July 12: Fooled for the last time

I learned again today that tired, sweaty, excitement can lead to blind repetition of past follies…

It was a very hot day at GBH, but a great one for butterfly watching. I saw a Spicebush Swallowtail (Papilio troilus), Black Swallowtails (Papilio polynexes), Tiger Swallowtails (Papilio glaucus), Fritillaries (Speyeria sp.), American Painted Ladies (Vanessa virginiensis), Coppers (Lycaena phlaeas), Sulphurs (Colias sp.),  and tons of skippers including Little Glassywings (Pompeius verna). As for hairstreaks I saw plenty Edwards’ (Satyrium edwardsii) and Banded (Satyrium calanus) many of which were tattered survivors. I also saw my first Coral Hairstreak (Satyrium titus) of the year.

Coral Hairstreak (Satyrium titus).

My moment of error came when I saw two dazzling and immaculate hairstreaks that were nectaring at common milkweed (Asclepias syriaca) on the slope. I watched them for at least 30 minutes as they flitted about the flowers and daintily drew in nectar with their proboscises. Any other day, I would have recognized the pale gray-blue background color to the wings and the orange tinge on the internal edge of the post-medial line. But today, I was exhausted from the heat and in high hopes of seeing another Oak Hairstreak. These two were mesmerizingly pristine and since I had just seen an Oak in the same area earlier this week, it was hard not to let my anticipation and desire get the best of me. I even went to the extent of posting the sightings on the MassLep listserv. Sorry about that! In reality these were of course Gray Hairstreaks (Strymon melinus) – distracting yet gorgeous misidentifications.

I did experience something worse than a misidentification today though. When I reached the summit and made my way to thistle patch which I have spent much time rescuing from the strangling grip of Black Swallow-wort (Cynanchum louiseae), I met a devastating and rather depressing sight. The entire patch had been mowed completely. Not a single flower left! This is a shame because the flowers were in bloom and I did not yet observe many hairstreaks nectaring at them. Members of the Massachusetts Butterfly Club have repeatedly told me that the thistle is one of the most reliable spots to observe many butterflies, including Oak Hairstreaks, so this is a major loss for avid butterfly watchers in the area.

The thistle patch where so many butterfly watchers enjoy observing hairstreaks has sadly been mowed.

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July 9: Monarchs and Thistle

I saw a surprisingly paltry number of hairstreaks today, but I did come across 3 healthy Monarch caterpillars (Danaus plexippus). They were all chomping away at common milkweed (Asclepias syriaca) and 2 were very easy to locate based on their conspicuous feeding damage. There aren’t too many insects that eat the latex-leaking leaves of milkweed, so when you come across plant with half-consumed leaves it’s a strong indication that a Monarch may be present.

Characteristically conspicuous Monarch feeding damage on common milkweed (Asclepias syriaca).

Characteristically conspicuous Monarch feeding damage on common milkweed (Asclepias syriaca).

After seeing the relentless spread of invasive Black Swallow-wort (Cynanchum louiseae) at GBH, I was delighted and relieved to see these caterpillars. Along the slope where I found them, many milkweeds are being strangled by the invasive plant making the chances for Monarch survival look grim. The thistle patch near the observatory has also been devastatingly invaded and entwined. I have devoted a few solid hours during recent visits to untying and uprooting the swallow-wort from this productive butterfly nectar source. The thistle flowers are in  bloom now and I hope my efforts to unencumber them pay off. I did not see any hairstreaks there today.

Common Milkweed (Asclepias syriaca) being choked by Black Swallow-wort (Cynanchum louiseae).

The thistle patch as it looked on June 27 – completely overrun by Black Swallow-wort.

The thistle patch now – in bloom and cleared of much of the invasive strangler.

July 7: A risky visit pays off

With the promise of a storm in the forecast, I made my way up GBH around 6:30PM. I figured if I could check the various nectar sources along the slope before it started to rain, then the day would not be lost. Near the top of the hill, my eyes fell upon a tattered little hairstreak nectaring at common milkweed (Asclepias syriaca). The wing patterns were dull and it was missing its tails and a decent chunk of its hindwings. From the angle I first saw it, I could barely guess the species. Then it turned around…

It was small, it was worn, it was bitten, but it was an Oak Hairstreak (Satyrium favonius ontario). I could still tell from the shape of the ‘W’ mark. This one must have been on the wing for a while and I presume damage is the result of predation. Despite its condition it was still an agile flier and I followed it from plant to plant for 15 minutes or so. I only observed it nectar from milkweed and it stayed on each plant for less than 20 seconds. A light rain began to fall and it was either the weather or my camera that finally drove the hairstreak away. Like the other Oak Hairstreak I had observed on the hill, it took off toward the high canopy of the nearby trees. The directed retreat suggests to me again that the tree tops are a safety zone for this butterfly species where most of its adult life takes place.

