The mineral profile of plumage in captive lesser snow geese JOHN P. KELSALL' AND W.J. PANNEKOEK* Canadian Wildlife Service, Department of Environment, 5421 Robertson Road, Delta, British Columbia
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Received September 16, 1975 KELSALL,J. P., and W. J. PANNEKOEK. 1976. The mineral profile of plumage in captive lesser snow geese. Can. J. Zool. 54: 301-305. This is a contribution to a larger study aimed at development of a technique to determine the origins of waterfowl from their feather chemistry. Results are reported of an experiment designed to show whether there were differences in the mineral profile between primary feathers one-half to two-thirds grown and fully formed feathers, within a population of captive lesser snow geese. Primaries 1 and 10 were used as sample materials and the elements Na, Ca, K , Fe, Cu, Mn, Mg, Zn, and Si were used as variables. Statistically significant differences were shown between stages of growth in respect to all variables except Cu and Zn. The experiment also showed significant differences between different primary feathers in respect to all variables, and some differences attributable to the sex of birds from which samples were taken.
J. P., et W. J. PANNEKOEK. 1976. The mineral profile of plumage in captive lesser snow KELSALL, geese. Can. J. Zool. 54: 301-305. Cet article fait partie d'une Ctude d'enverpure destinke b mettre ail point une technique visant h determiner les origines des oiseat~xaqtrdtiques d'aprk la nature chimique de leur plumage. On donne ~ c ki s rkultats d'une experience stir des petltes oies blanches par laquellr on a voulu cnnstater s'il existe ou non des difference5 de profil rnin6ral entre des remiges primaires ayant atteint de la moitii aux deux tierr de leur dkvelopprnenl et der plumes adultes. On a util~sb$ cette fin ley rkmiges primaires 1 et 10 el les ilementq Na. Ca, K. Fe. Crr, Mn, Mg. Zn et Si ont servi dc vartahles. IIexiste des differences s~gnificativesentre les divers starles de cmissance dans Ie cas de routes le9 variables, sauf Cu et Zn. t'expbrience a d i m o n t e tgalemenr qu'il existe d e ~ d ~ f l ~ t e n c e~ignificativcs. s dans le cas de toutes ler variables, entre ies differentes remiges prlmaires: il cxiste aussi des differences attrihuabler au sexc des oiseaux don1 un a examink les plumes. [Traduit par le journal]
Introduction The Canadian Wildlife Service began testing the possibility of determining the origins of waterfowl through their feather chemistry in 1968. Waterfowl shed their primary flight feathers simultaneously, and are grounded until they grow new ones. It seems axiomatic that each set of flight feathers will, to some degree, reflect the chemistry of the particular area in which it was grown. Some preliminary success in identifying the origins of birds by chemical means have been reported (Hanson and Jones 1968: Devine and Petede 1968). Our investigations first centered on mallards (Anas p/at~~rl~vnchos), black ducks (Anas rubripes), and lesser scaup (Ayihyu afinis). Methods for wet chemical analysis have been adapted or developed, and significant differences have been observed between species, and between sexes and 'Author to whom requests for reprints should be addressed. 'Present address: Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan.
year classes within species, using 9 to 1 1 chemical elements, and computerized multivariate discriminant analysis (Kelsall 1970a, 1970b; Kelsall and Calaprice 1972; Pannekoek et al. 1974; Kelsall rr at. 1975S). In 197 1 lesser snow geese (Anser caerulescens) were chosen as a continuing experimental species because they are colonial nesters and, theoretically, present a relatively simple ecological situation for investigation. A great cnncern is the possibiIity that the quantity of some, or all, of t h e chemical elements in primary flight feathers may change significantly between the time t h e feathers are grown in late summer and early aulumn. and the time they are moulted, usually in late July the next year. If there are changes in chemical composition in time, then it would nor be possible to identify the origins of birds from chemical profiles in feathers directly. Tn such a case diamostic feathers and unknowns would all have to be collected at the same time of the year, or rates of chemical change would have to be measured and compensated for. Both possibil-
302
CAN. J. ZOOL.
ities impose severe limitations on the practicality of the technique. An experiment was designed to explore some chemical differences in time.
Can. J. Zool. Downloaded from www.nrcresearchpress.com by UNIVERSITY OF MICHIGAN on 11/18/14 For personal use only.
