Reproductive Biology of Striated Heron (Butorides striata) in Argentina

OLGUIN, P.; BELTZER, A.; GIRAUDO, A.; REGNER, S.; JUANI, M.; VIANCO, M.; MARIANO, E.; LORENZÓN, R.; LEÓN, E.

WATERBIRDS (DE LEON SPRINGS, FLA.)

WATERBIRD SOC

Año: 2015 vol. 38 p. 396 - 400

1524-4695

Reproductive biology of the Striated Heron (Butorides striata) was studied in the lagoon of the University Reserve, Universidad Nacional del Litoral, Santa Fe, Argentina during two breeding seasons: September 2012- February 2013 (n = 77) and September 2013 ? March 2014 (n = 125). All nests (n = 202) were built on waxy-leaf nightshade (Solanum glaucophyllum) 0.99 ± 0.27 m above water level. The incubation period was 20-23 (21.71 ± 1.57) days; laying and hatching took place on successive days. Up to 4 (2.63 ± 0.60) opaque pale blue eggs were recorded per nest. Length, width and weight of eggs did not differ between seasons. Double (n = 43) and triple (n = 47) broods were recorded. A total of 631 eggs were monitored; no differences were detected in breeding, hatching, nesting, or fledging success between seasons. The time spent by chicks in the nest was 14.6 ± 2.16 days and the average number of chicks per nest was 2.15 ± 0.55. Age-specific mortality rate for eggs was 22% and 38% and for chicks 47% and 35% for the first and second season, respectively. Nest failures were related disappearance of eggs or chicks from the nests (45% failure) possibly due to predation and climatic factors.