Reproductive Biology of Striated Heron (Butorides striata) in Argentina

OLGUIN, PAMELA; BELTZER, ADOLFO; GIRAUDO, ALEJANDRO; REGNER, SILVIA; JUANI, MARCELO; VIANCO, MERCEDES; MARIANO, EMILIANO; LORENZON, RODRIGO; LEON, EVELINA

WATERBIRDS (DE LEON SPRINGS, FLA.)

WATERBIRD SOC

Año: 2015 vol. 38 p. 396 - 400

1524-4695

The reproductive biology of the Striated Heron (Butorides striata) was studied in the lagoon of theReserve of the Universidad Nacional del Litoral, Santa Fe, Argentina, during two breeding seasons: September2012-February 2013 (n = 77) and September 2013-March 2014 (n = 125). All nests (n = 202) were built on waxy-leafnightshade (Solanum glaucophyllum) at 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. An average of 2.63 ± 0.60 (Range = 2-4) opaque paleblue 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 detectedin 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 was22% and 38% and for chicks 47% and 35% for the first and second seasons, respectively. Sixty-one percent of nestfailures were related to the disappearance of eggs or chicks from the nests, possibly due to predation or climaticfactors.