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Full text of "North American fauna"

BOSTON PUBLIC LIBRARY 



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The 

TRUMPETER 



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OCCIDENTAL C0LLEG8 

MY 4 1960 

LIBRARY 



UNITED STATES 

DEPARTMENT OF THE INTERIOR 

FISH AND WILDLIFE SERVICE 



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The 

TRUMPETER SWAN 



Frontispiece: A pair of trumpeters 
in flight over their breeding grounds 
on the Red Rock Lakes Refuge, 
southwestern Montana. 



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The 

TRUMPETER SWAN 

ITS HISTORY, HABITS, AND 
POPULATION IN THE UNITED STATES 



By 

Winston E. Banko 
Refuge Manager, Branch of Wildlife Refuges 
Bureau of Sport Fisheries and Wildlife 




NUMBER 63 



UNITED STATES 
DEPARTMENT OF THE INTERIOR 

Fred A. Seaton, Secretary 

FISH AND WILDLIFE SERVICE 

Arnie J. Suomela, Commissioner 

BUREAU OF SPORT FISHERIES AND WILDLIFE 

Daniel H. Janzen, Director 




North American Fauna, Number 63 



Published by U.S. Fish and Wildlife Service 
April 30, I960 



United States Government Printing Office • Washington 



1960 



For sale by the Superintendent of Documents, U.S. Government Printing Office 
Washington 25, D.C. - Price $1.00 



CONTENTS 



Page 

Foreword 1 

Introduction 4 

Legend and tradition 4 

Description and systematics 5 

Distribution and status 8 

Geological occurrence 8 

Primitive history 9 

Early historical notes (1632-1832) 10 

Later historical notes (1833-1925) 14 

Early migration notes 25 

Spring migration (departure) 25 

Spring migration (arrival) 26 

Fall migration (departure) 27 

Fall migration (arrival) 27 

Recent occurrence, breeding, and migration reports, to 1957_. 28 

Pacific fly way 28 

Central fly way 35 

Mississippi and Atlantic flyways 37 

H ABIT at 38 

Breeding habitat 38 

Life zone characteristics 38 

Physical characteristics 39 

Red Rock Lakes Refuge 40 

Yellowstone National Park 48 

Copper River Basin, Alaska 52 

Wintering habitat 54 

Island Park 56 

Red Rock Lakes Refuge 58 

Yellowstone National Park 58 

National Elk Refuge 60 

Madison River 60 

Winter counts 60 

Life cycle 62 

Description 62 

Species description 62 

External appearance 65 

Voice 68 

Plumages and molting 70 

Flight 74 

Behavior and related characteristics 77 

Escape-distance 78 

Interspecific tolerance 79 

M emory 82 

Sensory perception 83 

Some general behavior attitudes 84 

Display 86 

Breeding 93 

Pair formation 94 



VI CONTENTS 

Page 

Breeding age 94 

Mating fidelity 96 

Prenesting habits and behavior 99 

Territory and territorial behavior 100 

Nesting 111 

Nest sites 111 

Nest building 111 

Egg description 113 

Clutch size 114 

Egg laying 114 

Incubation 114 

Hatching data 115 

Renesting 116 

Cygnet development 117 

Food 122 

Feeding habits and food of young 122 

Feeding habits and food of older cygnets, immatures, and 

adults 124 

Limiting factors 130 

Egg failure 130 

Preflight cygnet mortality 131 

Mortality of immatures and adults 133 

Longevity 143 

Population 144 

Annual swan census, 1929-57 144 

Population dynamics 145 

Red Rock Lakes Refuge populations 151 

Yellowstone National Park populations 155 

Population outside Red Rock Lakes Refuge and Yellow- 
stone National Park -- 160 

Summary 161 

Conclusions - 163 

Discussion - — 163 

Management 165 

Protective legislation 165 

Captivity record.. 167 

National Park Service investigations 172 

Swan management on the Red Rock Lakes Refuge 176 

General practices. 176 

Transplanting program 178 

Banding 182 

Management recommendations 183 

Bibliography 189 

Appendix 1 — Excerpt from "Observations on the genera of the 

swans", by Alexander Wetmore 198 

Appendix 2 — Status and distribution of trumpeter swans in the 

United States, 1954 199 

Appendix 3 — Measurements of trumpeter swan eggs 201 

Appendix 4 — Food analysis 202 

Appendix 5 — Supplementary data, annual swan census 205 

Index 207 



ILLUSTRATIONS 

Page 
Frontispiece. Pair of trumpeters in flight over their breeding 
grounds on the Red Rock Lakes Refuge, southwest- 
ern Montana. 
Figure 

1. Locations of some Hudson's Bay Company posts which en- 
gaged in swan-skin trade, 1828-84 18 

2. A day's bag of waterfowl in 1895 at Red Rock Lakes included 

a trumpeter swan 22 

3. Former breeding and wintering range, trumpeter swan 26 

4. Aerial view of trumpeter breeding grounds in lower Copper 
River Basin, Alaska, at confluence of Tasnuna, Bremner, and 
Copper Rivers 34 

5. Presently known breeding and wintering range, trumpeter 
swan 39 

6. Map of Red Rock Lakes Migratory Waterfowl Refuge 40 

7. The Red Rock Lakes owe their stable waters to the Centennial 
Mountains which tower above them to the south, trapDing 
abundant snows that feed the numerous creeks and springs 
entering the marsh system _ 41 

8. Aerial view of Red Rock Lakes. Lower Lake in foreground 
is dotted with beds of bulrush. The marsh system is at the 
upper left, and the Upper Lake is in the center background... 42 

9. Trumpeter swan nest located on an old muskrat house on a 
cattail-sedge island in Lower Red Rock Lake. In the back- 
ground the Centennial Mountains wear a snow mantle normal 

for June — 43 

10. Numerous channels, sloughs, and potholes set in a bog-mat 
environment of beaked sedge typify the Red Rock Lakes 
marsh. Darker shoreline vegetation is bulrush, cattail and 
rushes — 44 

11. A trumpeter nest located in the predominant sedge environment 
of the Red Rock Lakes marsh. Stem and leaf parts of both 
sedge and cattail form the bulk of the nest material both for 

the muskrat lodge nest foundation and the nest proper 45 

12. Swan Lake is a shallow marsh sealed off from Upper Red Rock 
Lake by a natural sedge-willow anchored dike. Islands and 
peninsulas are chiefly sedge bog-mat while many extensive 

beds of spikerush also occur in these stable shallow waters — 46 

13. A trumpeter pen on her nest in a shoreline stand of pure sedge, 
Upper Red Rock Lake. The Centennial Mountains escarp- 
ment forms a chilly backdrop 49 

