ABOUT BOM SPECIES LIST BUTTERFLY HISTORY PIONEER LEPIDOPTERISTS METHODS
The Butterflies of Massachusetts
16 Bog Copper Lycaena epixanthe (Boisduval & LeConte, 1833)
History Host Plants and Habitat Relative Abundance Today State Distribution Broods and Flight Period Outlook
Boggy areas and acidic wet meadows with cranberry in many parts of our state provide critical habitat for the diminutive Bog Copper. It is a very local butterfly. While it can reach high concentrations in the bog where it reproduces, prompting some dispersal along streams or into open wet meadows, it is not a strong flier and does not colonize new areas quickly (Cech, 2005; NatureServe 2010; Scudder 1889: 988). In Massachusetts, as elsewhere, there is much seemingly suitable habitat in which it is not found. Therefore the focus in this case should be on protecting the butterfly directly, not simply on conserving likely habitat.
Bog Copper is thought to be a relict of the glacial era; it has probably been with us since the Pleistocene. In some of their mid- 19th century writings, Scudder (1862) and Harris (1841) call Bog Copper “rather rare.” This may be because the more remote bog populations were inaccessible and unknown. As Scudder’s own later records show, Bog Copper was not rare in the 1800s. Maynard (1886:42), for example, says he found it “common in low, peaty meadows in Massachusetts, in July.”
Photo T. Murray Tully Lake Athol 6-27-2004
Bog Copper undoubtedly decreased in eastern Massachusetts between 1900 and 2000, as industrial and suburban development obliterated many bogs and wet meadows (Table 2). Scudder reports Bog Copper from many eastern Massachusetts locations where it cannot be found today. He lists specimens from “Andover (Sanborn, Clapp), "the great meadows between Belmont and Lexington," “abundant” (Thaxter), Malden “hundreds” (F.H. Sprague), Newton (Faxon, Minot), West Roxbury (Faxon), Cambridge and Milton (Harris) and Walpole (Guild) (1889: 988).” It is not found in any of these towns except Walpole today.
Museum specimens underscore Bog Copper’s robust presence in eastern Massachusetts around 1900, and add additional locations to Scudder’s list. From the large but now-extinct Malden colony, F. H. Sprague collected about 36 specimens between July 13 and 21, 1883; these are now preserved in the Harvard MCZ. Sprague also mentions finding the species in Wollaston (and in Belchertown; Sprague 1878). From those “great meadows between Belmont and Lexington” Charles Bullard collected ten specimens July 18 through 24, 1897. From Newtonville, there is an 1888 specimen in the C. J. Paine collection. There are no reports from any of these towns---Malden, Wollaston, Belmont, Lexington, Arlington or Newton--- today. They are all heavily built-up suburbs.
Milton, where Thaddeus Harris lived and did most of his collecting, was well-known for Bog Copper at the turn of the century. There are Milton specimens from 1899, 1900, and 1902 (H. H. Newcomb) at the American Museum of Natural History (AMNH), Boston University, and the Smithsonian. C. L. and P. S. Remington collected two specimens at “Milton Blue Hills” in 1936; these are now at Yale Peabody Museum. Today some habitat in Milton is preserved as the Great Blue Hills Reservation, including Fowl Meadow Reservation, but there are no reports of Bog Copper from these areas.
Milton is surrounded by the towns of Dedham, Westwood, Norwood, Canton and Randolph; these have been productive areas for many butterfly species, and Canton/Randolph hosts the important Ponkapoag Bog site, from which Bog Copper was reported by B. Cassie and by T. Murray in 2003. H. Clench found Bog Copper in Norwood in 1941 and 1942 (McGuire; AMNH; Smithsonian). W. P. Rogers found it in Dedham in 1941 (Yale), and W. Winter found it in Westwood in the mid-1970's (MCZ). It is highly unlikely that Bog Copper could be found in Westwood today, due to housing development and re-growth of woodlands (E. Nielsen, pers. comm. 12/22/2011).
