{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/16979"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/16979","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"The pre-reproductive period in a tropical bird: parental care, dispersal, survival, and avian life histories","abstract":"The period between offspring birth and recruitment into the breeding population is considered one of the least understood components of animal life histories. Yet, examining this period is essential for studies of parental care, dispersal, demography, and life histories. Studies of the pre-reproductive period are particularly few in tropical regions, where the organization of life histories are predicted to differ compared to northern hemisphere species. For my dissertation I used radio-telemetry, mark-resighting, and field observations to study the pre-reproductive period in a Neotropical bird, the western slaty-antshrike (Thamnophilus atrinucha), in Panama. First, I found that parental care after offspring left the nest (the post-fledging period) was greater than care during the nestling period. Prolonged care resulted in a clear trade-off for parents as they did not nest again until fledglings from the first brood were independent. Parents fed offspring for a prolonged duration during the post-fledging period and higher post-fledging survival was observed compared to many northern hemisphere species. Second, I observed that offspring that remained with parents for longer periods on the natal territory had higher survival both while on the natal territory and after dispersal compared to those dispersing earlier. Parental aggression towards offspring increased with offspring age and offspring dispersed earlier when parents renested. Contrary to other family living species, only a small proportion of antshrike offspring remained on the natal territory until the following year and all dispersed to float. Floating is when juveniles wander within other breeding pairs’ territories. These results suggest that the benefits of delayed dispersal declined with offspring age and with renesting by parents. Third, I observed that survival during the dependent period and first year was greater in slaty antshrikes compared to that of northern hemisphere species. Pre-reproductive survival relative to adult survival was equal or greater than that observed in northern hemisphere species. The date offspring left the nest, mass, and age at dispersal influenced offspring survival, whereas offspring sex and year did not. Relatively high survival during the pre-reproductive period coupled with comparatively low annual productivity clarifies how many tropical species achieve replacement. High juvenile survival appears to obtain from extended post-fledging parental care, delayed dispersal, low costs of dispersal, and a less seasonal environment. Lastly, I experimentally manipulated begging at the nest to examine changes in parental behavior. Under elevated begging, parents increased provisioning rates and reduced the time between arrival to the nest and feeding of nestlings, potentially to reduce begging sounds. Furthermore, parents switched to preferentially feed the closest offspring during the begging treatment. This suggests parents either allowed sibling competition to influence feeding decisions, or feeding the closer nestling increased the efficiency of provisioning. In summary, I found that slaty antshrikes have delayed age at reproduction, higher post-fledging and first year survival, extended post-fledging parental care, equal or greater pre-reproductive survival relative to adult survival, and delayed dispersal compared to many northern hemisphere passerines. These results suggest that this tropical species has a strategy of high investment into few offspring. Furthermore, reproductive effort is equal or greater at least in slaty antshrikes compared to northern hemisphere species, suggesting that the latitudinal gradient in clutch size is not explained by a gradient in reproductive effort.","abstract_html":"The period between offspring birth and recruitment into the breeding population is considered one of the least understood components of animal life histories. Yet, examining this period is essential for studies of parental care, dispersal, demography, and life histories. Studies of the pre-reproductive period are particularly few in tropical regions, where the organization of life histories are predicted to differ compared to northern hemisphere species. For my dissertation I used radio-telemetry, mark-resighting, and field observations to study the pre-reproductive period in a Neotropical bird, the western slaty-antshrike (Thamnophilus atrinucha), in Panama. First, I found that parental care after offspring left the nest (the post-fledging period) was greater than care during the nestling period. Prolonged care resulted in a clear trade-off for parents as they did not nest again until fledglings from the first brood were independent. Parents fed offspring for a prolonged duration during the post-fledging period and higher post-fledging survival was observed