Understanding population change in migratory songbirds: long-term and experimental studies of Neotropical migrants in breeding and wintering areas
Article first published online: 5 MAR 2007
Volume 149, Issue Supplement s2, pages 2–13, November 2007
How to Cite
HOLMES, R. T. (2007), Understanding population change in migratory songbirds: long-term and experimental studies of Neotropical migrants in breeding and wintering areas. Ibis, 149: 2–13. doi: 10.1111/j.1474-919X.2007.00685.x
- Issue published online: 5 MAR 2007
- Article first published online: 5 MAR 2007
- Received 28 June 2006; revision accepted 8 January 2007.
Effective conservation and management of migratory bird species requires an understanding of when and how their populations are limited and regulated. Since 1969, my colleagues and I have been studying migratory songbird populations in their breeding quarters at the Hubbard Brook Experimental Forest in north-central New Hampshire, USA, and since 1986, in their winter quarters in the Greater Antilles (Jamaica). Long-term data on the abundance and demography of these populations, coupled with experimental tests of mechanisms, indicate that processes operating in the breeding area (e.g. density-dependent fecundity, food limitation) are sufficient to limit and regulate the local abundance of these species. At the same time, limiting factors operating in the non-breeding season (e.g. climate-induced food limitation in winter quarters and especially mortality during migration) also have important impacts on migrant populations. Furthermore, recent studies have shown that limiting processes during the winter period can carry over into the breeding season and affect reproductive output. These findings clearly demonstrate that to understand changes in abundance of long-distance migrant species requires knowledge of events operating throughout the annual cycle, which presents a challenge to researchers, managers and others concerned with the welfare of these species.