ABOUT BOM      SPECIES LIST      BUTTERFLY HISTORY      PIONEER LEPIDOPTERISTS      METHODS

The Butterflies of Massachusetts

  27  Henry’s Elfin   Callophrys henrici (Grote and Robinson, 1867)

Charming and adaptable, Henry's Elfin uses a variety of habitats, and different host plants in different geographical areas. It has even added alien buckthorns (Rhamnus spp.) to its diet, a change which has allowed it to increase its numbers in New England. Henry’s Elfin has a wide range in eastern North America, from southern Canada to Texas and Mexico (Kirk 2003).

Henry’s Elfin was routinely confused with Frosted Elfin and Hoary Elfin by early lepidopterists. Scudder, along with others in the nineteenth century such as Godart, described something called Incisalia irus, which could have included any of the three elfins mentioned, not just Frosted.  Recently, much of Scudder’s description of irus has been determined to be a description of Henry’s Elfin rather than Frosted Elfin.

Photo: Chelmsford, Mass. Concord Road power line, T. Whelan,  April 2004

The original descriptions of the larva and pupa of “C. irus” are found in Boisduval and Le Conte (1829 [1837]), but they are from John Abbot’s notes and figures, which Calhoun has shown are actually of C. henrici (Calhoun 2004).  Descriptions of the second, third, and fourth-instar larva, pupa, larval hosts, and feeding habits of “C. irus” in Scudder (1889) are taken from W. H. Edwards’ notes on C. henrici, and the larva and pupa figured in Scudder are reproduced from Abbot’s drawings of C. henrici in Boisduval & Le Conte (Calhoun 2004; Albanese et al, 2007b).

As a result of this early confusion, we know hardly anything about the abundance or distribution of Henry’s (or Frosted or Hoary) in Massachusetts at the turn of the century, except that all three species were thought of as rare.  But through retroactive museum determinations, we can be reasonably certain that there were at least two pre-1900 locations for Henry’s Elfin in the state: Waltham and Wollaston. (Frosted and Hoary Elfins were also found in Waltham prior to 1900.)  There are at least ten 1897 specimens in the MCZ and the AMNH, taken in April and May in Waltham by C. Bullard.  There are also specimens in the MCZ retroactively labeled Henry’s collected in Wollaston (now in Quincy) in 1878 and 1897 by F. H. Sprague.

Museum specimens also indicate that there were a few locations for Henry’s Elfin in eastern Massachusetts between 1900 and 1950, and then a great increase in reports and locations beginning in the 1960’s.  We have examined a large dataset of Massachusetts elfin specimens from most major museums, including the Museum of Comparative Zoology (MCZ) at Harvard, the American Museum of Natural History (AMNH), the Smithsonian, the McGuire Center at University of Florida, Yale Peabody, Boston University (BU), Cornell University, and the University of New Hampshire (UNH). Also included are all Lepidopterists’ Society Season Summary and Correspondence (LSSSC) reports, supplied courtesy of Mark Mello.  These data were compiled in 2010 by a lycaenid and climate change working group at Boston University led by Dr. Richard Primack, and were kindly made available by him.

For eastern Massachusetts there are retroactively-identified 1900-1950 specimens from Wayland (1920, 1921, C. J. Paine Collection), and Sudbury (1926, C. J. Paine Collection) in the Harvard MCZ. There is a specimen from Concord (1914, W. Reiff) in the Smithsonian.  There are many specimens from Fall River in the 1930s and 1940s:  (1930-1935, W. P. Rogers, AMNH; 1943, 1944, 1946, D. J. Lennox, UNH; 1948, W. P. Rogers, Yale).  The number of locations is smaller than the number of locations for Frosted Elfin or even Hoary Elfin for this time period.

There are no reports from Cape Cod or the Islands, as there were for the other two elfin species. Jones and Kimball (1943) do not record Henry's Elfin as present on Martha's Vineyard or Nantucket, and it is still not found there today.  The first report for Cape Cod appears to be a 1952 specimen from Barnstable (C. P. Kimball collection) in the Harvard MCZ.

