TY - JOUR
T1 - Family living in a Neotropical bird
T2 - Variation in timing of dispersal and higher survival for delayed dispersers
AU - Tarwater, Corey E.
AU - Brawn, Jeffrey D.
N1 - Funding Information:
We thank S. Bassar, R. Bassar, D. Buehler, A. Castillo, B. Hancock, B. Lascelles and M. Meadows for help collecting the field data that made this study possible. In particular, we thank C. Batista, I. Gallo and I. Ochoa, who stuck it out in the field with us for multiple years. We are grateful to J.P. Kelley for general support. We thank J.T. Foster, M. Griesser and one anonymous referee for helpful comments on the manuscript. The Autoridad Nacional del Ambiente granted us permission to work in the Republic of Panama. Great thanks to the Smithsonian Tropical Research Institute and Raineldo Urriola, in particular, for providing logistical support. This work was funded by National Science Foundation grant IBN-0212587 , grants from University of Illinois, Smithsonian Tropical Research Institute, Cooper Ornithological Society, Wilson Ornithological Society, and the Environmental Science Program from the Smithsonian Tropical Research Institute.
PY - 2010/9
Y1 - 2010/9
N2 - Prompt natal dispersal and reproduction of offspring is viewed as the strategy to maximize lifetime reproductive success. Yet, across many species, offspring remain with their parents after independence rather than disperse. Why some species live in family groups and the behavioural mechanisms influencing the extent of family living remain unresolved. Family living is predicted to arise through slow life history traits predisposing certain lineages to family living, and then through social and ecological factors resulting in greater benefits of remaining with parents compared to dispersing. We studied family living in the western slaty-antshrike, Thamnophilus atrinucha, a bird with a slow life history, in Panama. We quantified the extent of delayed dispersal, and examined both the behavioural mechanisms influencing dispersal as well as the survival consequences. We observed that delayed dispersal increased offspring survival. Parental aggression towards offspring increased with offspring age and, in particular, when parents renested. Thus, offspring dispersed earlier when their parents renested. Fledging date and mass of offspring also influenced timing of dispersal. Although we observed higher survival of delayed dispersers, only a small proportion of offspring delayed dispersal until the next year and all dispersed to wander within other breeding pairs' territories (i.e. 'float'). Our results support theoretical predictions stating that benefits to parents from offspring retention decrease with offspring age and with renesting, leading to natal dispersal. Furthermore, we observed a reduced survival benefit of retention once offspring reached a certain age. Examining parental tolerance, the costs of floating, and how they vary with offspring age are essential to understand the costs/benefits of family living.
AB - Prompt natal dispersal and reproduction of offspring is viewed as the strategy to maximize lifetime reproductive success. Yet, across many species, offspring remain with their parents after independence rather than disperse. Why some species live in family groups and the behavioural mechanisms influencing the extent of family living remain unresolved. Family living is predicted to arise through slow life history traits predisposing certain lineages to family living, and then through social and ecological factors resulting in greater benefits of remaining with parents compared to dispersing. We studied family living in the western slaty-antshrike, Thamnophilus atrinucha, a bird with a slow life history, in Panama. We quantified the extent of delayed dispersal, and examined both the behavioural mechanisms influencing dispersal as well as the survival consequences. We observed that delayed dispersal increased offspring survival. Parental aggression towards offspring increased with offspring age and, in particular, when parents renested. Thus, offspring dispersed earlier when their parents renested. Fledging date and mass of offspring also influenced timing of dispersal. Although we observed higher survival of delayed dispersers, only a small proportion of offspring delayed dispersal until the next year and all dispersed to wander within other breeding pairs' territories (i.e. 'float'). Our results support theoretical predictions stating that benefits to parents from offspring retention decrease with offspring age and with renesting, leading to natal dispersal. Furthermore, we observed a reduced survival benefit of retention once offspring reached a certain age. Examining parental tolerance, the costs of floating, and how they vary with offspring age are essential to understand the costs/benefits of family living.
KW - Delayed dispersal
KW - Family living
KW - Natal dispersal
KW - Parent-offspring conflict
KW - Thamnophilus atrinucha
KW - Tropical
KW - Western slaty-antshrike
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U2 - 10.1016/j.anbehav.2010.06.017
DO - 10.1016/j.anbehav.2010.06.017
M3 - Article
AN - SCOPUS:77955579760
SN - 0003-3472
VL - 80
SP - 535
EP - 542
JO - Animal Behaviour
JF - Animal Behaviour
IS - 3
ER -