14. A female trumpeter, on her nest after returning from a feeding 
period in the Lower Lake, shakes the water from her plumage. 
The nest is located on a muskrat house behind a protective screen 
of bulrush. Note elevation of nest in tall, dense cover, 
and discoloration of swan's head and neck from contact with 
ferrous organic matter. 51 

vn 



VIII CONTENTS 



Page 



15. Geographical features of the trumpeter swan breeding and 

w intering areas in the United States 52 

16. Trumpeter swan nesting site at Grebe Lake in Yellowstone 
National Park. Note exposed situation of sedge sod nest. 
Beds of wokas appear in the background, molted feathers in 

the foreground 53 

17. Aerial view of trumpeter nesting habitat in lower Tasnuna 
River Basin, Alaska. Trumpeter nest was found in small 
restricted slough in the lower right hand corner of photo 54 

18. Aerial view of Henrys Fork (North Fork) of the Snake River 
below the Railroad Ranch, Island Park, Idaho. This stretch of 
river offers habitat to wintering trumpeters. The warm Harri- 

man Springs keep these waters open even below — 30° 57 

19. Aerial view of trumpeters wintering on Henrys Fork of the 
Snake River below the Railroad Ranch. Gray birds are cyg- 
nets-of-the-year. Trumpeters from the Grande Prairie, 
Alberta, region have wintered in this area 58 

20. Aerial view of 80 trumpeters in east Culver Spring, Red Rock 
Lakes Refuge, January 1956. Air temperature —20° F. 
Note moose tracks in willow growth 59 

21 . Trachea and sternum of whistling swan 66 

22. Trachea and sternum of trumpeter swan 67 

23. A pair of trumpeters on Grebe Lake, Yellowstone National 
Park, with 3 cygnets of the normal gray color phase and 2 
cygnets of the uncommon white phase 71 

24. Six trumpeters circle the open water at Culver Pond on the 
Red Rock Lakes Refuge in southwestern Montana. Seldom 
more than 6 or 8 of these birds fly together in local flights 
unless a large flock flushes together 73 

25. A pair of trumpeters show the 2 ways of carrying "landing 
gear" during flight. The normal method is by folding them 
back under the tail, but in sub-zero weather cold feet may be 
tucked up forward and be quite invisible in the warm feathers 

and down 75 

26. The normal and "exerting" neck attitudes are shown by 2 
trumpeters. Most commonly bent in this peculiar attitude 
during take-off, the neck straightens out in full flight 75 

27. Six trumpeters landing "flaps down" on Culver Pond, Red 
Rock Lakes Refuge. The feet are thrown forward before 
the moment of impact to ski the bird to a stop. Note various 

web positions guiding birds into landing 77 

28. Trumpeters on Culver Pond display the 2 methods of plumage- 
shaking, 1 employing the wings. The elevated position neces- 
sary for either position is attained by rapidly treading the 
water 84 

29. A small flock of trumpeters feeding with goldeneyes at Culver 
Pond, Red Rock Lakes Refuge. Typical drinking attitude is 
shown by swan with outstretched neck, right of center 85 

30. A typical mutual display of 2 wild trumpeters on wintering 
waters, Red Rock Lakes Refuge 87 

31. Trumpeters face each other in mutual display (right fore- 
ground) and a swan indulges in a wing-flapping plumage shake 
(center background while an adult bald eagle watches from a 
background snowbank in March on Red Rock Lakes Refuge 88 



CONTENTS IX 

Page 

32. Two trumpeters landing on Culver Pond are greeted by dis- 
playing swans. Band on left leg of lower bird marks it as a 
pen (female). Both Barrow's and common goldeneye ducks 

are present in this scene 90 

33. "Solo" display, trumpeter swan on Culver Pond, Red Rock 
Lakes Refuge 92 

34. Rear view of "solo" display (left) 93 

35. While a pair of trumpeters engages in mutual display (left 
center), 4 gather in a group exhibit (right). Mallards and 
pintails in the irregular foreground 93 

36. Aggressive action of trumpeter following group display, Culver 
Pond wintering waters 95 

37. Aggressive pursuit terminating a group display of 5 trumpeters, 

Red Rock Lakes Refuge 97 

38. Observations on the territorial traits of trumpeters can be made 
by a single observer over several thousand acres, since the high 
mountains provide ideal vantage points. Here the birds on 
Lower Red Rock Lake are studied from an observation post on 

the northern flank of Centennial Mountains 102 

39. Nest locations, 1954-57, Upper Red Rock Lake and Swan Lake 
marsh. (Approximately 8,000 acres in map) 108 

40. Nest locations, 1954-57, Lower Red Rock Lake. (Approxi- 
mately 3,000 acres in map) 109 

41. Newly-hatched trumpeter cygnet, Lower Red Rock Lake 118 

42. Close-up of trumpeter cygnet showing fine, grayish-white 
down .. 119 

43. Swan family at loafing site, Grebe Lake, Yellowstone National 
Park. The special foot position of the adult is commonly 
seen with mute swans. This brood is approximately a month 

old 121 

44. Trumpeter swan productivity rates, total population, 1931-57. 149 

45. Nonbreeding trumpeter swans censused at Upper Red Rock 
Lake and Lima Reservoir, 1 940-57 151 

46. Trumpeter swan census, Red Rock Lakes Refuge, 1932-57 152 

47. Trumpeter swan productivity rates, Red Rock Lakes Refuge, 
1936-57 153 

48. Trumpeter swan census, Yellowstone Park, 1931-57 156 

49. Trumpeter swan productivity rates, Yellowstone Park, 1931- 

57 157 

50. Trumpeter swan census outside Red Rock Lakes Refuge and 
Yellowstone Park, 1931-57 160 

51. Trumpeter swan cygnets captured on the Red Rock Lakes by 

the Wetmore family for the live swan trade about 1900 171 

52. The U. S. Fish and Wildlife Service "snowplane" en route to the 
Culver Pond swan wintering grounds for semi-weekly feeding 
of small graii'. The Centennial Mountains in background 

form the Continental Divide along their 10,000-foot crest 179 

53. These trumpeters are only part of the flock of over 200 which 
pass the late winter months on the Refuge awaiting the Spring 
break-up. The 94 trumpeters visible in this single photograph 

are more than existed in the entire United States 25 years ago 184 

54. Trumpeters feed in Culver Pond with mallards, Barrows 
goldeneyes, and common goldeneyes on grain placed out by 
Refuge personnel-. 187 



