Hilton Jr., B. 1994. Carpodacus finches in South Carolina's Piedmont: Migration, site fidelity, sex ratios, and longevity. North American Bird Bander 19(1):1-11.
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INTRODUCTION
HOUSE FINCH BANDING RESULTS
PURPLE FINCH BANDING RESULTS
SEX RATIOS IN Carpodacus FINCHES
RECOVERIES, RECAPTURES, AND RETURNS
DISCUSSION
ACKNOWLEDGEMENTS
LITERATURE CITED
[NOTE: Haemorhous is the revised genus name for these finches, replacing Carpodacus.]
INTRODUCTION
In 1982 I began banding birds at my residence at Hilton Pond Center for Piedmont Natural History near York in central York County, South Carolina USA, Lat 34°58'N, Long 81°13'W (Appendix I). The study site is in the Piedmont physiographic province, about halfway between the mountains and the coast. Through June 1990, I banded 14,637 birds representing 108 species, of which 32.3% (n=4,730) were Carpodacus finches (Table 1). These included 2,028 House Finches (C. mexicanus) and 2,702 Purple Finches (C. purpureus).
Although Purple Finches historically have bred, migrated, and overwintered throughout the eastern U.S., House Finches are newcomers to the region. There is strong evidence (Aldrich and Weske 1978) that virtually all eastern House Finches are descendants of perhaps a few dozen birds illegally imported from the West Coast and released in 1940-1941 on Long Island, New York, by bird dealers (Elliot and Arbib 1953). These introduced birds were the nucleus for a viable, expanding population that soon appeared together with Purple Finches at winter feeders in the Northeast.
In their western range, House Finches are relatively sedentary (Bergtold 1913), but after their New York release some eastern birds or their progeny apparently began extended migratory flights similar to those of Purple Finches. A House Finch came as far south as Zebulon in Wake County, North Carolina, in 1963, and the species was first seen in South Carolina at Greenville in December 1966 (Grimm and Shuler 1967). The first House Finch banding in South Carolina was at Hartsville in March 1967 (Morrison 1967). While subsequent banding records show that many House Finches still migrate to the Carolinas in autumn and back north in spring (Stewart 1989, Belthoff et al. 1990), others apparently dispersed from the Northeast and established permanent residence in several Eastern states.
The first report of House Finch breeding in South Carolina was from Greenville in 1979 (Grimm 1979), and nests were found in 1983 at Clemson University (Hamel and Wagner 1984). The first published nesting records for York County were from Rock Hill in June 1988 (Hilton 1988a, 1988b), although nesting had been suspected there as early as 1976 (Boatwright 1977). It is likely that York County breeding pre-dated 1988 reports by several years because the first House Finch nests in North Carolina were found in 1975 at Charlotte in Mecklenburg County, which adjoins York County (Teulings 1975).
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HOUSE FINCH BANDING RESULTS
From 1967 through 1987 (the last year for which the Bird Banding Lab has compiled records), banders in South Carolina handled 1,843 House Finches, of which I captured 88.0% (n=1,622) at the Hilton Pond Center banding station (Belthoff et al. 1990). Virtually all York birds were apparent migrants that began arriving in late October and departed about the fourth week in March (Table 2), defining their "winter season" as 21 October through 30 March. This period differs from that of Stewart (1989), whose House Finch winter season in North Carolina extended from December through April.
An irruption of House Finches in the winter of 1983-1984 yielded 976 banded birds at Hilton Pond Center. Christmas Bird Counts published in American Birds (e.g., vols. 30-38) and Bird Banding Laboratory records for South Carolina and adjoining states suggest that House Finches at York during that winter may have comprised the southernmost large concentration for the species up to that time. The number of birds (n=58) dropped considerably in the following winter of 1984-1985, and no other season from 1982-1990 produced a similarly-large influx of House Finches at York (Table 1).