compared to many northern hemisphere species. Second, I observed that offspring that remained with parents for longer periods on the natal territory had higher survival both while on the natal territory and after dispersal compared to those dispersing earlier. Parental aggression towards offspring increased with offspring age and offspring dispersed earlier when parents renested. Contrary to other family living species, only a small proportion of antshrike offspring remained on the natal territory until the following year and all dispersed to float. Floating is when juveniles wander within other breeding pairs’ territories. These results suggest that the benefits of delayed dispersal declined with offspring age and with renesting by parents. Third, I observed that survival during the dependent period and first year was greater in slaty antshrikes compared to that of northern hemisphere species. Pre-reproductive survival relative to adult survival was equal or greater than that observed in northern hemisphere species. The date offspring left the nest, mass, and age at dispersal influenced offspring survival, whereas offspring sex and year did not. Relatively high survival during the pre-reproductive period coupled with comparatively low annual productivity clarifies how many tropical species achieve replacement. High juvenile survival appears to obtain from extended post-fledging parental care, delayed dispersal, low costs of dispersal, and a less seasonal environment. Lastly, I experimentally manipulated begging at the nest to examine changes in parental behavior. Under elevated begging, parents increased provisioning rates and reduced the time between arrival to the nest and feeding of nestlings, potentially to reduce begging sounds. Furthermore, parents switched to preferentially feed the closest offspring during the begging treatment. This suggests parents either allowed sibling competition to influence feeding decisions, or feeding the closer nestling increased the efficiency of provisioning. In summary, I found that slaty antshrikes have delayed age at reproduction, higher post-fledging and first year survival, extended post-fledging parental care, equal or greater pre-reproductive survival relative to adult survival, and delayed dispersal compared to many northern hemisphere passerines. These results suggest that this tropical species has a strategy of high investment into few offspring. Furthermore, reproductive effort is equal or greater at least in slaty antshrikes compared to northern hemisphere species, suggesting that the latitudinal gradient in clutch size is not explained by a gradient in reproductive effort.","abstract_has_math":false,"creators":["Tarwater, Corey E."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Ecol, Evol, Conservation Biol","degree_department":null,"school":null,"contributors":["Brawn, Jeffrey D.","Weatherhead, Patrick J.","Ricklefs, Robert E.","Suarez, Andrew V.","Fuller, Rebecca C."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-08-31T20:02:54Z","date_published":"2010-08-31T20:02:54Z","updated_at":"2026-07-22T22:25:09Z","subjects":["begging","parent-offspring conflict","dispersal","survival","tropical","life histories","family living","Parental care","juvenile"],"languages":["en"],"rights":["Copyright 2010 Corey E. Tarwater"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/16979","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Brawn, Jeffrey D.","Weatherhead, Patrick J.","Ricklefs, Robert E.","Suarez, Andrew V.","Fuller, Rebecca C."]},{"key":"dc:creator","label":"Author","values":["Tarwater, Corey E."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2010-08-31T20:02:54Z","2012-09-07T16:43:33Z","2010-08"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Ecol, Evol, Conservation Biol"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["begging","parent-offspring conflict","dispersal","survival","tropical","life histories","family living","Parental care","juvenile"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2010 Corey E. Tarwater"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/16979"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The period between offspring birth and recruitment into the breeding population is considered one of the least understood components of animal life histories. Yet, examining this period is essential for studies of parental care, dispersal, demography, and life histories. Studies of the pre-reproductive period are particularly few in tropical regions, where the organization of life histories are predicted to differ compared to northern hemisphere species. For my dissertation I used radio-telemetry, mark-resighting, and field observations to study the pre-reproductive period in a Neotropical bird, the western slaty-antshrike (Thamnophilus atrinucha), in Panama. First, I found that parental care after offspring left the nest (the post-fledging period) was greater than care during the nestling period. Prolonged care resulted in a clear trade-off for parents as they did not nest again until fledglings from the first brood were independent. Parents