Materials and Methods Feathers were taken from captive snow geese that were hatched, raised, and maintained at Brooks, Alberta. All the birds were kept on common rations and in a common enclosure with water freely available. Rations were fed ad libitum-a pheasant starter ration for three weeks after hatching and then a pheasant grower ration on a continuing basis. There was somc opportunity to supplement the standard rations with grasses and rorbs growing in the goose yard. It seems unlikely that dietary changes of any significance could have occurred during the short period or primary feather growth. Primary feathers one-half to two-thirds grown were clipped from one-third of the birds in August 1972. This would be a convenient time to collect diagnostic material from wild populations since the birds are flightless and on their moulting areas. Fully formed feathers from an additional one-third of the birds were clipped near the end of October 1972. Plans to incorporate feathers from the final third of the flock, clipped the next May, were curtailed by circumstances beyond our control. An analysis of varlance was designed to examine the differences between (a) half-grown and whole feathers, (b) males and females, (c) right wings and left wings, and (d) 1st and 10th primary feathers. The 1st and 10th primaries were chosen since atomic absorption :flame emission analysis, the technique used, is destructive. We wished to retain most of the feathers for later analysis by X-ray fluorescing spectroscopy. Each sample consisted of 10 feathers, 1 from each of 10 birds of like sex. They were first laundered in two successive, 2-min washes of tetrachloroethylene, one of distilled water, and one of acetone, all in an ultrasonic cleaner. Each sample was then dried, chopped, mixed, and subsampled for analysis. Each sample was analyzed for nine chemical elements: potassium (K), calcium (Ca), sodium (Na), copper (Cu), iron (Fe), manganese (Mn), magnesium (Mg), silicon (Si), and zinc (Zn) These were chosen because they could be determined rapidly, using established methods that are described elsewhere (Pannekoek er al. 1974). A Jarrel-Ash model 82-500 atomic absorption :flame emission spectrometer was used with the flame emission mode for Na and K, and the atomicabsorption mode for Ca, Cu, Fe, Mg, Mn, and Zn. Silicon was determined gravimetrically. The analysis of variance was carried out on an IBM 1130 computer, using a program developed by Clyde Computing Service, 9555 North Kindall Drive, Miami, Florida. All data from the experiment and analysis are held at Canadian Wildlife Service, Pacific and Yukon Region headquarters, Delta, British Columbia.
Results and Discussion The results of our chemical analyses are given in Table 1 and of the analysis of variance in Table 2. The range of values shown for seven chemical elements (Table 1) are within those
VOL.
54. 1976
determined previously for waterfowl flight feathers (Kelsall1970a; Hanson and Jones 1974). However, two new high values were found: Fe at 412 ppm (previous high 3 14 ppm) and Mn at 55.7 ppm (previous high 10 ppm). As in previous analyses the range in values within chemical elements was large. The range is least in Zn, where the largest value is only 1.5 times the smallest, and it is greatest in Mn, where the largest value is 20.6 times than the smallest. It is shown elsewhere that some of this variability is likely due to analysis error--equipment and (perhaps) techniques that give inconsistent results (Kelsall et al. 1975~). Table 2 shows statistically significant differences between partly grown and wholly grown feathers ('stage of growth' row) in seven of the nine chemical elements. Even superficial scrutiny of Table 1 shows that whole feathers contain more Si, Ca, Fe, Mg, and Mn than partly grown feathers on a basis of