After 1987, other South Carolina banders began capturing larger numbers of House Finches (John Cely, South Carolina Nongame Program, pers. comm.), including breeding birds and fledglings trapped or netted outside the winter season. The first summer records of House Finches at Hilton Pond Center came in June 1988 when two free-flying but apparently local fledglings with partially-grown rectrices and brown plumage were banded. (One of these, #2051-14537, was banded on 23 June 1988 and was recaptured in red plumage at York on 1 November 1989; on a second recapture on 29 April 1990, this adult male had a cloacal protuberance, implying that some House Finches in South Carolina may remain to breed near localities where they are hatched.) The presence of breeding birds in and around York now makes it difficult to determine precise early arrival and late departure dates for migrant House Finches.
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PURPLE FINCH BANDING RESULTS
Unlike House Finches, Purple Finches have not expanded their traditional breeding ranges from Canada and the northern U.S. into South Carolina (Post and Gauthreaux 1989); they continue to migrate to York as early as the end of November and leave by late April (Table 2). Purple Finches at Hilton Pond Center show an alternating fall migration pattern with first birds arriving in late November or early to mid-December one year and in January the next. Purple Finches fell outside this pattern only in the winter of 1986-1987, when five birds banded at York in previous winters showed up "early" on 28 November (AHY-F), 14 December (ASY-M), 31 December (one ASY-M, one AHY-F), 18 January (ASY-F). After small numbers of birds were captured during the first three winters of banding at Hilton Pond Center (beginning 1982-1983), seasonal banding totals for Purple Finches for the next three years climbed to 558 (in 1985-1986), 685, and 611 (Table 1); the total dropped again in 1989-90 to 224, possibly because of an exceptionally mild winter and early spring or because feeders at Hilton Pond Center were not stocked during the preceding winter of 1988-89. Of the 8,516 Purple Finches banded during the winters of 1955-1987 in South Carolina, 21.7% (n=1,850) were captured at Hilton Pond Center, where banding did not begin until 1982 (Belthoff et al. 1990).
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SEX RATIOS IN Carpodacus FINCHES
Analysis of all Carpodacus finches banded at York from 1982 through June 1990 indicate that sex ratios fluctuate somewhat from year to year (Table 1). House Finches can be sexed reliably in the fall of their hatching year when nearly all young males have red plumage; a small number of birds with pinkish wash could be old females or young males and are best sexed as Unknown. Through the nine-year study, 959 (47.3%) of 2,028 banded House Finches were obvious males, 1,009 (49.8%) were obvious females, and 60 (2.9%) were of indeterminate sex. These data are not significantly different from an "expected" 1:1 ratio of males to females (x2 = 1.74, p > 0.1, n.s.).
© Hilton Pond Center
With experience, a "red" After-Second-Year male Purple Finch (above left) can be easily separated from a "red" male House Finch at the feeder. Here are some hints:
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PURPLE FINCH
Noticeable reddish-white line above eye
The hint of a crest
No white wingbar
Top edge of upper bill is straight
Tends to hunch a bit at feeder
Legs appear short |
HOUSE FINCH
Head somewhat flattened on top
White wingbars
Top edge of upper bill is decurved
Posture more erect at feeder
Legs appear long |
© Hilton Pond Center
Many observers find it easier to differentiate between female Carpodacus finches. Here are some hints for doing so:
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PURPLE FINCH
Pronounced white line above eye
The hint of a crest
Top edge of upper bill is straight
Tends to hunch a bit at feeder
Legs appear short |
HOUSE FINCH
No white line above eye
Head somewhat flattened on top
Top edge of upper bill is decurved
Posture more erect at feeder
Legs appear long |
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Warning!
Brown Purple Finches may be either adult females, young females, or young males. The same is true of Purple Finches with reddish or gold wash. Male Purple Finches are not fully red until late in their second summer, while all male House Finches acquire red plumage their first autumn.