As I retreated down the hill to the parking lot, nature seemed to smile upon my encounter with a rainbow set over Great Blue Hill.

 

July 5: Survivors

I’m starting to see more damaged individuals like the Banded Hairstreak (Satyrium calanus) pictured below. Hairstreak hind wings are pretty things, but their purpose is to distract predators, not dazzle observers. If you’re out to photograph butterflies and you come across a tattered and worn individual with a good chunk of wing missing, don’t disparage it for its loss of beauty. These are the clever survivors that should be held in high regard for outwitting the cruel forces of nature.

July 2: High-perching and finger-licking hairstreaks

I started my day in the hairstreak hotspot adjacent the chairlift, wading through scrub oak sending Satyrium butterflies flying. As usual, these were nearly all Edwards’ with the odd Banded now and then. The white oak I had climbed last visit looked inviting once again, and I wondered if I might be able to tap it if I could find a stick long enough. After searching in vain, I decided to just toss a small stick up at the high branches and the result was excitingly surprising. Although my eyes were a good 60ft from the top of the tree, the instant the stick made contact, I saw a small dark spot zip off the leaves, whiz around in the air and land again. I couldn’t see close enough with binoculars, but to my amazement, when I zoomed in with my camera and slowly searched the unsteady leaves, I spotted a hairstreak! I took dozens of pictures adjusting every parameter of the camera’s set up to gain any clarity I could. The distance required full digital zoom to spot the butterfly at all and that resulted in a loss of fine resolution. I was amazed that the hairstreak remained on the same leaf as the breeze whipped it around every minute or so. After tireless photography from every angle I could manage, my best images verify it as being a Satyrium hairstreak but the species identity is inconclusive. Based on the amount of orange that shows up in the picture, I think it is most likely a Banded Hairstreak (Satyrium calanus) which is not surprising because I have see this species retreat to high branches. This oak tree was directly adjacent the patch of scrub oak that teems with Edwards’ and Banded hairstreaks, so it is likely one may have flew up to this higher perch. If the individuals I observed from the bucket truck were indeed Oak Hairstreaks, then I imagine they would be more active further inward and even above the oak canopy.

 

A zoomed in view of the hairstreak in the image above. The visible pattern suggests Banded Hairstreak (Satyrium calanus).

I continued to walk the trails tapping oaks and found a number of hairstreaks near Eliot tower. One Banded hairstreak was particularly friendly. When I offered my sweaty finger, it climbed aboard and unhesitatingly began to lick up the salty offering. Sodium is an important yet limited resource for butterflies in the wild and males especially will sieze any opportunity to collect it from a number of unattractive sources. The behavior is generally called ‘puddling’ because butterflies can often be seen at puddles of water (or urine…or piles of excrement) drinking in the sodium and amino acid-rich fluid. A sweaty finger proves another good candidate.

June 30: Back up in the trees

Today was a usual day full of hairstreaks on oak. I saw my first Striped Hairstreak (Satyrium liparops) of the season, but failed to get a decent photograph. Edwards’ Hairstreaks (Satyrium edwardsii) continue to be in abundance and I suspect that the ones encumbered with swollen abdomens are females bursting with eggs. The bloated bodies of some made me question how they could fly at all!

A male Edwards’ Hairstreak (Satyrium edwardsii). Note the conspicuous bulge of scent scales on the forewing.

A hefty female. Note the swollen abdomen.

I admit that I already miss the bucket truck and the fantastic vantage point it allowed. In an attempt to return to the canopy, I found a climbable white oak near the ski lift and made my way up it. Although I got to the top, it still wasn’t high enough to look out over enough of the upper sunlit leaves in search of perching butterflies. I remained motionless and hyper observant for a time, but nothing came of it.