parts per million. Presumably the blood supply system, visible along the ventral groove of the shaft of feathers which are even two-thirds grown, carries minerals until growth is about complete. There is less Na and K in whole feathers. Those elements might be more subject to leaching than the rest, as they are highly water soluble in many of their forms. It is worth noting that the differences observed between whole and half feathers are, roughly, of about the same order of magnitude as differences between these whole feathers and comparably aged whole feathers from wild young birds, as reported by Kelsall et al. (1975~).Statistical comparisons are not warranted because here we analyzed primaries 1 and 10, and Kelsall et al. analyzed primaries 3 to 7 inclusive. However, in every case except Fe, values for feathers from wild birds deviate toward those of half-grown feathers, if the values from whole feathers from captive birds are considered as a baseline. Since, in most cases, half feathers have lesser values, it may be that the diets of the wild birds examined were less rich in most elements than were the diets of the captives. Table 2 also shows consistently significant differences between primary feathers 1 and 10 in all minerals tested. Other studies (Kelsall et al. 1975a) show gradations in relative quantity of most chemical elements through the spectrum of primary feathers, from the third to seventh inclusive, with the first several primaries tending
1155 2180 2034 2640 2718 2648 3346 4466
1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2
1 1 1 1 10 10 I0 EO
1 1 1 1 10 10 10 10 1 1 1 1 10 10 10 10
1694 1150 2331 3059 2156 2202 1910 3521
663 566 1184 976 1320 1146 1130 2605
889 1033 784 837 1622 1660 1325 1726
1 2 1 2 1 2 1 2
1 1 1 1 10 10 10 10
1034 1056 1116 1077 1390 1618 1480 1468
609 611 669 590 817 609 585 930
1090 983 1215 1189 1349 1247 1594 1571
601 427 574 634 567 594 540 592
9.9 13.0 12.4 10.1 16.4 16.7 11.9 14.0
12.1 8.2 10.7 11.9 15.6 13.1 14.8 15.4
11.5 11.4 10.0 11.6 12.7 13.3 12.4 14.1
10.4 10.6 11.7 13.1 13.4 16.4 14.1 12.0
171.0 111.8 213.1 365.6 193.9 254.0 214.9 412.0
69.1 60.6 120.0 139.2 120.8 114.3 92.7 204.7
141.6 232.8 267.1 242.0 275.8 223.4 344.7 376.2
76.8 89.1 96.6 84.7 152.5 141.7 189.5 145.4
303.0 273.9 333.3 287.2 365.3 311.4 378.4 349.1
187.4 191.3 212.2 182.8 231.6 199.7 190.1 231.5
306.0 260.8 281 .O 338.8 334.3 346.9 322.2 357.2
190.7 144.6 169.9 160.3 169.3 167.2 154.5 191.2
35.6 26.5 43.1 50.5 23.3 29.3 34.1 37.3
7.4 16.0 7.5 11.2 9.1 2.7 2.7 14.8
41.8 45.8 55.7 52.6 33.4 25.2 36.4 42.3
9.2 5.6 9.9 7.3 7.2 5.6 1.6 5.8
97.0 112.9 100.3 105.1 130.6 120.1 107.2 118.9
113.7 99.8 109.7 99.7 127.5 122.1 129.0 114.9
102.2 108.6 96.7 101.9 124.1 98.5 113.9 134.8
102.5 101.3 87.3 91.6 110.7 102.6 118.6 108.8
223 214 174 204 162 240 131 167
350 415 382 353 181 224 191 157
158 172 121 166 148 127 186 214
361 429 403 370 178 153 174 205
.Om fcsrher from each nT 10 birds per sample. +Leftand right mCer to feathem from 3eR and right wings; numbers 1 and 10 refer to the 1st and 10th individual primary feathers starting at the dIstal end of the wing. $Each category of sarnplc was prepared and analyzed in replicate.
Left Left Right Right Left Left Right Right Wholly grown 86 Left Left Right Right Left Left Right Right Half-grown ? ? Left Left Right Right Left Left Right Right Wholly grown 99 Left Left Right Right Left Left Right Right
Half-grown 68
snow geese
TABLE 1. Values, in parts per million, for nine chemical elements from bulked* samples of half and wholly grown primary feathers from captive lesser
Can. J. Zool. Downloaded from www.nrcresearchpress.com by UNIVERSITY OF MICHIGAN on 11/18/14 For personal use only.
Can. J. Zool. Downloaded from www.nrcresearchpress.com by UNIVERSITY OF MICHIGAN on 11/18/14 For personal use only.
