Wednesday, December 3, 2014

Winter moths

On my recent hike I'd noticed the yellow-rumped warblers were acting like flycatchers and I wondered what they could be preying on after the recent hard frosts.  Lately the temperatures have been milder and in the past few days I've noticed dozens of small, drab brown moths gathering at the windows and at the porch light.

a male winter moth
It turns out that this is the aptly named "winter moth."  Around Thanksgiving, in mild weather the adults emerge to fly and mate - gathering at trees that the females (who are effectively wingless) clamber up.

Unfortunately, they are an invasive species from Europe that has established itself in New England.  Without the predators that control them in Europe they have become a significant pest - able to defoliate trees - including oaks, maples, apples, crabapples and blueberries.

I was already familiar with gypsy moths and tent caterpillars, both of whom I've seen strip entire hillsides, but the winter moth is a new one for me.

The larvae's most nefarious habit is to creep into buds as they swell in the spring - and if the budding process is delayed by cool or wet weather, the caterpillars can kill off a plant's flowers and leaves before they even have a chance to unfurl.  (For this reason they are especially detested by blueberry cultivators.)

So - something else to pay attention to in the spring.  I wonder what predators I can encourage to come discourage them.  Where are those yellow-rumped warblers when you need them?

winter moths at night