TABLES 

Page 

1. — Classification of the subfamily Cygninae 6 

2. — Trumpeter swan breeding records in the United States and 

Alaska to 1925 24 

3. — Swans censused, Alaskan waterfowl inventory, January, 1949 

to 1957 32 

4. — Winter swan counts, Greater Yellowstone region, 1950 to 

1957 61 

5. — Overlapping weights and dimensions of small trumpeter and 

large whistling swans 64 

6. — Cygnet mortality at Red Rock Lakes Refuge, 1949 133 

7. — Swan census data, 1931 to 1957 146 

8. — Nonbreeding trumpeter swan populations at Upper Red Rock 
Lake, Lima Reservoir, and other important areas, 1940 to 

1957 147 

9. — Trumpeter swan production data, 1931 to 1957 148 

10. — Trumpeter swan production data, Red Rock Lakes Refuge, 

1936 to 1957 152 

11. — Variations in Refuge swan nesting density 154 

12. — Trumpeter swan production data, Yellowstone Park, 1931 

to 1957 158 

13. — Characteristics of some Yellowstone Park lakes and their 

record of use by swans, 1931 to 1957 159 

14. — Trumpeter swans transferred from the Red Rock Lakes 

Refuge, 1938 to 1957 180 

15. — Trumpeter swan nesting data, National Elk Refuge, Wyo- 
ming, 1944 to 1957 180 

16.— Swans banded at the Red Rock Lakes Refuge, 1945 to 1957- 182 



ILLUSTRATION CREDITS 

Credits for illustrations are as follows : Frontispiece and figures 7-14, 
18-20, 24-37, 42, 45-47. Winston E. Banko : figures 2 and 44. Ceci\ Wet- 
more ; figures 4 and 17, Mel Monson ; figure 16, David de Lancey Con- 
don ; figures 23 and 43, W. Verde Watson; figure 38, U. S. Fish and 
Wildlife Service ; drawings in figures 21 and 22, Mrs. P. W. Parnialee ; 
maps and other illustrations, Shirley A. Briggs. 




IWT? 



FOREWORD 

The appeal of swans to man throughout history has come down to 
us in legend, custom and in many forms of art. That the world's 
largest species of this storied bird should have become nearly extinct 
in its native North America was thus especially tragic. The con- 
tinuing recovery in numbers of this beautiful and graceful symbol 
of American wilderness is a major accomplishment in wildlife 
preservation. 

The establishment of the Red Rock Lakes Migratory Waterfowl 
Refuge was the climax of this effort in the United States, and any 



2 FOREWORD 

study of the trumpeter swan necessarily focuses on the Refuge and 
the adjoining country. In this magnificent mountainous setting a few 
of the swans had survived, and the remoteness of the country has 
made it possible to maintain the wilderness environment favored by 
the birds. 

The present United States population of trumpeters is found 
mainly in a 60-mile radius encompassing parts of southwestern Mon- 
tana where the Refuge is found, eastern Idaho, and northwestern 
"Wyoming, including Yellowstone National Park. 

This report on the trumpeter evolved from studies made from 1948 
to 1957 when I served first as an assistant and later as manager, of 
the Red Rock Lakes Refuge. I have also drawn extensively on the 
records of the National Park Service, the U. S. Fish and Wildlife 
Service, and the National Museum in Washington, D. C. Other perti- 
nent information bearing on the life history of the trumpeter swan in 
the United States has been extracted from published articles, unpub- 
lished reports and records, firsthand accounts and correspondence. 
This account includes a historical record of this bird in the United 
States and Alaska, an outline of its habits and characteristics in its 
native Rocky Mountain environment, and furnishes information nec- 
essary to guide its future. 

A comparable study of the trumpeter by the Canadian Wildlife 
Service has also been underway since about 1950. These investiga- 
tions are being conducted chiefly in British Columbia and Alberta 
by Mr. Ronald H. Mackay, Wildlife Biologist, who made available 
some preliminary results of swan banding studies in Alberta, and was 
helpful in many other ways. For the most part, I have dealt with 
the trumpeter in Canada only in a general way since the Canadian 
findings will probably be published later. 

I wish to express my appreciation for the cooperation received over 
the years from the many individuals and agencies who furnished in- 
formation useful in preparing this report. Generally, acknowledg- 
ment, for this has been handled directly in the text, but special thanks 
and credit are due to several individuals. 

Edmund B. Rogers, former Superintendent, and David de Lancey 
Condon, Chief Naturalist, Yellowstone National Park, generously 
opened the Park files to me and furnished every help possible. Con- 
don and Walter H. Kittams, Park Biologist, reviewed the manuscript 
in its final stages. 

James Rooney of Yakima, Washington, supplied valuable biblio- 
graphic assistance. Lowell Adams, U. S. Fish and Wildlife Service, 
also gave an early review and critique of the MS. 

The information regarding the geological background of Red Rock 
Lakes, Montana, was supplied by Dr. George Kennedy, Geophysicist, 



FOREWORD 6 

University of California, who has an intimate knowledge of this 
region. 

Dr. Herbert K. Friedmann, U. S. National Museum, provided the 
technical physical descriptions of both species of swans native to 
North America from an unpublished manuscript. 

Joseph Flakne, Programming Director, and Marie Tremaine, Chief 
Bibliographer, Arctic Institute of North America, provided for an 
inquiry into the possible role of the swans in the economic life of 
Alaska before acquisition by the United States, and made available 
interesting and scattered notes regarding Old World swans in arctic 
Russia. 

H. Albert Hochbaum, Director, and Dr. Frank McKinney, Assistant 
Director, Delta Waterfowl Research Station, reviewed the manuscript 
and were generous with helpful comments and suggestions. Dr. 
McKinney, and indirectly, Paul Johnsgard of Cornell University, 
supplied me with the English translation (Johnsgard) of O. Hein- 
roth's (1911) classic German work on the ethology and psychology of 
the Anatidae. 

I am grateful to several residents of the Red Rock Lakes region 
who contributed to the historical aspect of this work. Credit and 
thanks are due the following residents of Monida, Montana: Cecil 
Wetmore, James F. and Alta Hanson, and A. Blaine Fordyce. Sam 
A. Trude of Island Park, Idaho, furnished information on that area in 
the early 1900's. 