June 27: Up in the treetops

The hypothesis I am working to substantiate through this study is that Oak Hairstreaks appear more rare than they actually are due to their elusive canopy-dwelling habits. From my encounters with the species so far, I find this theory to be believable – larvae have been relatively common and the adults that I have seen were quick to dash away into the treetops. Most of the Satyrium favonius ontario observations at Great Blue Hill that I am aware of have been made only where they can be – at flowers when the butterflies descend from their oak perches to nectar. To test the theory that this species spends most of its time out-of-sight of most butterfly watchers requires a heightened vantage point. Today, we brought in the necessary equipment to achieve this – a bucket truck!

An early morning Banded Hairstreak (Satyrium calanus) on a dewy grass blade.

Fueled by a boyish excitement to operate heavy machinery, I arrived very early. As I waited for the bucket truck I searched around the dew-covered flowers and oak branches for butterflies. As things started to dry in the morning sun, I saw a couple Bandeds and one Edwards’ hairstreak. I also came face to face with an animal I’ve never seen before. As I was photographing a butterfly, I heard the grass rustle nearby. I turned to see the vegetation jostle as something covertly approached. The movement of the grass stopped suddenly, and a little furry head popped up out of the undergrowth. It was a weasel of some sort, either an Ermine (Mustela erminea) or a Least Weasel (Mustela nivalis), and it seemed confused to have encountered me. I snapped one good photograph before it turned to take refuge in a derelict pipe behind the utility building.

A weasel (Mustela sp.) who was perplexed to encounter a human on its morning stroll.

The bucket truck arrived around 9AM and after a bit of safety training, I was up above the treetops overlooking all of Great Blue Hill and much of Norfolk County. For the sake of space, logistics, and courtesy to trail users, the truck was parked in the gravel lot across the access road from the observatory. This also allowed me to overlook an area where I had collected at least one Oak Hairstreak prepupa. From the bucket I could clearly see how much Red Oak (Quercus rubra) dominates the landscape. I was armed with my camera, a good pair of binoculars and my field notebook and I was hell-bent on seeing Oak Hairstreaks flitting about the canopy. What I didn’t plan for was the wind…

Billy the bucket truck driver. We positioned over the most accessible area of trees where I haven collected Oak Hairstreak prepupae.

 

It was a clear day and I had a good view of Boston off in the distance. I was probably the highest point in Norfolk County for an hour.

You don’t usually see the trees like from this vantage point. This was likely from the highest position of the bucket.

Although it was a mild sunny day below the trees, once I rose above them, the wind became problematic. It was very difficult to focus on any patch of leaves with the binoculars or camera before the breeze violently whipped them about. I was able to focus on a few bees that landed on leaves within 15ft of the bucket, but more distant trees were impossible to zoom in on for more than a few seconds.

 

The effort was not in vain though! Along with a few high-flying Tiger Swallowtail (Papilio glaucus) and Pine Warbler (Setophaga pinus) sightings, I did see hairstreaks. My most promising observation was of two hairstreaks flitting about the top of a pine tree that was higher than the surrounding oaks. They did not seem to be fighting and continued to land in close proximity to each other. Because of the tree they were on I initially thought they were Pine Elfins (Callophrys niphon), but I later realized it is very late in their flight period (mainly mid-April to early June). These may have been two Oak Hairstreaks mating in the high canopy, but I can’t say for certain since they were too far away to identify.

 

Kevin positioning himself over the oaks.

I stayed up in the bucket for about an hour before switching out with a fellow lab mate, Kevin, who came up today to assist. He also saw a couple hairstreaks in the canopy, but the wind and the distance did not allow for species IDs. The two of us enjoyed our rare view of GBH, but we did not collect any verifiable evidence of Oak Hairstreaks on the turbulent treetops. Even though today was not exceptionally windy and our binoculars are not too shabby, the bucket truck observation method may prove more fruitful on a calmer day with more powerful equipment.

A Pine Warbler (Setophaga pinus) singing merrily from its perch far above the ground. I’ve never got a better look at one of these.

June 25: The Oak Hairstreak I didn’t even know I saw

Here it is! The beautiful Oak Hairstreak (Satyrium favonius ontario) that I only realized I was observing when I reviewed the video later in the day. Last summer, I was easily tricked into falsely identifying Gray Hairstreaks (Styrmon melinus) as Oaks, but now the distinction is clear and I have a strong serach image for the field. Oak Hairstreaks have a light gray-brown color to the ventral wing service with thin white and black postemedial bands forming a strong, clean ‘W’ pattern near the tails. Grays are noticeably steely blue-gray often with an internal orange tinge to the postmedial band. The orange hindwing marks around the large blue spot are small and separate on Oaks whereas in Grays the orange area is more diffuse and blue spot is small.

