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Avian Research 2017, 8(1): 3 https://doi.org/10.1186/s40657-017-0061-x
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Lophozonia tree cavities used for nesting by Slender-billed Parakeets (Enicognathus leptorhynchus) in the central valley of southern Chile: a potentially vanishing keystone resource

Show Author's Information Thomas H.White Jr.1 ( ),  Jaime E. Jiménez2,3,4
Puerto Rican Parrot Recovery Program, United States Fish and Wildlife Service, Box 1600, Rio Grande, PR 00745, USA
Sub-Antarctic Biocultural Conservation Program, Department of Biological Sciences, University of North Texas, Denton, TX 76201, USA
Sub-Antarctic Biocultural Conservation Program, Department of Philosophy and Religion, University of North Texas, Denton, TX 76201, USA
Omora Etnobotanical Park, Universidad de Magallanes, Puerto Williams, Chile
Keywords:
Regeneration, Conservation, Habitat loss, Deforestation, Lophozonia obliqua , Pellines, Psittacidae
Cite this article:
H.White Jr. T, E. Jiménez J. Lophozonia tree cavities used for nesting by Slender-billed Parakeets (Enicognathus leptorhynchus) in the central valley of southern Chile: a potentially vanishing keystone resource. Avian Research, 2017, 8(1): 3. https://doi.org/10.1186/s40657-017-0061-x
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Abstract Full text About this article
Background

The Slender-billed Parakeet (Enicognathus leptorhynchus) is a psittacine endemic to southern Chile and an obligate secondary cavity-nester. In the central valley of southern Chile, most (94%) of the known Slender-billed Parakeet nests have occurred in large, mature southern beech (Lophozonia obliqua) trees (locally known as "pellines"). As relicts of the original old-growth forests of southern Chile, most pellines have been lost due to extensive land-clearing throughout the region, potentially threatening long-term persistence of the Slender-billed Parakeet.

Methods

We conducted our study in the central valley of southern Chile, near the city of Osorno during three consecutive nesting seasons (November–January, 2008–2011). Nest trees used by Slender-billed Parakeets were located by direct observation of parakeet activities and through interviews with local residents, some of whom were former parrot nest poachers. Nest cavities were accessed, inspected and measured using single-rope climbing techniques. We report means, standard errors, 95% confidence intervals and ranges for 11 cavity-related variables. We also report clutch sizes encountered in active nests, and age estimates of nest trees based on known growth rates of Lophozonia trees in southern Chile. Linear regressions were used to evaluate potential relationships between cavity-related variables and clutch size.

Results

We located and measured 38 Lophozonia tree cavities used for nesting by Slender-billed Parakeets. Compared to those used by other psittacines, nest trees were relatively large, averaging 30.4 ± 1.1 m in height with a mean diameter at breast height of 134.5 ± 4.7 cm. Based on estimated annual diameter increment, ages of nest trees ranged from approximately 209–485 years. Nest cavities entrances averaged 12.5 ± 0.9 m in height above ground level. Cavity entrance widths averaged 51.0 ± 13.3 cm (vertical) by 11.5 ± 0.7 cm (horizontal). Cavity entrance orientations were apparently random, with no directional preferences detected. Nest cavities were also relatively large, with a mean internal diameter of 39.6 ± 2.4 cm and mean depth of 90.3 ± 24.2 cm. Clutch sizes (2–9) were unusually large for psittacines of this size (ca. 280–300 g) and broods of up to seven well-developed nestlings were observed.

Conclusions

We found that the deep and spacious cavities provided by pellines facilitate successful rearing of large broods, thereby maximizing productivity and fitness. The existence of pellines has apparently allowed Slender-billed Parakeets to adapt successfully to a wholesale loss of ancestral habitat to anthropogenic modifications. Immediate and strategic conservation measures, such as protection of existing pellines and the regeneration and recruitment of additional ones, are recommended for ensuring the survival of Slender-billed Parakeet populations throughout the central valley of southern Chile.