In the Branch of Wildlife Research, Earl L. Atwood, Chief Bio- 
metrician, Patuxent Research Refuge, assisted in determining the 
significance of the population statistics. 

In the Branch of Wildlife Refuges, special recognition is due Rich- 
ard E. Griffith for his particular interest in the manuscript work 
which extended over a period of many years. In a large measure his 
patient and unflagging support made this report possible. The final 
draft was typed under the direction of Miss Winifred G. Baum, who 
deserves mention for positive action when time counted most. I am 
also greatly indebted to Dr. Ray Erickson and Miss Shirley A. Briggs 
for their tireless efforts in checking and editing the final draft, work 
made especially difficult under the prevailing deadline. 

It is impossible to mention everyone who has been helpful in pre- 
paring this report. 

Winston E. Banko. 

May 1, 1958. 




INTRODUCTION 



LEGEND AND TRADITION 

Of all the earth's varied avian forms, the swans have been woven 
into the cultural expressions of previous civilizations to a greater 
extent than any other group of birds, with the exception perhaps of 
the birds of prey. With their great size, migratory habits, graceful 
manner, and distinctive voice, the majestic swans have apparently 
inspired all the peoples who knew them. 

No doubt our more primitive ancestors were most interested in swans 
because of their value for food. Although wild swans were appar- 
ently never preferred, their availability and size caused them to be 
taken when other sources of meat were short. As man gradually 
developed a regard for spiritual values, swans were employed as an 
important symbolic element in the myths and religious ceremonies 
of many of the early cultures. This was true not only among the 
early peoples of northern Slavic or Nordic origin, but also in the 
regions along the Mediterranean where the long migrations of some of 
the northern-reared swans terminated. 

Although there is frequent mention of swans in Greek mythology, 
they were apparently not included among the many varieties of birds 
and animals commonly kept by the Romans. Swans were known to 
the ancient Egyptians and to the early Christian prophets. In early 
canons, the latter listed swans among the birds and animals which 
were not to be eaten. 

The use of swans as common subjects in story, myth, and ceremony 
was most prominent in the culture of the more northern races of 
mankind, where these birds entered into the ceremonies of the shamans 
of the East, the wizard men of Lapland, and the medicine men of our 



DESCRIPTION AND SYSTEMATICA 

own native Indians (Beebe, 1906: 159). The notable interest of the 
ancients in these distinctive fowl grew with the passing of centuries. 
This later expressed itself in the widely prevalent Eurasian "swan- 
maiden" legend, and more tangibly in such items as some of the early 
coins of Germany and the badge of Henry IV of England. 

Many of the legends which slowly evolved out of early European 
swan mythology are perpetuated in the fairy tales, customs, and tradi- 
tions of certain countries, being now for the most part only relics of a 
forgotten age. "Swan upping" (the taking up of swans for the pur- 
pose of pinioning and marking) is still practiced annually upon the 
Thames River. Records of the English interest in swans date back 
over 800 years to the 12th century A. D. during which the complica- 
tions of swan ownership resulted in the enactment of special laws and 
regulations. After 40 years of study, Norman F. Ticehurst (1957) 
has thoroughly documented the long and interesting history of the 
mute swans in England. 

Swans have been accorded a special place in the folklore, history, 
literature, drama, arts, and musical expressions of contemporary 
peoples as well. In fact, it is difficult to name a medium of man's 
expression that does not owe a modicum of debt to these birds. In 
this respect the swans as a group are unique in the bird world. 

It is evident therefore that much of the present interest in these 
noble birds stems in part from the traditions of many previous civili- 
zations and peoples, extending far back into history. With this 
heritage in mind, we have a responsibility for the welfare of this 
group of birds, and must perpetuate such living symbols of beauty 
and grace for the enjoyment and inspiration of generations yet to 
follow. 

DESCRIPTION AND SYSTEMATICS 

The swans are similarly specialized waterfowl of the diverse and 
prolific family of the Anatidae, and as such they have been given 
status as a subfamily, the Cygninae. This group of waterfowl is 
characterized by necks as long as, or longer than, the large heavy 
body, and short strong legs and feet equipped with large webs and 
prominent nails. This combination of characteristics adapts them 
well for a specialized shallow-water existence, in which they consume 
large quantities of leafy aquatic plants, and dig and root out suc- 
culent rootstocks and tubers. 

With the exception of the black swan of Australia {('henopis 
atratus) and the black-necked swan of South America (Cygnus 
melancoriphns), the adult plumage of all species of swans is entirely 
white. With the further exception of the common mute swan of 
Europe {Cygnus olor), which possesses a prominent knob at the base 



6 



INTRODUCTION 



of the upper mandible in common with the black-necked swan, the 
remaining four species are all smooth-billed (that is without a basal 
knob), white-plumaged, distinctive-voiced swans with an exclusively 
circumpolar distribution. A general account of the characteristics, 
distribution, and habits of all species of swans, with emphasis on their 
traits and requirements in captivity is given by Jean Delacour (1954: 
57-90). In this work, the plumage and appearance of both adults 
and cygnets have been accurately portrayed in full color by Peter 
Scott. 

The division of the swans of the world into 3 genera, 2 subgenera, 
and 7 species is generally accepted as most nearly logical and correct 
(Wetmore, 1951: 338). The systematics of the swans will not be 
treated here. ( See appendix 1 . ) 

Using Wetmore's classification of the swans, which has been 
adopted by the American Ornithologists'' Union, the classification 
and current principal distribution of the swans is outlined in table 1. 
The status, distribution, migration and habits of mute, Bewick's, and 
whooping swan populations in Eurasia are treated by Alfred Hil- 
precht (1956: 8-17), Witherby et al. (1939: 168-179), and G. P. 
Dementiev and N. A. Gladkov (1952) . 

Table 1. — Classification of the subfamily Cygninae 



Scientific name 


Common name 


Principal distribution 




Breeding 


Wintering 


Olor cygnus (Linnaeus) 

Olor bewickii Yarrell 

Olor columbianus (Ord) ... 

Olor buccinator (Richardson). 

Cygnus olor (Gmelin).. 

Cygnus melancoriphus (Mol- 
ina). 
Chenopis atratus (Latham) . 


Whooper Swan 

Bewick's Swan 

Whistling Swan 

Trumpeter Swan 

Mute Swan 

Black-necked Swan... 


