Study traces evolutionary origins of migration in New World birds

August 4, 2014, University of Chicago Medical Center
The Baltimore Oriole is one of many songbirds featured in The Field Museum's latest study. Credit: Arlene Koziol (c)2014 The Field Museum

Every year, millions of birds make the journey from North America to Central and South America for the winter. But the evolutionary origins of this long-distance migration have remained opaque due to the complex geographic distributions of modern and ancient bird ranges.

Now, a team of scientists from the University of Chicago have developed a new method to reveal the ancestral ranges of New World birds, and discovered that in the Americas evolved in that resided in North America. Their work also offers evidence that many tropical bird species descended from migratory ancestors that lost migration. The study was published Aug 4 in the Proceedings of the National Academy of Sciences.

Seasonal migration – which occurs when species breed in one geographical area and winter in another – is commonly hypothesized to have evolved as ancestral species native to the tropics began to shift their breeding ranges northward. However, this has been difficult to prove as hundreds of species with large and dynamic geographic ranges have to be studied.

To better understand the of this phenomenon, Benjamin Winger, a graduate student of the Committee on Evolutionary Biology at the University of Chicago, and his colleagues Keith Barker, PhD, a University of Chicago alumnus now at the University of Minnesota in St. Paul, and Richard Ree, PhD, of the Field Museum of Natural History in Chicago, developed a new model to infer the historical geographic distributions of migratory birds.

Using emberizoid passerines – the largest lineage of New World migratory birds, which includes warblers, sparrows, orioles, blackbirds and cardinals – Winger and his colleagues described over 750 passerine species' breeding and wintering patterns by geographical location. They mapped these ranges to a phylogenetic tree – a diagram which shows the evolutionary relationships of each passerine species and their common ancestors – to reconstruct where ancestral passerines lived. The team then computationally inferred the trends in range evolution among ancestral and descendant birds.

Contrary to common hypotheses, they found that the most likely origin of migration in this group lay in ancestral species that resided in North America and gradually moved further and further south for the winter. Shifts in range from North America to tropical areas were the dominant pathway for geographical change, and evolved much more frequently than shifts northward from tropical areas. They also found evidence that ancestral migratory bird species colonized the tropics, eventually losing migration and diversifying into the species that today stay in the tropics year-round.

"We find that a North American species is ancestral to migratory birds in the New World," said Winger, who is the corresponding author on the study. "It's been assumed that because species density is so high in the tropics, that must come out of the tropics. But our study suggests the opposite happened more frequently in this group. The evolution of is a complex system. Our study highlights the importance of using phylogenies to study this phenomenon."

Explore further: Environmental conditions may impact bird migration

More information: Temperate origins of long-distance seasonal migration in New World songbirds, PNAS,

Related Stories

Environmental conditions may impact bird migration

May 14, 2014

Wind conditions during spring migration may be a predictor of apparent annual survival and the timing of breeding in yellow warblers, according to results published May 14, 2014, in the open access journal PLOS ONE by Anna ...

Study provides insights into birds' migration routes

July 21, 2014

By tracking hybrids between songbird species, investigators have found that migration routes are under genetic control and could be preventing interbreeding. The research, which is published in Ecology Letters, was conducted ...

Ancient birds from North America colonized the South

July 13, 2010

Scientists studying ancient species migration believe northern birds had the ability to colonise continents that southern species lacked. The research, published in Ecography, reveals how the ancient 'land bridge' of Panama, ...

Tiny plants ride on the coattails of migratory birds

June 12, 2014

Since the days of Darwin, biologists have questioned why certain plants occur in widely separated places, the farthest reaches of North American and the Southern tip of South America but nowhere in between. How did they get ...

Recommended for you

Scientists shed light on biological roots of individuality

February 16, 2018

Put 50 newborn worms in 50 separate containers, and they'll all start looking for food at roughly the same time. Like members of other species, microscopic C. elegans roundworms tend to act like other individuals their own ...

Plants are given a new family tree

February 16, 2018

A new genealogy of plant evolution, led by researchers at the University of Bristol, shows that the first plants to conquer land were a complex species, challenging long-held assumptions about plant evolution.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Aug 06, 2014
Common sense... if you are in the tropics... migrate??

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.