Browsing by Subject "Birds -- Nests"
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Item Nest predation and habitat utilization by striped skunks(Texas Tech University, 1995-05) Vander Lee, Bruce A.I monitored the fates of 1435 and 920 artificial ground nests m 1993 and 1994, respectively, to determine the effects of vegetation density, striped skunk removal (1993 only), and prey supplementation on the success of ground nests. I randomly placed artificial nests (1/4.3 ha) into two categories of cover density, dense and sparse. Striped skunk removal (one night per week) and supplemental prey treatments (catfood, fish, meat by-products) were randomly assigned to study plots. Nests in dense vegetation were more successful both years (P < 0.05). There were no differences in nest success among skunk removal, prey supplementation, and control plots m 1993 (P = 0.347), but success was higher on supplemental prey plots m 1994 (P = 0.037). Mammalian predation was greater on nests in sparse vegetation on supplemental prey plots (P < 0.05), but did not differ between vegetation categories on removal or control plots (P > 0.05). Cover density was an important determinant of nest success. Skunk removal provided no observable benefits, perhaps due to compensatory predation by other mammalian species. Prey supplementation may be an effective alternative to traditional predator management techniques. The introduced prey source may have affected the ability of mammalian predators to detect well concealed nests. I also examined habitat use by striped skunks, an important nest predator, by testing for selection of habitats using point locations, within home ranges, and within home range overlap areas. Utilization of small habitats was detected most efficiently using point locations. Skunks used potential nesting habitat (CRP) in proportion to its availability, selected against croplands, and for areas near roads. Skunks were probably using roads and right-of-ways as travel corridors and for foraging. Habitat in areas of home range overlap between two or more skunks was variable. Skunks probably do not defend exclusive territories or particular habitat types. Skunks chose habitats based on the availability of prey rather than vegetative structure. Supplemental prey treatments may have the potential to alter skunk habitat use and distributions as well as foraging strategies. Both habitat and predator management are essential for the effective, long-term management of grassland nesting areas.Item Nesting of ring-necked pheasants in the Texas Panhandle(Texas Tech University, 1980-12) Taylor, Tim ThomasNesting studies of the ring-necked pheasant (Phasianus oolchicus) were conducted during 1979 and 1980 on 3 study areas in Castro County, Texas. Playa basins had higher density of nests (2.21/ha) and greater production of chicks (8.37/ha) than wheat, alfalfa, roadside/strip, oat, and rye habitats. Nest initiation began on approximately 23 March and continued through 13 July. Peak nesting activity occurred from 29 April to 4 May and 23 to 28 May during both years. Similarity of nesting phenology between the Texas Panhandle and northem pheasant range suggested consistent nesting behavior over a wide latitudinal distribution. Young were produced in 24% of the nests (N = 221). Harvesting, predators, abandonment, and flooding contributed to 32, 21, 15, and 5% of the nest losses, respectively. Larger clutch sizes in playas, alfalfa, and oats were attributed to early nest initiation in these habitats relative to rye and wheat fields. The respective mean weight, volume, and eggshell thickness for both years was 26.3 ± 0.18 g, 26.3 ± 0.13 ml, and 0.256 ± 0.001 mm. There was an unexplained difference in eggshell thickness between habitat types with alfalfa, wheat, and roadside/strips having a greater (P < 0.05) thickness than playas, oats, and rye fields. The mean fertility rate was 93.0 ± 0.0"% for eggs in successful nests. Playa basins and roadside/strip cover were the most promising habitat types available for management of nesting cover in the Texas Panhandle.