Red Admiral butterflies back again in large numbers

It looks like another wave of those migrating butterflies we told you about a couple of weeks ago is passing through.

The Red Admiral Butterfly was seen again in unusually large numbers on Thursday. The butterfly darts along roadways and frantically flits around the yard creating swirls of orange, white and brown.

Seeing the Red Admiral in the region is not rare — it typically arrives at the end of May — but seeing the butterfly in such numbers and so early is unusual. Scientists call this an irruption, a sudden upsurge in numbers that often occurs when natural ecological factors are disturbed.

The  migration of Red Admirals is 4 to 5 weeks earlier than usual, Cheryl Tyndall, curator of the Niagara Butterfly Conservatory in Niagara Falls, Ont., told us in a story published April 21.

Tyndall says she has not seen a migration this large in the 16 years she has been at the Conservatory. Other butterfly watchers have suggested its been even longer.

And it’s possible that we will continue to see more Red Admirals than in past years. The butterfly produces several broods each season, and likely has laid eggs as they pass through the region. When those eggs hatch several weeks from now, more Red Admirals could be observed, Tyndal said.

Clusters of the Red Admiral were first reported in our area around April 16.

News reports from Canada suggest this second wave may be bigger than the first.

“It was as far as Toronto (on Wednesday). It is said be two to three times bigger than the previous one, which was the largest one on record by a landslide,” University of Ottawa biologist Maxim Larrivée told the Ottawa Citizen.

The Red Admirals have a black-brown upperside with white spots near the apex and red or orange bands around its forewing and hindwing.

Several factors likely contributed to the mass migration. A very mild winter allowed more Red Admirals to survive and reproduce, and the early spring helped plants needed by the Red Admiral grow.

Red Admirals migrate north from Guatemala to northern Ontario beginning in March, but their trip north is dependent upon weather conditions along the way and the food that is available