Reports and specimens of Henry’s Elfin expand dramatically in the mid-1960’s, possibly reflecting the adoption of buckthorns as host plants.  In May 1964 J. D. Turner captured a specimen in Sherborn, which is now in the McGuire Center in Florida.  In May 1965 Charles G. Oliver took a female specimen in North Acton on May 6, which he thought [erroneously] “may be a new record for Middlesex County, Massachusetts.”  That specimen is now in the Yale Peabody museum.  Another capture was reported June 1, 1966 in Framingham, by J. W. Cadbury and C. Curtis. The first report for Essex County, and a bona fide new record there, came in 1967, when James P. Holmes captured 2 males and a female on May 21, 1967, and another female on May 28, all in the town of Essex.  He says that these 1967 finds are his “first personal record of this scarce species.” He found another the next year, 1968 and another in 1971 (LSSSC 1965-71). Holmes had collected intensively on Cape Ann for two years prior to 1967, and not found this species.

The first report for the Connecticut River valley area comes in 1968, when a specimen, now in the MCZ, was taken on June 3 in the vicinity of Mount Tom, north of Holyoke, by John M. Burns, E. Hanson and D. Hottenstein. The species may still have been uncommon in that region, because P. Carey did not find it, despite collecting in the Springfield and Mt. Tom areas in 1972 and 1973.

The 1970’s were punctuated by more findings in eastern Massachusetts south and west of Boston.  J. Ingraham found Henry’s Elfin in Needham, Dover and Dedham(?) in 1973 (Yale, LSSSC 1973). Dave Winter found it in Needham in 1973 and Wellesley (Babson Park) in 1974 (MCZ and AMNH specimens).  And D. Willis reported Henry’s Elfin as a “new species” in the Holliston-Sherborn-Framingham area in 1974 (LSSSC 1974; location probably the Sherborn power line). After 1974, the Babson College site in Wellesley became a favorite collecting location, and there are many Wellesley specimens extant: 1976 W. Winter (LSSS); 1974, 1976, 1977, 1980, R. Robbins (Smithsonian); 1979, 1980, E. Williams (pers. coll.); 1984, R. Godefroi (McGuire).  In 1979, R. Busby reported Henry’s Elfin from Needham and North Reading (LSSSC 1979).  In 1980, C. Shiffer collected a specimen in the Blue Hills Reservation (Milton and Canton) (McGuire).

In 1985, the dramatic discovery that Henry’s Elfin had switched to introduced aggressive buckthorns was made at the Wellesley site by Dale Schweitzer (see below).  Henry’s Elfin appears to have increased in eastern Massachusetts since about 1965, probably as a result of its adoption of this widespread plant, and is so listed on Table 2. 

Host Plants and Habitat

Throughout its wide geographic range Henry’s Elfin uses a number of different host plants, but usually only one or two in any given area. On the mid-Atlantic east coast the two main hosts are Redbud (Cercis canadensis) and American Holly (Ilex opaca). The redbud-feeding populations are mainly in rich forested areas inland and in the Appalachians, while the holly-feeding populations are along the coastal plain, especially New Jersey north to Rhode Island. But Massachusetts is north of redbud’s historic range, and American Holly is found here mostly on Cape Cod and the Islands.

The original native host plant here may not have been American Holly but the closely related Nemopanthus mucronata, or Common Mountain-holly (Schweitzer, Lep.Soc.Seas.Sum. 1985; Kirk 2003).  This species is used as a host plant in New Brunswick, and was abundant near the site where Henry’s was first discovered using the introduced Rhamus spp. On the other hand, the original native host might have been blueberry (Vaccinium) and huckleberry (Gaylussaca) species, which are also common hosts in Canada (Kirk 2003).  There is very little actual evidence for Massachusetts.  Scudder thought the native host plant was Vaccinium. In Rhode Island, the species probably uses American Holly, since it is usually found associated with it, but it is also found in areas without holly (Pavulaan, quoted in Kirk 2003).  Mello and Hansen thought that Henry’s Elfin might use Ilex on Cape Cod (Mello and Hansen 2004), but there is no real evidence.

Massachusetts is one of the first states where Henry’s Elfin was shown to have switched to exotic, aggressive buckthorns, both Rhamnus frangula (=alnus) and R. cathartica, as host plants.  Today, buckthorns are probably its most common host here.  In 1985 Dale Schweitzer first reported from a site in Wellesley that females commonly sat among thickets of R. frangula, and several ovipositions were observed on the flower buds. Photos by Dave Winter of the larvae on R. frangula in Wellesley in July 1985 are in the MBC slide collection. At the same location, females did not rest on or oviposit on 3-4 abundant species of blueberry.  The larvae ate blossoms and berries of Rhamnus, even the foliage, and successfully pupated.  In another nearby area studied by Schweitzer, there was no other likely native food plant around except Nemopanthus[Ilex] mucronata, or mountain-holly, which was abundant and in Schweitzer’s view was the most plausible candidate for a native, pre-Rhamnus food plant there (News of the Lepidopterists Society, 1985; Kirk 2003; Stichter 2011).

