Browsing by Author "Richard A. Lancia, Committee Chair"

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Breeding Biology of Swainson's Warblers in a Managed South Carolina Bottomland Forest
    (2005-07-22) Thompson, Jennifer Laurie; Richard A. Lancia, Committee Chair; Kenneth H. Pollock, Committee Member; Heather M. Cheshire, Committee Member; Phillip D. Doerr, Committee Member
    Conservation plans for the southeastern U.S. have identified Swainson's Warblers (Limnothlypis swainsonii) to be among the more vulnerable Neotropical migrants. However, a lack of life history information, in particular breeding, jeopardizes sound management decisions. My study examined a population in Britton's Neck, South Carolina on timberland owned by International Paper Co. From 1999-2001, I conducted a breeding biology study that examined nesting, territory, vegetative, and landscape characteristics. I discovered 98 SWWA nests, 63 of which were active. SWWA nesting success equaled 60% using the Mayfield success estimator. Contrary to the notion of SWWA requiring mature forests to breed, SWWA bred successfully in 20-year old regenerating clearcuts. Multiple brooding, where a pair initiates nesting attempts after their first is successful, was detected in 20% of the pairs. An individual's seasonal fecundity was doubled by multiple brooding, increasing the young per female from 1.5 to 3.7. Brown-headed Cowbirds (Molothrus ater) parasitized only 10% of nests. No SWWA chicks were observed fledging in the presence of Cowbirds. Apparent population density was 17 territories/km2, equaling the highest density ever recorded for SWWA. One-fifth the site contained 59 territories/km2, compared to the remaining four-fifths with 12 territories/km2. I examined vegetative differences between nests built in high- versus low-density areas using a discriminant function analysis (DFA). The DFA results indicated understory thickets accounted for the largest difference between high- and low-density nest sites. Nests in the high-density area were more associated with understory thickets.
  • No Thumbnail Available
    Implications of Quality Deer Management on Population Demographics, Social Pressures, Dispersal Ecology, and the Genetic Mating System of White-tailed Deer at Chesapeake Farms, Maryland.
    (2005-07-20) Shaw, Jonathan Christopher; Richard A. Lancia, Committee Chair
    Quality deer management (QDM) is widely accepted as a principled management practice, yet QDM implications for population processes are unclear. Our research primarily focused on components of (1) dispersal ecology and (2) the genetic mating system of white-tailed deer (Odocoileus virginianus) under QDM at Chesapeake Farms, Maryland. The objectives of our dispersal ecology research were: (1) to compare pre- and post-QDM dispersal parameter estimates, and (2) evaluate inbreeding avoidance and sexual-competition hypotheses as mechanisms of dispersal. Emigration of yearling males pre-QDM was 0.70 + 0.07, and post-QDM was 0.54 + 0.10. Genetic maternity analysis indicated that dispersal of orphans and non-orphans was similar. Dispersers exhibited breeding competition with other yearling males more often than nondispersers, and yearling male antler points appeared to be related to dispersal status in both pre- and post-QDM populations. Overall breeding behaviors of yearling males decreased from pre- to post-QDM. Our results fail to support inbreeding avoidance and support sexual-competition as a cause of fall dispersal at Chesapeake Farms. Through QDM, an older male age structure may have suppressed breeding competition in yearling males and decreased dispersal rates. The objectives of our genetic mating system research were to evaluate: (1) age-specific male breeding success; (2) relationships of weight and antler size with male breeding success; (3) instances of multiple paternity in single litters; and (4) male and female mate selection. We observed higher breeding success of males >3.5-years old in comparison to males <2.5-years old; however, several males across age-classes bred; antler and body size were not important factors in breeding success; instances of multiple paternity of single litters occurred; and mate selection did not occur. Our results fail to support the prevailing observation-based mating system paradigm where few dominant males monopolize breeding opportunities. In populations with high estrous synchrony, dominant males fail to effectively monopolize tending bonds, and subordinate males may successfully breed surplus females via surreptitious fertilization.