Evaluación del efecto de variables ambientales y comportamentales sobre el empollamiento en la Ratona Aperdizada Cistothorus platensis en Uspallata, Mendoza, Argentina
Extreme environmental temperatures compromise the development of eggs and nestlings. The nestlings of altricial birds are born with reduced mobility, without feathers and incapable of thermoregulation. In response to extreme environmental temperatures, birds can modify their behavior to increase the...
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| Otros Autores: | , , , , |
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2020
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| Acceso en línea: | https://bdigital.uncu.edu.ar/fichas.php?idobjeto=15069 |
| Sumario: | Extreme environmental temperatures compromise the development of eggs and nestlings. The nestlings of altricial birds are born with reduced mobility, without feathers and incapable of thermoregulation. In response to extreme environmental temperatures, birds can modify their behavior to increase the thermal stability of the nest, as well as selecting a nesting site and building a nest that helps mitigate extreme temperatures. This research has two objectives: to evaluate the effect of the environmental temperature on the brooding behavior of nestlings of the Sedge Wren Cistothorus platensis and to evaluate the behavioral strategies used by adults to mitigate the effect of ambient temperature on the thermal stability of nestlings. During three breeding seasons (2015 to 2017), ambient temperature was recorded continuously with thermistors placed near the nesting sites. To quantify parental care, nests with nestlings were filmed during three age intervals: young (2-3 days old; n = 172), intermediate (7-8 days old; n = 141) and late (10-11 days old; n = 112). The relationship between ambient temperature and the following brooding variables were analyzed: nest attentiveness (total incubation time / total recording time), the average duration of brooding sessions, and the number of brooding bouts per hour. It was assessed how the vegetation structure of the nesting site and the nest structure affected brooding behavior. The models also considered the relative male feeding contribution, julian day, year and nestlings age. Brooding behavior decreased with nestling age, and was rare for late nestlings. At low ambient temperatures, females increased nest attentiveness and the number of brooding bouts per hour for young and intermediate nestlings. Females also increased nest attentiveness with increased male contribution to feeding nestlings for all the behavioral variables considered. Females whose nests were built at closer distances from the edge of substrate plant spent less time brooding than females whose nest were located farther from the edge. Also, females in bigger nests spent more time brooding than females in smaller nests. This could be the consequence of greater parental investment on bigger nests that may contain more nestlings. The results suggest that environmental temperature, male feeding contribution and nestling age affected the brooding behavior. |
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