TRENTON, N.J. (AP) — A swarm of butterflies have been making their way through New Jersey in recent days.

Experts say some ecological switch apparently got flicked somewhere, because red admiral butterflies apparently decided to leave the warmer confines of the South and migrate north.

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And many of them seem to be hanging out in New Jersey.

It’s believed that a change in temperatures or in the length of day likely served as the basis for the migratory trigger.

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The typical lifespan of an adult butterfly is three months. But because many of these butterflies have flown hundreds of miles from their likely birthplaces in Georgia or the Carolinas, it’s unclear how much longer the immigrants fluttering outside will last.

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