CAN. J . ZOOL. VOL. 54, 1976
to be more highly mineralized than the others. The difference between feathers is, therefore, not surprising. Sexual differences between birds are shown, at the 5% level of significance, in respect to Mg and Zn. It is surprising that there are not more such differences. Kelsall and Calaprice (1972) showed the elements Zn, Fe, Ca, K, P, and Cu, in descending order of importance, contributing to the statistically significant separation of feathers from three species of captive ducks, by sex. Feathers of young and adult wild lesser snow geese were separated sexually by Fe, K, Cu, Na, Mg, and Si (Kelsall et al. 1975~). Morphologically and behaviorally, however, male and female lesser snow geese are more alike than most duck species and, in this experiment, all the birds were the young of the year. Perhaps this is reflected in similar feather chemistry. Sexual differences might become more apparent when the birds diverge physiologically and behaviorally on reaching breeding age. There are two significant differences between left wings and right wings (Si and Fe). We have consistently looked for such differences in the past without finding any that were thought to be of biological significance. There is a suspicion that, in this case, differences may be an artifact resulting from the permanent pinioning to which the birds were subjected. Right wings were consistently pinioned and provided the highest values for Si and Fe; pinioned wings are often frayed and are visibly dirty with contaminants from the soil and water; Si and Fe are common contaminants, and our laundering techniques (while thorough) may be imperfect. There are 6 additional points of significant variance among the 99 possible, due to interaction between 2 or more of the ~ r i m a r vsources of variance. Stage x feather accounts for three of those, with respect to Ca, Na, and K, and in each case the primary sources vary significantly within themselves. Other points of significant interaction (all at the 5% level) can be seen on Table 2. They are of doubtful biological significance. Sex x wing shows a significant interaction in respect to N a although the two primary sources of variation do not differ within themselves. Significance in this case may well be due t o chance alone. Our primary purpose, to show whether or not the chemistry of partly grown feathers differs from that of whole feathers, has been met con-
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KELSALL AND PANNEKOEK: MINERALS IN PLUMAGE OF SNOW GEESE
clusively. There are significant differences that virtually preclude the possibility of using immature feathers, which would be easy to collect in the field, for diagnostic purposes. Furthermore, there is a suggestion that elements which form compounds that are highly water soluble, such as Na and R,may leach from feathers. There is a need to continue this experiment, and to include whole feathers from several points in time between September, when feathers are wholly grown, and July, when they are moulted ; such work i s planned. Work by Franmann and Arneson (1973) on moose hair (like feathers, also hard keratin) suggests that values for a number of elements (Pb (lead), Cd (cadmium), K, Na, Ca, Mg, Mn, Zn, and Cu) tend to diminish through winter. In the case of Fe, values tend to increase (from about 35 to 65 ppm) from August to the following May. If the proportions of chemical elements in wholly grown primary feathers also vary significantly in time, the possibility of accurately identifying the origins of waterfowl through chemical means becomes complicated.
Acknowledgments We are grateful to the staff of the Pacific Biological Station, Nanaimo, where we were supplied with office and laboratory space, and instruments for our work. Mr. Frank Nash, of
305
the Station, did the analysis of variance for us and Dr. John Calaprice was helpful with many arrangements. Computer Services of Canada Ltd., Vancouver, assisted with the experimental design. DEVJNE, T., and T. J. PETERLE.1968. Possibledifferentiation of natal areas of North American waterfowl by neutron activation analysis. J . Wildl. Manage. 32(2): 274-279. FRANZMANN, A. W., and P. D. ARNESON. 1973. Moose productivity and physiology. Alaska Dep. Fish Game, Job Prog . Rep. 14. HANSON,H. C., and R. L. JONES.1968. Use of feather minerals as biological tracers to determine the breeding and moultinggrounds of wildgeese. 111. Nat. Hist. Surv. Biol. Notes, 60. 1974. An inferred sex differential in copper metabolism in Ross' geese (Anser rossii); biogeochemical and physiological considerations. Arctic, 27(2): 1 1 1-1?0. KELSALL.J. P. 1970~.Chemical elements in waterfowl flight feathers. Can. Wildl. Serv. Prog. Notes, 17. 14711h. Comparative analysis d feather parts from wild mallards. Can. Wildl. Serv. Plag. Notes, 18. KELSALL, .I. P.. and J . R. CALAPRICE. 1972. Chemical content uf waterfowl plumage as a potenrial diagnostic tool. J. Wildl. Manage. 36(4): 1088-1097. KELSALL,J. P., W. J . PANNEKOEK, and R. BURTON. 1975a. Chemical variability in plumage of wild lesser snow geese. Can. J . Zool. 53: 1369-1375. -1975b. Variability in the chemical content of waterfowl plumage. Can. J. Zool. 53: 1379-1386. and R. BURTON. 1974. PANNEKOEK, W. J., J. P. KELSALL, Methods of analyzing feathers for elemental content. Environ. Can. Fish. Mar. Serv. Tech. Rep. 498.
