Fidel Hernandez

Impacts of Precipitation on Northern Bobwhite Production in South Texas

Despite a long history of research on northern bobwhites (Colinus virginianus; hereafter, bobwhites), there has not been a comprehensive assessment of how bobwhite productivity varies across a landscape in relation to environmental factors such as weather. Due to concerns of global climate change and range-wide decline of the bobwhite, further understanding the relationship between weather and bobwhite population dynamics is needed. The objectives of this study were to determine 1) how do among-year bobwhite masses, age ratios, and sex ratios change at the landscape scale, 2) can fall...

Year
2011

Vegetation Response to Timing of Discing to Manage Northern Bobwhite Habitat in Texas

Discing is commonly recommended to improve northern bobwhite (Colinus virginianus) habitat. However, little information exists regarding optimal timing of discing or the duration of discing effects on semiarid rangelands. Our objectives were to evaluate vegetation response to autumn (October 2003), winter (January 2004), and spring (March 2004) discing in two ecoregions of Texas (Rio Grande Plains and Rolling Plains). Our study design was a completely randomized, two-factor (treatment and soil texture) factorial with repeated measures. We collected data on percent bare ground, forb...

Year
2009

Three Year Post Treatment Effects of Habitat Management on a Wintering Grassland-bird Community in South Texas

Ecologically sound habitat management will be essential to reverse the current decline of grassland birds. The objective of this study is to evaluate the effects of two habitat management practices: (1) summer prescribed fire [SF], (2) a combined treatment of roller chopper, summer prescribed fire, and chemical application [CT], and (3) an open grassland [C] as “control” on wintering grassland-shrub bird community composition and abundance. Line transects of variable lengths were used to assess the bird community structure. Grassland bird species richness during first season was 31 and 15...

Year
2008

Overwinter Survival of Northern Bobwhites on Non-hunted Areas in Texas

As part of an ongoing investigation of sustainable harvest strategies for northern bobwhite (Colinus virginianus) populations, we are estimating overwinter survival in two Texas ecoregions that have stable bobwhite population trends, the Rolling Plains and the Rio Grande Plains. Estimating overwinter survival in the absence of hunting is an important variable in developing a sustained-yield harvest strategy for bobwhites. Overwinter bobwhite survival was estimated using radio-marked bobwhites from 16 November 2007 to 29 February 2008. Overwinter survival estimates were calculated using...

Year
2008

Nesting Habitat of White-winged Doves in Urban Environments of Southern Texas

Changes in white-winged dove (Zenaida asiatica) distribution and habitat use have occurred in Texas since the 1940s. Breeding populations are now common in urban areas throughout Texas. These changes have resulted in unique challenges for monitoring populations in urban environments because of factors such as traffic, construction, and residential development. Delineating potential breeding habitat within urban areas may make surveys more efficient. Our objectives were to examine nest tree selection and identify habitat attributes associated with urban populations of white-winged doves. We...

Year
2008

Exotic Grass Impacts on Northern Bobwhite Habitat in South Texas

There is growing concern about the impacts that exotic grasses may have on northern bobwhite (Colinus virginianus) and other grassland birds. Large areas of South Texas have been seeded to or have been invaded by several species of exotic grasses including Guinea grass (Urochloa maxima), Bermuda grass (Cynodon dactylon), King Ranch bluestem (Bothriochloa ischaemum), Kleberg bluestem (Dichanthium annulatum), buffelgrass (Pennisetum ciliare), and Lehmann lovegrass (Eragrostis lehmanniana). Impacts of exotic grasses on northern bobwhite are largely unknown. While exotic grasses such as...

Year
2008

Density Dependence, Harvest, and Population Dynamics in New World Quail: Implications for Harvest Theory in Upland Gamebird Management

Long-term population declines and conservation concerns resulting from large scale habitat loss have brought into question the biological justification of fixed, liberal harvest regulations as they apply to new world quail (Odontophoridae). As available quail habitat declines, biologically justifiable and sustainable methods of harvest will become essential components of quail management. Two hypotheses, the doomed-surplus hypothesis and the additive mortality hypothesis, attempt to provide a conceptual framework regarding the nature of mortality in hunted populations (i.e., compensatory...

Year
2008

An Evaluation of Sampling Methods for White-winged Dove Surveys in Urban Areas

Texas Parks and Wildlife Department (TPWD) has used auditory call counts annually since 1949 to monitor white-winged dove (Zenaida asiatica) populations in the Lower Rio Grande Valley of Texas. Recently, white-winged doves have been expanding their distribution, and now the largest populations occur in urban areas north of their historic south Texas range. It has become necessary to develop an urban survey method to better monitor these populations. We compared two call count sampling methods for surveying white-winged doves in urban environments (i.e., transects vs. grid-points in Austin...

Year
2004

Effects of Pen-raised Northern Bobwhite Introductions on Wild Bobwhites in South Texas

Although restocking wild populations with pen-raised bobwhites (Colinus virginianus) is considered ineffective, it has become popular and acceptable among sportsmen to supplement hunting opportunities. Nonetheless, their impact on wild bobwhite populations remains unknown. The objectives of this study were to compare bobwhite survival, core area of use, and relative predator abundance between treatment (release of pen-raised bobwhites) and control areas. We monitored 136 wild bobwhites via radiotelemetry from September to February 2000-01 and 2001-02 on 2 areas (1 release and 1 control...

Year
2003