Geology topics

Mary K. Skoruppa

Publications and source records attributed to Mary K. Skoruppa.

3 recordsLinked to original sources

USGS2012

Evaluation of capture techniques for long-billed curlews wintering in Texas

Texas coast harbors the largest, eastern-most populations of Long-billed Curlews (Numenius americanus) in North America; however, very little is known about their migration and wintering ecology. Curlews are readily captured on their breeding grounds, but experience with capturing the species during the non-breeding season is extremely limited. We assessed the efficacy of 6 capture techniques for Long-billed Curlews in winter: 1) modified noose ropes, 2) remotely controlled bow net, 3) Coda Netgun, 4) Super Talon net gun, 5) Hawkseye whoosh net, and 6) cast net. The Coda Netgun had the highest rate of captures per unit of effort (CPUE = 0.31; 4 curlew captures/13 d of trapping effort), followed by bow net (CPUE = 0.17; 1 capture/6 d of effort), whoosh net (CPUE = 0.14; 1 capturel7 d of effort), and noose ropes (CPUE = 0.07; 1 capturel15 d of effort). No curlews were captured using the Super Talon net gun or a cast net (3 d and 1 d of effort, respectively). Multiple capture techniques should be readily available for maximum flexibility in matching capture methods with neophobic curlews that often unpredictably change referred feeding locations among extremely different habitat types.

Texas↗

USGS2007

Winter ecology of the western burrowing owl ( Athene cunicularia hypugaea ) in southern Texas 1999-2004

This study examines the winter ecology of the western burrowing owl ( Athene cunicularia hypugaea ) in five Texas counties surrounding Corpus Christi, in southern Texas. There is a substantial gap in information on the owl's life cycle during migration and non-breeding winter months; almost all previous research on western burrowing owls has been conducted during the breeding season. The western burrowing owl currently is federally threatened in Mexico, federally endangered in Canada, and in the United States is considered a National Bird of Conservation Concern by the U.S. Fish and Wildlife Service. Topics investigated included status, effectiveness of public outreach, roost sites and use of culverts and artificial burrows, roost site fidelity, diet, contaminant burdens, body mass, and ectoparasites. Early ornithological reports and a museum egg set revealed that burrowing owls once bred in southern Texas and were common in winter; however, since the 1950's they have been reported in relatively low numbers and only during winter. In this study, public outreach increased western burrowing owl detections by 68 percent. Owls selected winter roost sites with small-diameter openings, including culverts less than or equal to 16 centimeters and artificial burrows of 15 centimeters, probably because the small diameters deterred mammalian predators. Owls showed strong roost site fidelity; 15 banded birds stayed at the same roost sites within a winter, and 8 returned to the same site the following winter. The winter diet was over 90 percent insects, with crickets the primary prey. Analyses of invertebrate prey and regurgitated pellets showed that residues of all but 3 of 28 carbamate and organophosphate pesticides were detected at least once, but all were below known lethal concentrations. Mean body mass of western burrowing owls was 168 grams and was highest in midwinter. Feather lice were detected in low numbers on a few owls, but no fleas or other ectoparasites were found.

Texas↗

USGS1999

Discovery of a second population of white-collared seedeaters, Sporophila torqueola (Passeriformes: emberizidae) along the Rio Grande of Texas

The range of the white-collared seedeater (Sporophila torqueola), a tropical grassland species, extends from Central America northward along both coasts of Mexico (Eitniear, 1997), including Tamaulipas and Nuevo Leon (Howell and Webb, 1995). White-collared seedeaters historically occurred commonly in extreme southern Texas (Oberholser, 1974; Rappole and Blacklock, 1994). However, since about 1950, white-collared seedeaters have undergone a precipitous decline in south Texas. Studies during 1994-1996 identified only seven to nine breeding pairs in the only population known to occur in Texas, located ca. 55 km downriver of Laredo, Texas, in Zapata Co. (Eitniear, 1997). Outside of the historical range, very few records are documented. Oberholser (1974) reported that three white-collared seed- eater specimens were collected in 1948 in Webb Co., northwest of Laredo, and Arnold (1980) also collected a white-collared seedeater in Webb Co. Vagrants also have been sighted as far afield as Corpus Christi (Blacklock, 1964), ca. 200 km north of the Rio Grande (Fig. 1).

Southwestern Naturalist↗