-
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Received September 16, 1975 KELSALL,J. P., and W. J. PANNEKOEK. 1976. The mineral profile of plumage in captive lesser snow geese. Can. J. Zool. 54: 301-305. This is a contribution to a larger study aimed at development of a technique to determine the origins of waterfowl from their feather chemistry. Results are reported of an experiment designed to show whether there were differences in the mineral profile between primary feathers one-half to two-thirds grown and fully formed feathers, within a population of captive lesser snow geese. Primaries 1 and 10 were used as sample materials and the elements Na, Ca, K , Fe, Cu, Mn, Mg, Zn, and Si were used as variables. Statistically significant differences were shown between stages of growth in respect to all variables except Cu and Zn. The experiment also showed significant differences between different primary feathers in respect to all variables, and some differences attributable to the sex of birds from which samples were taken.
J. P., et W. J. PANNEKOEK. 1976. The mineral profile of plumage in captive lesser snow KELSALL, geese. Can. J. Zool. 54: 301-305. Cet article fait partie d'une Ctude d'enverpure destinke b mettre ail point une technique visant h determiner les origines des oiseat~xaqtrdtiques d'aprk la nature chimique de leur plumage. On donne ~ c ki s rkultats d'une experience stir des petltes oies blanches par laquellr on a voulu cnnstater s'il existe ou non des difference5 de profil rnin6ral entre des remiges primaires ayant atteint de la moitii aux deux tierr de leur dkvelopprnenl et der plumes adultes. On a util~sb$ cette fin ley rkmiges primaires 1 et 10 el les ilementq Na. Ca, K. Fe. Crr, Mn, Mg. Zn et Si ont servi dc vartahles. IIexiste des differences s~gnificativesentre les divers starles de cmissance dans Ie cas de routes le9 variables, sauf Cu et Zn. t'expbrience a d i m o n t e tgalemenr qu'il existe d e ~ d ~ f l ~ t e n c e~ignificativcs. s dans le cas de toutes ler variables, entre ies differentes remiges prlmaires: il cxiste aussi des differences attrihuabler au sexc des oiseaux don1 un a examink les plumes. [Traduit par le journal]
Introduction The Canadian Wildlife Service began testing the possibility of determining the origins of waterfowl through their feather chemistry in 1968. Waterfowl shed their primary flight feathers simultaneously, and are grounded until they grow new ones. It seems axiomatic that each set of flight feathers will, to some degree, reflect the chemistry of the particular area in which it was grown. Some preliminary success in identifying the origins of birds by chemical means have been reported (Hanson and Jones 1968: Devine and Petede 1968). Our investigations first centered on mallards (Anas p/at~~rl~vnchos), black ducks (Anas rubripes), and lesser scaup (Ayihyu afinis). Methods for wet chemical analysis have been adapted or developed, and significant differences have been observed between species, and between sexes and 'Author to whom requests for reprints should be addressed. 'Present address: Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan.
year classes within species, using 9 to 1 1 chemical elements, and computerized multivariate discriminant analysis (Kelsall 1970a, 1970b; Kelsall and Calaprice 1972; Pannekoek et al. 1974; Kelsall rr at. 1975S). In 197 1 lesser snow geese (Anser caerulescens) were chosen as a continuing experimental species because they are colonial nesters and, theoretically, present a relatively simple ecological situation for investigation. A great cnncern is the possibiIity that the quantity of some, or all, of t h e chemical elements in primary flight feathers may change significantly between the time t h e feathers are grown in late summer and early aulumn. and the time they are moulted, usually in late July the next year. If there are changes in chemical composition in time, then it would nor be possible to identify the origins of birds from chemical profiles in feathers directly. Tn such a case diamostic feathers and unknowns would all have to be collected at the same time of the year, or rates of chemical change would have to be measured and compensated for. Both possibil-
302
CAN. J. ZOOL.
ities impose severe limitations on the practicality of the technique. An experiment was designed to explore some chemical differences in time.
Can. J. Zool. Downloaded from www.nrcresearchpress.com by UNIVERSITY OF MICHIGAN on 11/18/14 For personal use only.
