Estimating Waterfowl Densities in a Flooded Forest: a Comparison of Methods

During winter, aerial surveys are used to estimate densities of ducks that occupy open-water habitats. However, such surveys are ineffective for sampling forest-dwelling species, especially Aix sponsa (Wood Ducks), Anas platyrhynchos (Mallards), and Lophodytes cucullatus (Hooded Mergansers). We evaluated fixed-radius plot (FRP) and Reynolds and Goodrum variable-radius plot (VRP) methods for estimating waterfowl densities in a flooded hardwood bottomland. We constructed 15 elevated blinds on the Angelina River flood plain in eastern Texas and established a 1-ha FRP around each blind; color-coded markers were placed at fixed intervals from each blind. Observers surveyed waterfowl from blinds for 21 mornings during January–March, 1990. For FRPs, species, sex, and time a bird entered and exited the plot were recorded. For VRPs, similar data and estimated observer-to-bird distance were recorded. Data were arranged in a randomized block design and tested using 1-way analyses of variances. Wood Ducks, Mallards, and Hooded Mergansers comprised 68, 18, and 10% of the birds recorded, respectively. Wood Duck density estimates (per ha) for FRP, Reynolds VRP, and Goodrum VRP methods were 0.65, 0.49, and 1.00 (P \u3c 0.001), respectively; for Mallards, estimates were 0.27, 0.20, and 0.33 (P \u3c 0.001), respectively; and estimates were 0.09, 0.13, and 0.15 (P = 0.003) for Hooded Mergansers, respectively. Based on ease of implementation, complexity of data analyses, and precision of density estimates, the FRP and Goodrum VRP methods are recommended for sampling waterfowl in flooded forests

Activity Patterns and Habitat Use of Northern Bobwhite Females in 2 Grazing Systems

During spring and summer of 1985 and 1986, we investigated activity patterns and habitat use of female northern bobwhite (Colinus virginianus) on 2 sites in south Texas. One site had been subjected to a short duration grazing (SDG) system and the other to a continuous grazing (CG) system. Nineteen females were radio-tagged in 1985 and 28 in 1986. Rainfall was above average in 1985 and below average in 1986; as a result, herbaceous ground cover was more dense in 1985 than in 1986. Due to extensive fencing, 58% of the SDG cell was within 25 m of a mowed roadside, fencerow, or pipeline right-of-way; the same was true for 30% of the CG pasture. There were no differences (P \u3e 0.05) in distances moved between successive locations or in the breeding season home range sizes of females in the 2 systems. In 1985, females preferred zones within 25 m of mowed areas and avoided those ~50 m from such areas. In the SDG cell during 1986 only, females preferred recently grazed paddocks. The results suggest that the most important difference between the 2 grazing systems was the increased proportion of mowed areas in the SDG cell during the abnormally wet year. In the Texas Coastal Bend, landowners unable to adjust stocking rates during wet years should consider mowing to improve bobwhite habitat

Activity Patterns and Habitat Use of Northern Bobwhite Females in 2 Grazing Systems

During spring and summer of 1985 and 1986, we investigated activity patterns and habitat use of female northern bobwhite (Colinus virginianus) on 2 sites in south Texas. One site had been subjected to a short duration grazing (SDG) system and the other to a continuous grazing (CG) system. Nineteen females were radio-tagged in 1985 and 28 in 1986. Rainfall was above average in 1985 and below average in 1986; as a result, herbaceous ground cover was more dense in 1985 than in 1986. Due to extensive fencing, 58% of the SDG cell was within 25 m of a mowed roadside, fencerow, or pipeline right-of-way; the same was true for 30% of the CG pasture. There were no differences (P \u3e 0.05) in distances moved between successive locations or in the breeding season home range sizes of females in the 2 systems. In 1985, females preferred zones within 25 m of mowed areas and avoided those ~50 m from such areas. In the SDG cell during 1986 only, females preferred recently grazed paddocks. The results suggest that the most important difference between the 2 grazing systems was the increased proportion of mowed areas in the SDG cell during the abnormally wet year. In the Texas Coastal Bend, landowners unable to adjust stocking rates during wet years should consider mowing to improve bobwhite habitat

