Papilo cresphontes!

As I wrote in yesterday's post "Black Swallowtail it was." Except that it wasn't.

Sunday night, as we were eating dinner, a huge 'moth' came flitting to a light just outside the kitchen window. I tried to pin it down as some kind of silk moth but, embarrassingly enough, it wasn't a moth at all (moth antennae are quite different) but a swallow-tailed butterfly. I managed to photograph it but then couldn't download it to my computer. When I finally managed to overcome the problem, I attached the photo to a post identifying it as a Black Swallowtail, Papilio polyxenes. Which it wasn't. Lorna was the first to point out that it didn't look like a Black Swallowtail and now I have a raft of e-mails telling me that it was something a lot more extraordinary: a Giant Swallowtail, the largest butterfly north of the Rio Grande and a wow of an insect!

Giant Swallowtail, Papilio cresphontes, is a spectacular creature. I've never seen it before and I'm amazed that it even occurs on Long Island; its larval foodplants are members of the citrus family. The sheer size and the brown background color -- neither obvious in the photo but both seen on the live insect -- should have been a giveaway. There are other good field marks that can be seen in the picture: the yellow band across the center of the forewing (forming a triangle with the yellow band on the lower wing), the yellow dot on the tails (what looks like a second swallowtail is the shadow from the light above); also, the pattern near the tip of the forewing with graduated yellow marks of different sizes.

What's it doing here? Steve Biasetti congratulated me on finding one -- but I didn't find it, it found me! According to Rick Cech, this normally southern species has 'invaded' our area from its normally southern home base. I still don't think it's very common and, unless I'm mistaken most of the sightings this year have been in the NYC area or Hudson Valley but not Eastern LI.

Another example of a southern species expanding its range northward? Of course, this doesn't explain its appearance well after dark, attracted to the nightlight like a giant moth. That in itself is unusual for a butterfly (although apparently not unknown).

Any southern birds around? In fact, there has been a steady increase in southern species reaching these shores and often staying to breed. The most spectacular examples of the past few years are the Blue Grosbeaks in the Calverton/Manorville area and the vultures -- Turkey and Black -- that invaded ELI in 2008 (Turkey Vultures are breeding; the situation with Black Vulture is less clear). Currently, Royal and Forster's Terns from the south are fishing our bays and estuaries (while our breeding terns have mostly skeddadled, at least from their breeding sites). There should be northern birds coming through as well but all I could find this morning was a lonely Redstart and a couple of N. Waterthrushes. It seemed as though most of the birds have moved away from the shore as if they were expecting a hurricane to blow in on the heavy, humid southeast winds. The highlight of the morning was the sight of a couple of young American Goldfinches begging for food from their mother, a confirmation of the notion that this species is both local and late as a breeder.

Eric Salzman