Materials and Methods Feathers were taken from captive snow geese that were hatched, raised, and maintained at Brooks, Alberta. All the birds were kept on common rations and in a common enclosure with water freely available. Rations were fed ad libitum-a pheasant starter ration for three weeks after hatching and then a pheasant grower ration on a continuing basis. There was somc opportunity to supplement the standard rations with grasses and rorbs growing in the goose yard. It seems unlikely that dietary changes of any significance could have occurred during the short period or primary feather growth. Primary feathers one-half to two-thirds grown were clipped from one-third of the birds in August 1972. This would be a convenient time to collect diagnostic material from wild populations since the birds are flightless and on their moulting areas. Fully formed feathers from an additional one-third of the birds were clipped near the end of October 1972. Plans to incorporate feathers from the final third of the flock, clipped the next May, were curtailed by circumstances beyond our control. An analysis of varlance was designed to examine the differences between (a) half-grown and whole feathers, (b) males and females, (c) right wings and left wings, and (d) 1st and 10th primary feathers. The 1st and 10th primaries were chosen since atomic absorption :flame emission analysis, the technique used, is destructive. We wished to retain most of the feathers for later analysis by X-ray fluorescing spectroscopy. Each sample consisted of 10 feathers, 1 from each of 10 birds of like sex. They were first laundered in two successive, 2-min washes of tetrachloroethylene, one of distilled water, and one of acetone, all in an ultrasonic cleaner. Each sample was then dried, chopped, mixed, and subsampled for analysis. Each sample was analyzed for nine chemical elements: potassium (K), calcium (Ca), sodium (Na), copper (Cu), iron (Fe), manganese (Mn), magnesium (Mg), silicon (Si), and zinc (Zn) These were chosen because they could be determined rapidly, using established methods that are described elsewhere (Pannekoek er al. 1974). A Jarrel-Ash model 82-500 atomic absorption :flame emission spectrometer was used with the flame emission mode for Na and K, and the atomicabsorption mode for Ca, Cu, Fe, Mg, Mn, and Zn. Silicon was determined gravimetrically. The analysis of variance was carried out on an IBM 1130 computer, using a program developed by Clyde Computing Service, 9555 North Kindall Drive, Miami, Florida. All data from the experiment and analysis are held at Canadian Wildlife Service, Pacific and Yukon Region headquarters, Delta, British Columbia.
Results and Discussion The results of our chemical analyses are given in Table 1 and of the analysis of variance in Table 2. The range of values shown for seven chemical elements (Table 1) are within those
VOL.
54. 1976
determined previously for waterfowl flight feathers (Kelsall1970a; Hanson and Jones 1974). However, two new high values were found: Fe at 412 ppm (previous high 3 14 ppm) and Mn at 55.7 ppm (previous high 10 ppm). As in previous analyses the range in values within chemical elements was large. The range is least in Zn, where the largest value is only 1.5 times the smallest, and it is greatest in Mn, where the largest value is 20.6 times than the smallest. It is shown elsewhere that some of this variability is likely due to analysis error--equipment and (perhaps) techniques that give inconsistent results (Kelsall et al. 1975~). Table 2 shows statistically significant differences between partly grown and wholly grown feathers ('stage of growth' row) in seven of the nine chemical elements. Even superficial scrutiny of Table 1 shows that whole feathers contain more