Winter Food Habits and Preferences of Northern Bobwhites in East Texas

During late winter, 1994 and 1995, we investigated food habits and preferences of northern bobwhites (Colinus virginianus; hereafter, bobwhites) collected on forested lands in east Texas. Crops for bobwhites were collected from areas under 3 management regimes, namely intensively managed for bobwhites (QMA) (i.e., tree basal area reduced, annually burned, numerous multi-stage food plots, etc.), extensively managed for timber and wildlife (NBS) (i.e., burned every 3-5 years, scattered 2-stage food plots with corn feeders), and unmanaged for wildlife (i.e., burned every 5-7 years). With years pooled, partridge pea (Cassia fasciculata), Hercules club (Zanthoxylum clava-herculis), and pine (Pinus spp.) seeds, and clover leaflets (Trifolium spp.) comprised 93% by weight of foods of 79 bobwhites foods on QMA. On NBS, 81% of 40 bobwhite diets was butterfly pea (Centrosema virginianum), browntop millet, pine, wild bean (Strophostyles spp.), and corn seeds and clover leaflets; millet and corn were from food plots and feeders, respectively. For unmanaged areas, 79% of 19 bobwhite diets was butterfly pea, rush (Juncus spp.), pine, partridge pea, and American beautyberry (Callicarpa americana) seeds, and clover leaflets. Top-ranked food items on QMA were pine, hairy vetch, and Hercules club seeds in 1994 and butterfly pea, partridge pea, and wax myrtle (Myrica cerifera) seeds in 1995 (P \u3c 0.05). On NBS, hawthorn (Crataegus spp.) and beautyberry seeds were top-ranked in 1994 as were kobe lespedeza, wild bean, and butterfly pea seeds in 1995. On unmanaged areas, butterfly pea and partridge pea seeds and clover leaflets were highest ranked in 1995. On forested lands, activities (e.g., disking, burning, establishing food plots) which provide seed-bearing plants, especially legumes, and clover greenery benefit bobwhites

Winter Food Habits and Preferences of Northern Bobwhites in East Texas

During late winter, 1994 and 1995, we investigated food habits and preferences of northern bobwhites (Colinus virginianus; hereafter, bobwhites) collected on forested lands in east Texas. Crops for bobwhites were collected from areas under 3 management regimes, namely intensively managed for bobwhites (QMA) (i.e., tree basal area reduced, annually burned, numerous multi-stage food plots, etc.), extensively managed for timber and wildlife (NBS) (i.e., burned every 3-5 years, scattered 2-stage food plots with corn feeders), and unmanaged for wildlife (i.e., burned every 5-7 years). With years pooled, partridge pea (Cassia fasciculata), Hercules club (Zanthoxylum clava-herculis), and pine (Pinus spp.) seeds, and clover leaflets (Trifolium spp.) comprised 93% by weight of foods of 79 bobwhites foods on QMA. On NBS, 81% of 40 bobwhite diets was butterfly pea (Centrosema virginianum), browntop millet, pine, wild bean (Strophostyles spp.), and corn seeds and clover leaflets; millet and corn were from food plots and feeders, respectively. For unmanaged areas, 79% of 19 bobwhite diets was butterfly pea, rush (Juncus spp.), pine, partridge pea, and American beautyberry (Callicarpa americana) seeds, and clover leaflets. Top-ranked food items on QMA were pine

Movement Patterns of Resident and Relocated Northern Bobwhites in East Texas

We compared home range sizes and movement patterns of resident and relocated northern bobwhites (Colinus virginianus) on an area managed specifically for the species in the Pineywoods of east Texas. During the winters of 1990–1992, 155 south Texas, 136 east Texas, and 139 resident bobwhites were radiomarked, released, and thereafter regularly located. Bird locations were plotted on a digitized map, and home range sizes and movement patterns of each group of birds were estimated. Resident bobwhites moved longer daily distances in March and had larger home ranges during the nesting season (May-Jul) than relocated birds (P0.05). Managers that elect to relocate northern bobwhites should consider doing so in the fall and only into habitats of ample size

