A scientist who travels to New Zealand from Canada each year to study monarch butterflies has published important discoveries about the species migration patterns in the North America and Mexico.
Neuroscientist Barrie Frost, a New Zealander has been studying birds -- including muttonbirds -- for decades and specialises in avian brain behaviour.
But rather than building a flight simulator in a laboratory to study bird navigation, he tried the idea on monarchs, which in Canada travel more than 3500 km to Mexico to escape winter weather.
"They migrate to a small place in Mexico every year so they must be using a complex navigation system," Prof Frost told the Kingston Standard newspaper in Ontario.
He tested 18 monarchs by placing them in the simulator and watching them fly southwest direction, toward their winter resting place in Mexico.
To test the accuracy of the monarchs' "time-compensated" sun compass, he put them in conditions where their biological "clocks" were advanced by six hours, and they instead travelled southeast.
Prof Frost said his research showed the monarchs used other techniques to find the few hectares in Mexico where most North American Monarchs rest each winter.
"We think the geography funnels them into the coastal plains of Mexico," he said. "We think they have a rule in their heads that says, `Don't fly over bodies of water or over high mountains'. "
And the butterflies used another tool -- possibly smell -- to find the specific area for their winter rest.
He said that he visits New Zealand every year to study the monarchs there. He has noted that they always form clusters in the same trees to which they migrate.
"It's not only the same tree, but sometimes the same branch," he said.
He said he thinks the monarchs leave behind substances to mark their places, which they later find through smell.
"What we're working on now is trying to identify these substances," he said.
