Neotropical migrant songbird use of shade-coffee plantations in Colombia
Status – current
Neotropical migratory bird populations have seriously declined in recent decades with those that overwinter in South America declining at greater rates than those wintering elsewhere. These declines are associated, in part, with habitat loss and deterioration on the wintering grounds. The northern Andes of South America are an exclusive wintering area for several Neotropical migrants, including species of global conservation concern such as the Cerulean Warbler, Canada Warbler and Olive-sided Flycatcher. However, over 90% of the northern Andes of South America have been deforested.
Traditional shade-grown coffee plantations are one of the few remaining “forested” habitats in the northern Andes. In this agroecosystem, the native canopy is maintained or replaced by leguminous nitrogen-fixing trees and the understory is occupied exclusively by coffee bushes. The relative species richness and abundance of Neotropical migrants has been found to be higher in shade-coffee compared to other agroecosystems and a number of declining species are known to occupy this habitat. These findings, combined with unprecedented rates of habitat loss, have led to shade-grown coffee plantations being considered as one of the only suitable and widely-distributed habitats left for Neotropical migrants in northern South America. Indeed, in Colombia, the elevation range at which the highest species richness of Neotropical migrants occurs, overlaps almost entirely with the prime coffee growing areas between 1200 and 1800 m. Yet, more than 60% of traditional shade-grown coffee was converted to sun coffee by 1990 in Colombia alone, and the remnants of this valuable agro-ecosystem are in danger of being lost. Despite the implied importance of shade-coffee for Neotropical migrants, its quality and ability to maintain populations of Neotropical migrants when compared to natural habitats, has never been evaluated in South America.
This project aims to assess the relative quality of shade-grown coffee plantations versus remaining native forest as winter habitat for Neotropical migrants in Colombia. We will use demographic measures (e.g., density and survival) and individual level trait measures (e.g., physical condition and response to stressors) as indicators of habitat quality for three focal species: Canada Warbler, Swainson’s Thrush and Gray-cheeked Thrush. We will also assess the conservation value of these habitats at continental scales, by assessing the carry-over effects of habitat occupancy on migratory strategies and arrival times at breeding sites through stable isotopes and geolocator technology.
Assessing winter habitat quality for Neotropical migrants and its effect on overwinter ecology and demographics is critical to identifying the factors driving population declines or limiting population growth, and to predict how environmental changes will impact migratory populations. Results from this project will provide basic scientific information needed to support ongoing local conservation strategies to protect winter and staging habitats of long-distance migrants in the Neotropics. In particular, the results for Canada Warbler will directly contribute to the development of a non-breeding season conservation plan by the “Canada Warbler International Conservation Initiative” for this species of concern.
This project is the result of a partnership between SELVA, Environment Canada and the University of Saskatchewan. It forms part of the doctoral studies of Colombian student Ana María Gonzalez.
Key findings and achievements
- In 2013, three study sites were set up in the Colombian Andes in the department of Cundinamarca. At each site, stations were established in shade-coffee and native forest.
- During the first field season (2013-2014), 418 Swainson’s Thrushes and 49 Canada Warblers were captured and marked.
- In early 2014, 40 geolocators were attached to Swainson’s Thrushes occupying the two habitats under study.
– Environment Canada: www.ec.gc.ca
Project director – Ana María Gonzalez
Assistant researchers – Jeyson Sanabria, Catalina Gonzalez, Angela Caguazango, Nestor Espejo, Ana María Díaz