Red-neck phalarope: A migratory divide towards the Pacific Ocean and Arabian Sea

An exceptional strategy when winter comes

Date:  April 26, 2019

Source:  University of Barcelona

When winter comes, populations of red-neck phalarope from the Western Palearctic migrate to two different destinations -the Pacific Ocean or the Arabian Sea- following an exceptional migratory divide strategy which has never been described in this geographical area.

A part of these bird populations -which breed in Greenland, Island and the British Islands- cross more than 10,000 kilometres to reach the Pacific Ocean, while populations in Scandinavia and Russia go to the Arabian Sea in the Indian Ocean, more than 6,000 kilometres away from their breeding areas.

This migratory behaviour is now described for the first time in an article published in Frontiers in Ecology and Evolution -in which the researchers Raül Ramos and Jacob González-Solís, from the Faculty of Biology and the Biodiversity Research Institute of the University of Barcelona (IRBio) take part.

An uncommon wintering species in the peninsula

The red-neck phalarope (Phalaropus lobatus) is a migratory bird from the family of phalaropes that live in the tundra and high polar latitudes during their reproduction season. These small shore birds spend a part of their annual cycle -mainly the wintering period- at open sea, and therefore they are regarded as pelagic birds. During the migratory routes after breeding season -from August to September- this species can be occasionally seen in peninsular areas such as the Ebro Delta or the Atlantic and the Cantabrian coasts.

Continued

Backpack-toting birds help researchers reveal migratory divide, conservation hotspots

"Birds of a feather do not necessarily flock together," says Kira Delmore, a PhD student with UBC's Department of Zoology and lead author of the paper. 

Pictue: Wikipedia

"Our teams of thrushes took dramatically different routes to get to their wintering grounds, either south along the west coast to Central America, or southeast to Alabama and across the Gulf of Mexico to Columbia." 

The study, to be published this week in the Proceedings of the Royal Society of London B, is the first to collect a complete year's worth of data from individual birds to document such a migratory divide. 

"This detailed level of migration and stopover data helps us pinpoint vital feeding and rest habitats that the birds rely on at key points during their long journey – just before crossing the Gulf of Mexico, for example," Delmore adds. 

The researchers say the study also raises the possibility that migratory behavior may play a role in speciation, the process by which one species evolves into two. 

"Given that migratory behavior is under genetic influence in many species of birds, these results raise the question of what hybrids between these two subspecies would do," says Darren Irwin, associate professor of Zoology at UBC and co-author of the paper. 

"One possibility is that hybrids would take an intermediate route, leading to more difficulties during migration. If so, the migratory differences might be preventing the two forms from blending into one."

Read more at: http://phys.org/news/2012-09-backpack-toting-birds-reveal-migratory-hotspots.html#jCp

More information on Swainson's thrush (Catharus ustulatus):

http://www.allaboutbirds.org/guide/swainsons_thrush/id

http://www.birdweb.org/birdweb/bird/swainsons_thrush