Bonus Hint for Banders:
Male and female Purple Finches almost always bite the hand that holds them; House Finches almost never do! :-)
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Purple Finches present a more difficult sexing problem because males do not acquire red plumage until late in their second summer; therefore, brown Purple Finches may be females of any age, or young males aged as Hatch-Year (HY) or Second-Year (SY). According to Bird Banding Lab protocol, red males in autumn are aged as After-Hatch-Year (AHY), but on 1 January these birds become After-Second-Year (ASY). Of the 2,702 Purple Finches banded from 1982 through June 1990 at Hilton Pond Center, 72.3% (n=1,953) were brown birds sexed as Unknown (U); the remaining 27.7% (n=749) were red males (Table 1). If a third of brown Purple Finches in winter are adult females, a third are young females, and the remainder are young males, the percentages at Hilton Pond Center are close to a 1:1 ratio of males (51.8%) to females (48.2%). However, for this ratio to be correct, it must be assumed that male and female Purple Finches overwinter at the same locations and that survival rates of all age classes and sexes are equal; it is difficult--perhaps impossible--to derive such information from available, limited banding data.
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RECOVERIES, RECAPTURES, AND RETURNS
Only 19 (0.13%) of 14,637 birds of all species banded at Hilton Pond Center through June 1990 have been recovered or recaptured outside York County. This is well below the national average of about 2% annual recoveries--excluding waterfowl--reported by the Bird Banding Lab, and may be due to low human population densities and the scarcity of banders in southeastern states. Of the 19 foreign encounter reports on York birds, 11 were for Carpodacus finches (Table 3); all these were banded during winter months but were recovered or recaptured at various times of the year. Purple Finches and House Finches recovered or recaptured elsewhere from April through mid-October were probably on or near their breeding grounds.
An interesting recovery of a York bird came when a winter-banded, After-Fifth-Year (A5Y) female House Finch (#0980-32484) was killed in midsummer by a cat, probably while on breeding grounds in North Carolina less than 100 miles northeast of York, SC (Table 3). This report suggests that some House Finches make relatively short migrational flights. One female House Finch (#0980-32732) that was banded at Hilton Pond Center in December 1983 was found dead the following December in New Jersey, and another (#2000-76064) banded in January 1984 was recaptured 12 months later in Maryland. These two records suggest that long distance migration in eastern House Finches is not obligatory but may depend on severity of weather, availability of food, or other factors--a suggestion supported further by the fact that both those birds were banded at York during the big House Finch irruption in the winter of 1983-1984. These records also allow for comparison with the sedentary behavior of many House Finches in the West, where migratory behavior may have been "suppressed" by moderate weather and "became operative" when House Finches were introduced into more rigorous climates that occur in parts of the eastern U.S. It is worth noting, however, that some House Finches in western mountain habitats (e.g., Colorado) appear not to migrate despite winter weather that is sometimes severe (Bergtold 1913).
Straight lines drawn between Hilton Pond Center and each bird's recovery or recapture site (Figure 1 and Figure 2) indicate that migrant Carpodacus finches banded at York follow a narrow migrational corridor from South Carolina's central Piedmont to the Mid-Atlantic and New England states and neighboring Canada. The one exception was a Purple Finch (#2051-13286) recovered in Wisconsin. The longest known movement from York was by a Purple Finch (#2051-14295) banded at Hilton Pond Center and found dead about 1,700 straight-line miles away at Lewisporte, Newfoundland--the very northern limit of the species' range. Five Carpodacus finches were banded elsewhere and recaptured and released during winter at Hilton Pond Center (Table 4); maps of theoretical straight-line migrational paths for these birds provide further evidence that Carpodacus finches migrate along a narrow pathway (Figure 3 and Figure 4).
During the last winter of the study (1989-1990), 26 "old" Purple Finches banded in previous years at Hilton Pond Center returned to York and were recaptured and released. These returns provide data on longevity and winter site fidelity at a location in the southeastern U.S.--an area from which such records are scarce. Returns at Hilton Pond Center included the following 18 males: one After-Eighth-Year or A8Y (#2000-76315), one A6Y, three Sixth-Year (6Y), one 5Y, five A4Y, five 4Y, one A3Y, and one 3Y; and these eight Purple Finch females: one A8Y (#980-32286), one A6Y, two A5Y, one A4Y, two A3Y, and one A2Y. Two male House Finches, one an A6Y (#2000-76226) and the other an A5Y (#2000-76836) were also noteworthy. Kennard (1975) reports the oldest known wild Purple Finch was banded in Hillsborough, NC, and retrapped in the same area when 12 years and 8 months old. A western female House Finch at Sacramento, CA, was 10 years and 10 months old when retrapped and released (Kennard 1975); Klimkiewicz et al. (1989) list an eastern female House Finch banded at Schenectady, New York, in December 1973 and retrapped in January 1985 at an estimated age of 11 years and 7 months.
