Tropical Screech-Owl Nestling in Amazonian Tree Hollow

Screech-Owl Secrets: What Nesting Habits Tell Us About Amazonian Biodiversity

Mira Elwood in Science & Nature June 2025 • 4 min read.

"A rare glimpse into the nesting behavior of the tropical screech-owl in the southwestern Amazon reveals vital clues for conservation and understanding local ecosystems."

The tropical screech-owl (Megascops choliba), a widespread resident of the Neotropical region from Costa Rica to Argentina, is an adaptable species found in diverse habitats. These range from open savannas to the dense rainforests of the Amazon basin. Though common, especially in human-impacted areas, detailed insights into their breeding patterns, particularly within the Amazon, have been scarce. A recent study sheds light on this knowledge gap, presenting a detailed account of a successful nesting event in the southwestern Amazon, Acre, Brazil.

Researchers monitored an active M. choliba nest from egg-hatching to the fledglings' departure, carefully documenting the owls' development. This observation offers essential data on growth rates and nesting behaviors. The study provides a baseline for understanding how these owls adapt to their environment and contribute to the region's biodiversity.

The research focused on a nest discovered in a broken trunk of a dead tucumā palm (Astrocaryum aculeatum), near the Zoobotanical Park of the Federal University of Acre (UFAC). The team tracked the nestlings' weight gain, physical development, and behavior. Their findings reveal patterns that align with those observed in other bird species, with some unique adaptations.

Nestling Development: A Detailed Look

Tropical Screech-Owl Nestling in Amazonian Tree Hollow

Upon hatching, the nestlings were meticulously weighed every two days to track their growth. The young owls remained in the nest for approximately 30 days. The weight gain pattern mirrored trends seen in other avian studies: an initial rapid increase in weight over the first 15 days, followed by a marked deceleration in growth rate during the latter half of their development. This pattern suggests an efficient allocation of resources early in life to ensure rapid development, followed by a consolidation phase as they prepared to fledge.

The physical transformation of the nestlings was equally remarkable. Initially covered in white plumage with closed eyes, the owlets rapidly developed darker, barred plumage and their eyes opened within the first two weeks. This transformation indicates the critical development stages required for adapting to their nocturnal, predatory lifestyle. The detailed observations highlight the importance of undisturbed nesting sites for the successful rearing of these birds.

Key observations during the study include:

Consistent weight gain patterns similar to other bird species.
Rapid physical development from hatchlings to fledglings.
Thirty-day nest occupancy.
Insight into nesting behavior during research monitoring.

Interestingly, the breeding season observed in this southwestern Amazonian nest appeared consistent with that reported for M. choliba in the northern hemisphere. This consistency suggests that environmental cues, rather than geographical location alone, might dictate breeding cycles. The findings contribute valuable insights into the reproductive biology of the species and its adaptability across different regions.

Conservation Implications and Future Research

This study not only provides baseline data on the tropical screech-owl in a previously understudied region but also underscores the importance of preserving nesting habitats within the Amazon. Protecting these sites is crucial for maintaining biodiversity and ensuring the survival of species like M. choliba. Further research should focus on broader ecological factors influencing nesting success, diet, and long-term population trends.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1590/1809-4392201700502, Alternate LINK

Title: Nestling Development Of The Tropical Screech-Owl ( Megascops Choliba ): A Successful Case Report From The Southwestern Amazon

Subject: General Agricultural and Biological Sciences

Journal: Acta Amazonica

Publisher: FapUNIFESP (SciELO)

Authors: Edson Guilherme, Izabele Rodrigues De Souza

Published: 2017-07-01

Everything You Need To Know

Where are tropical screech-owls typically found, and why is studying their breeding patterns in the Amazon important?

The tropical screech-owl (Megascops choliba) is found in diverse habitats from Costa Rica to Argentina, including the Amazon basin. While they are adaptable and common, particularly in human-impacted areas, detailed knowledge about their breeding patterns within the Amazon has been limited, making studies like this one in Acre, Brazil, essential for understanding their ecology.

How did researchers study the nesting behavior of tropical screech-owls in the southwestern Amazon?

Researchers monitored an active tropical screech-owl nest from egg-hatching to the fledglings' departure. They tracked the nestlings' weight gain, physical development, and behavior. The nest, located in a broken tucumā palm (Astrocaryum aculeatum) near the Zoobotanical Park of the Federal University of Acre (UFAC), provided an opportunity to gather detailed data on growth rates and nesting behaviors. This study offers a baseline for understanding how these owls adapt to their environment and contribute to the region's biodiversity.

What were the key observations regarding the development of the tropical screech-owl nestlings?

The nestlings of the tropical screech-owl exhibited rapid weight gain initially, followed by a deceleration as they approached fledging. They were initially covered in white plumage but developed darker, barred plumage and opened their eyes within two weeks. These observations underscore the importance of undisturbed nesting sites for the successful rearing of the tropical screech-owl. This aligns with general avian development strategies but provides species-specific data for M. choliba.

What does the consistent breeding season of tropical screech-owls in different hemispheres suggest about their adaptability?

The consistency of the breeding season observed in the southwestern Amazonian nest with that reported for tropical screech-owls (Megascops choliba) in the northern hemisphere suggests that environmental cues, rather than geographical location alone, might dictate breeding cycles. This adaptability highlights the species' resilience and its capacity to thrive across different regions, making them a valuable species for the local ecosystem and conservation efforts.

Why is it important to protect the nesting habitats of the tropical screech-owl, and what further research is needed?

Preserving nesting habitats within the Amazon is crucial for maintaining biodiversity and ensuring the survival of species like the tropical screech-owl (Megascops choliba). Future research should focus on broader ecological factors influencing nesting success, diet, and long-term population trends. Understanding the factors that impact their breeding is critical to implementing conservation strategies and maintaining their population.