Northern and middle 

Eurasia. 
Northern Eurasia 

Northern North Amer- 
ica. 

Northern and middle 
North America. 

Northern and Middle 
Eurasia. 

Southern South Amer- 
ica. 

Australia and New Zea- 
land. 


Southern and middle 

Eurasia. 
Southern and middle 

Eurasia. 
Southern and middle 

North America. 
Middle North America. 

Southern and middle 

Eurasia. 
Southern South America. 

Australia and New Zea- 






land. 



The significant specific differences among the swans in the genus 
Olor are primarily of an anatomical nature, principally in variations 
of the tracheal route through the furculum and along the sternum. 
The variations of the trachea are also responsible for voice differences 
which, with other external differences, are of definite value to the 
field worker in making positive identifications wherever the ranges 
of the various species overlap, as they do to a limited extent over the 
circumpolar range of this genus. 

Since wild populations of the Bewick's swan ( Olor bewickii) have 
never been observed in North American waters, and the whooper 



DESCRIPTION AND SYSTEMATICS 7 

swan (Olor cygnus), though formerly breeding in Greenland, has 
only three recent Continental records (St. Paul Island: Wilke, 1944: 
655; Karl Kenyon, 1949 (letter) ; Amchitka : Kenyon, 1957 (letter)), 
the American field ornithologist need be concerned mainly with dis- 
tinguishing the trumpeter (Olor buccinator) from the whistling swan 
(Olor columbianus) . Although field identification of trumpeters vs. 
whistlers may be fairly certain in those cases where the bird in ques- 
tion gives voice, or where a distinct yellow spot is visible on the lores, 
it may be difficult or impossible to determine the species with certainty 
without a postmortem examination if these characteristics are not 
evident. (The subtle superficial differences between these two species 
will be treated later under the topic Life Cycle.) 

In considering the circumpolar distribution of the genus Olor, 
another point should be mentioned here. The two largest species of 
this group, the trumpeter and the whooper, according to the author- 
ities (Delacour, 1954: 72-73, 84-85; Witherby, et al., 1939: 171, 174) 
range during their breeding season principally over the interior of the 
continents with which they are associated, while the breeding ranges 
of the two smaller species, whistling and Bewick's swans, are primarily 
along the continental fringes and the islands of the Arctic Ocean. 

The numerical status of the trumpeters in North America is only 
partially understood at this time owing to the difficulty of censusing 
completely the wintering trumpeters in Alaska and British Columbia. 
The best recent estimates of this rather obscure population place it 
between 600 and 1,000 birds (Munro, 1949 : 710), while the 1957 trum- 
peter-swan census in the United States found 488 individuals in this 
country. Thus, the total continental population of trumpeters prob- 
ably numbers 1,500 or more. 

The status of whistling swans in North America is much different. 
The midwinter inventory by the U. S. Fish and Wildlife Service in 
January 1958 found 78,425. Wintering populations fluctuate and 
are about equally divided between the Pacific and Atlantic flyways 
(Stewart and Manning, 1958 : 205-207) . 



4GUG60 O— 60- 




DISTRIBUTION AND STATUS 

GEOLOGICAL OCCURRENCE 



At one time or another in the distant past, before man appeared 
on the North American Continent, trumpeter swans must have 
occurred commonly within nearly every region of what is now the 
United States. The advance and retreat of a succession of ice ages 
in the northern hemisphere determined the distribution and status 
of this species as it did those of the other faunal elements. The 
climatic changes may also have been responsible for the passing of 
one North American species of swan from the scene. This extinct 
species has been tentatively designated Cygnus paloregonios, the 
remains of which were discovered at Fossil Lake, Oregon. (In 
addition one Eurasian species has also become extinct at some time 
in the distant past. This is the giant swan of Malta, Palaeocycnus, 
which was larger than any of the swans in existence today.) 

Remains of the progenitors of both trumpeters and whistlers have 
been identified from widely separated geologic formations in the 
United States. Alexander Wet more (1956 : 25) lists trumpeter occur- 
rences in such deposits as follows, "Modern form reported from 
Pleistocene: Aurora, Illinois; Itchtucknee River, Florida. Late 
Pleistocene : Fossil Lake, Oregon." In Illinois the trumpeter remains 
were associated with bones of the giant beaver and mastodon 
(Wetmore, 1935: 237), while in Florida remains of the trumpeter 
were found in Pleistocene material together with the bones of such 
birds as the California condor (Gymnogyps calif ornianus) , whooping 
crane (Grus americana), and jabiru stork (Jabhii mycteria) (Wet- 
more, 1931:19), all of which are of course now unknown in that 
whole region. An unusual Pleistocenic associate of the trumpeter 



PRIMITIVE HISTORY 9 

identified from Fossil Lake, Oregon, deposits was a flamingo 
(Phoenicopterus copei). Dr. Herbert Friedmann (1935 : 23) has also 
recorded the presence of trumpeter bones from Kodiak Island, Alaska. 
So through the centuries the ancestors of the trumpeters existed under 
far different circumstances and in regions which today might no longer 
be considered suitable. 

PRIMITIVE HISTORY 

Long before Caucasian man made his appearance in North America, 
swans were used in various ways by many of the indigenous Indian 
tribes. The swans were undoubtedly sought principally for food, 
and today their remains are occasionally exhumed in archeological 
excavations. The bones of the trumpeter can be specifically identified 
in many such instances. 

H. K. Coale (1915: 89), in his valuable early treatise on the status 
of this species, quotes a reliable source from Ohio as stating: 

We have in our collection a great many bones of the trumpeter swan. It 
.seems that this bird, although a very rare migrant at the present time, was 
here in great numbers in pre-historic time, and we find their bones in the villages 
of the old Indians, who always used the leg bone for making implements, while 
the wing bones were seldom used. I found specimens in the Baum, Bartner, 
and Madisonville village sites. 

In bibliographical material furnished by E. S. Thomas, Curator 
of Natural History of the Ohio Historical Society, various other 
authors have also reported unearthing bones of the trumpeter swan 
among kitchen-midden material from at least four ancient Indian 
village sites in that State. The remains of the trumpeters found in 
these excavations varied greatly in age, from early historic, in the 
case of the Fairport Harbor Village site, to from 2,377 to 2,750 years 
ago for the Kettle Hill Cave and Toepfner Mound sites, as estimated 
by Thomas using carbon- 14 datings. 

