Donald P. Althoff

Evaluation of a reproductive index to estimate dickcissel reproductive success

Intensive monitoring of bird nests to measure reproductive success is time-consuming and may influence the fate of nests. Reproductive indices that do not require searching for and visiting nests may be reasonable alternatives to nest monitoring if they provide results similar to nest-searching efforts. We evaluated the reproductive index of Vickery et al. (1992) for estimating reproductive success of the dickcissel (Spiza americana) in northeast Kansas, USA. We used nest searching and Vickery et al.s (1992) reproductive index to compare reproductive success on 20 plots (200 x 200 m). Daily nest survival (DNS) rates averaged 0.911 (SE = 0.011, n = 72 nests), and brown-headed cowbirds (Molothrus ater) accounted for 21% of all nest failures. Surveyors underestimated reproductive index ranks when compared to nest-searching efforts and were inaccurate in their assignment of reproductive success. In particular, surveyors reported successful nests on 3 study plots that fledged no young, probably because young dickcissels moved onto plots after fledging from their natal territories. Our results indicate that the reproductive index of Vickery et al. (1992) may be inappropriate for wary species or those heavily parasitized by brood parasites. We suggest that before relying on the index alone, investigators should use pilot trials to determine whether results from this index are concordant with results from intensive nest-searching efforts for species of interest.

Daytime habitat selection by cottontails in central Pennsylvania

Information on behavioral responses of wildlife to habitat alterations is needed to allow restoration and maintenance of suitable habitats for a variety of vertebrate species. We studied the use by radiotagged eastern cottontail rabbits (Sylvilagus floridanus) of habitats within a terrestrial ecosystem scheduled to be used for disposing secondarily-treated effluent (domestic wastewater) in central Pennsylvania. Cottontails selected old-fields and shrublands for daytime use, but croplands were used when oats and corn matured during summer and fall: Aboveground bedding sites (forms) were associated with relatively dense cover, indicating that cottontails recognized variations in microhabitat within habitat types. Females frequently used underground burrows when air temperature was less than 0 C, whereas males seldom used burrows except when air temperature was less than -5 C during winter. Cottontails encountered a wide range of microclimates at forms. Air temperature, net radiation, and wind speed extremes were -7.1 to 38 C, -21 to 70 W/ m 2 , and 0.0 to 11.3 cm/sec. Air temperature, net radiation, and wind speed were greater at open sites than those at forms used by cottontails during each season. Cottontails selected micro-environments in which the insulating effect of dense cover may allow conservation of metabolic energy or reduction of heat loss. Provision of dense herbaceous and shrub cover is essential to management of cottontail habitat because it allows the animal to maintain a positive energy balance as well as avoid predators. Typically, cottontails occupied a form from sunrise to sunset. Thus, the structure of vegetation associated with forms may be a key indicator of suitable cottontail habitat. Shrub-woodland habitat appeared to be especially important to cottontails during late winter and early spring because of increased cover associated with early leaf-out of shrubs.

Coyote Family Spatial Relationships with Reference to Poultry Losses

Spacing of 19 coyotes (Canis latrans), representing 8 families, and their proximity to 2 turkey production sites (TPS) were studied during summer and fall 1976 and 1977 near Waverly, Nebraska. Sixteen of the 19 coyotes were radio-tagged and toe-clipped; 3 were ear-tagged and toe-clipped. Related pups remained closer together (average distance apart during day = 0.42 km, during night = 0.37 km) than related adults and pups (average distance apart during day = 1.15 km, during night = 1.59 km), or mated adults (average distance apart during day = 1.63 km, during night = 1.85 km). Family groups occupied nonoverlapping, contiguous home ranges. Three of 9 coyotes tracked during 1976 and 5 of 13 coyotes tracked in 1977 survived and remained on the area until the next denning season. Mortality due to hunting and trapping during the winter was 9 of 11 coyotes. Although 8 families ranged within 5 km of the TPS, only 3 tagged coyotes from 2 different families were responsible for losses. Pups were not responsible for increased turkey losses observed during late summer and fall. J. WILDL. MANAGE. 45(3):641-649 Understanding coyote spatial relationships requires consideration of their social structure and hunting behavior. The social unit among coyotes is the family, and revolves primarily around a reproductive female (Gier 1975). Coyotes are considered efficient, solitary hunters of small prey, but are known to hunt in pairs or as a family unit (Young and Jackson 1951, Dobie 1961, Ryden 1975, Camenzind 1978). Little is known about the postdenning relationships of adult coyotes and their pups, especially among coyotes damaging poultry and livestock. Ryden (1975), Hallett (1977), and Camenzind (1978) presented limited observations of family interactions and movements during the pup-rearing period. Andelt and Gipson (1979) reported on domestic turkey losses to radio-collared coyotes, but did not determine the impact on turkeys of pups of adults known to cause turkey losses. Our objectives were to identify (1) coyote intraand interfamily spatial relationships during the postdenning period and (2) the relationships of movements of damaging adult coyotes and their pups to turkey losses at turkey production sites. We are indebted to L. I. Bevans, R. M. Bevans, B. L. Bevans, W. B. Bevans, and E. V. Sheary of the Bevans Turkey Farm for supplying information regarding poultry losses; D. A. Baker, J. G. Bruner, E. S. Jochum, S. A. Kilpatrick, D. G. Luce, and B. R. Mahan for field assistance; R. K. Allen and W. G. Sheehan for pilot services; J. M. Inguanzo and K. C. Nelson for computer consulting; W. F. Andelt, R. M. Case, H. T. Gier, H. L. Gunderson, and W. M. Tzilkowski for manuscript review; and J. L. Andelt for typing earlier drafts of the manuscript.

