The spreadsheet at the first link below lists each year’s early and late dates for all 107 (108?) butterfly species we have found so far in South Jersey, 2008-202o. The column for First Dates 2021 shows the species as they appear this year.
The extreme dates are in color:
Green = earliest date we have recorded so far.
Orange = latest date we have recorded so far.
When dates are duplicated year to year (= a tie), both dates are highlighted.
Blue = first reports of a species that are problematic. (See “A Problem With January Reports” below).
Six “nitty-gritty” notes for especially-interested readers:
1. Updating as the current year progresses.
Our two log moderators try to update the spreadsheet as each new species emerges. Look under the first column, 2021 First, for the full list as it develops. If we miss an FOY (in other words, a new species has appeared but the spreadsheet hasn’t been updated), let one of the Jacks know. Sometimes, especially May-July, they come in bunches and make it tricky to keep up.
2. New line for “White Admirals” as of 2019.
As of December 2019, we’ve added a line on the spreadsheet to document “white admiral” reports.
The status of white admirals in NJ is confusing, to say the least. Although white-admiral-type individuals seen in North Jersey are sometimes considered representatives of the northerly sub-species of the Limenitis arthemis complex or hybrids of the two sub-species (white admiral x red-spotted purple), neither of those descriptions likely fits those we see in South Jersey. We are simply too far away from the southernmost populations of true white-admirals (southern New York).
The more likely explanation seems to be that oddly-marked/white-banded individuals seen here are showing “atavistic” (ancestral) traits. Genetic studies indicate that red-spotted purples descended from white admirals, apparently as the ancestral population moved into areas occupied by pipevine swallowtails and developed Batesian mimicry. (Red-spotted purples are protected from predators by their mimicry of the colors and patterns of poisonous pipevine swallowtails that birds avoid.) The ancestral genes for white wing bands and other patterns can show occasionally on red-spotted purples whose parents lived nowhere near true white-admirals. See the log post linked below for some of the details.
Over the years our observers in South Jersey have photo’d several Limentis individuals that showed markings (especially extra white) that do not match textbook red-spotted purples. The most striking “white admiral” photographs we have in our records are those taken by Kerri Sellers of an eye-catching white-banded individual at Rancocas Nature Center in Burlington County on 8-2-12 (see the blog post above), and the white-banded individual photographed by Sue Canale at Winslow WMA in Camden County on 9-4-2019 (post link below).
We have decided to add a line to our spreadsheet compilation to give a place to compile and document future photographs and reports of similarly marked individuals. (There is already a box available on the log checklist.) We ask observers to photo any of such individuals if at all possible. Following Gochfeld and Burger, and Cech and Tudor (and other experts), however, we are calling these a “form” of red-spotted purple, not a full species or sub-species, and we are using quotations and brackets on the spreadsheet to indicate that. We welcome comments on this decision.
3. Southern Broken-Dash, Our Potential “108th” species.
We have one “hypothetical” or “pending species” since 2016: southern broken-dash (Wallengrenia otho) was added as a hypothetical species (in italics), based on a photograph from Forsythe NWR, ATL, on 7-26-16 (and a couple of other suggestive photos from CMY). A similar individual was found in 2017. Whether southern broken-dash can be positively identified w/o a specimen is a matter of debate among experts. No potential SBDs were reported in 2018 or 2019 and so the situation remains uncertain. Is the species wandering northward into NJ at least in small numbers or were those photo’d in 2016 and 2017 flukish strays (or possibly simply oddly-marked NBDs)?
If we can collect other photographs and records of southern broken-dash over the next several years, we might be able to claim that the northward expansion of this species into southern NJ has become obvious — even without collected specimens.
4. Our 107th Species: Great Purple Hairstreak
The newest certain addition to our all-time log list was added in 2017: great purple hairstreak (Atlides balesus), found and photo’d by Beth Polvino in her garden in June that year:
5. A Problem With January Reports
January sightings can be awkward to handle on our spreadsheet — with December 31 and January 1 artificially separating “last” and “first” butterflies reported. During warm winters late-flying individuals of some species can live past the New Year. Orange sulphurs are perhaps the most difficult to assess. We could find an orange sulphur on December 31 somewhere and consider it tying our latest-ever record, and find the same individual the next day and record it as the earliest-ever. That is somewhat misleading. The species usually does not eclose until late March or April in our area. However, according to Art Shapiro (fide Gochfeld and Burger), they occasionally emerge in mid-winter when temperatures are 60+ degrees.
Monarchs also sometimes survive until January — but these individuals are flying too late to reach Mexico and are almost certainly doomed to expire before spring. Calling a monarch seen in January our first of year is clearly misleading, so these are not colored green.
On the other hand, some species frequently over-winter as adults (mourning cloak is the best example, but red admiral, American lady, common buckeye, American snout and one or two others perhaps also live through the winter as adults.) The emergence of these over-winterers in January seems a different kind of phenomenon than the late-flying sulphur or monarch. They are not necessarily on their last legs — and could very well return to their hiding places (or find new ones) and survive to spring and breed then. These are colored green.
6. The December 2015 and January 2016 Blueberry Azures:
Even more problematic for our chart are the blueberry azures that emerged in CMY in December 2015 and January 2016. These were all fresh individuals, apparently very recently-emerged. According to David Wright, this species had never been recorded in NJ in either month. One could argue that those December individuals breaking diapause in mid-winter are new early records for our log. In other words, butterflies of 2015 should be considered the first of 2016. That is awkward, however. Also, they were almost certainly doomed, as were those azures that apparently emerged in early January 2016. It is almost certain that all expired as more normal winter weather set in during mid-January.
Since the January individuals emerged in 2016, I have decided to call them earliest-ever, following the weak logic that they did emerge in the calendar year.
Anyone with a better way to handle this freakish phenomenon (or any other suggestions for management of this spreadsheet) is invited to write to me or to Jack Miller.
South Jersey Butterfly Project, 2008-2021