Trumpeter bones have also been exhumed in ancient kitchen-midden 
material in Illinois. P. W. Parmalee, Curator of Zoology at Illinois 
State Museum, wrote (correspondence) that findings in six sites cov- 
ered a time range of at least 1,500 years. Most of the swans seem to 
have been used for food, though some bones were cut into beads. At 
the Cahokia village site, near East St. Louis, about 375 trumpeter 
bones have been identified. This village is thought to have been 
vacated just before the coming of the white man. (See also Parmalee, 
1958, in Bibliography.) 

Swans also entered the lives of the early peoples by contributing to 
their dress, ceremony, and legend. The journals of a number of early 
American explorers and travelers, gathered and edited by R. G. 



10 DISTRIBUTION AND STATUS 

Thwaites (1906), contain many firsthand references to the roles 
played by these great white birds in the lives of the Indians. Like 
the plumage of the eagle, feathers of the swans were valued for their 
decorative and symbolic value. 

Although little pertinent life-history information can be learned 
from the accounts of our native swans during pre-Caucasian times, 
we do find that the swans were present and taken frequently enough 
to have entered the lives of the natives as a recognizable part of their 
culture. 

EARLY HISTORICAL NOTES (1632-1832) 

Early accounts of our native swans, and of trumpeters in particu- 
lar, are brief and scattered in the literature over a long period of time. 
A New Englander, Thomas Morton, wrote of the native swans in 
1632 (Force's Historical Tracts, vol. 2 : 46) : 

And first of the Swanne, because she is the biggest of all the fowles of that 
Country. There are of them in Merrimack River, and other parts of the Country, 
greate Store at the seasons of the yeare. The flesh is not much desired of the 
inhabitants, but the skinnes may be accompted a commodity, fitt for divers uses, 
both for f ethers, and quiles. 

Although Morton gives no clue to the species identity of the swans 
which seasonally visited that part of New England in the early days, 
later accounts by other observers indicate that both trumpeters and 
whistlers probably were represented. Jeremy Belknap (1784) listed 
a New Hampshire swan with a "sound resembling that of a trumpet'', 
C. Hart Merriam (1877) thought that both were in Connecticut in 
early times, with one trumpeter reported in his day, and J. A. Allen 
(1878) stated that the trumpeter doubtless was common in Massa- 
chusetts 200 years earlier, and "may still be looked for as a straggler." 

The next early report appears to have been in a history written 
by John Lawson, Surveyor-General of North Carolina, and first 
published in 1709. It is the first to separate the trumpeter as a bird 
distinct from the lesser species and positively record its occurrence 
on the eastern seaboard. This record is as follows (Lawson, 1714: 
86) : 

Of the Swans we have two sorts : the one we call trompeters because of a 
sort of Trompeting Noise they make. These are the largest sort we have ; which 
come in great Flocks in the Winter, and stay, commonly in the fresh Rivers, 
until February, when the Spring comes on, when they go to the Lakes to breed. 
A Cygnet, that is a last year's Swan, is accounted a delicate dish, as indeed it 
is. They are known by their Head and Feathers, which are not so white as 
Old ones. 

Lawson's account is pertinent for several other reasons. First, 
we learn that the early settlers were familiar enough with Olor hue- 



EARLY HISTORICAL NOTES (1632-1832) 11 

cinator to give it the common name of "trumpeter"; second, the 
presence of this species in "large flocks'' on the "fresh Rivers" gives 
us the first and only clues to its original status and winter habitat 
along the east coast ; and third, the positive remark calling attention 
to the time of departure (February) when "they go to the Lakes to 
breed" suggests the nesting of this species somewhere to the east of 
the accepted eastern limits of the breeding range of this species which 
was documented later. Lawson's specific use of the term "Lakes" is 
especially interesting, inasmuch as he does not hint of the breeding 
grounds of the whistling swan in his notes on the lesser species, and 
trumpeters are indeed wholly pond or lake breeders, never known to 
nest along the banks of rivers. The trumpeter is not mentioned again 
in United States ornithological literature for another century, and so 
the possible breeding status of this species east of the Ohio River 
before settlement by the white man remains obscure. 

More than half a century was to elapse before the next perti- 
nent record of swans was left by Samuel Hearne, an employee 
of the Hudson's Bay Company. Hearne's diary contains several brief 
remarks on the swans made on his epic journey from Hudson Bay 
to the Arctic Ocean during the period 1769-72. One of his state- 
ments (Hearne, 1795: 371) not only initially documents the entry 
of the plumage of the swans into the world of commerce but records 
that great numbers of swans were taken for food by the Hudson 
Bay Indians. He states : 

In fact, the skinning of a Rear spoils the meat thereof, as much as it would 
do to skin a young porker or roasting pig. The same may be said of swans 
(the skins of which the Company have lately made an article of trade) ; other- 
wise thousands of their skins might he brought to market annually, by the 
Indians that trade with the Hudson's Bay Company's servants at the different 
settlements about the Bay. 

In the accounts which follow, the plumage of these great birds, first 
valued by the earliest colonists, gradually became and remained an 
article of frontier commerce for over a hundred years, eventually 
reaching the London fur market by the thousands of skins. This fact, 
perhaps more than any other now apparent, caused the gradual reduc- 
tion of numbers and range of both the North American swans, and 
particularly the near extinction of the trumpeter. 

Lewis and Clark appear to be the next explorers who mention 
the swans to any extent. Observations of these birds were made 
several times during the course of their transcontinental journey dur- 
ing the period 1804-6. The following brief note is found in Elliot 
Coues' edited account of this expedition (1893: 1284). The notation 
was made in northwestern Missouri on July 4, 1804, during the begin- 
ning of their ascent of the Missouri River and while nearly opposite 



12 DISTRIBUTION AND STATUS 

the present town of Atchison, Kansas, and records, "A great number 
of young swans and geese on a lake opposite Fourth of July Creek." 
This strengthens the brief note by Widmann (1007) and Blines 
(1888) that swans once bred in north Missouri. In the Lewis and 
Clark account (Coues, 1803: 743-015) the two North American swans 
are correctly separated on the basis of size and voice for the second 
time. The first of these observations was penned while Lewis and 
Clark were in winter quarters at Fort Clatsop near the mouth of the 
Columbia River. This note suggests for the first time the name "whis- 
tling swan" for the lesser swans observed. The last paragraph was 
written on March 28-20, 1806, while the expedition was ascending the 
Columbia River on their return journey home. (In quotations from 
this source, interpolations in brackets are by Dr. Coues) : 

The birds which most strike our attention are the large [Cygnus buccinator's, 
as well as the small, or whistling swan [C. columbianus]. 