Si, Ca, Fe, Mg, and Mn than partly grown feathers on a basis of parts per million. Presumably the blood supply system, visible along the ventral groove of the shaft of feathers which are even two-thirds grown, carries minerals until growth is about complete. There is less Na and K in whole feathers. Those elements might be more subject to leaching than the rest, as they are highly water soluble in many of their forms. It is worth noting that the differences observed between whole and half feathers are, roughly, of about the same order of magnitude as differences between these whole feathers and comparably aged whole feathers from wild young birds, as reported by Kelsall et al. (1975~).Statistical comparisons are not warranted because here we analyzed primaries 1 and 10, and Kelsall et al. analyzed primaries 3 to 7 inclusive. However, in every case except Fe, values for feathers from wild birds deviate toward those of half-grown feathers, if the values from whole feathers from captive birds are considered as a baseline. Since, in most cases, half feathers have lesser values, it may be that the diets of the wild birds examined were less rich in most elements than were the diets of the captives. Table 2 also shows consistently significant differences between primary feathers 1 and 10 in all minerals tested. Other studies (Kelsall et al. 1975a) show gradations in relative quantity of most chemical elements through the spectrum of primary feathers, from the third to seventh inclusive, with the first several primaries tending
1155 2180 2034 2640 2718 2648 3346 4466
1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2
1 1 1 1 10 10 I0 EO
1 1 1 1 10 10 10 10 1 1 1 1 10 10 10 10
1694 1150 2331 3059 2156 2202 1910 3521
663 566 1184 976 1320 1146 1130 2605
889 1033 784 837 1622 1660 1325 1726
1 2 1 2 1 2 1 2
1 1 1 1 10 10 10 10
1034 1056 1116 1077 1390 1618 1480 1468
609 611 669 590 817 609 585 930
1090 983 1215 1189 1349 1247 1594 1571
601 427 574 634 567 594 540 592
9.9 13.0 12.4 10.1 16.4 16.7 11.9 14.0
12.1 8.2 10.7 11.9 15.6 13.1 14.8 15.4
11.5 11.4 10.0 11.6 12.7 13.3 12.4 14.1
10.4 10.6 11.7 13.1 13.4 16.4 14.1 12.0
171.0 111.8 213.1 365.6 193.9 254.0 214.9 412.0
69.1 60.6 120.0 139.2 120.8 114.3 92.7 204.7
141.6 232.8 267.1 242.0 275.8 223.4 344.7 376.2
76.8 89.1 96.6 84.7 152.5 141.7 189.5 145.4
303.0 273.9 333.3 287.2 365.3 311.4 378.4 349.1
187.4 191.3 212.2 182.8 231.6 199.7 190.1 231.5
306.0 260.8 281 .O 338.8 334.3 346.9 322.2 357.2
190.7 144.6 169.9 160.3 169.3 167.2 154.5 191.2
35.6 26.5 43.1 50.5 23.3 29.3 34.1 37.3
7.4 16.0 7.5 11.2 9.1 2.7 2.7 14.8
41.8 45.8 55.7 52.6 33.4 25.2 36.4 42.3
9.2 5.6 9.9 7.3 7.2 5.6 1.6 5.8
97.0 112.9 100.3 105.1 130.6 120.1 107.2 118.9
113.7 99.8 109.7 99.7 127.5 122.1 129.0 114.9
102.2 108.6 96.7 101.9 124.1 98.5 113.9 134.8
102.5 101.3 87.3 91.6 110.7 102.6 118.6 108.8
223 214 174 204 162 240 131 167
350 415 382 353 181 224 191 157
158 172 121 166 148 127 186 214
361 429 403 370 178 153 174 205
.Om fcsrher from each nT 10 birds per sample. +Leftand right mCer to feathem from 3eR and right wings; numbers 1 and 10 refer to the 1st and 10th individual primary feathers starting at the dIstal end of the wing. $Each category of sarnplc was prepared and analyzed in replicate.
Left Left Right Right Left Left Right Right Wholly grown 86 Left Left Right Right Left Left Right Right Half-grown ? ? Left Left Right Right Left Left Right Right Wholly grown 99 Left Left Right Right Left Left Right Right
Half-grown 68
snow geese
TABLE 1. Values, in parts per million, for nine chemical elements from bulked* samples of half and wholly grown primary feathers from captive lesser
Can. J. Zool. Downloaded from www.nrcresearchpress.com by UNIVERSITY OF MICHIGAN on 11/18/14 For personal use only.
