Irrupting All Over the Place

I learned a new word the other day.  Irruption.  That is a natural event when conditions are favorable for a particular species, and that species responds to those conditions by dramatically increasing the size of its population.

We are having an irruption right now, particularly of red admirals. 

I do butterfly surveys over my lunch break.  Today I saw 2.4 butterflies per minute.  Normally this time of year I see that many in an hour.  Seventy percent of the butterflies I saw today were red admirals.

Red admirals perch in the sunlight in the evening, then fly out and chase any other butterfly that goes past.  Pairs will circle each other (maybe rivals rather than mates) then land again.

Irruption is a noun.  I don’t think there is a corresponding verb.  Too bad…

About the roused bear

Nature photographer from central Iowa.
This entry was posted in Biological diversity, butterflies, butterfly surveys and tagged , . Bookmark the permalink.

3 Responses to Irrupting All Over the Place

  1. theresagreen says:

    What a beautiful way to spend a lunch break. Hope I don’t come across as a smart-a**e, but I love our language and was intrigued, so looked up the verb ‘to irrupt’. Although its use is uncommon, the verb IRRUPT has 3 meanings:1. enter uninvited 2. erupt or intensify suddenly 3. increase rapidly and in an uncontrolled manner.

  2. Finn Holding says:

    Are other butterflies irrupting as well as the red admirals? 2.4 per minute seems like a very impressive strike rate, is there a specific reason for the increased numbers?

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