This study explores the potential impact of variation in forest habitats and management on Chuck-will’s-widow density

Beckett, Hannah E.

English

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• Cryptic, nocturnal, migrants and ground-nesting breeders in southeast US• Nest in open, deciduous, mixed pine and hardwood forests➢ Nests consist of a simple scrape either on bare ground or leaf litter oftennear woodland edges in dense cover.• Little else is known about the habitat requirements due to their nocturnalnature.Pine Habitat Characteristics Associated with Variation in Chuck-will’s-widowCommunities Hannah Beckett, Dr. Donald Burt Department of Biology, Stephen F. Austin UniversityDr. Daniel Saenz, James Childress, US Forestry Service, 506 Hayter St. Nacogdoches, TX• Data collection occurred 26 May to 24 June in 2019• Sampled eighteen sites representing pine forests under different management• Ten sites thinned and controlled burned• Five sites thinned• Three sites received no management• Bird vocalization data collected using audio data loggers set for ten-minuteintervals an hour after sunset every day• Recordings analyzed for presence or absence of Chuck-will’s-widow andnumber of singing detections each day• Performed detection analysis using the audio software, Kaleidoscope(Figure 1)• Habitat variables recorded at each site• Forest type determined by dominant tree species• Age, height, and diameter at breast height (DBH) measured from one treerepresentative of all trees within each site• Percentages of pine basal area, woody, and bare ground estimated at eachsite• Pine basal area - density of pine tree species in each site• Woody – woody plant material on forest floor• Bare - amount of ground not covered by litter (dead plant material)• Midstory-vegetation and snag density rated on a scale of 0 to 5• 0=absence of midstory and snags, 5=dense midstory and snags• We use a step-wise linear regression approach to build a predictive model ofthe habitat variables that best predict CWWI vocal detections (JMP v.14.3)• Chuck-will’s-widows are detected more often in forestswith:• Younger stands,• More bare ground and woody ground cover• Fewer snags,• Abundant midstory and larger DBH of pines.• Forests with little or no forest management had no Chuck-will’s-widows.• Previous studies indicated the importance of forest opennessand edges more suitable nesting sites. In contrast, this studyfound a greater density of Chuck-will’s-widows in forestswith great midstory density.Since most nocturnal birds display sporadic calling behaviors, single-year auditory surveys may not  be reliable for estimating population size and the results of this study should be considered preliminary. However, if theses results hold, midstory density may be an underappreciated habitat component for this species or habitat selection behaviors differ in east Texas compared to other regions. The reclusiveness of Chuck-will’s-widows proves a difficult challenge in determining habitat preferences and requires long-term studies to fully understand the impact of habitat variables and forest management.• Dewey, T. 2009. Caprimulgus carolinensis. Animal DiversityWeb. [accessed 2020 Nov 5, 2020].https://animaldiversity.org/accounts/Caprimulgus_carolinensis• Iglay R.B, Greene R.E, Leopold B.D, Miller D.A. 2018. Birdconservation potential of fire and herbicide treatments inthinned pine stands. Forest Ecology and Management.409:267-275.• JMP Software. Cary, NC: JMP Statistical Discovery From SAS;[accessed 2019 Dec 2]. https://www.jmp.com/en_us/home.html• Johnson, James B.; Saenz, Daniel; Burt, D. Brent; Conner,Richard N. 2002. An automated technique for monitoringnocturnal avian vocalizations. Bulletin of the TexasOrnithological Society. 35(2):24-29.• Kaleidoscope Software. Maynard, MA: Wildlife Acoustics,Inc.; [accessed 2019 Sept]. https://www.wildlifeacoustics.com/.• O’Connor R.S. 2013. Breeding Biology of Chuck-Will’s-Widows: Incubation, Brooding, and Provisioning Behavior AndCharacteristics of Nest Sites [thesis]. [Richmond, KY]: Eastern Kentucky University.• Daniels, Dick. Chuck-will's-widow (Caprimulgus carolinensis)in Exum, North Carolina. Chuck-will's-widows has amazingcamouflage. 27 May 2012. http://carolinabirds.org/Figure 4. Increasing midstory density is associated with more Chuck-will’s-widows and snag density has a negative impact on vocalization.Figure 5. Other habitat variables showing significant influence on Chuck-will’s-widowpresence were the amounts of pine basal area, woody vegetation, and bare ground. Pine basal area had a positive relation to Chuck-will’s-widow presence, while woody vegetation and bare ground had a negative relation.Figure 3. Forest age was the habitat variable with the greatest explanatory power for Chuck-will’s-widow vocalizations. A negative relation between Chuck-will’s-widow presence and forest age is observed.Figure 2. The habitat model developed in this study has significant predictive power. The predicted presence of Chuck-will’s-widows closely corresponds with the actual observations of Chuck-will’s-widow presence. CWWI = Chuck-will’s-widowFigure 1. Chuck-will’s-widow song as it appears on a sonagram.Chuck-will’s-widows (Antrostomus carolinensis)Methods and MaterialsResults DiscussionReferences• This study explores the potential impact of variation in foresthabitats and management on Chuck-will’s-widow density.Study Objectiveshttp://carolinabirds.org/

Pine Habitat Characteristics Associated with Variation in Chuck-will’s-widow Communities

https://scholarworks.sfasu.edu/cgi/viewcontent.cgi?article=1407&context=urc

Pine Habitat Characteristics Associated with Variation in Chuck-will’s-widow Communities

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