Notes on the nesting behavior of the Collared Forest Falcon (Micrastur semitorquatus) in Ceiba trichistandra within a dry deciduous forest of Guayaquil, Ecuador

The Collared Forest Falcon ( Micrastur semitorquatus ) is a falconid species distributed across the Americas, including Ecuador. Despite its broad geographic range, information regarding its breeding ecology remains limited in many regions. Nesting of this species has been previously reported in caves, human settlements and various tree species. Our observations reveal new data related to the ecology of this raptor in a highly threatened ecosystem, the dry deciduous forest. We describe observations of a nest associated with a cavity in a mature Ceiba trichistandra tree located within Bosque y Vegetación Protector La Prosperina, an urban remnant of dry deciduous forest in southwestern Ecuador. Observations were conducted between January and February 2020, with 3 additional visits between 2023 and 2025. Total tree height, diameter at breast height and nest dimensions were measured. These observations provide additional information on nest-sites used by M. semitorquatus and emphasize the ecological value of mature cavity-bearing trees within fragmented and urban-associated dry deciduous forest ecosystem.