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About this article

Lophozonia tree cavities used for nesting by Slender-billed Parakeets (Enicognathus leptorhynchus) in the central valley of southern Chile: a potentially vanishing keystone resource

Show Author's information Thomas H.White Jr.1 ( ), Jaime E. Jiménez2,3,4
Puerto Rican Parrot Recovery Program, United States Fish and Wildlife Service, Box 1600, Rio Grande, PR 00745, USA
Sub-Antarctic Biocultural Conservation Program, Department of Biological Sciences, University of North Texas, Denton, TX 76201, USA
Sub-Antarctic Biocultural Conservation Program, Department of Philosophy and Religion, University of North Texas, Denton, TX 76201, USA
Omora Etnobotanical Park, Universidad de Magallanes, Puerto Williams, Chile

Abstract

Background

The Slender-billed Parakeet (Enicognathus leptorhynchus) is a psittacine endemic to southern Chile and an obligate secondary cavity-nester. In the central valley of southern Chile, most (94%) of the known Slender-billed Parakeet nests have occurred in large, mature southern beech (Lophozonia obliqua) trees (locally known as "pellines"). As relicts of the original old-growth forests of southern Chile, most pellines have been lost due to extensive land-clearing throughout the region, potentially threatening long-term persistence of the Slender-billed Parakeet.

Methods

We conducted our study in the central valley of southern Chile, near the city of Osorno during three consecutive nesting seasons (November–January, 2008–2011). Nest trees used by Slender-billed Parakeets were located by direct observation of parakeet activities and through interviews with local residents, some of whom were former parrot nest poachers. Nest cavities were accessed, inspected and measured using single-rope climbing techniques. We report means, standard errors, 95% confidence intervals and ranges for 11 cavity-related variables. We also report clutch sizes encountered in active nests, and age estimates of nest trees based on known growth rates of Lophozonia trees in southern Chile. Linear regressions were used to evaluate potential relationships between cavity-related variables and clutch size.

Results

We located and measured 38 Lophozonia tree cavities used for nesting by Slender-billed Parakeets. Compared to those used by other psittacines, nest trees were relatively large, averaging 30.4 ± 1.1 m in height with a mean diameter at breast height of 134.5 ± 4.7 cm. Based on estimated annual diameter increment, ages of nest trees ranged from approximately 209–485 years. Nest cavities entrances averaged 12.5 ± 0.9 m in height above ground level. Cavity entrance widths averaged 51.0 ± 13.3 cm (vertical) by 11.5 ± 0.7 cm (horizontal). Cavity entrance orientations were apparently random, with no directional preferences detected. Nest cavities were also relatively large, with a mean internal diameter of 39.6 ± 2.4 cm and mean depth of 90.3 ± 24.2 cm. Clutch sizes (2–9) were unusually large for psittacines of this size (ca. 280–300 g) and broods of up to seven well-developed nestlings were observed.

Conclusions

We found that the deep and spacious cavities provided by pellines facilitate successful rearing of large broods, thereby maximizing productivity and fitness. The existence of pellines has apparently allowed Slender-billed Parakeets to adapt successfully to a wholesale loss of ancestral habitat to anthropogenic modifications. Immediate and strategic conservation measures, such as protection of existing pellines and the regeneration and recruitment of additional ones, are recommended for ensuring the survival of Slender-billed Parakeet populations throughout the central valley of southern Chile.

Keywords: Regeneration, Conservation, Habitat loss, Deforestation, Lophozonia obliqua , Pellines, Psittacidae

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Publication history

Received: 18 July 2016
Accepted: 11 January 2017
Published: 06 February 2017
Issue date: January 2017

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© The Author(s) 2017.

Acknowledgements

Acknowledgements

We are grateful to the Laboratorio de Vida Silvestre at Universidad de Los Lagos, the United States Fish and Wildlife Service—Puerto Rican Parrot Recovery Program, Parrots International, Amigos de las Aves—USA, Canadian Parrot Society, International Conure Association, Parrot Conservation Fund, and Tony Pittman for funding and/or logistical support of this research. We also thank the administration of INIA—Remehue and the many private landowners who allowed us access to their properties. Numerous students and volunteers also assisted with nest monitoring and cavity measurements, especially Samuel Alywin, Ana Carneiro, Magdalena Contreras, Gemma Ffrench, Claire Foster, Daniel Gonzalez, Gemma Harding, Mauricio Ojeda, Nelson Ojeda, Suzan Payne, Nicole Pueschel, Marie Stafford and Mark Stafford. Two anonymous reviewers provided valuable comments that helped improve a prior version of this article. The findings and conclusions are those of the authors and do not necessarily represent the views of the US Fish and Wildlife Service. Use of trade names in this article does not imply endorsement by the United States Government.

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