Abstract

MONTANI, Eugenia et al. Nesting of Callonetta leucophrys and Dendrocygna autumnalis in nest boxes in Corrientes, Argentina. Hornero [online]. 2019, vol.34, n.1, pp.07-16. ISSN 0073-3407.

In Argentina, the Ringed Teal (Callonetta leucophrys) and the Black-bellied Whistling Duck (Dendrocygna autumnalis) are common but scarcely studied species. To characterize the seasonal distri­bution of nesting, the number of eggs per nests, and the eggs of these duck species, nest boxes were surveyed during six reproductive seasons in several wetlands from southwestern Corrientes province. From all these surveys, 389 nesting events were recorded for C. leucophrys and 979 nesting events for D. autumnalis. The nesting peak for C. leucophrys occurred in October-November, whereas the peak for D. autumnalis was in January-Fe­bruary. The clutch size was smaller for C. leucophrys than for D. autumnalis (median: 10 and 14 eggs, respectively). The inside of the nest boxes occupied by C. leucophrys were covered with down, whereas D. autumnalis did not add any extra material to cover it. Eleven females of C. leucophrys were recaptured along various reproduc­tive seasons, at the same wetlands, and even at the same nests that they had been banded. Recaptured females of D. autumnalis did not return to the same nest box. The eggs of C. leucophrys were smaller than those of D. au­tumnalis (length: 46.19 ± 1.79 mm vs. 50.76 ± 1.95 mm; width: 34.04 ± 1.14 mm vs. 37.65 ± 1.19 mm; weight: 27.68 ± 2.89 g vs. 38.65 ± 3.73 g, respectively). These results highlight the utility of nest boxes to increase our knowledge about the reproductive biology of duck species that nest in cavities.

Keywords : Callonetta leucophrys; Dendrocygna autumnalis; Eggs; Nest boxes; Nesting.