The alarm calls of some birds are functionally referential and may provide nestlings with information about the threat posed by potential predators. However, few investigators have examined the responses of nestlings in cavity nests to the anti-predator vocalizations of adults. Therefore, the objectives of my study of cavity-nesting Eastern Bluebirds (Sialia sialis) were to examine (1) the vocal responses of adult Eastern Bluebirds to different predators, and (2) the behavioral responses of nestlings to those adult vocalizations. My study was conducted from April - July 2013 at the Blue Grass Army Depot in Madison County, Kentucky. Pairs of Eastern Bluebirds nesting in nest boxes were exposed to four potential nest predators, including taxidermy mounts of a raccoon (Procyon lotor) and an eastern chipmunk (Tamias striatus), a study skin of an American Kestrel (Falco sparverius), and a rubber model of a black rat snake (Pantherophis obsoletus). My control was a study skin of a Mourning Dove (Zenaida macroura). To assess responses during 3-min trials, predators or the control were placed adjacent to or on nest boxes with 12-19-day-old nestlings. During trials, adult vocalizations were recorded and the behavior of nestlings was simultaneously recorded with a camcorder. I conducted 48 trials at 27 nest boxes. Adult bluebirds did not respond vocally during 10 trials (20.8%), but did call during all 12 trials with the raccoon. In addition, adult bluebirds uttered alarm calls and chatter calls that were significantly longer in duration at significantly higher rates in response to the raccoon. Adult bluebirds uttered significantly more chatter calls and alarm calls during trials when nestlings responded (23 of 39 trials [59%], excluding control trials) by crouching (21 trials), climbing the walls of the nest box (one trial), or fledging (one trial). Crouching may reduce the risk of predation by predators too large to enter the nest cavity, but potentially able to reach into a cavity. Remaining in a nest cavity is likely advantageous because premature fledging by young unable to fly or fly very well when a predator is nearby would increase the risk of mortality. My results indicate that adult Eastern Bluebirds do not produce predator-specific, functionally referential alarm vocalizations, but, by varying call characteristics and call rates, appear to provide nestlings with information about potential predators that generates appropriate anti-predator responses.
","abstract_html":"<p>The alarm calls of some birds are functionally referential and may provide nestlings with information about the threat posed by potential predators. However, few investigators have examined the responses of nestlings in cavity nests to the anti-predator vocalizations of adults. Therefore, the objectives of my study of cavity-nesting Eastern Bluebirds <em>(Sialia sialis)</em> were to examine (1) the vocal responses of adult Eastern Bluebirds to different predators, and (2) the behavioral responses of nestlings to those adult vocalizations. My study was conducted from April - July 2013 at the Blue Grass Army Depot in Madison County, Kentucky. Pairs of Eastern Bluebirds nesting in nest boxes were exposed to four potential nest predators, including taxidermy mounts of a raccoon <em>(Procyon lotor)</em> and an eastern chipmunk <em>(Tamias striatus)</em>, a study skin of an American Kestrel <em>(Falco sparverius)</em>, and a rubber model of a black rat snake <em>(Pantherophis obsoletus)</em>. My control was a study skin of a Mourning Dove <em>(Zenaida macroura)</em>. To assess responses during 3-min trials, predators or the control were placed adjacent to or on nest boxes with 12-19-day-old nestlings. During trials, adult vocalizations were recorded and the behavior of nestlings was simultaneously recorded with a camcorder. I conducted 48 trials at 27 nest boxes. Adult bluebirds did not respond vocally during 10 trials (20.8%), but did call during all 12 trials with the raccoon. In addition, adult bluebirds uttered alarm calls and chatter calls that were significantly longer in duration at significantly higher rates in response to the raccoon. Adult bluebirds uttered significantly more chatter calls and alarm calls during trials when nestlings responded (23 of 39 trials [59%], excluding control trials) by crouching (21 trials), climbing the walls of the nest box (one trial), or fledging (one trial). Crouching may reduce the risk of predation by predators too large to enter the nest cavity, but potentially able to reach into a cavity. Remaining in a nest cavity is likely advantageous because premature fledging by young unable to fly or fly very well when a predator is nearby would increase the risk of mortality. My results indicate that adult Eastern Bluebirds do not produce predator-specific, functionally referential alarm vocalizations, but, by varying call characteristics and call rates, appear to provide nestlings with information about potential predators that generates appropriate anti-predator responses. </p>","abstract_has_math":false,"creators":["Grabarczyk, Erin E."],"institution":"Eastern Kentucky University","degree_name":"Master of Science (MS)","degree_level":"Master's","degree_discipline":"Biological Sciences","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-01-01T08:00:00Z","date_published":"2014-01-01T08:00:00Z","updated_at":"2026-07-24T02:15:25Z","subjects":["alarm call","anti-predator behavior","communication","Eastern bluebird","nest predators","Behavior and Ethology","Ornithology"],"languages":[],"rights":["Copyright 2014 Erin E. Grabarczyk"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://encompass.eku.edu/etd/263","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Grabarczyk, Erin E."