Henry’s Elfin is one of a surprising number of butterfly species which have switched to non-native hosts during historical times, and may be the only elfin to have done so (Table 3). It uses Rhamnus both in our area and in Ontario and Nova Scotia and perhaps other areas. This switch has been coincident with an increase in the abundance of this species (Layberry et al. 1998).

Henry’s Elfin does not make as much use of open areas as do other elfins, being found usually in forests, forest edges, or tall shrub swamps where one of its host plants is present.

Relative Abundance Today

The Atlas found Henry's in only 29 of the 723 blocs searched, making it “Uncommon.” MBC reports 2000-2007 rank it similarly, at the lower end of “Uncommon” (Table 5).  It is not as frequently reported as Hoary Elfin, but Table 5 does not include the post-2007 increases in sightings. Henry’s is reported from a larger number of towns, and is more widely distributed, than Hoary (see map below).

Henry's Elfin is probably increasing in Massachusetts. There is an upward trend in MBC sightings of this species, 1992-2009 (Chart 27), which is most evident in 2008 and 2009. Until then, fluctuations every few years seemed to be the norm.

Chart 27: MBC Sightings per Total Trip Reports, 1992-2009

A similar overall finding for 1992-2009 comes from a list-length analysis of MBC data. In this study Henry's Elfin showed a statistically significant 175% increase over the period (G. Breed et al. 2012).  Further confirmation of the trend comes from descriptive statistics published  in the Massachusetts Butterflies Season Summary:  the average number of Henry’s Elfins seen on a trip in 2007 was down 60% compared to the average for preceding years back to 1994, but was up 126% in 2008, and 386% in 2009 (Nielsen 2008, 2009, 2010).

The large increase in 2009 is mainly due to one report of 25 from Fowl Meadows in Milton. While this report is probably a good estimate, it is the first report in MBC records to exceed 8 at any one site. Even excluding that report, the trend through 2009 is still upward. The years 2010, 2011 and 2012 saw continued increase in the total numbers of Henry's Elfins reported, though fuller analysis remains to be done.

State Distribution and Localities

Henry’s Elfin is found almost solely in the eastern and southeastern parts of the state, although there are very few on Cape Cod and none on the islands. Both MBC sightings (Map 27) and the 1986-90 MAS Atlas show a similar distribution picture, but MBC reports now extend the distribution into the central area of the state around Quabbin Reservoir.  It is not clear whether the butterfly’s range has expanded or whether more intensive searches are the cause. There are multiple reports from the towns of Petersham and Amherst, but other than those two locations, most of the MBC reports from west of Worcester (New Salem, Northampton, Belchertown, Springfield, and Heath), are single reports of single butterfly individuals.

Henry's Elfin has not been found 1991-2009 in the Berkshires, either north or south. (There are reportedly three specimens from the 1950's labeled Henry's Elfin, Tyringham, in the Berkshire Museum, but the August dates are not within the flight period for this species, so these cannot be accepted.) Henry's is still not credibly reported from the northern Connecticut River valley. 

Henry's Elfin still has not been reported from either Martha's Vineyard (Pelikan 2002) or Nantucket (LoPresti 2011).

The Atlas had only one report from Cape Cod, from Mashpee; MBC reports now show Falmouth (Crane WMA) and Truro (Pilgrim Heights) to be good locations for Henry’s. Mello and Hansen (2004) suggest several other possible locations, but call the species elusive. It apparently has not been found at Ashumet Holly Reservation in Falmouth, despite the presence of a possible host plant.

Map 27: MBC Sightings by Town, 1991-2009

If we compare these MBC reports to the locations known for Henry’s Elfin in the 1970s and 1980s mentioned above, a marked expansion in the geographical distribution (range) and number of towns is apparent.  Map 27 shows MBC reports from 43 towns. Compared with the other two elfin species, Henry's is found in a greater number of towns: MBC records for the same time period show Frosted Elfin from 29 towns, and Hoary Elfin from only 10 towns.  By this measure Henry's is the most abundant of the three elfins.

