A team led by Guelph researchers discovered that for some male birds traveling to areas with lighter rainfall comes at the cost of attracting a female when they return home.
Alice Boyle, a former U of G post-doc, Prof. Ryan Norris and Prof. Chris Guglielmo, a biologist at the University of Western Ontario, examined the breeding behaviour of the white-ruffed manakin. This small Costa Rican bird is partially migratory, choosing each year whether to migrate or stay.
During the heavy rainy season some Manakins will migrate to lower elevations where the lighter rainfall makes it easier to forage for food.
The researchers discovered the males that choose to stay behind may gain better breeding sites and are more likely to increase or maintain their standing within the population, making them more attractive to females.
"The manakins are faced with the choice of boosting their chances of survival or boosting their chances of breeding," said Norris, an integrative biology professor. "Most animals migrate because of the cold but in the tropics you see some populations that are partially migratory. These species provide a window into the evolution of migrating and a unique opportunity to examine the costs and benefits of this behaviour."
The study published today in Biology Letters is the first to investigate costs and benefits of staying or going in a partially migratory species.
During two breeding seasons, the researchers tagged almost 200 birds to observe their status and mating success. Alpha males in the population often have the most prominent breeding sites and perform the most elaborate aerobatic displays to attract the females.
To learn which birds had migrated or not before the breeding season, the scientists tested samples of their claws. Migrating birds have more heavy hydrogen in their claws. Rain at the lower elevation contains more of these isotopes, which end up in plants and berries eaten by the manakins, said Norris.
"These isotopes of hydrogen then become fixed in their nails," he said. "The problem with studying migration is that it's hard to follow the animals around, but this method allowed us to go back in time to find out what the bird was doing before we captured it."
The researchers found that males that did not migrate had better breeding sites, a higher status and attracted more females than the migrating males.
Choosing to stay or go is likely based on a number of factors, said Boyle.
"Birds that are younger are more likely to migrate because they still have several years of breeding opportunities ahead of them," she said. "It's often the older birds with a higher status that stay not only because there is a sense of urgency to breed but also they know staying will improve their chances of becoming an alpha."
Migrating birds are often in poorer condition and less likely to survive the heavy rains, said Boyle. They also aren't next in line to becoming an alpha so they won't be losing out on the opportunity if they leave, she added.
"These factors can change from year to year which is why we see these birds choose different options each year. They have to decide what makes the most sense for them based on their status and condition."
* Two videos are available to accompany this story. They are posted on YouTube at:
Ryan Norris | EurekAlert!
New insights into the information processing of motor neurons
22.02.2017 | Max Planck Florida Institute for Neuroscience
Wintering ducks connect isolated wetlands by dispersing plant seeds
22.02.2017 | Utrecht University
In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
22.02.2017 | Power and Electrical Engineering
22.02.2017 | Life Sciences
22.02.2017 | Innovative Products