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DISCUSSION
Banding recoveries and recaptures provide evidence that some House Finches overwinter in South Carolina but breed elsewhere. There is also an apparently resident population that breeds and overwinters in the state, but very little banding information has verified the size of this group; for example, only three House Finches color-marked during the nesting season at Clemson, SC, were sighted at nearby winter feeding stations (Belthoff et al. 1990).
There may, in fact, actually be several overlapping eastern House Finch "populations" with different breeding and wintering strategies, including the following groups:
-- House Finches that breed in New England and Mid-Atlantic states, some of which migrate to and from Southeastern states where some are banded in winter;
-- House Finches that dispersed from New York and gradually extended their breeding range down the eastern edge of the Appalachian Mountain range into the Greenville and Clemson areas of South Carolina and then further eastward;
-- House Finches that dispersed short distances from New York and gradually extended their breeding range down a "Piedmont flyway" through Virginia and North Carolina into South Carolina;
-- House Finches that dispersed long distances ("one-way migration") down a "Piedmont flyway" into central South Carolina and are now permanent residents.
With so few Carpodacus finches banded, recovered, and retrapped in South Carolina, these groupings are speculative; however, the gradual westward and southward advances of nesting House Finches from eastern populations may indicate that breeding range extensions for the species occur more slowly than extensions in migratory ranges (Appendix II). An increase in the number of licensed banders in the Southeast would undoubtedly improve the Carpodacus data base and allow for better evaluation of the ecology of South Carolina populations of House Finches and Purple Finches. Ornithology would also be well-served if the general public were more familiar with the federal bird banding program and knew the importance of reporting recoveries of banded birds.
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ACKNOWLEDGEMENTS
I would like to thank James R. Belthoff and Sidney A. Gauthreaux Jr. of Clemson University for their encouragement and for sharing their initial analysis of South Carolina Carpodacus records from the Bird Banding Lab (BBL) in Laurel, Maryland. Danny Bystrak of the BBL was helpful in verifying recapture data, and Terry Wiens provided information about Midwestern House Finch records. Keith L. Bildstein, David E. Blockstein, and Harry E. LeGrand Jr. made suggestions about the manuscript, and comments by James L. Howitz were especially valuable. Activities at the Hilton Pond Center banding station have been funded in part by grants from Susan B. Hilton and the Nongame Program of the South Carolina Wildlife and Marine Resources Department.
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LITERATURE CITED
-- Aldrich, J.W. and J.S. Weske. 1978. Origin and evolution of the eastern House Finch population. Auk 95:528-536.
-- Belthoff, J.R., S.A. Gauthreaux Jr., and B. Hilton Jr. 1990. Breeding ranges of Carpodacus finches wintering in South Carolina. Chat 54(3):61-62.
-- Bergtold, W.H. 1913. A study of the House Finch. Auk 30:40-73.
-- Blankespoor, G. 1989. House Finches breed in Sioux Falls. South Dakota Bird Notes 41(4):63.
-- Boatwright, M. 1977. House Finch in Briefs for the Files. Chat 41:16.
-- Elliot, J.J. and R.S. Arbib Jr. 1953. Origin and status of the House Finch in the eastern United States. Auk 70:31-37.
-- Grimm, W. 1979. House Finch in Briefs for the Files. Chat 43:101.
-- Grimm, W.C. and J. Shuler. 1967. First sight record of House Finch in South Carolina. Chat 31:45-46.