******* 

The small differs only [mainly] from the large in size and note; it is about 
one-fourth less, and its note is entirely different. It cannot be justly imitated 
by the sound of letters : it begins with a kind of whistling sound, and terminates 
in a round full note, louder at the end ; this note is [not] as loud as that of the 
large species ; whence it [this small swan] might be denominated the whistling 
swan ; its habits, color, and contour appear to be precisely those of the larger 
species. These birds were first found below the great narrows of the Columbia, 
near the Chilluckittequaw nation ; that were very abundant in this neighborhood, 
and remained with the party all winter ; in number they exceeded those of the 
larger species in the proportion of five to one. 

******* 

Deer Island is surrounded by an abundant growth of cottonwood, ash, and 
willow, while the interior consists chiefly of prairies interspersed with ponds. 
These afford refuge to great numbers of geese, ducks, large swan [Cygnus 
buccinator], ... In the course of the day we saw great numbers of geese, 
ducks, and large and small swans [Ciignus buccinator and C. columbianus], which 
last are very abundant in the ponds where the wappatoo grows, as they feed 
much on that root. 

Hans Pilder (1014 : 170) furnished some information on the trade in 
swan skins by the Hudson's Bay Company and the Canadian Company 
during the years 1806-22. According to his data the -numbers of 
swan skins which Avere exported by these companies were as follows: 
1806, 306 skins (Hudson's Bay Company); 1807, 1,102 (Hudson's 
Bay Company): 1818, 2,463 ( Hudson's Bay Company) plus 600 
(Canadian Company): 1820, 800 (Canadian Company); 1822, 1,800 
(Hudson's Bay Company). Since the companies merged in 1822, 
the last figure is apparently that of the combined export. 

Apparently the first record of trumpeters breeding in the United 
States is found in Dr. T. S. Roberts' (1936 : 2'05) account of a journal 
entry by Count G. II Beltrami on July 13, 1823. Count Beltrami 



EARLY HISTORICAL NOTES (1632-1832) 13 

accompanied Major Stephen H. Long's expedition into the Minnesota 
and Red River Valleys, encamping at that date near what is now 
called Swan Lake (Nicollet County) where Beltrami noted, "In the 
evening we halted near a little wood which lies along the banks of the 
Lake of Swans. It was the season at which these beautiful birds 
cannot fly — the old ones, because they are changing their feathers; 
the young, because they have yet only a soft down." 

William Keating (1825, vol. 1: 446), geologist with the Long ex- 
pedition, recorded that at the Lake Traverse fur post, on the border 
of Minnesota and South Dakota, 2 packs of 60 swan skins were worth 
120 Spanish dollars. This is the first reference to swans being taken 
in the United States for commercial purposes. 

Uses made of these swan skins are not itemized by these early 
writers. Delacour (1954: 76) says they were used for the manufac- 
ture of powder puffs. E. H. Forbush ( 1929 : 306 ) says that "the trade 
in swansdown offered further incentive for the destruction of the 
species." The feathers were certainly used for adornment in many 
ways, and the quills made excellent pens. John James Audubon, 
America's noted early ornithologist and artist, preferred trumpeter 
quills for drawing fine detail, as in the feet and claws of small birds, 
saying (1838 : 538) that they were "so hard, and yet so elastic, that the 
best steel pen of the present day might have blushed, if it could, to be 
compared with them." 

During the late 1820's the traffic in swan skins apparently increased. 
C. P. Wilson, editor of the Hudson's Bay Company publication, The 
Beaver, furnished additional notes regarding that Company's trade in 
swan skins. He wrote (correspondence) : 

In regard to the old sale lists . . . 5,072 skins were sold in London on 16th 
April, 1828, and on the following 10th. December .'{47,298 goose, swan and eagle 
quills and wings were sold. On the 29th. October that year the Company im- 
ported 4,263 swan skins from York Factory and Mackenzie River districts ; 18 
from Moose River and East Main in the southern part of James Bay: and 26 
from the Columbia region, but no distinction is made between Trumpeters and 
Whistlers. 

In 1828, Audubon set down a significant account of an Indian swan 
hunt. These notes record for the second time the taking of swans 
specifically for their plumage in the United States proper. 1 All other 
instances of this sort have a Canadian origin. Audubon's account 
(McDermott 1942 : 154) describes the deliberate slaughter of "at least 



1 The calendar of the American Fur Company's papers of 1834-47 (Nute. 1945) gives no 
information. The records of the North-West Company, the only other big fur company 
in North America exclusive of the Hudson's Bay Company, were either amalgamated with 
those of the Hudson's Bay Company in the merger of the two concerns in 1821 or have 
been lost. Thus, there seems little likelihood that further information on this subject 
will ever come to light. 



14 DISTRIBUTION AND STATUS 

50" swans by Indians near the confluence of the Mississippi and Ohio 
Rivers (in Kentucky), the skins of which were "all intended for the 
ladies of Europe." 

A year or so after the noted English ornithologist William Yarrell 
had demonstrated a systematically reliable difference between the 
anatomy of the Avhooper swan and that of its smaller relative, the Be- 
wick's swan, Sir John Richardson was successful in discovering 
similar constant differences between the two closely related North 
American species (Swainson and Richardson, 1832, vol. 32: 438, 464). 
Although these two species had previously been separated on the basis 
of both size and note, and indeed the common names of trumpeter and 
whistling swan were already in use among the ornithologists of that 
day, it remained for Richardson to describe a positive method of 
identifying these two closely related species which would invariably 
serve when more superficial characteristics were either absent or in 
doubt. The differing point of anatomy discovered by Richardson, the 
form and route of the trachea through the sternum, is the only reliable 
characteristic allowing positive speciation today. 

Richardson's notes are also helpful in outlining the former range 
and distribution of this species and in stressing its importance in the 
fur trade. Richardson contributed : 

This is the most common Swan in the interior of the fur-counties. It breeds 
as far north as latitude 61°, but principally within the Arctic Circle. ... It 
is to the trumpeter that the bulk of the Swan-skins imported by the Hudson's 
Bay Company belong. 

