We describe nests, eggs, and some breeding aspects of the Rusty-margined Guan (Penelope superciliaris) and Speckled Chachalaca (Ortalis guttata) in the Atlantic Rainforest of northeastern Brazil. Two active nests of P. superciliaris were found, the first was 50 cm above the ground and the second was 2.6 m. Both were bowl shaped and had three and two eggs, respectively. One egg from each nest was measured and weighed: 64.3 × 42.1 mm (61.5 g) and 55.5 × 38.0 mm (42.5 g). An active nest of O. guttata was found 3.2 m high on top of a tree. Initially, there was a single egg in the nest but two more were laid. The average egg measurements and weight were 55.0 × 38.4 mm and 43.3 g. The eggs of both species were rather similar with a dull white color, rough shell, and smeared with organic matter from the nest. We observed an incubation period of 29–30 days for the chachalaca, which was longer than previous estimates of this species. The guan nests were found in an advanced stage of development, which prevented accurate tracking of their incubation periods. Although the primary social reproductive strategy in most cracids is monogamy, it is possible that P. superciliaris is polygynous in our study area, justifying the absence of a male near the nest or even a nest territory.
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