The golden-crowned sparrow (Zonotrichia atricapilla) is a large species of New World sparrow found in the western part of North America. University of Nebraska-Lincoln researcher Anastasia Madsen and colleagues previously found that sparrows show consistent flocking relationships across years, and that familiarity between individuals influences the dynamics of social competition over resources. Their new research shows that: (i) golden-crowned sparrows exhibit interannual fidelity to winter home ranges on the scale of tens of meters and (ii) the precision of interannual site fidelity increases with the number of winters spent, but (iii) this fidelity is weakened when sparrows lose close flockmates from the previous year.
“We found that a golden-crowned sparrow returning to California after a winter migration — one that can stretch as many as 3,000 miles — resettled an average of just 90 feet away from the center of its previous year’s range,” the authors said.
“But golden-crowned sparrows appearing for at least their third consecutive winter began to drift from their preferred locales when their closest flockmates failed to rejoin them down south — hinting that, even for sparrows, home is where the heart is.”
“The fact that they come back to this winter site and then hang out with the same individuals — and it’s important for them to be with the same individuals — is kind of a crazy thing that we’re still wrapping our heads around.”
Dr. Madsen and co-authors undertook the research hoping to untangle the knot of what she called a ‘chicken-and-egg question.’
Many animals, including the golden-crowned sparrow, share space with members of their species. In many cases, they also spend time around and interact with those neighbors.
Golden-crowned sparrows, for instance, have adopted what are called fission-fusion networks, spending minutes or hours congregating in small groups before dispersing, only to later reassemble with…
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