Orange Sulphur
Back in March, when my law firm’s downtown office shut down and I began working from home as a result of the Covid-19 pandemic, I had expected some semblance of normal life to return by the fall. I had guessed that by September the office would be open again, and that once again I would lose two hours of my day to the daily commute. I was wrong, however, and Covid-19 cases are climbing once again in an indisputable second wave. My law firm is still not fully open yet; however, I’m back at work downtown providing administrative support for a lengthy civil trial. The trial is taking place over Zoom, with the judge, court staff, court reporter, both sets of counsel, both sets of experts, and all parties to the lawsuit participating via videoconference. Once again I’m a slave to the city’s public transportation schedule, and while I’m really happy that both the bus and LRT are virtually empty, I’m not thrilled to lose those precious two hours and almost all of my weekday birding time as a result. I am really hoping that when life does return to normal one day, full-time attendance in the office won’t be mandatory and that I will still be able to enjoy at least a couple days a week working from home and getting out for birding walks in the morning and butterfly walks at lunch.
The one good thing about my temporary return to the office is that I’ve been able to get out to Hurdman at lunch again. I’ve missed my frequent walks here; I’ve missed looking for spring migrants in the woods, summer breeding birds in the fields and on the river, and unique odonates such as Rainbow Bluets and Cherry-faced Meadowhawks in season. On September 1st I brought my camera to work and headed out at lunch to see if I could find some warblers. Although there should have been plenty of fall migrants around, I was surprised at how quiet it was. Perhaps the weather was too warm, and the migrants up north were waiting for a cold front to push them into flying south. However, when I got to the field on the north side of the new LRT station, I realized I was looking for the wrong kind of wildlife: I should have been looking for bugs, not birds! The field was full of wildflowers, and at first it was the swarm of dragonflies that caught my attention – several Common Green Darners and Wandering Gliders were buzzing through the air above the field! My focus was fixed on the Wandering Gliders as I left the bike path to cut through the knee-high vegetation, hoping to see one of them land or perhaps startle one up out of the vegetation. When I was unable to find a cooperative glider I started looking at the butterflies instead. There were a few Monarchs, and a good many Cabbage Whites and Clouded Sulphurs, our standard butterfly species this time of year.
Clouded Sulphur
Then I saw a sulphur zip by, and its wings appeared orange in flight – not yellow! While the Clouded Sulphur is the expected sulphur species in our area, and is abundant in open fields, pastures, parks and along roadsides, the Orange Sulphur is a migrant, breeding further south in Ontario and flying north in optimal conditions. I have only had one potential sighting in Ottawa, which remains in dispute on iNaturalist, but have seen enough at Presqu’ile to immediately recognize the hurried flight style and brilliant orange of its wings. Fortunately it landed, and I was able to get some photos of this uncommon butterfly.
Orange Sulphur
I wasn’t able to get a photo of the distinctive orange upper wings; this is extremely difficult to do as sulphurs habitually perch with their wings closed. Occasionally it is possible to get a photo of the top side while the butterfly is just taking off from its perch, or slowly opening and closing its wings as it feeds. From the underside, the only real distinguishing feature is a faint blush of orange on the forewing between the single black ring and the edge of the hindwing. This orange spot is usually darker in colour, and may only be a slightly deeper golden-yellow than the surrounding yellow. It is usually more obvious in photos where the sun is behind the butterfly, shining through the wings. This area in Clouded Sulphurs, in contrast, is usually a paler or whiter shade of yellow than the surrounding yellow (see photo above).
While the upper sides of the wings are seldom seen, both sexes have a thick black border along the outer edges that faintly show through the underside. However, the border is solid black in the male Orange Sulphurs, while in females the black border has several yellow spots contained within it. This is true of Clouded Sulphurs as well. And similar to the Clouded Sulphur, the Orange Sulphur has a faint row of small black marginal spots on the underside and a central pink ring with a silver center on the hindwing which is variable: while most individuals show two rings, others – such as this one – show a single ring. While the underside of the wings in both species is yellow – ranging from nearly white to golden yellow – some females are entirely white instead, and white form Orange Sulphurs cannot be distinguished from white form Clouded Sulphurs in the field.
Orange Sulphur
I had a lot of fun photographing the Orange Sulphur, and was thrilled when I saw a second one in the same field. It was amazing being surrounded by so many butterflies (there were at least 10 Cabbage Whites, 10 Clouded Sulphurs, and three Monarchs all in the same area) and I was reluctant to go back to work. However, I returned again two days later on another hot day. This time I proceeded straight to the butterfly meadow, where the same Wandering Gliders and Common Green Darners were still patrolling over the field. It took a bit of walking, but I found two Orange Sulphurs again. I lost one right away as it flew south over the bus lanes toward the large hill (I wondered if any more butterflies were feeding there but didn’t have time to check). The other remained in the same field, and I spent some time following it around and photographing it. I speculated whether it was the same individual I had photographed two days earlier, as it only shows a single pink ring on the hindwing. It would have been nice to get photos of both individuals.
Orange Sulphur
It is believed that the Orange Sulphur is not hardy enough to tolerate our winters. As such, the first individuals appearing in southern Ontario in April or May are likely migrants that hatched further south. These migrants will lay their eggs here, and the second generation can travel as far north as James Bay. They do not migrate south again, but instead will perish close to where they hatched.
Orange Sulphur
I spent too much of my lunch hour following the Orange Sulphur to get any equally nice photos of the Clouded Sulphur. However, I was able to remedy that today with a trip to Mud Lake. While I had gone primarily to look for birds, it was after noon by the time I left, and I spent some time in the open sumac field on the west side of the conservation area looking at the butterflies. I found one cooperative individual nectaring on some blue Veronica flowers. Note the double pink ring on the hindwing as well as the paler yellow colour of the forewing.
Clouded Sulphur
Although it says in my field guide that Clouded Sulphurs “frequently nectar on flowers”, it seems I only see them doing this late in the summer – they fly throughout the spring and summer, but earlier in the season I mainly see them perching in grassy vegetation close to the ground (which is hardly photogenic)! However, in the fall once the asters, Veronica, and other late-blooming flowers begin to blossom, I start seeing them on flowers more frequently.
While I was watching the sulphur, a white butterfly flew in and the sulphur gave chase. I assumed that the white butterfly was a garden-variety Cabbage White, but when it landed I was surprised to see that it had the markings of a Clouded Sulphur instead. I edged closer to it to get some photos – this is the first time I had seen a white form Clouded Sulphur, and I was keen to add a couple of photos to my records!
White form Clouded Sulphur
Although the hindwing was a very pale shade of lemon yellow, the forewing was white. It looked completely white in flight as well. Only the females have a white form, and, indeed, you can see that the black border showing through the wings has the pale spots contained within it. These white forms, referred to as “Alba”, make up between 5 and 30% of the female population. This is a significantly large proportion, and because females with orange or yellow wings are preferred by males, the Alba females should be at a disadvantage from a breeding perspective and eventually die out. However, genetic work shows that the wing colour is just one facet of the differences between normal and Alba females; they also demonstrate unique reproductive strategies. It is currently theorized that the biological resources needed for pigment synthesis are used for other developmental processes within the developing pupa instead.
White form Clouded Sulphur
Because the sulphurs are so common and fly throughout the full summer season, I generally don’t pay a lot of attention to them; however, seeing two different species and two different forms of the Clouded Sulphur in the past two weeks has given me a deeper appreciation of these common and widespread butterflies. They are at their peak numbers in late August and September, so I’ll definitely be spending more time watching them when I visit appropriate habitats!
The Pathless Wood 