The question arose last week when I was leading a group of kids on one of our nature hikes at Trinity River Audubon Center. As part of the activity where we're studying insects on the TRAC property, they were engaged in trying to find certain common objects so that their team could make a "nature bingo." When I make these game sheets, I keep the objects simple and easy to find so that everyone can contribute to the overall success of the group. Two of the things on the bingo list were "yellow butterfly" (the sulfurs, Phoebis sp) and "white butterfly" (Pieris rapae). On the "harder but possible to find", I also listed the Tiger Swallowtail and Monarch. I figured that Monarch would be an easy "hit" for that day, since there had been a release of a group of Monarch butterflies at TRAC just the week before.
But when I talked to the group, they said they didn't see any butterflies. Then a second group made the same report. In casually chatting to the other teachers, I discovered that no one had really noticed any butterflies around that week.
That was interesting.
So the next day on the insect hike, I took a group of kids out on a butterfly spotting expedition. We walked for 40 minutes but only spotted two butterflies of any type (Sulfurs (Phoebis)). There were no butterflies in the butterfly garden, which has nectar sources and water sources and was set up specifically by the Texas Master Gardeners to attract butterflies. Once the kids left, I decided to satisfy my curiosity and hiked two other trails on the property. During my 30 minute excursion I only saw two sulfurs plus a third butterfly that appeared to be one of the Nymphalinae. I didn't spot moths, though I saw other insects including wasps and the ever-present grasshoppers.
So where are they?
I mentioned this to others at TRAC and several answers were suggested that really didn't satisfy me. One was that they'd been eaten by the large group of swallows that we've had flying over the pond in the past week or so. Although it's a possibility, it doesn't explain why ALL the butterflies (including the monarchs and the very tiny butterflies) are gone. A second explanation was that it was too hot to fly. While I initially dismissed that one, it turns out that butterflies apparently will hunker down in the shade when it's too hot -- but that doesn't explain why they're not out flittering around at 9am, when it's an optimal temperature.
As far as I can tell, they breed throughout our summer season so we should have some butterflies during any given month.
The next step is to check some of the host plants in the butterfly garden and look again -- but as far as I can tell, the butterflies are getting scarce at Trinity River Audubon Center and right now I'm not sure what the cause is.
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