Life History of the Andean Condor in Ecuador

Background and Research Aims: Little information exists on the breeding behavior of the Andean Condor ( Vultur gryphus). Its global population, estimated at 6700 adult individuals, is declining throughout its distribution range. With less than 150 condors, the Endangered condor population in Ecuador is of conservation concern. This study aimed to analyze the breeding behavior of wild-born Andean Condors in Ecuador. Methods: Between 2009 and 2021, we monitored 22 egg-laying attempts in eight Andean Condor nests, evaluated the parental care of three breeding pairs of condors and recorded the species' interactions with other raptors and mammals during the nestling-rearing season, and examined the breeding success of an Andean Condor pair during a decade of monitoring. Results: Our breeding records indicated that Andean Condor lay eggs throughout the year, and 16 nestlings spent between six and 10 months in the nest before making their first flights. We found differences in the length of time that the parents remain with the nestling, and described agonistic encounters between condors and other raptors and a Spectacled Bear ( Tremarctos ornatus) in the condor nesting areas. The breeding success of the monitored condor pair was 0.88 nestlings per clutch, and the female laid an egg on average every 15 months. Conclusion: Considering the small size of the Andean Condor population in Ecuador, studies on the breeding behavior of wild-born condors are a high research priority to assess population trends and prevent extinction. Specifically, we recommend further research on parental care, breeding success, nestling survivorship, and nesting phenology. Implications for Conservation: Beyond the importance of the protected area system, strategic planning of key areas for the maintenance of condor populations in the northern Andes must encompass the evaluation of new potential protected areas that offer direct benefits to these birds. These should include nesting sites in human-dominated landscapes such as rural Andean areas.