fed offspring for a prolonged duration during the post-fledging period and higher post-fledging survival was observed compared to many northern hemisphere species. Second, I observed that offspring that remained with parents for longer periods on the natal territory had higher survival both while on the natal territory and after dispersal compared to those dispersing earlier. Parental aggression towards offspring increased with offspring age and offspring dispersed earlier when parents renested. Contrary to other family living species, only a small proportion of antshrike offspring remained on the natal territory until the following year and all dispersed to float. Floating is when juveniles wander within other breeding pairs’ territories. These results suggest that the benefits of delayed dispersal declined with offspring age and with renesting by parents. Third, I observed that survival during the dependent period and first year was greater in slaty antshrikes compared to that of northern hemisphere species. Pre-reproductive survival relative to adult survival was equal or greater than that observed in northern hemisphere species. The date offspring left the nest, mass, and age at dispersal influenced offspring survival, whereas offspring sex and year did not. Relatively high survival during the pre-reproductive period coupled with comparatively low annual productivity clarifies how many tropical species achieve replacement. High juvenile survival appears to obtain from extended post-fledging parental care, delayed dispersal, low costs of dispersal, and a less seasonal environment. Lastly, I experimentally manipulated begging at the nest to examine changes in parental behavior. Under elevated begging, parents increased provisioning rates and reduced the time between arrival to the nest and feeding of nestlings, potentially to reduce begging sounds. Furthermore, parents switched to preferentially feed the closest offspring during the begging treatment. This suggests parents either allowed sibling competition to influence feeding decisions, or feeding the closer nestling increased the efficiency of provisioning. In summary, I found that slaty antshrikes have delayed age at reproduction, higher post-fledging and first year survival, extended post-fledging parental care, equal or greater pre-reproductive survival relative to adult survival, and delayed dispersal compared to many northern hemisphere passerines. These results suggest that this tropical species has a strategy of high investment into few offspring. Furthermore, reproductive effort is equal or greater at least in slaty antshrikes compared to northern hemisphere species, suggesting that the latitudinal gradient in clutch size is not explained by a gradient in reproductive effort.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-06-30T19:56:26Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Tarwater_Corey.pdf: 791852 bytes, checksum: 99fd8c39399bf890ed3a800c57db38e6 (MD5)","Made available in DSpace on 2010-08-31T20:02:54Z (GMT). No. of bitstreams: 3 Tarwater_Corey.pdf: 791852 bytes, checksum: 99fd8c39399bf890ed3a800c57db38e6 (MD5) 1_Tarwater_Corey.pdf: 791848 bytes, checksum: fec5bfee8c0279805de90e0126c2f396 (MD5) license.txt: 4064 bytes, checksum: 5567f5de9fa48c4cb61d858ff68da3ee (MD5)","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by William Ingram (wingram2@illinois.edu) on 2010-08-31T20:04:49Z Item is restricted until 2012-08-31T20:04:44Z","Item reinstated by Sarah Shreeves (sshreeve@illinois.edu) on 2012-09-07T16:43:33Z Item was in collections: University of Illinois Dissertations and Theses (ID: 204) Dissertations and Theses - Ecology, Evolution, and Conservation Biology (ID: 750) No. of bitstreams: 4 1_Tarwater_Corey.pdf.txt: 254291 bytes, checksum: f5aab9f23247620d189a6ad250ab0933 (MD5) Tarwater_Corey.pdf: 791852 bytes, checksum: 99fd8c39399bf890ed3a800c57db38e6 (MD5) 1_Tarwater_Corey.pdf: 791848 bytes, checksum: fec5bfee8c0279805de90e0126c2f396 (MD5) license.txt: 4064 bytes, checksum: 5567f5de9fa48c4cb61d858ff68da3ee (MD5)","Item released from any restrictions by Sarah Shreeves (sshreeve@illinois.edu) on 2012-09-07T16:43:33Z"]},{"key":"dc:title","label":"Title","values":["The pre-reproductive period in a tropical bird: parental care, dispersal, survival, and avian life histories"]}]}],"canonical_facts":{"dc:contributor":["Brawn, Jeffrey D.","Weatherhead, Patrick J.","Ricklefs, Robert E.","Suarez, Andrew V.","Fuller, Rebecca C."],"dc:creator":["Tarwater, Corey E."],"dc:date":["2010-08-31T20:02:54Z","2012-09-07T16:43:33Z","2010-08"],"dc:description":["The period between offspring birth and recruitment into the breeding population is considered one of the least understood components of animal life histories. Yet, examining this period is essential for studies of parental care, dispersal, demography, and life histories. Studies of the pre-reproductive period are particularly few in tropical regions, where the organization of life histories are predicted to differ compared to northern hemisphere species. For my dissertation I used radio-telemetry, mark-resighting, and