Sexual habitat segregation in migrant warblers along a shade gradient of Jamaican coffee farms

Aaron B. Spidal, Matthew D. Johnson

Abstract


Shade coffee has been shown to provide wintering habitat for migratory bird species. Canopy cover has been cited as a good indicator of habitat quality on coffee farms. Many species of sexually dimorphic migrant warblers show sexual habitat segregation on their wintering grounds, often related to habitat quality. To test if degree of habitat segregation followed a gradient of habitat quality, we sampled canopy cover and avian communities at nine different sites in coffee farms ranging from full sun to highly shaded. Proportion of all species of wintering warblers that were male was positively correlated with percent canopy cover. Species-specific male proportions of American Redstarts (Setophaga ruticilla), Black-throated Blue Warblers (S. caerulescens), and Prairie Warblers (S. discolor) showed positive correlations with canopy cover, though small sample sizes limited statistical power.

Se ha demostrado que el café de sombra brinda un hábitat invernal para las especies de aves migratorias. La cobertura del dosel se ha citado como un buen indicador de la calidad del hábitat en las granjas cafetaleras. Muchas especies de paseriformes migratorios sexualmente dimórficos muestran, en las áreas de invernada, una segregación sexual en el hábitat usualmente relacionada con la calidad del mismo. Para examinar si el grado de segregación del hábitat sigue un gradiente relacionado con su calidad, muestreamos la cobertura del dosel y las comunidades de aves en nuevos sitios diferentes en granjas cafetaleras con una variación de esa cobertura desde totalmente al sol a altamente sombreada. La proporción de individuos de todas las especies de paseriformes migrantes que fueron machos estuvo correlacionada positivamente con el porcentaje de cobertura del dosel. Las proporciones especie-específica de machos de Setophaga ruticilla, S. caerulescens y S. discolor mostraron correlaciones positivas con la cobertura del dosel, a pesar de la potencia estadística limitada por los pequeños tamaños muestrales.

Il a été montré que les plantations de café d’ombre fournissent un habitat d’hivernage à certaines espèces d’oiseaux migrateurs. La couverture de la canopée a été reconnue comme un bon indicateur de la qualité de l’habitat dans les plantations de café. De nombreuses espèces de parulines migratrices ayant un dimorphisme sexuel présentent une ségrégation de l’habitat en fonction du sexe dans leurs aires d’hivernage, souvent liée à la qualité de l’habitat. Pour vérifier si ce degré de ségrégation suit le gradient de qualité de l’habitat, nous avons échantillonné la couverture de la canopée et les communautés d’oiseaux des plantations de café sur neuf sites différents allant du plein soleil à des situations très ombragées. La proportion de mâles de l’ensemble des espèces de parulines hivernantes était positivement corrélée au pourcentage de couverture de la canopée. La proportion de mâle, au sein de chaque espèce, était positivement corrélée à la couverture de la canopée pour la Paruline flamboyante (Setophaga ruticilla), la Paruline bleue (S. caerulescens) et la Paruline des prés (S. discolor), bien que la taille réduite des échantillons ait limité la portée statistique de l’analyse.


Keywords


Coffee; Habitat Quality; Habitat Segregation; Migrants; Neotropics; Parulidae; Shade Coffee

Full Text:

PDF

References


Askins, R.A., J.F. Lynch, and R. Greenberg. 1990. Population declines in migratory birds in eastern North America. Current Ornithology 7:1–57.

Faaborg, J. 2002. Saving Migrant Birds: Developing Strategies for the Future. University of Texas Press, Austin, TX.

Greenberg, R., P. Bichier, A.C. Angon, C. MacVean, R. Perez, and E. Cano. 2000. The impact of avian insectivory on arthropods and leaf damage in some Guatemalan coffee plantations. Ecology 81:1750–1755.

Greenberg, R., P. Bichier, A.C. Angon, and R. Reitsma. 1997. Bird populations in shade and sun coffee plantations in central Guatemala. Conservation Biology 11:448–459.

Jha, S., C.M. Bacon, S.M. Philpott, V.E. Méndez, P. Läderach, and R.A. Rice. 2014. Shade coffee: update on a disappearing refuge for biodiversity. BioScience 64:416–428.

Johnson, M.D., J.L. Kellermann, and A.M. Stercho. 2010. Pest reduction services by birds in shade and sun coffee in Jamaica. Animal Conservation 13:140–147.

Johnson, M.D., T.W. Sherry, R.T. Holmes, and P.P. Marra. 2006. Assessing habitat quality for a migratory songbird wintering in natural and agricultural habitats. Conservation Biology 20:1433–1444.

