Browsing by Author "Maza, Mariano de la"

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    Aphrastura spinicauda change their reproductive strategy with altitude in the Andean temperate forest of South America
    (2015) Altamirano, Tomás A.; Ibarra Eliessetch, José Tomás; Maza, Mariano de la; Navarrete, Sergio A.; Bonacic Salas, Cristian
    Elevational gradients have been proposed as a driver of change in avian reproductive lifehistory strategies. The eventual shorter breeding season and higher predation risk at highaltitudes can produce a decline in fecundity, a reduction of clutch sizes, and an increase inparental care and survival. We studied whether the breeding strategy of the Aphrasturaspinicauda varies along an elevation gradient in the Andean temperate forests of Chile. Weinstalled 240 nest-boxes between 260 and 1,115 m a.s.l., and monitored the breedingactivity of 162 nests over two seasons (2010-2011, 2011-2012). As predicted, the breedingseason was 28% and 55% shorter in highland forests during the two seasons. Timing of egglaying (1 egg every second day) and incubation period (average 15 days) did not vary withaltitude. We found smaller clutch sizes (average 4.1 vs. 4.5), a fewer number of nestlingsper clutch (average 3.5 vs. 4.2), and longer nestling period (22.2 vs. 21.6 days) in highlandthan lowland forests. The breeding success declined with altitude, mainly due to predationby the Dromiciops gliroides which was 83% in highland and 35% in lowland forests. Ourfindings suggest that Aphrastura spinicauda change their reproductive strategy alongaltitudinal gradients to a slower one, likely as an adaptation to shorter breeding seasons.Yet, these changes do not appear to compensate for the increased predation rates at higherelevations, questioning the potential adaptive significance of this strategy