There are turn-of-the-century Bog Copper specimens from Sherborn (E.J. Smith, A.P. Morse, BU). C. J. Frost collected Bog Copper in Framingham (South Framingham) between 1901 and 1907; many specimens are in the MCZ and at Boston University. There are no Atlas or MBC reports today from either of these towns.
North of Boston on Cape Ann, a colony in Gloucester, perhaps in the area now called Dogtown, was known by 1896. F. H. Sprague collected six specimens there July 4, 1896; these are still extant and in good condition in the Harvard MCZ. W. T. M Forbes collected there again in 1931 and 1939; specimens are at Cornell. This colony may or may not still be in existence; but there is a small, better-known colony today in Rockport. Also north of Boston, C. V. Blackburn collected Bog Copper in Stoneham –probably in what is now Middlesex Fells— on July 23, 1933 (AMNH). A. H. Clark found it in Essex in 1924 or 1925 (Clark 1925). It was in Tyngsboro in 1915 (MCZ), and W. Winter found it in nearby Dunstable in the mid-1970's (MCZ). There are no recent records from any of these towns, even from Middlesex Fells despite many visits by butterfly watchers.
Specimens from the huge and wonderful Hockamock Swamp in the southeastern Massachusetts towns of Raynham, Taunton, Norton, Easton, Bridgewater, and West Bridgewater begin in 1932. Many collectors documented Bog Copper there in 1932-1936: there are specimens from E.T Learned at AMNH, C.L. and P.S. Remington at Yale, D.J. Lennox at UNH, and others at the Smithsonian and at McGuire Center. There are no current MBC or Atlas records from this area, but it has not been visited recently.
The earliest evidence of Bog Copper on Cape Cod comes in 1891 from Chatham Harbor: five specimens dated 7/16/1891 in the A. G. Weeks Collection at the Harvard MCZ. There are at least four samples from Chatham in the C. J. Paine Collection at Harvard, dated July 1920, and from Woods Hole there are ten specimens collected by W.T.M. Forbes on July 13, 1919, at Cornell and the American Museum of Natural History. There are few subsequent records of Bog Copper from these two towns; only one Atlas report from Chatham (6/26/1989, B. Nikula), and no MBC reports. But Bog Copper is found in many other Cape Cod towns.
Bog Copper is first mentioned for Martha’s Vineyard and Nantucket in the 1920’s, and is well documented in the 1930’s and 1940’s by F. M. Jones and C. P. Kimball. 1926-1928 specimens from Nantucket, probably collected by C. W. Johnson, are at Boston University today. Bog Copper remains common on the Vineyard today, but may be gone from Nantucket (see below).
Scudder (1899) reports Bog Copper absent from west of the Connecticut River valley. This is still the case today according to recent MBC records (see current map below).
Host Plants and Habitat
Scudder and other early lepidopterists were not familiar with Bog Copper’s host plant or early life stages. These were finally described in great detail in the 1980s (Wright, 1983). The sole host plant is cranberry; usually Large Cranberry (Vaccinium macrocarpon), but also Small Cranberry (V. oxycoccos), both of which are common in Massachusetts. Beyond these, this species has not adopted any new host plants so far as is known and is not among the "Switchers."
Bog Coppers can survive only in un-worked cranberry bogs; commercial bogs do not support it, because of heavy insecticide use and mechanical disturbance. Many habitats may have been lost due to the development of cranberry farming, especially in Plymouth County, although specimen evidence is lacking.
Boggy areas and acidic wet meadows with cranberry are the usual habitat, but Atlas and MBC observers have found several sizable colonies in acidic wet meadows, at times associated with alluvial soils of river flood plains, as well as in bogs. Any acidic, open, sunny, and year-round wet situation, which is infrequently mowed, can probably act as habitat and/or dispersal corridor if cranberry is present. Cranberry is sometimes found on drier soils, but Bog Coppers do not utilize these habitats.
Bog Copper eggs are laid on the underside of the cranberry leaf close to the surface of the bog, where they overwinter, surviving the ice and periodic inundations. The larvae emerge in spring and eat the cranberry leaves; cranberry is also used for nectar by adults. There is a single flight period in late June through July. Mating occurs shortly after emergence.
