How migratory birds help spread plant species

Did you know that pollens travel as far off as across continents? And how do they travel? On the wings of migratory birds.

A study offers critical insight into the ecology and evolution of plants that are represented across continents.

The study, done by the University of Connecticut (UConn) researchers, found 23 regenerative plant diaspores (plant seeds) trapped in the feathers of migratory birds leaving the Arctic harbour for South America.

The researchers studied American golden plovers, semi-palmated sandpipers and red phalaropes - all birds that breed in coastal tundra.

"Many of the plant parts found in their feathers belonged to mosses, which are especially hardy plants and often need only one dispersal event to establish in a new place," said lead author Lily Lewis, a doctoral fellow in the department of ecology and evolutionary biology at UConn, US.

Although wind is the primary means for long distance dispersal of diaspores around the world, it is an unlikely candidate for explaining distribution between the hemispheres.

Yet previous evidence of birds dispersing plant seeds or spores across the tropics had been only circumstantial.

The behaviour of these migrant birds in their northern breeding grounds likely promotes their inadvertent acquisition of diaspores, according to the study.

Shallow nests are constructed by scraping depressions into the ground with breast, feet and beaks and are commonly lined with plant materials.

The timing of molt and migratory behaviour also increases the likelihood of attached diaspores being dispersed across the birds' migratory range.

The findings were published in the online journal PeerJ.