Plant community and bare ground trends on Fort Riley, Kansas: Implications for monitoring of a highly disturbed landscape

Abstract The Land Condition Trend Analysis (LCTA) program was developed by the US Army and implemented on Fort Riley, Kansas, to monitor trends in plant communities so that managers could maintain quality training lands without the loss of ecological diversity. As a standard protocol, vegetation surveys using the point-intercept method were conducted from 1994–2001. Presence of bare ground, soil erosion, and military vehicle traffic were also recorded. At the community level, species richness usually fluctuated < 10% annually and declined 6% from 1994–2001. Species richness per plot increased from 1994 to 2001 by 6.5% as compared to the 1994 estimate. Annual species richness of noxious plants ranged from 18–26 species; noxious species per plot averaged 1.0–2.4 species annually with higher estimates usually observed in grassland (vs. woodland) habitats. Modest year-to-year changes were noted at the species level for the most frequently observed species based on an index of relative difference. Two noxious plant species, sericea lespedeza (Lespedeza cuneata) and Johnsongrass (Sorghum halepense), first detected during the second year of monitoring, expanded their distribution considerably on the fort. This expansion may have resulted when mechanized training facilitated transport of seed on vehicles from one training area to another. The patterns of expansion (both on a plot and on a training area basis) by these two noxious species revealed that our analysis approach may be useful for detecting early stages of infestations on this highly disturbed landscape. Bare ground conditions increased on an average of 1.5% per year, but may not be completely attributable to military training activities. Because there appears to be little year-to-year fluctuation in the diversity of the plant communities and trends for most individual plant species monitored on Fort Riley, we recommend detailed plant surveys not be conducted annually. An exception would be monitoring of noxious plant species with a method other than the point-intercept technique, which is extremely time-consuming.

Altered Herbivore Distribution Associated With Focal Disturbance

Abstract Natural disturbances historically created structurally diverse patterns across the landscape, and large herbivores concentrated herbivory in areas where disturbance decreased standing senesced biomass that acted as a grazing deterrent through decreased palatability and overall forage quality. However, following European settlement, many natural large-scale disturbance regimes that influence vegetation and herbivore grazing selection were altered or removed and replaced with fine-scale anthropogenic disturbances. It is unclear how fine-scale focal disturbance and alteration of vegetation structure influences livestock distribution and grazing. Therefore we used a tracked vehicle as a disturbance agent in a mesic mixed-grass prairie to assess the influence of focal anthropogenic disturbance on livestock distribution and grazing. Track vehicle disturbance decreased the height of vegetation (P < 0.05) but did not alter plant species composition (P > 0.05). Cattle fecal pat density was greater (P ≤ 0.05) in locations with track vehicle disturbance. Little bluestem tiller height was shorter (P ≤ 0.05) in tracked locations than nontracked locations in grazed treatments, but was not different in nongrazed locations the first growing season following disturbance. Fecal pat density and tiller height were not different (P > 0.05) between tracked and nontracked locations following the second growing season. Therefore, we concluded that fine-scale focal anthropogenic disturbance alters herbivore distribution and defoliation and can maintain structural heterogeneity, but the effect is ephemeral and does not create long-lasting grazing lawns.

Nest site characteristics of eastern meadowlarks and grasshopper sparrows in tallgrass prairie at the Fort Riley military installation, Kansas

Abstract Knowledge of nest site characteristics and nest success of grassland birds is important in the conservation and preservation of species such as the eastern meadowlark (Sturnella magna) and grasshopper sparrow (Ammodramus savannarum). We documented nest site characteristics of these two species and compared each nest site to a paired random site. We also compared the eastern meadowlark nest sites to the grasshopper sparrow nest sites. Eastern meadowlark nests were significantly further from an edge than random (P=0.049). Grasshopper sparrow nests were significantly further from a shrub/tree (P=0.042) and a perch (P=0.004) than random. Eastern meadowlarks selected sites further from a bare ground patch (≥1 m2; P=0.007), with more litter depth (P=<0.001), smaller bare ground percent (P=0.083) and higher visual obstruction readings (VOR) (P=0.037) than grasshopper sparrows. Military training, conducted before the current breeding season, did not appear to affect the location and success of EAME and GRSP nests. Based on distance to nearest military vehicle track, we conclude that minimal military disturbance is not a deterrent to EAME or GRSP nest site selection. We recommend that management of nesting habitat for eastern meadowlarks include consideration of litter depth (more is better), bare ground (less is better), and amount of woody vegetation and/or edge habitat (less is better). For grasshopper sparrow nesting habitat, minimal or no litter, modest amounts of bare ground, and shorter vegetation is recommended.