Food Plot Use by Juvenile Northern Bobwhites in East Texas

We examined use of spring-summer (i.e., warm-season) food plots by northern bobwhites (Colinus virginianus) with broods using radio telemetry on a 563-ha study area in Trinity County, eastern Texas, where habitat was modified to enhance it for these birds. Bobwhites from South Texas and disjunct areas of East Texas were introduced to supplement a small, resident population. All relocated and most resident bobwhites were fitted with necklace-style transmitters. Bobwhites which produced chicks were intensively radiotracked (≥3 times/day) for ≥4 weeks or until the radio-marked parent was lost. Nine hens moved their broods to food plots within an average of 2.1 days after the eggs hatched; average distance moved was 217 m. Use of food plots by 12 broods was proportionally greater than that of native vegetation (P \u3c 0.001). Food plots had lower quail-level foliage density (P = 0.015) and more arthropods (P \u3c 0.001) than native vegetation. Our results demonstrate that warm-season food plots can potentially provide brood habitat for bobwhites in eastern Texas

Food Plot Use by Juvenile Northern Bobwhites in East Texas

We examined use of spring-summer (i.e., warm-season) food plots by northern bobwhites (Colinus virginianus) with broods using radio telemetry on a 563-ha study area in Trinity County, eastern Texas, where habitat was modified to enhance it for these birds. Bobwhites from South Texas and disjunct areas of East Texas were introduced to supplement a small, resident population. All relocated and most resident bobwhites were fitted with necklace-style transmitters. Bobwhites which produced chicks were intensively radiotracked (≥3 times/day) for ≥4 weeks or until the radio-marked parent was lost. Nine hens moved their broods to food plots within an average of 2.1 days after the eggs hatched; average distance moved was 217 m. Use of food plots by 12 broods was proportionally greater than that of native vegetation (P \u3c 0.001). Food plots had lower quail-level foliage density (P = 0.015) and more arthropods (P \u3c 0.001) than native vegetation. Our results demonstrate that warm-season food plots can potentially provide brood habitat for bobwhites in eastern Texas

Movement Patterns of Resident and Relocated Northern Bobwhites in East Texas

We compared home range sizes and movement patterns of resident and relocated northern bobwhites (Colinus virginianus) on an area managed specifically for the species in the Pineywoods of east Texas. During the winters of 1990–1992, 155 south Texas, 136 east Texas, and 139 resident bobwhites were radiomarked, released, and thereafter regularly located. Bird locations were plotted on a digitized map, and home range sizes and movement patterns of each group of birds were estimated. Resident bobwhites moved longer daily distances in March and had larger home ranges during the nesting season (May-Jul) than relocated birds (P \u3c= 0.05). Conversely, no differences were detected among groups in mean of daily distances moved in April or dispersal during the breeding season (Mar-Jun) (P 0.05). Annual dispersal distances (x¯ = 1.43 km) of birds that survived into November were similar among groups (P \u3e 0.05). Managers that elect to relocate northern bobwhites should consider doing so in the fall and only into habitats of ample size

Invertebrate Biomass and Richness in Various Food Plot Types in East Texas

As northern bobwhite (Colinus virginianus) chicks are dependent on invertebrates for food, land managers often use spring/summer food plots to meet these needs. We examined invertebrate production in native vegetation and 6 different food plot types (i.e., fallow disking only; fallow disking and fertilizing; or disking, fertilizing, and planting a single species [browntop millet, iron and clay peas, or sorghum] or a multi-species mix [browntop millet, catjang peas, iron and clay peas, Japanese millet, and pearl millet]) in the Pineywoods of east Texas. Invertebrates were collected weekly during the summers of 1997 and 1999 and for 5 weekly sampling periods during summer, 1998. For each food plot type, invertebrates were separated from debris, air dried, and weighed as a group. Bi-weekly, a 100-invertebrate sub-sample was randomly selected from each sample and sorted to order with weight and number of individuals recorded. When spring precipitation was sufficient, multi-species food plots produced greater (P \u3c 0.05) invertebrate biomass than fallow or native vegetation plots, and all cultivated plots had more (P \u3c 0.05) biomass than native vegetation. Likewise, all cultivated plots had more (P \u3c 0.05) biomass than fallow plots in early summer but not in mid- and late summer. A combination of multi-species (with legumes) food plots and fallow disking should provide bobwhite chicks with invertebrates throughout most summers