field observations to study the pre-reproductive period in a Neotropical bird, the western slaty-antshrike (Thamnophilus atrinucha), in Panama. First, I found that parental care after offspring left the nest (the post-fledging period) was greater than care during the nestling period. Prolonged care resulted in a clear trade-off for parents as they did not nest again until fledglings from the first brood were independent. Parents fed offspring for a prolonged duration during the post-fledging period and higher post-fledging survival was observed compared to many northern hemisphere species. Second, I observed that offspring that remained with parents for longer periods on the natal territory had higher survival both while on the natal territory and after dispersal compared to those dispersing earlier. Parental aggression towards offspring increased with offspring age and offspring dispersed earlier when parents renested. Contrary to other family living species, only a small proportion of antshrike offspring remained on the natal territory until the following year and all dispersed to float. Floating is when juveniles wander within other breeding pairs’ territories. These results suggest that the benefits of delayed dispersal declined with offspring age and with renesting by parents. Third, I observed that survival during the dependent period and first year was greater in slaty antshrikes compared to that of northern hemisphere species. Pre-reproductive survival relative to adult survival was equal or greater than that observed in northern hemisphere species. The date offspring left the nest, mass, and age at dispersal influenced offspring survival, whereas offspring sex and year did not. Relatively high survival during the pre-reproductive period coupled with comparatively low annual productivity clarifies how many tropical species achieve replacement. High juvenile survival appears to obtain from extended post-fledging parental care, delayed dispersal, low costs of dispersal, and a less seasonal environment. Lastly, I experimentally manipulated begging at the nest to examine changes in parental behavior. Under elevated begging, parents increased provisioning rates and reduced the time between arrival to the nest and feeding of nestlings, potentially to reduce begging sounds. Furthermore, parents switched to preferentially feed the closest offspring during the begging treatment. This suggests parents either allowed sibling competition to influence feeding decisions, or feeding the closer nestling increased the efficiency of provisioning. In summary, I found that slaty antshrikes have delayed age at reproduction, higher post-fledging and first year survival, extended post-fledging parental care, equal or greater pre-reproductive survival relative to adult survival, and delayed dispersal compared to many northern hemisphere passerines. These results suggest that this tropical species has a strategy of high investment into few offspring. Furthermore, reproductive effort is equal or greater at least in slaty antshrikes compared to northern hemisphere species, suggesting that the latitudinal gradient in clutch size is not explained by a gradient in reproductive effort.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-06-30T19:56:26Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Tarwater_Corey.pdf: 791852 bytes, checksum: 99fd8c39399bf890ed3a800c57db38e6 (MD5)","Made available in DSpace on 2010-08-31T20:02:54Z (GMT). No. of bitstreams: 3 Tarwater_Corey.pdf: 791852 bytes, checksum: 99fd8c39399bf890ed3a800c57db38e6 (MD5) 1_Tarwater_Corey.pdf: 791848 bytes, checksum: fec5bfee8c0279805de90e0126c2f396 (MD5) license.txt: 4064 bytes, checksum: 5567f5de9fa48c4cb61d858ff68da3ee (MD5)","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by William Ingram (wingram2@illinois.edu) on 2010-08-31T20:04:49Z Item is restricted until 2012-08-31T20:04:44Z","Item reinstated by Sarah Shreeves (sshreeve@illinois.edu) on 2012-09-07T16:43:33Z Item was in collections: University of Illinois Dissertations and Theses (ID: 204) Dissertations and Theses - Ecology, Evolution, and Conservation Biology (ID: 750) No. of bitstreams: 4 1_Tarwater_Corey.pdf.txt: 254291 bytes, checksum: f5aab9f23247620d189a6ad250ab0933 (MD5) Tarwater_Corey.pdf: 791852 bytes, checksum: 99fd8c39399bf890ed3a800c57db38e6 (MD5) 1_Tarwater_Corey.pdf: 791848 bytes, checksum: fec5bfee8c0279805de90e0126c2f396 (MD5) license.txt: 4064 bytes, checksum: 5567f5de9fa48c4cb61d858ff68da3ee (MD5)","Item released from any restrictions by Sarah Shreeves (sshreeve@illinois.edu) on 2012-09-07T16:43:33Z"],"dc:identifier":["http://hdl.handle.net/2142/16979"],"dc:language":["en"],"dc:rights":["Copyright 2010 Corey E. Tarwater"],"dc:subject":["begging","parent-offspring conflict","dispersal","survival","tropical","life histories","family living","Parental care","juvenile"],"dc:title":["The pre-reproductive period in a tropical bird: parental care, dispersal, survival, and avian life histories"],"thesis:degree_discipline":["Ecol, Evol, Conservation Biol"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:09Z"}