News

Durham scientists help solve migration mystery

(21 March 2007)

Research by Durham University scientists could help predict the arrival of avian carried diseases such as bird flu.

Concerns about the spread of bird flu means there is an urgent need to find better ways of monitoring the movements of migrating birds. Measurements of metal found in bird feathers could unravel mysteries of their migration patterns, helping to predict the spread of disease.

Dr Laura Font and colleagues in Durham University’s Earth Sciences department have developed a technique which can measure very low concentrations of strontium isotopes in bird feathers.

The team measured strontium isotope levels in the feathers of the sedge warbler and mapped how this changed with geographic location.

Dr Font said: “The routes of migrant birds have previously been studied using a variety of techniques, such as marking individuals with unique metal leg-rings, radio or satellite tags, or simply by counting bird numbers at migratory stop-over points.

“But these labour-intensive methods generate relatively little data and often do not reveal the origin of individual birds.”

Migratory birds regularly renew their feathers, often prior to migration, and these feathers tend to reflect the “isotope signature” of the region in which they were grown.

Although analyses using carbon, nitrogen, hydrogen and oxygen isotopes in feathers can give a rough idea of their origin, said Font, strontium isotope ratios in the bones, claws and egg shells of birds tend to provide a much more precise location.

Bone analysis is too invasive for routine use, and while loose feathers can be easily collected from nesting sites, these contain very low levels of strontium. Dr Font's technique has finally made accurate analysis of strontium in feathers a viable option for tracking birds.

Dr Font said: “By determining migration pathways, the arrival of potential vectors of diseases from infected areas can be anticipated.

“Knowledge of migratory routes also helps evaluate the likelihood that individual avian influenza outbreaks could be related to migratory bird movements rather than anthropogenic activities, such as poultry movements, which are believed to be the main vector of avian influenza in most outbreaks.”

SOURCE INFORMATION: **Sr isotope analysis of bird feathers by TIMS: a tool to trace bird migration paths and breeding sites** Laura Font, Geoff M. Nowell, D. Graham Pearson, Chris J. Ottley and Stephen G. Willis, /J. Anal. At. Spectrom./, 2007 **DOI:** 10.1039/b616328a

Reproduced by permission of The Royal Society of Chemistry -http://www.rsc.org/Publishing/Journals/JA/article.asp?doi=b616328a

Picture credited to Dr. Steve Willis (co-author of the paper)