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CAN. J . ZOOL. VOL. 54, 1976
to be more highly mineralized than the others. The difference between feathers is, therefore, not surprising. Sexual differences between birds are shown, at the 5% level of significance, in respect to Mg and Zn. It is surprising that there are not more such differences. Kelsall and Calaprice (1972) showed the elements Zn, Fe, Ca, K, P, and Cu, in descending order of importance, contributing to the statistically significant separation of feathers from three species of captive ducks, by sex. Feathers of young and adult wild lesser snow geese were separated sexually by Fe, K, Cu, Na, Mg, and Si (Kelsall et al. 1975~). Morphologically and behaviorally, however, male and female lesser snow geese are more alike than most duck species and, in this experiment, all the birds were the young of the year. Perhaps this is reflected in similar feather chemistry. Sexual differences might become more apparent when the birds diverge physiologically and behaviorally on reaching breeding age. There are two significant differences between left wings and right wings (Si and Fe). We have consistently looked for such differences in the past without finding any that were thought to be of biological significance. There is a suspicion that, in this case, differences may be an artifact resulting from the permanent pinioning to which the birds were subjected. Right wings were consistently pinioned and provided the highest values for Si and Fe; pinioned wings are often frayed and are visibly dirty with contaminants from the soil and water; Si and Fe are common contaminants, and our laundering techniques (while thorough) may be imperfect. There are 6 additional points of significant variance among the 99 possible, due to interaction between 2 or more of the ~ r i m a r vsources of variance. Stage x feather accounts for three of those, with respect to Ca, Na, and K, and in each case the primary sources vary significantly within themselves. Other points of significant interaction (all at the 5% level) can be seen on Table 2. They are of doubtful biological significance. Sex x wing shows a significant interaction in respect to N a although the two primary sources of variation do not differ within themselves. Significance in this case may well be due t o chance alone. Our primary purpose, to show whether or not the chemistry of partly grown feathers differs from that of whole feathers, has been met con-
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KELSALL AND PANNEKOEK: MINERALS IN PLUMAGE OF SNOW GEESE
clusively. There are significant differences that virtually preclude the possibility of using immature feathers, which would be easy to collect in the field, for diagnostic purposes. Furthermore, there is a suggestion that elements which form compounds that are highly water soluble, such as Na and R,may leach from feathers. There is a need to continue this experiment, and to include whole feathers from several points in time between September, when feathers are wholly grown, and July, when they are moulted ; such work i s planned. Work by Franmann and Arneson (1973) on moose hair (like feathers, also hard keratin) suggests that values for a number of elements (Pb (lead), Cd (cadmium), K, Na, Ca, Mg, Mn, Zn, and Cu) tend to diminish through winter. In the case of Fe, values tend to increase (from about 35 to 65 ppm) from August to the following May. If the proportions of chemical elements in wholly grown primary feathers also vary significantly in time, the possibility of accurately identifying the origins of waterfowl through chemical means becomes complicated.
Acknowledgments We are grateful to the staff of the Pacific Biological Station, Nanaimo, where we were supplied with office and laboratory space, and instruments for our work. Mr. Frank Nash, of
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the Station, did the analysis of variance for us and Dr. John Calaprice was helpful with many arrangements. Computer Services of Canada Ltd., Vancouver, assisted with the experimental design. DEVJNE, T., and T. J. PETERLE.1968. Possibledifferentiation of natal areas of North American waterfowl by neutron activation analysis. J . Wildl. Manage. 32(2): 274-279. FRANZMANN, A. W., and P. D. ARNESON. 1973. Moose productivity and physiology. Alaska Dep. Fish Game, Job Prog . Rep. 14. HANSON,H. C., and R. L. JONES.1968. Use of feather minerals as biological tracers to determine the breeding and moultinggrounds of wildgeese. 111. Nat. Hist. Surv. Biol. Notes, 60. 1974. An inferred sex differential in copper metabolism in Ross' geese (Anser rossii); biogeochemical and physiological considerations. Arctic, 27(2): 1 1 1-1?0. KELSALL.J. P. 1970~.Chemical elements in waterfowl flight feathers. Can. Wildl. Serv. Prog. Notes, 17. 14711h. Comparative analysis d feather parts from wild mallards. Can. Wildl. Serv. Plag. Notes, 18. KELSALL, .I. P.. and J . R. CALAPRICE. 1972. Chemical content uf waterfowl plumage as a potenrial diagnostic tool. J. Wildl. Manage. 36(4): 1088-1097. KELSALL,J. P., W. J . PANNEKOEK, and R. BURTON. 1975a. Chemical variability in plumage of wild lesser snow geese. Can. J . Zool. 53: 1369-1375. -1975b. Variability in the chemical content of waterfowl plumage. Can. J. Zool. 53: 1379-1386. and R. BURTON. 1974. PANNEKOEK, W. J., J. P. KELSALL, Methods of analyzing feathers for elemental content. Environ. Can. Fish. Mar. Serv. Tech. Rep. 498.
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