-- Hamel, P.B. and S.J. Wagner. 1984. Status of the House Finch in South Carolina, including discovery of two nests in Clemson. Chat 48:5-7.
-- Hilton Jr., B. 1988a. Piedmont Naturalist: "Red bird" turns out to be a House Finch. Herald, Rock Hill, South Carolina, 12 June 1988, p. 1D.
-- Hilton Jr., B. 1988b. Piedmont Naturalist: Finding may be county's first House Finch nest. Herald, Rock Hill, South Carolina, 24 June 1988, p. 1B.
-- Howitz, J.L. 1989. House Finches in Huron. South Dakota Bird Notes 41(3):44-45.
-- Howitz, J.L. and L.A. Bartsch. 1988. House Finches invade LaCrosse. Passenger Pigeon 49(4):182-183.
-- Janssen, R.B. 1989. Minnesota's first House Finch nest. Loon 61:93.
-- Johnsgard, P.A. 1979. Birds of the Great Plains; Breeding Species and Their Distribution. Univ. of Nebraska Press, Lincoln. pp. 456-457.
-- Kennard, J.H. 1975. Longevity records of North American birds. Bird-Banding 46(1):55-73.
-- Klimkiewicz, M.K. and A. G. Futcher. 1989. Longevity records of North American birds, supplement 1. J. Field Ornithol. 60(4):491.
-- Morrison, W.M. 1967. House Finch banded at Hartsville, S.C. Chat 31:47.
-- Peterson, R. and J. Peterson. 1989. House Finch nesting in Edgemont. South Dakota Bird Notes 41(3):44.
-- Post, W. and S.A. Gauthreaux Jr. 1989. Status and distribution of South Carolina birds. Charleston Museum, South Carolina.
-- Potter, E.F., J.F. Parnell, and R.P. Teulings. 1980. Birds of the Carolinas. Univ. of North Carolina Press, Chapel Hill, pp. 367-369.
-- Stewart, P.A. 1989. Nesting localities of House Finches wintering in North Carolina. Chat 53:90.
-- Teulings, R.P. 1975. Southern Atlantic Coast Region. Amer. Birds 29:957-960.
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APPENDIX I--FEEDING AND BANDING BIRDS AT HILTON POND CENTER FOR PIEDMONT NATURAL HISTORY
Feeders at the 11-acre Hilton Pond Center tract near York, SC, are stocked year-round with black sunflower, whole or cracked corn, thistle, and white millet. Platform feeders also serve as winter trap stands. About 25 net lanes sample all local habitat types ranging from pond edge to old fields to stream bottomlands. Unless weather is mild, nets are not deployed December through February when traps are the principal capture method. On most netting days, 10-12 nets (30mm or 36mm mesh) are deployed dawn to dusk and are checked hourly. Traps include 1-cell McCamey, 3-and 4-cell Potter, dove (ground), Wharton multi-catch, thistle-funnel, and "government" sparrow traps. At Hilton Pond Center, Carpodacus finches enter all these, but 90% are trapped in any of several kinds of pull-string, drop-door devices that allow selective captures of from one to 20 birds at a time.
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APPENDIX II--WESTWARD EXPANSION OF HOUSE FINCHES
Westward movement of House Finches from eastern populations has been as gradual as the southerly advance. The first House Finch nest in Wisconsin was found in 1987 at LaCrosse (Howitz and Bartsch 1988), while Minnesota's first report came two years later at Winona (Janssen 1989). From New York, it took House Finches almost 50 years to extend their breeding range 900 miles to these cities on the Wisconsin-Minnesota border, while it took them about 35 years to extend the breeding range 600 miles to Charlotte on the North Carolina-South Carolina line. (Although it may be coincidental, these rates--about 18 miles per year--are remarkably similar.) The species now breeds in eastern regions of the Dakotas (Blankespoor 1989, Peterson et al. 1989) and Nebraska (Howitz 1989), and it is probably will not be long until "exotic" eastern House Finches encounter the endemic western House Finches that have bred for many years in extreme western Nebraska (Johnsgard 1979).
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