Relative Abundance Today
Despite an undoubted decline in eastern Massachusetts since the 19th century, Bog Copper appears to be holding its own generally in the state, and may even be increasing. The Audubon Atlas found Bog Copper in 26 of the 723 blocks surveyed, making it “Uncommon.” The Atlas label “locally common” can obscure the overall low relative abundance in comparison to other species. MBC sightings data also rank the species as Uncommon to Common (Table 5), but the high numbers reported -- most of them rough estimates made from the edge of the bog--- may distract attention from the extreme dependence of this species on a fragile habitat.
MBC records suggest that Bog Coppers may have been decreasing in the late 1990's, but increasing since 1999 (Chart 16). In Chart 16, the apparent high in 1992 is an artifact of the low number of total trip reports for any species, and should be ignored. The number of Bog Coppers reported per total trips reporting that species 1992-2009 shows a similar pattern to Chart 16, except that readings for 1992 and 1993 are much lower.
Chart 16: MBC Sightings per Total Trip Reports 1992-2008
The statewide result in Chart 16 depends greatly on the reports from one NABA Count, Central Franklin. Over the years of that long-running count, the areas actually visited have increased, and more and more bog habitats have been found, which partly accounts for the increasing numbers reported (M. Fairbrother, NABA count reports). Bog Copper has been found on this count every year since 1990, with numbers ranging from lows of 9 (1991) and 25 (1999) to a high of 781 (1995) in the 1990s, and from 102 (2000) to 1509 (2008) in the 2000’s. Raw numbers adjusted for total party-hours in count years 1990-2010 reveal peaks in 1995 and 1996, then low readings 1997-2000, and another set of peak readings in 2005-2008. This pattern may reflect fluctuations in populations in that count area. It also generally accords with the pattern shown in Chart 16.
Statewide in 2007, 2008, and 2009, the average number of Bog Coppers per report of that species increased 196%, 211%, and 53% respectively, relative to the average for preceding years back to 1994. The number of reports of this species, and the maximum number reported, also increased in 2007 and 2009 relative to prior years. (Nielsen, Season Summary, MB 2008-2010, Nos. 30, 32, 34). These calculations show a similar picture to Chart 16 for 2007 and 2008.
State Distribution and Locations
Map 16: MBC Sightings by Town, 1992-2011
Many generalized range maps show the whole of Massachusetts as within the range of the Bog Copper (e.g. Cech 2004; Opler and Krizek 1984). However, there are no MBC reports from any towns in Berkshire County, and no reports from the Central, Southern or Northern Berkshire NABA Counts 1992-2009. The 1986-90 Audubon Atlas did not find Bog Copper in Berkshire County except for one specimen from Otis (E. Neumuth 7/23/1989). A search of museum specimens yields no older records for this county.
Similarly, neither the Atlas nor MBC has any records for the southern Connecticut River valley, or for most areas south of the Quabbin Reservoir and Worcester. Neither the Atlas nor MBC has any records for inner suburban areas around Boston. There are no recent records for most of inland southeastern Massachusetts (Plymouth and Bristol Counties) away from the south coast, probably owing to commercial cranberry farming.
Both Atlas and MBC records attest to Bog Copper’s robust presence in Franklin County, which is perhaps its greatest stronghold today. Bog Copper has been reported on the Central Franklin NABA Count every year since its inception in 1990. Productive areas are found in Colrain, Leverett, Warwick and Wendell. Historically, Bog Copper seems to have been first reported for Montague in 1976 by Deane Bowers (LepSocSeasSum, 1976), and was subsequently collected in Wendell State Forest on July 7, 1985 by R. G. Webster (McGuire).
