Assessing Habitat Quality for a Migratory Songbird Wintering in Natural and Agricultural Habitats

• Published in: Conservation biology Vol. 20; no. 5; pp. 1433 - 1444
• Main Authors: JOHNSON, MATTHEW D., SHERRY, THOMAS W., HOLMES, RICHARD T., MARRA, PETER P.
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.10.2006; Blackwell Science; Blackwell; Blackwell Publishing Ltd
• Subjects: Agriculture; American Redstart; Animal, plant and microbial ecology; Animals; Applied ecology; Aves; Biological and medical sciences; Bird migration; Bird songs; Birds; body condition; body mass; Body Weight; café; Citrus; Coastal forests; coffee; condición corporal; Conservation biology; Conservation of Natural Resources; Conservation, protection and management of environment and wildlife; Deforestation; densidad; Density; Dry forests; Ecosystem; Female; Forest habitats; Fundamental and applied biological sciences. Psychology; Habitat conservation; Habitats; Jamaica; Male; Mangrove forests; masa corporal; migratoria neotropical; Models, Biological; Neotropical migrant; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Rainforests; Seasons; Setophaga ruticilla; Setophaga rutinilla; Songbirds; Songbirds - physiology; supervivencia; survival; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Central America; Jamaica; America; West Indies; Physiological condition; Overwintering; Body weight; body mass; Density; Survival; Agroecosystem; Vertebrata; Migratory; body condition; coffee; Neotropical migrant; Habitat; American Redstart; Aves; Neotropical Region; Jamaica; Environmental protection; Environment quality
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/j.1523-1739.2006.00490.x

As tropical forests are cleared, a greater proportion of migratory songbirds are forced to winter in agricultural and disturbed habitats, which, if poorer in quality than natural forests, could contribute to population declines. We compared demographic indicators of habitat quality for a focal species, the American Redstart (Setophaga ruticilla), wintering in Jamaican citrus orchards and shade coffee plantations with those in four natural habitats: mangrove, coastal scrub, coastal palm, and dry limestone forests. Demographic measures of habitat quality included density, age and sex ratio, apparent survival, and changes in body mass. Measures of habitat quality for redstarts in citrus and coffee habitats were generally intermediate between the highest (mangrove) and lowest (dry limestone) measurements from natural habitats. The decline in mean body mass over the winter period was a strong predictor of annual survival rate among habitats, and we suggest that measures of body condition coupled with survival data provide the best measures of habitat quality for nonbreeding songbirds. Density, which is far easier to estimate, was correlated with these more labor-intensive measures, particularly in the late winter when food is likely most limiting. Thus, local density may be useful as an approximation of habitat quality for wintering migrant warblers. Our findings bolster those of previous studies based on bird abundance that suggest arboreal agricultural habitats in the tropics can be useful for the conservation of generalist, insectivorous birds, including many migratory passerines such as redstarts.