Male parental care in Greater Rheas (Rhea americana) in Argentina

Greater Rheas (Rhea americana) are precocial birds that show uniparental male care. We evaluated the extent of nest attention by males and estimated its effect on viability and survival of eggs. We assessed whether male absences during incubation were constrained to avoid embryos reaching lethal tem...

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Autores principales: Fernández, G.J., Reboreda, J.C.
Formato: JOUR
Materias:
male
time allocation
Aves
Gallus gallus
Rhea
Rhea americana
Rheiformes
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00048038_v120_n2_p418_Fernandez
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00048038_v120_n2_p418_Fernandez
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spelling todo:paper_00048038_v120_n2_p418_Fernandez2023-10-03T14:03:03Z Male parental care in Greater Rheas (Rhea americana) in Argentina Fernández, G.J. Reboreda, J.C. male time allocation Aves Gallus gallus Rhea Rhea americana Rhea americana Rheiformes Greater Rheas (Rhea americana) are precocial birds that show uniparental male care. We evaluated the extent of nest attention by males and estimated its effect on viability and survival of eggs. We assessed whether male absences during incubation were constrained to avoid embryos reaching lethal temperatures or to minimize risk of egg predation. We estimated (1) effect of nest attention on viability of eggs by comparing egg temperature in nests with and without male attention; and (2) effect of male care on egg predation, by comparing survival of eggs in nests with and without male care. Rhea males attended the eggs for 42 days, but effective incubation started 5-7 days after laying of the first egg. The proportion of time that males spent at the nest increased from 64% during egg laying (days 1-10) up to 97.5% during mid and late incubation (days 20-40). Male absences occurred at the warmest hours of the day and their lengths were positively correlated with the temperature of the environment. Male nest attention reduced the rate of egg losses and kept eggs above lower lethal temperatures for embryos during the night. We also estimated relative cost of parental care after hatching by comparing the time allocated to feeding and vigilance by males with chicks, males in nonreproductive groups, and nonreproductive solitary males. Males took care of the chicks for 4-6 months. They allocated less time to feeding and more time to vigilance than males in groups of adults or solitary males. Investment in vigilance decreased as chicks aged. Our results indicate that Greater Rhea males would require high levels of energetic reserves to start a breeding attempt. That high demand could explain why less than only 20% of the males attempt to nest during a breeding season. Fil:Fernández, G.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Reboreda, J.C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00048038_v120_n2_p418_Fernandez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic male
time allocation
Aves
Gallus gallus
Rhea
Rhea americana
Rhea americana
Rheiformes
spellingShingle male
time allocation
Aves
Gallus gallus
Rhea
Rhea americana
Rhea americana
Rheiformes
Fernández, G.J.
Reboreda, J.C.
Male parental care in Greater Rheas (Rhea americana) in Argentina
topic_facet male
time allocation
Aves
Gallus gallus
Rhea
Rhea americana
Rhea americana
Rheiformes
description Greater Rheas (Rhea americana) are precocial birds that show uniparental male care. We evaluated the extent of nest attention by males and estimated its effect on viability and survival of eggs. We assessed whether male absences during incubation were constrained to avoid embryos reaching lethal temperatures or to minimize risk of egg predation. We estimated (1) effect of nest attention on viability of eggs by comparing egg temperature in nests with and without male attention; and (2) effect of male care on egg predation, by comparing survival of eggs in nests with and without male care. Rhea males attended the eggs for 42 days, but effective incubation started 5-7 days after laying of the first egg. The proportion of time that males spent at the nest increased from 64% during egg laying (days 1-10) up to 97.5% during mid and late incubation (days 20-40). Male absences occurred at the warmest hours of the day and their lengths were positively correlated with the temperature of the environment. Male nest attention reduced the rate of egg losses and kept eggs above lower lethal temperatures for embryos during the night. We also estimated relative cost of parental care after hatching by comparing the time allocated to feeding and vigilance by males with chicks, males in nonreproductive groups, and nonreproductive solitary males. Males took care of the chicks for 4-6 months. They allocated less time to feeding and more time to vigilance than males in groups of adults or solitary males. Investment in vigilance decreased as chicks aged. Our results indicate that Greater Rhea males would require high levels of energetic reserves to start a breeding attempt. That high demand could explain why less than only 20% of the males attempt to nest during a breeding season.
format JOUR
author Fernández, G.J.
Reboreda, J.C.
author_facet Fernández, G.J.
Reboreda, J.C.
author_sort Fernández, G.J.
title Male parental care in Greater Rheas (Rhea americana) in Argentina
title_short Male parental care in Greater Rheas (Rhea americana) in Argentina
title_full Male parental care in Greater Rheas (Rhea americana) in Argentina
title_fullStr Male parental care in Greater Rheas (Rhea americana) in Argentina
title_full_unstemmed Male parental care in Greater Rheas (Rhea americana) in Argentina
title_sort male parental care in greater rheas (rhea americana) in argentina
url http://hdl.handle.net/20.500.12110/paper_00048038_v120_n2_p418_Fernandez
work_keys_str_mv AT fernandezgj maleparentalcareingreaterrheasrheaamericanainargentina
AT reboredajc maleparentalcareingreaterrheasrheaamericanainargentina
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