In addition to Franklin County, northern Worcester County is home to many Bog Coppers. The species has been reported every year since 1996 on the Northern Worcester County NABA counts, usually in double digits, with a high of 181 in 7/7/2002. Some of the highest numbers reported per trip have come from Athol Reservoir, and Tully Dam and Tully Lake in Royalston (for example, 125 at Tully Lake 7/13/2003, C. Kamp and D. Small). Wachusett Reservoir in Clinton/Sterling is another important site in Worcester County. Older museum specimens come from Dunstable and Ashburnham.
Towns to the southwest of Boston, such as Mansfield, Walpole and Millis, probably still have Bog Coppers, although most reports are from the 1990's and recent counts are lacking. Bog Coppers from Mansfield were reported on the Foxboro NABA Count each year 1992-1997. Suburbs to the west, such as Sudbury and Acton, also still report Bog Copper, at least through the 1990's. Good numbers were reported from Sudbury and Acton in the 1990s. Bog Copper has been reported almost every year on the Concord NABA Count (which includes parts of Sudbury and Acton) since 1990, with numbers varying from a low of 2 on 7/10/1993 to a high of 86 on 7/12/2003, but only 5 were reported in 2009 and none in 2010 or 2011.
Historically, these areas west and southwest of Boston did produce Bog Coppers (see above). In the 1960’s Bog Copper was actively collected in the towns of Acton and Littleton by C. G. Oliver (specimens now at Yale). In the 1970’s, Bog Copper was documented in Dover in 1973 by J. S. Ingraham (specimens at Yale) and William D. Winter (specimens in MCZ); in Westwood July 6,1974 by William D. Winter (MCZ); and in Carlisle 18 July 1973 by E. Peters, (LepSocSeas Sum 1973).
In Essex County today, only two small colonies of Bog Copper are known: one in Rockport (max. 44 on June 26, 2001, F. Goodwin; recent max. 30 on July 1, 2011, M. Arey), and one at Cedar Pond Bog in Wenham, a MassAudubon property (max about 10). The Rockport colony has been visited consistently for many years to determine flight dates. The 1986-90 Atlas had reported Bog Copper from Newburyport, possibly from Parker River National Wildlife Refuge on Plum Island, but no subsequent reports from the Refuge, either from MBC or from refuge biologists, include Bog Copper. The most recent report from Gloucester is 1998; more searches are needed there. Historically, between 1900 and 1934, Bog Copper was reported from Boxford (D. W. Farquhar, 1930’s), Essex (A. H. Clark, 1924-5), and nearby Stoneham (23 July 1933, C. V. Blackburn, AMNH; Farquhar 1934); but MBC has no reports today from Boxford, Essex or Stoneham (Middlesex Fells).
In Andover, Bog Copper does not appear to be present today. Scudder had reported the species there a century ago, and Robert Godefroi collected four specimens in the 1980s (July 4, 1984; July 7, 1985; July 7, 1987; and July 1, 1988; McGuire Center), which were not reported by the MAS Atlas. Reportedly, he found these in a small wetland which is today the site of the Orchard Crossing housing development, and Bog Copper is no longer there despite searches. Oddly, Bog Copper has not been found in the well-known Andover bog at Ward Reservation TTOR. (H. Hoople, pers. com. 11/13/2011, 12/18/2011).
Bog Copper is common on Cape Cod, as indicated by both MBC and Atlas records. It is reported from Falmouth, Brewster, Eastham, and Truro, with many seen especially at Pilgrim Lake in Truro. Mello and Hansen (2004: 35) agree that Bog Coppers are "common and widespread throughout the acid wetlands of Cape Cod;” they note that in the Provincelands, the butterfly may be found in the wet depressions between sand dunes.
For Martha’s Vineyard, there were no 1986-90 Atlas reports, but since 1990 many MBC reports have come in, and the Vineyard checklist rates Bog Copper as “common” (Pelikan 2002). It is usually reported on the yearly Vineyard NABA Counts. Edgartown and Tisbury have perhaps the best areas on the Vineyard for Bog Copper. Historical specimens from Martha’s Vineyard are in the MCZ (C. P. Kimball, 20 July1928) and at Yale (W. P. Rogers, 2 July and 23 July, 1941, and F. M. Jones 10 July 1941 and other dates). Bog Copper was reported as “sometimes abundant in cranberry bogs” on the Vineyard by Jones and Kimball (1943).
