There are several species of butterfly that emerge in late April to early May. This year, spring was very slow to appear, so my records seem to run a little late. One of the first butterflies to appear in the mountains is the tiny Brown Elfin. My earliest siting date is 23 March (2012). This year’s first Brown Elfin siting was 20 April, a single individual on a warm day followed by considerable cool and wet weather. I did not see them again until 1 May.
Brown Elfins like to perch on Mountain Laurel leaves.
Brown Elfin caterpillars feed on a variety of heaths. I have never seen a caterpillar.1 I find the adults in and around blueberry patches, and they seem to like to perch on Mountain Laurel leaves. Around here, they are a ridge-top species. I have never found them on low ground.
In the right place, at the right time, Brown Elfins are fairly easy to find.
Right place and right time seems to be a characteristic of Elfins.
The genus Callophrys includes all five of Pennsylvania’s native Elfins and one species of “Hairstreak.”2 All five Elfins are univoltine.3 Flight periods are relatively short, 2-3 weeks, so if you want to find one, the first thing to know is when to look.
Where to look has to do with host plants, what the Elfins eat. As noted above, Brown Elfin caterpillars feed on a variety of heaths. Pine Elfin caterpillars–as you might expect–feed on various pines, and that is where I find the adults.
Pine Elfin; this is a very fresh specimen. The purplish sheen will fade.
Perhaps our most uncommon Elfin is the Frosted Elfin.
Frosted Elfin on Wild Indigo, from Centre Co. PA. That black dot on the hind wing is diagnostic.
Frosted Elfins are particularly finicky. Their caterpillars only feed on larger, coarser members of the Pea family. The only place I know to find them is on a stand of Wild Indigo up in Centre County.
They also like Lupines; I regularly check our two local Lupine patches–so far, no joy.
Wild Lupine, Perry Co. PA
Here in the mountains, the caterpillars of Henry’s Elfin feed only on Redbud.4
Henry’s Elfin was the original quest bug that I posted about, and I finally caught up with one last May.
Henry’s Elfin, 11:21 AM. Note the three white marks on the wings.
Sometimes it is not enough to know the right time of the year; you also have to know the right time of day. Henry’s Elfin tends to stay in the treetops. It only descends to nectar in the morning until about 11 and in the afternoon between 3 and 4. Apparently the best way to look for the adults is to walk about with a long stick, whacking the tops of the Redbuds to see if you can make them fly!
Henry’s Elfin under the Redbuds and Juniper Hairstreaks on the Junipers. Right time and place: May 2013.
The fifth Pennsylvania native Elfin is the Hoary Elfin. Sadly, the Hoary Elfin has been extirpated in Pennsylvania.5 I don’t have a picture of a Hoary Elfin, but if you go to the Butterflies and Moths of North America page, there are a number of good images.
The caterpillar of Hoary Elfins feed on Kinnikinnick, or Bearberry. Kinnikinnick is also extirpated in Pennsylvania. According to the folks at PAFlora, “bearberry…has been lost from the state due to excessive deer browsing.”6
Hoary Elfins have also been reported to eat Trailing Arbutus, which is plentiful in the mountains. I keep an eye on the big patches–quixotic perhaps, but hope springs, and all that. Besides, I have always wanted an excuse to post this picture.
A large patch of Trailing Arbutus. It is uncommon to find this much pink hereabouts.
Finally, about that hairstreak: the Juniper Hairstreak hangs around Juniper (Eastern Red Cedar). Unlike the rest, they have two flights a year, the first in spring, the second in late summer.7 For a great article, go here.8
Juniper Hairstreak on Juniper–where it belongs.
- I’ve never seen a caterpillar of any Elfin, for that matter. [↩]
- Hairstreaks are in quotes here because it includes members of several different genera, such as Satyrium and Strymon. [↩]
- Univoltine is a fancy word that means there is only one generation of adult per year, hence “one flight.” [↩]
- They are reported elsewhere to feed on the flowers of Wild Cherry [↩]
- Extirpated is a lot like extinct, but only within a given locality. Technically, when something is extinct, it is extinct everywhere. Hoary Elfins still may be found outside of Pennsylvania. [↩]
- “Deer eating the future of Pennsylvania’s Forests!,” PAFlora, last modified 12 November 2000, accessed 4 May 2014. [↩]
- South of here, they have three broods. [↩]
- Well, it’s not a BAD article. [↩]
Amazing pictures, John.