Karp, D.S., C.D. Mendenhall, R.F. Sandí, N. Chaumont, P.R. Ehrlich, E.A. Hadly, and G.C. Daily. 2013. Forest bolsters bird abundance, pest control and coffee yield. Ecology Letters 16:1339–1347.

Kellermann, J.L., M.D. Johnson, A.M. Stercho, and S.C. Hackett. 2008. Ecological and economic services provided by birds on Jamaican Blue Mountain coffee farms. Conservation Biology 22:1177–1185.

Lack, D. 1976. Island Biology, Illustrated by the Land Birds of Jamaica. University of California Press, Berkeley, CA.

Lemmon, P.E. 1956. A spherical densiometer for estimating forest overstory density. Forest Science 2:314–320.

Lynch, J.F., E.S. Morton, and M.E. Van der Voort. 1985. Habitat segregation between the sexes of wintering Hooded Warblers (Wilsonia citrina). Auk 102:714–721.

Marra, P.P., and R.T. Holmes. 2001. Consequences of dominance-mediated habitat segregation in American Redstarts during the nonbreeding season. Auk 118:92–104.

Marra, P.P., T.W. Sherry, and R.T. Holmes. 1993. Territorial exclusion by a long-distance migrant warbler in Jamaica: a removal experiment with American Redstarts (Setophaga ruticilla). Auk 110:565–572.

Moguel, P., and V.M. Toledo. 1999. Biodiversity conservation in traditional coffee systems of Mexico. Conservation Biology 13:11–21.

Morton, E.S. 1990. Habitat segregation by sex in the Hooded Warbler: experiments on proximate causation and discussion of its evolution. American Naturalist 135:319–333.

Newton, I. 2004. Population limitation in migrants. Ibis 146:197–226.

Ornat, A.L., and R. Greenberg. 1990. Sexual segregation by habitat in migratory warblers in Quintana Roo, Mexico. Auk 107:539–543.

Perfecto, I., R.A. Rice, R. Greenberg, and M.E. Van der Voort. 1996. Shade coffee: a disappearing refuge for biodiversity. BioScience 46:598–608.

Petit, D.R., J.F. Lynch, R.L. Hutto, J.G. Blake, and R.B. Waide. 1995. Habitat use and conservation in the Neotropics. Pp. 145–200 in Ecology and Management of Neotropical Migratory Birds: a Synthesis and Review of Critical Issues (T.E. Martin and D.M. Finch, eds.). Oxford University Press, Oxford, UK.

Pyle, P. 1997. Identification Guide to North American Birds, Part 1. Slate Creek Press, Bolinas, CA.

Railsback, S.F., and M.D. Johnson. 2014. Effects of land use on bird populations and pest control services on coffee farms. Proceedings of the National Academy of Sciences 111:6109–6114.

Reudink, M.W., C.E. Studds, P.P. Marra, T.K. Kyser, and L.M. Ratcliffe. 2009. Plumage brightness predicts non-breeding season territory quality in a long-distance migratory songbird, the American Redstart Setophaga ruticilla. Journal of Avian Biology 40:34–41.

Robbins, C.S., J.R. Sauer, R.S. Greenberg, and S. Droege. 1989. Population declines in North American birds that migrate to the Neotropics. Proceedings of the National Academy of Sciences 86:7658–7662.

Sherry, T.W. 2000. Shade coffee: a good brew even in small doses. Auk 117:563–568.

Smith, C.J., M.D. Johnson, B.R. Campos, and C.M. Bishop. 2012. Variation in aggression of Black-throated Blue Warblers wintering in Jamaica. Condor 114:831–839.

Studds, C.E., and P.P. Marra. 2005. Nonbreeding habitat occupancy and population processes: an upgrade experiment with a migratory bird. Ecology 86:2380–2385.

Tejeda-Cruz, C., and W.J. Sutherland. 2004. Bird responses to shade coffee production. Animal Conservation 7:169–179.

Wunderle, J.M., Jr. 1995. Population characteristics of Black-throated Blue Warblers wintering in three sites on Puerto Rico. Auk 112:931–946.

Wunderle, J.M., Jr., and R.B. Waide. 1993. Distribution of overwintering Nearctic migrants in the Bahamas and Greater Antilles. Condor 95:904–933.


Refbacks

  • There are currently no refbacks.


Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.

Questions, comments, or problems with the website?  Please contact Jason Townsend: townsend.jason.m@gmail.com