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:publisher","label":"Institution","values":["Encompass Digital Archive, Eastern Kentucky University"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biological Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Master's"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Eastern Kentucky University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["alarm call","anti-predator behavior","communication","Eastern bluebird","nest predators","Behavior and Ethology","Ornithology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2014 Erin E. Grabarczyk"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://encompass.eku.edu/etd/263"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The alarm calls of some birds are functionally referential and may provide nestlings with information about the threat posed by potential predators. However, few investigators have examined the responses of nestlings in cavity nests to the anti-predator vocalizations of adults. Therefore, the objectives of my study of cavity-nesting Eastern Bluebirds (Sialia sialis) were to examine (1) the vocal responses of adult Eastern Bluebirds to different predators, and (2) the behavioral responses of nestlings to those adult vocalizations. My study was conducted from April - July 2013 at the Blue Grass Army Depot in Madison County, Kentucky. Pairs of Eastern Bluebirds nesting in nest boxes were exposed to four potential nest predators, including taxidermy mounts of a raccoon (Procyon lotor) and an eastern chipmunk (Tamias striatus), a study skin of an American Kestrel (Falco sparverius), and a rubber model of a black rat snake (Pantherophis obsoletus). My control was a study skin of a Mourning Dove (Zenaida macroura). To assess responses during 3-min trials, predators or the control were placed adjacent to or on nest boxes with 12-19-day-old nestlings. During trials, adult vocalizations were recorded and the behavior of nestlings was simultaneously recorded with a camcorder. I conducted 48 trials at 27 nest boxes. Adult bluebirds did not respond vocally during 10 trials (20.8%), but did call during all 12 trials with the raccoon. In addition, adult bluebirds uttered alarm calls and chatter calls that were significantly longer in duration at significantly higher rates in response to the raccoon. Adult bluebirds uttered significantly more chatter calls and alarm calls during trials when nestlings responded (23 of 39 trials [59%], excluding control trials) by crouching (21 trials), climbing the walls of the nest box (one trial), or fledging (one trial). Crouching may reduce the risk of predation by predators too large to enter the nest cavity, but potentially able to reach into a cavity. Remaining in a nest cavity is likely advantageous because premature fledging by young unable to fly or fly very well when a predator is nearby would increase the risk of mortality. My results indicate that adult Eastern Bluebirds do not produce predator-specific, functionally referential alarm vocalizations, but, by varying call characteristics and call rates, appear to provide nestlings with information about potential predators that generates appropriate anti-predator responses.
"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:source","label":"Dc Source","values":["Encompass Digital Archive: Online Theses and Dissertations"]},{"key":"dc:title","label":"Title","values":["Vocal responses of adult Eastern Bluebirds (Sialia sialis) to potential nest predators and the behavioral responses of nestlings"]}]}],"canonical_facts":{"dc:creator":["Grabarczyk, Erin E."],"dc:description.abstract":["The alarm calls of some birds are functionally referential and may provide nestlings with information about the threat posed by potential predators. However, few investigators have examined the responses of nestlings in cavity nests to the anti-predator vocalizations of adults. Therefore, the objectives of my study of cavity-nesting Eastern Bluebirds (Sialia sialis) were to examine (1) the vocal responses of adult Eastern Bluebirds to different predators, and (2) the behavioral responses of nestlings to those adult vocalizations. My study was conducted from April - July 2013 at the Blue Grass Army Depot in Madison County, Kentucky. Pairs of Eastern Bluebirds nesting in nest boxes were exposed to four potential nest predators, including taxidermy mounts of a raccoon (Procyon lotor) and an eastern chipmunk (Tamias striatus), a study skin of an American Kestrel (Falco sparverius), and a rubber model of a black rat snake (Pantherophis obsoletus). My control was a study skin of a Mourning Dove (Zenaida macroura). To assess responses during 3-min trials, predators or the control were placed adjacent to or on nest boxes with 12-19-day-old nestlings. During trials, adult vocalizations were recorded and the behavior of nestlings was simultaneously recorded with a camcorder. I conducted 48 trials at 27 nest boxes. Adult bluebirds did not respond vocally during 10 trials (20.8%), but did call during all 12 trials with the raccoon. In addition, adult bluebirds uttered alarm calls and chatter calls that were significantly longer in duration at significantly higher rates in response to the raccoon. Adult bluebirds uttered significantly more chatter calls and alarm calls during trials when nestlings responded (23 of 39 trials [59%], excluding control trials) by crouching (21 trials), climbing the walls of the nest box (one trial), or fledging (one trial). Crouching may reduce the risk of predation by predators too large to enter the nest cavity, but potentially able to reach into a cavity. Remaining in a nest cavity is likely advantageous because premature fledging by young unable to fly or fly very well when a predator is nearby would increase the risk of mortality. My results indicate that adult Eastern Bluebirds do not produce predator-specific, functionally referential alarm vocalizations, but, by varying call characteristics and call rates, appear to provide nestlings with information about potential predators that generates appropriate anti-predator responses.
"],"dc:format":["application/pdf"],"dc:identifier":["https://encompass.eku.edu/etd/263"],"dc:publisher":["Encompass Digital Archive, Eastern Kentucky University"],"dc:rights":["Copyright 2014 Erin E. Grabarczyk"],"dc:source":["Encompass Digital Archive: Online Theses and Dissertations"],"dc:subject":["alarm call","anti-predator behavior","communication","Eastern bluebird","nest predators","Behavior and Ethology","Ornithology"],"dc:title":["Vocal responses of adult Eastern Bluebirds (Sialia sialis) to potential nest predators and the behavioral responses of nestlings"],"dc:type":["Master Thesis"],"thesis:degree_discipline":["Biological Sciences"],"thesis:degree_level":["Master's"],"thesis:degree_name":["Master of Science (MS)"],"thesis:institution_name":["Eastern Kentucky University"]},"updated_at":"2026-07-24T02:15:25Z"}