Wednesday, September 28, 2016

Paying attention to detail

We went out to our son's house in Tucson to see our brand new (and first) grandson.  I know this is mainly an insect blog, but I hope I can be excused this single mammal photograph.

Actually, I'm going to go on and discuss another vertebrate animal, a bird.

Cheryl was there to help out with the new baby, and my job was, essentially, to stay out of everyone's way. It was still summer and their bird feeders had not been in operation, but it was late summer with birds beginning to move around, so I started things up by filling a finch feeder with niger seed.

I spent a lot of time out on the back porch watching the insect, spider, lizard activity, and, when they arrived (almost immediately), the birds at the feeder. This was one of those diabolical feeders that would only offer food to desirable Lesser Goldfinches, leaving the over-abundant House Finches out in the cold (not a good metaphor when the temperature is in the 90's).

The way it works is, instead of the holes being above the perches, the holes are below them, and they can only be accessed by hanging upside down, which in theory only the goldfinches can deal with. It more or less worked, though there was a male House Finch who mastered it, and came regularly.

Where we live in Jonesboro, NE Arkansas, we have American Goldfinches, a related but different species. The Lesser Goldfinch is a western bird we only see when we come to Tucson, so we are not overly familiar with it. I remembered reading at some point that the Lesser comes with its back in two color forms, though I couldn't remember what the two colors were, or how the two species were distributed.  So I got out my Sibley and read "adult males in southern Texas are black-backed; frequency of green-backed adult males increases north and west to near 100% west of New Mexico." We were west of New Mexico, so 99% of the adult males here should be green-backed.

The theme of this blog is paying attention to details and here was a detail I had paid no attention to and I had never even noticed the back color of these birds. So I looked, and sure enough, the males were all green-backed.

And then virtually the next bird I saw was black-backed.

And what a beautiful bird it was, and if I hadn't been paying attention to details I would have missed it entirely, and so I would have missed this lovely 1% rarity (though it occurs to me I must have not paid attention to them by the million in South Texas, where we often go, and where they are common).

Here's another example of learning new things by paying attention to detail. In our backyard in Jonesboro there is a sugarberry tree, which is closely related to hackberry trees. In fact, Hackberry Butterflies lay their eggs on it, just as they do on regular hackberries, and we raise Hackberry Emperors by the score, a pretty orange and black butterfly. In our son's backyard there is, similarly, a hackberry tree, and it is covered with identical looking caterpillars, and eggs laid by an orange and black butterfly which is virtually identical, the Princess Leilia. When we are in Arkansas, in the east, we know we are seeing a Hackberry Butterfly, and when we are in the desert southwest, we are seeing Princess Leilia.

So here is Princess Leilia laying eggs in the hackberry tree in my son's backyard in Tucson.

As I was taking this picture, a revelation came to me. This butterfly is one of a group of butterflies called Emperors, the Hackberry Emperor, the Tawny Emperor, a few others, and here, because a butterfly with a feminine name can't be an emperor, its name is Empress Leilia, and always before this I had mistakenly called it Princess Leilia (probably confusing it with the heroine in
Star Wars). Unfortunately I still automatically call it by the wrong name, but this was only the first of my errors of poor attention to details.

I opened my book, Butterflies of Arizona, A Photographic Guide (2001) to p. 208-9, and learned that the Hackberry Emperor and Empress Leilia occurred side by side (in other words, the Hackberry was not strictly eastern), and the details had to be studied very carefully to tell which was which. A first tip was, Empress Leilia laid its eggs in Desert Hackberry, and Hackberry Emperor laid its eggs in Netleaf Hackberry trees. I asked our son's wife (a tree expert) what kind they had, and she said it was a Netleaf, and I learned to my surprise that what we had in their yard were Hackberry Emperors, just like ours back home. So how do you tell them apart?

Let's take another look at the Hackberry.

If you look just to the left of the head (or just to the right of the head), along the front of the wing, there is a pale orange panel with two small dark spots on it, then, towards us a little way, a longer thin curved spot, a little bit like a smiley face. Those three spots make this a Hackberry Emperor. This is the one in our son's backyard. Note the egg-stuffed abdomen.

Then when we went out in the desert, in the vicinity of a Desert Hackberry tree we saw this one:

Now instead of having three little spots along the leading edge of the wings it has two bigger spots, with a pale creamy area between them. This is Empress Leilia. Here are the two close up.

Let me give just one more kind of interesting example of paying attention to details, and this creature is so tiny, 2-3 mm, you can barely see it at all, let alone its fine details. But the marvel of digital cameras helps out, to blow the picture up to visibility. In this case we are looking at mosquitoes in the genus Aedes, the genus that is so much in the news lately. Here is the one we have at home in Arkansas

It is Aedes albopictus, the Asian Tiger Mosquito. It's a very tiny mosquito, about half the size of most mosquitoes, looking like not much more than a black dot on your skin. It is quite handsome with its black and white leg bands and the white spots on its abdomen. It tends to bite during the day (morning and late afternoon). Besides being annoying, this one, in the tropics, carries dengue fever, which fortunately is very rare here. Here is the detail: Note, easier to see on the second view, a broken white dash going across the back of the thorax. Then, in front, a white stripe going down the center of the thorax.

When we got to Tucson, we found a different Aedes.

It is the same in all respects, except it doesn't have the white stripe down the center of the thorax. This is the notorious Aedes aegypti, the transmitter of the Zika virus. The mosquito seems to be established across the southern border of the country from Florida to California. So far, except for a couple of spots in Miami, there is no Zika virus around for it to carry, but naturally it is being closely watched.