Breeding Biology of Swainson's Warblers in a Managed South Carolina Bottomland Forest

population density;digital photogrammetry;multiple brooding;Neotropical migrant;aerial photography;nest success;habitat selection

Thompson, Jennifer Laurie ; Richard A. Lancia, Committee Chair,Kenneth H. Pollock, Committee Member,Heather M. Cheshire, Committee Member,Phillip D. Doerr, Committee Member,Thompson, Jennifer Laurie ; Richard A. Lancia ; Committee Chair ; Kenneth H. Pollock ; Committee Member ; Heather M. Cheshire ; Committee Member ; Phillip D. Doerr ; Committee Member

University:North Carolina State University

关键词: population density;    digital photogrammetry;    multiple brooding;    Neotropical migrant;    aerial photography;    nest success;    habitat selection;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/3236/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

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.