Productive sites for Henry’s Elfin have been

Acton Fort Pond Brook max 8 on 4/26/2008 J. Forbes; Lexington Arlington's Great Meadow max 6 on 4/29/2012 T. Whelan et al.; Harvard Oxbow NWR  max 4 on 5/3/2003 T. Murray and E. Nielsen;  Ipswich Willowdale SF max 5 on 5/11/2002  F. Goodwin; Medford Middlesex Fells max 3 on 5/7/2011, M. Arey; Milton Fowl Meadows max 25 on 4/24/2009 S. Jaffe; Newbury Old Town Hill TTOR  max 2 on 4/22/2008 S. Stichter; Newburyport Plum Island max 2 on 4/20/2004 R. Heil, and 2 on 5/15/2004 C. Kamp (MAS Atlas lists a maximum of 8 on 30 April 1994, Plum Island); Sherborn power line max 7 on 5/7/2011 B. Bowker et al., and Truro Pilgrim Heights max 5 on 5/7/2000, A. Robb.  Henry’s is also found at Crane WMA in Falmouth and Ipswich River WS Topsfield.

Broods and Flight Times

Henry’s Elfin is single-brooded throughout its wide continental range, flying for a little over a month. The onset of flight is earlier in southern regions; for a comparison of flight periods in different regions, see Kirk 2003.

In Massachusetts Henry’s flies mainly from mid-April to the end of May according to 1993-2008 MBC records (http://www.naba.org/chapters/nabambc/flight-dates-chart.asp).  There is no information from Scudder on flight dates in the 19th century due to the confusion over species identification.

Unlike Brown Elfin and Eastern Pine Elfin, Henry's Elfin does not seem to have advanced its flight time significantly during the years 1986-2009, according to a 2012 study done at Boston University using MBC and Atlas data (Polgar, Primack, et al. 2013).  But like most elfins studied, Henry's Elfin does show a statistically significant response of flight time to temperature variations in the two months prior to emergence (March, April), varying its flight time by 3.86 days for every ºC change in average spring temperature. This responsiveness to temperature is an adaptive trait.

First Sightings: In the unusually warm winter and spring of 2012, Henry's Elfin was reported on a record early date: 3/23/2012, 1, Georgetown/Boxford power line, M. Arey. The next earliest report that year is 4/13/2012, 5 at Milton Fowl Meadow, S. Jaffe, which equals the former early date listed below.

The earliest dates in the 20 years 1991 through 2010 are 13 April 2002, Plum Island, B. Walker, and 15 April 2000 Topsfield Ipswich River WS, F. Goodwin; the Atlas also reported an early date of 15 April 1986 Wilmington, S. Goldstein.  In 9 of these 20 years (1991-2010), the first butterflies were reported on the 20-24 of April.  Henry’s, Hoary and Frosted Elfins generally appear about the same time, with Frosted peaking a little later than the other two.

Last Sightings:  The latest flight dates in the 1991-2010 records are Falmouth, Crane WMA 8 June 1997, J. Sones; Falmouth Crane WMA 6 June 1999 A. Robb; and 7 June 2009 Holliston Brentwood CA B. Bowker. These are the only June reports in this 20-year period; in 9 of these 20 years, the last sighting date has been in the third or fourth week of May, not in June.  In 2011, the last sighting date was 6/4, but in 2012 it was 5/27.   Overall, the flight period in MBC data seems both a little earlier and a little later than that reported in the MAS 1986-90 Atlas, probably due to the greater number of records.

Outlook

Because of its use of aggressive buckthorns as host plants, Henry’s Elfin is expected to become more common in Massachusetts. Its present NatureServe rank is S4, or apparently secure. 

Henry’s Elfin is not expected a priori to be especially sensitive to climate warming.

Interestingly, in Connecticut, Henry’s Elfin’s rank is only S2S3, and it had not been found in the state for some 30 years prior to the start of the Atlas in 1990. Only 3 project and 4 pre-project specimens were found, and it is not clear what the host plant is in wild (O’Donnell et al. 2007).  

© Sharon Stichter 2011, 2012, 2013

page updated  4-12-2013

literature cited

ABOUT BOM      SPECIES LIST      BUTTERFLY HISTORY      PIONEER LEPIDOPTERISTS      METHODS