Monday, March 12, 2012

New Plant Hardiness Zones

The Plant Hardiness Zones have all shifted up about half a zone. When we moved into our house in Jonesboro 37 years ago we were barely clinging to the northern limit of Zone 7. Now we are quite centrally ensconced in it. St. Francis National Forest outside Marianna, where Crowley's Ridge comes to an end as it runs into the Mississippi River, and about 75 miles south of us, is in Zone 8. There, alligators survive the winter, and the long-awaited spring comes about two weeks earlier.

On Tuesday, March 6th, the forecast said it "might" be 70, and it "might" be sunny, though clouding up in the afternoon. We packed a lunch, grabbed our binoculars and cameras, and went. We reached Bear Creek Lake in Lee County about eleven, it was sunny and 62 degrees, but it was warm enough for a handful of Eastern Tiger and Spicebush Swallowtails (both new for us for the season) to be flying along the road. We walked the Nature Trail at Bear Creek Lake, adding a few flower flies and Tachinid flies and Orange Sulphurs and Spring Azures for insects, but the main attraction was the trail itself which went from one fine big specimen tree to another (all with identifying placards), and we noticed how much better in a way we could see the trees at this time when there were no leaves out and they were laid bare.

We continued on down the ridge road (highway 44, a "Scenic Byway") and pulled off at a favorite stop, a trail going down to a creek bottom. A mud puddle there had a small handful (we weren't seeing large numbers of anything) of male butterflies drinking up salts. It included the butterflies we had been seeing plus some of the runtiest Zebra Swallowtails I have ever seen. The first generation of Zebras have much shorter tails than the summer generation, but these virtually had stub tails and the butterflies themselves were not a lot bigger than the Comma/Questionmarks we were also seeing. I can't remember if it was flood or drought when these were caterpillars last fall, but somehow they didn't get much nourishment.

Also at the puddle were a few Juvenal's Duskywings, always the first skippers of the year, and always a sign that the season is really underway. It was 70 degrees now, but rapidly clouding over.

Cheryl was noticing all the wildflowers.

Trillium recurvatum

Dentaria laciniata

Pale Corydalis

Blue Phlox

Wood Violet

Indian Strawberry

We got back in the car and continued on down the road, making stops where it looked interesting. At one stop we saw a black rat snake stretched across a stick that had eaten such a big meal its pattern was stretched and exaggerated.

At another we picked up a long-jawed orb-weaver (Tetragnatha sp.) to examine it.

Cheryl spotted a Cuckoo Bee (Nomada sp.). These are cleptoparasitic bees. This one looks like it is carrying an orange ball of pollen but that is actually part of the flower. These bees have no pollen baskets on their hind legs like law-abiding bees. Some kind of solitary bee might provision a cell with pollen and honey and lay an egg in it, seal it, and fly away. This one comes along, breaks into the cell, puts in its own egg (which will hatch first and eat the other's egg and provisions), then seals the hole back up and flies away.

From time to time we picked up other butterfly species, Gray Hairstreak, American Snout, Mourning Cloak. Finally we got up to ten species, the first two-digit butterfly day of the year. We finished the day with this tiny flower fly (Platycheirus sp.), which, no more than 5 mm long, has larvae that are fierce predators of even tinier insects.

By then the overcast was so dark it was not worth staying any longer and we came home. I checked my records and many of the butterflies we saw down there were indeed out two weeks earlier than I would normally see them up here in Jonesboro. But now I have been so slow getting this blog done (almost a week) nothing seems very early anymore, and at the speed the hardiness zones are moving up to us, it really won't be many years before the alligators and early butterflies are up here with us. Maybe I shouldn't be wishing for an earlier spring every year; maybe it was better back where it used to be.

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