It is possible that Bog Copper is gone from Nantucket, like the Silver-bordered Fritillary (LoPresti, 2011). The Atlas did have a report from Nantucket (W. Maple, 7/17/1987), but since then there have been NO reports from that island, and further searches are needed. There are many historical specimens, however: from 1926-1928 at Boston University, and from 1 Jul-1938 C. P. Kimball, at the Maria Mitchell Museum. Sixty years ago, Jones and Kimball (1943) reported Bog Copper as “very common in cranberry bogs” on the island.
Broods and Flight Period
Bog Copper is a univoltine species, flying mainly from the last week in June to the end of July. The largest numbers are seen during the first two weeks of July (http://www.naba.org/chapters/nabambc/flight-dates-chart.asp). The earliest date reported in 1992-2009 MBC records is 6/21/1995 in Sudbury, T. Dodd., but just over half of all ‘first reports’ 1992-2009 came between 6/26 and 6/28. (The Atlas gave an early date of 16 June for Nantucket, but no year or observer is cited.)
Over a century ago, Scudder (1889:989) wrote that the earliest Bog Coppers appeared “the last of June---about the 25th.” This date is similar to the majority of reports today. He also wrote that they “become abundant during the first week in July,” a timing again similar to that of today.
The latest reports in MBC records are 8/5/1995 Clinton/Sterling T. Dodd, and 8/4/2004 Clinton/Sterling T. Whelan. These are both from Wachusett Reservoir. The Atlas late date was the same, 8/5/1989 T. French in Newburyport. The late date seems not to have changed much since a century ago, when Scudder (1889: 989) wrote that “they may be found until at least the end of the first week in August.”
In one small monitored colony in Rockport on Cape Ann, the site was visited frequently around the beginning and the end of the flight period for many years by D. Savich and C. Tibbits. Between 1996 and 2009, the earliest flight dates for this colony were 6/25/2001 (33 flying), 6/27/2008, and 6/28 in 2000, 2002, 2004 and 2007. The latest sightings, often with only one individual flying, were 7/21/1996, 7/19/2003, and 7/18/1998.
In Connecticut and Rhode Island, the conservation status of the Bog Copper is a concern: its rank in Rhode Island is S3 or “vulnerable,” while in Connecticut it is S2 or “imperiled,” and a state species of Special Concern (NatureServe, 2010). The 1995-9 Connecticut Atlas reported some probable decline, due to restricted habitat and succession in cranberry bogs. In New Jersey, although the status is S4, management to avert plant succession in cranberry bogs has been strongly recommended (Gochfeld and Burger 1997:147).
Ohio and Indiana stand as warnings of what can happen where cranberry bogs are unprotected. Bog Copper is presumed extirpated in both states; it has not been reported in Ohio since the 19th century, despite searches, and the cranberry bogs which were once widespread throughout northern and central Ohio have been largely destroyed through draining or flooding (Iftner et al 1992).
Conservation of the Bog Copper should be a priority in Massachusetts. We list it here as a Species of Conservation Concern. The many examples above of colonies lost in eastern Massachusetts ---from Andover, to Westwood, to Nantucket ---point to the need to protect remaining colonies. The NatureServe (2010) status of Bog Copper here is S4 or “apparently secure” at present, and state wetland protection laws seem reasonably strong. But conservation of the bog habitat does not guarantee that the butterfly will be present, since dispersal ability is weak and dense forest probably acts as a barrier (NatureServe 2010). Existing small isolated colonies of Bog Copper are vulnerable. In addition, this species is probably vulnerable to climate warming (Table 6), since its present range does not extend south of New Jersey or Wisconsin.
© Sharon Stichter 2010, 2011
page updated 11-14-2011
Species of Conservation Concern
ABOUT BOM SPECIES LIST BUTTERFLY HISTORY PIONEER LEPIDOPTERISTS METHODS