before moonset. Four species of owls and five species of nightjars were detected. Nightjars, as a group, were nearly five limes more abundant (mean number/count = 2.63) than owls (mean number = 0.55). The most, common owl, the great horned owl (Bubo virginianus), had a mean number of 0.25/point count. The mean for elf owls (Micrathene whitneyi) was 0.16/point count. The most common nightjars were the common poorwill (Phalaenoptilus nuttallii; 1.21/point count) and lesser nighthawk (Chordeiles acutipennir, 1.16/point count). Survey sites on the river supported more species (mean = 2.2) than did upland stock ponds (mean = 1.4). However, only one species (common pauraque, Nyctidromus albicollis) showed a preference for the river sites. Our results establish this segment of the Rio Grande in southern Texas as an area of high diversity of nightjars in the United States, matched (in numbers of species) only by southeastern Arizona and southwestern New Mexico.

Southwestern Naturalist↗
USGS2009

Rodents new to the diet of the western burrowing owl(athene CUNICULARIA HYPUGAEA )

The northern pygmy mouse (Baiomys taylori), fulvous harvest mouse (Reithrodontomys fulvescens), and Merriam's pocket mouse (Pemgnathus merriami) are new to the diet of the western burrowing owl (Athene cuniculana hypugaed). All three species were identified from remains in regurgitated pellets collected from roost sites of burrowing owls in southern Texas over a period of 4 winters. Together, northern pygmy mice and fulvous harvest mice represented 58% of mammals identified in 182 pellets regurgitated by western burrowing owls. Merriam's pocket mouse accounted for only 4% of identified mammalian prey. Frequency of occurrence in pellets was 16% for northern pygmv mice, 11% for fulvous harvest mice, and 3% for Merriam's pocket mice. The primary reason for absence of these species in previous studies of foods of western burrowing owls is that most were conducted in latitudes north of these southern-distributed species of mammals.

Southwestern Naturalist↗
USGS2007

Characteristics of roost sites used by burrowing owls (Athene cunicularia) wintering in Southern Texas

The western burrowing owl (Athene cunicularia hypugaea) is threatened in Mexico, endangered in Canada, and declining in most of the western United States. Most previous research has focused on burrowing owl breeding biology, and little is known about its winter ecology. We determined characteristics of roost sites used by western burrowing owls in southern Texas during winter. Data on 46 winter roost sites were collected from 15 November 2001 to 15 February 2002. Of these roost sites, 87% were located on agricultural land, 80% were along roads, and 74% were concrete, steel, or cast-iron culverts. Mean diameter (??SE) of roost site openings was 22 ?? 1.5 cm. Most roost sites (70%) were located on inaccessible private lands. Bare ground comprised 61% of ground cover within a 10-m radius of roost sites. We recommend that landowners and public-land managers should be encouraged to use smaller-diameter culverts when building roads or replacing old or damaged culverts and to graze livestock or mow around these culverts during winter.

Texas↗
USGS2007

Diet of western Burrowing Owls wintering in southern Texas

Winter diets of the western Burrowing Owl (Athene cunicularia hypugaea) are little known. We determined the diet of western Burrowing Owls wintering in southern Texas by analyzing the contents of 182 pellets collected over four winters (1999-2000, 2001-2002, 2002-2003, and 2003-2004) in three habitat types (agricultural, mainland grassland, and barrier island). Remains of a total of 7476 prey items were recovered, 98% of which were arthropods. Gryllidae (crickets) formed the largest component (50%) of the prey, followed by lepidopteran larvae (13%), beetles (8%), spiders (7%), and earwigs (6%). Although vertebrates, primarily small mammals and birds, represented only 2% of prey items by number, they represented most (71%) of the biomass. Northern pygmy mice (Baiomys taylori) and fulvous harvest mice (Reithrodontomys fulveccens) were the two most frequently consumed vertebrate species. In all habitats, arthropods, especially orthopterans, were the primary prey item by number, whereas vertebrates, primarily small mammals, were the most important by biomass. Greater consumption of arthropods by Burrowing Owls in agricultural areas may be a factor contributing to owl use of these highly altered environments. ?? 2007 The Raptor Research Foundation, Inc.

Texas↗
USGS2006

Ectoparasites of Burrowing Owls (Athene cunicularia hypugaea) wintering in southern Texas

Fifteen Western Burrowing Owls (Athene cunicularia hypugaea) were captured over two winters (2001-2003) in southern Texas and examined for ectoparasites. Four of the 15 owls (27%) harbored feather lice, and the maximum number of lice found on any individual was ??? three. Two species of feather lice were found: Colpocephalum pectinatum occurred on three of the owls, and Strigiphilus speotyti was found on four owls. No fleas or other ectoparasites were found on any of the Burrowing Owls. The low diversity and numbers of ectoparasites suggest that ectoparasites are not threatening the health of wintering Burrowing Owls in southern Texas.

Texas Journal of Science↗