Nesting ecology of the Saffron-crowned Tanager ( Tangara xanthocephala ) in western Colombia and eastern Ecuador

The Saffron-crowned Tanager (Tangara xanthocephala) inhabits humid Andean cloud forests from western Venezuela through Peru, ranging from 1000 to 3150 m asl. Despite its large distribution and abundance, its reproductive biology is poorly known. Here, we provide the first detailed description of nest architecture, eggs, incubation, nestling growth, and parental care. Fieldwork was conducted at four sites in Colombia and Ecuador, where we documented 12 active nests. Nests were open cups, constructed mainly of moss, stiff fibers, and monocot leaves, placed 0.9–7 m above ground, frequently near forest edges, trees, mud banks, or human structures. Clutches contained two eggs, pale pink with sparse reddish-brown flecking. Incubation lasted 15–19 days (n = 2 nests) and was performed by one adult. Nests were attended for 72 ± 1% of recorded time during daylight hours (38 nest-days, three nests) while nocturnal incubation lasted approximately 12 h. Both adults participated in nestling provisioning at the nest where parental care was monitored. Body mass of four nestlings from two nests followed a logistic growth trajectory (k = 0.50). Nestlings fledged fully feathered at 17–19 days. Compared to congeners, T. xanthocephala shares several reproductive characteristics with congeners, including open-cup nest and clutch characteristics; our observations provide new information on incubation behavior, nestling growth, and biparental provisioning that expands important knowledge into reproductive strategies within the genus.