I saw this individual before 9:30AM perched on scrub oak (Quercus ilicifolia) in close proximity to many Edwards’ and Banded hairstreaks. It walked about the leaf then settled in one spot rubbing its wings for a minute or two. When I finally proved to be too much of an annoyance, it took off from its perch up into the canopy nearby. I now know that Oak Hairstreaks will perch on scrub oak among their much more numerous congeners. Like all hairstreak butterflies, Satyrium favonius ontario adults rub their colorful, tailed hindwings when threatened to produce a distracting ‘false head’ display. Owing to the rarity of this encounter on scrub oak and the distant retreat of this individual, I find the theory that these butterflies normally perch high in the canopy on their host white oaks more convincing.

June 25: An exceptional day, at second glance…

Like magic, my interactions with hairstreaks on Great Blue Hill were exponentially more numerous today. I arrived quite early (around 7:30 AM) and I saw a great abundance of Banded and Edward’s Hairstreaks as I tapped scrub oak, especially the plants around the chairlift at the summit of the hill. I saw at least two Edward’s Hairstreaks attending leaf buds on the oaks – an interesting phenomenon that I observed last summer (see post). I wonder if Oak Hairstreaks are equally drawn to these secret sources of sugars and nutrients.

One of the numerous Banded Hairstreaks (Satyrium calanus) I found on scrub oak (Quercus ilicifolia) today.

As the morning went on, the hairstreaks became all too easy to locate. It seems as though there was a mass emergence over night and now the scrub oak is laden with adults manning their perches. I easily observed at least 10-15 Edward’s and slightly fewer Banded Hairstreaks in the same areas that I have been searching for the past few days. Perhaps this drastic change in numbers has more to do with the time of day that I came to the hill this morning. I do my best to stagger the timing of my visits to eliminate any diel bias to my observations, and today was one of my earlier arrival times.

An Edwards’ Hairstreak (Satyrium edwardsii) licking up the sugary secretions oozing from an infected oak bud.

When searching for hairstreaks, I am quite diligent in tracking down every individual I scare up in order to make a positive identification and then record any unique attributes or behaviors. It is a demanding task and although a few do fly out of sight, I am able to follow most that I encounter. After a seemingly endless procession of non-Oak hairstreaks on scrub oak, I decided to move on to another location, but first I wanted to capture a video of one of the many S. edwardsii rubbing its hindwings together. I made a conscious switch out of ‘identification mode’ and completely changed my focus to capturing the behavior, which was easily done.

When I watched the video later that day, I was flabbergasted when I realized what I had captured…. My first adult Oak Hairstreak (Satyrium favonius ontario) in the wild! I was so intent on video-recording the anti-predator behavior of what I comfortably assumed would be yet another Edward’s Hairstreak, that I didn’t even stop to make an ID and take pictures. Luckily, I was able to extract stills from the video. The video will follow in the next post.

My first adult Oak Hairstreak (Satyrium favonius ontario) that I unknowingly observed in the wild.

 

June 24: Oak Hairstreak release and other Satyrium at last

I transported my precious hairstreak cargo from Storrs, CT to Canton, MA in a chilled lunchbox this morning. My plan was to gently deposit the butterflies on flowers and get a few good photographs in the field, but that was wishful thinking. Although they did nectar for a minute on the milkweed that was in bloom at the base of the hill, it was hardly enough time for me to get a single focused shot. Interestingly, they both flew straight up into the high canopy from the flowers I placed them on. Their flight (though basically like most erratic, whirling hairstreaks) seemed strong, fast, and directed over all. The immediate, instinctive dash for the high treetops seems to suggest that this species maintains elusive dial habits.

A successfully reared adult Oak Hairstreak (Satyrium favonius ontario) being returned to its natural habitat.

After many hours of patient and diligent searching for hairstreak butterflies in the field over the past few days, I was finally able to heave a sigh of relieve today when I found an Edward’s (Satyrium edwardsii) among the scrub oak. I am surprised that my usual search techniques did not turn up any adults earlier. Based on the number of emergences in the lab from wild-caught larvae, I know there must be more of the butterflies on the wing now.

Edward’s Hairstreak (Satyrium edwardsii).