Elsewhere in his treatise on the northern zoology of the Continent, 
Richardson noted that the trumpeter was established across the Con- 
tinent and north to a latitude of 68°, breeding "in the interior between 
the sixtieth and sixty-eighth parallels." 

Richardson apparently was ignorant of Count Beltrami's account of 
swans breeding in Minnesota in 1823, and he apparently discounted 
Lawson's brief note that in North Carolina "they [trumpeters] go 
to the Lakes to breed" by omitting this remark in his 1831 description 
of this species, though he does mention some of Lawson's remarks 
regarding the trumpeter. We may conclude that Richardson believed 
the breeding range of this species to be confined mainly to the interior 
of Arctic Canada. 

LATER HISTORICAL NOTES (1833-1925) 

For two decades following Richardson's published description of 
the trumpeter and its range in North America, only a rather extensive 
account of the trumpeter by Audubon and a remark by Pierre Jean 
De Smet shed further light on the status of this species in the United 



LATER HISTORICAL NOTES (183 3-1925) 15 

States. By this time the trumpeters of the eastern seaboard appear 
to have been exterminated, as Audubon (1838: 536-537) relates: 

the larger Swan, the subject of this article, is rarely if ever seen to the eastward 
of the mouths of the Mississippi. 

******* 

This species is unknown to my friend, the Rev. John Bachman, who, during a 
residence of twenty years in South Carolina, never saw or heard of one there ; 
whereas in hard winters the Cygnus Americanus is not uncommon, although 
it does not often proceed further southward than that State. 

Audubon (1838: 537-538) does outline the occurrence of the trum- 
peter in the Ohio and Mississippi River valleys rather completely, 
furnishing at the same time a note on its abundance there, stating : 

The Trumpeter Swans make their appearance on the lower portions of the 
waters of the Ohio about the end of October. They throw themselves at once 
into the larger ponds or lakes at no great distance from the river, giving a 
marked preference to those which are closely surrounded by dense and tall 
canebrakes, and there remain until the water is closed by ice, when they are 
forced to proceed southward. During mild winters I have seen Swans of 
this species in the ponds about Henderson [Kentucky] until the beginning of 
March, but only a few individuals, which may have stayed there to recover from 
their wounds. When the cold became intense, most of those which visited the 
Ohio would remove to the Mississippi, and proceed down that stream as the 
severity of the weather increased, or return if it diminished. ... I have 
traced the winter migrations of this species as far southward as the Texas, 
where it is abundant at times, ... At New Orleans . . . the Trumpeters are 
frequently exposed for sale in the markets, being procured on the ponds of the 
interior, and on the great lakes leading to the waters of the Gulf of Mexico. . . . 
The waters of the Arkansas and its tributaries are annually supplied with 
Trumpeter Swans, and the largest individual which I have examined was shot 
• on a lake near the junction of that river with the Mississippi. It measured 
nearly ten feet in alar extent, and weighed above thirty-eight pounds. 

Whilst encamped in the Tawapatee Bottom when on a fur trading voyage, 
our keel boat was hauled close under the eastern shore of the Mississippi. . . . 
The great stream was itself so firmly frozen that we were daily in the habit 
of crossing it from shore to shore. No sooner did the gloom of night become 
discernible through the gray twilight, than the loud-sounding notes of hundreds 
of Trumpeters would burst on the ear ; and as I gazed over the icebound river, 
flocks after flocks would be seen coming from afar and in various directions, 
and alighting about the middle of the stream opposite to our encampment. 

Although Audubon apparently became familiar with migrating 
or wintering trumpeters during his widespread travels, and even kept 
a male in captivity for about 2 years when living at Henderson, Ken- 
tucky (1838: 541), he never was privileged to see a nest or young of 
this species. 

A noteworthy breeding record is contained in the writings of Pierre 
Jean De Smet, who was a noted early Jesuit missionary of the Pacific 
Northwest, On April 15, 1842, De Smet was traveling with a band 
of Flathead Indian warriors and was encamped near Flathead Lake 



16 DISTRIBUTION AND STATUS 

in western Montana when he wrote, according to Thwaites (1006, vol. 
27:359) : 

The warriors had gone on ahead and dispersed in every direction, some to 
hunt and others to fish. . . . The warriors returned in the evening with a bear, 
goose, and six swan's eggs. 

Since western Montana, and especially the Flathead Valley, was 
later the source of many trumpeter breeding reports, this record is 
believed valid. De Smet, in 1845, reported seeing swans during 
the summer on the marshy lakes in southeastern British Columbia 
which form the source of the Columbia River (Thwaites, 1906, vol. 
29:206). This suggests that the adjacent region of the Kootenays 
at one time may have been included in the ancestral breeding range 
of this species. 

The brief notes on the native swans made by the naturalists who 
accompanied the various expeditions sent out by the Secretary of War 
during the period of 1853-55 furnish some pertinent data on the oc- 
currence of the trumpeter, chiefly in the Far West. Dr. George 
Suckley accompanied one of these surveys as naturalist westward 
from the Mississippi River to the Pacific coast, and though he re- 
cords the trumpeter near the beginning of his journey in Minnesota 
and at the end on the Columbia River, no mention is made of this 
species between these two localities. Dr. Suckley (1859: 248-249) 
recorded : 

It [trumpeter] is, like the preceding species [whistler], more abundant on the 
Columbia river than at Puget Sound. In the winter of 1853-54 I noticed im- 
mense flocks of swans, apparently of this species, collected along the shores 
of the river mentioned, and spread out along the margin of the water for a 
distance varying from an eighth to a quarter of a mile. I obtained a fine 
trumpeter swan on Pike lake [near Fort Snelling] Minnesota, in June 1853. 
They are quite common on the lakes in that vicinity in summer, breeding and 
raising their young. 

Supplementing Dr. Suckley's notes, J. G. Cooper, another natural- 
ist on this expedition added (1869 : 249) : 

The trumpeter swan associates with the preceding species [whistler] at the 
same season and in the same places. Both arrive from the north in the begin- 
ning of December, but I have not had an opportunity of noticing their departure. 

Earlier, the naturalist of another similar survey, Dr. J. S. New- 
berry, noted that farther south the swans were not as abundant as 
they were on the Columbia River, writing (1857: 100) : 

The trumpeter swan visits California and Oregon with its congeners, the 
ducks and geese, in their annual migrations, but, compared with the myriads of 
other water birds which congregate at that season in the bays and rivers of 
the west, it is always rare. Before we left the Columbia, early in November, 
the swans had begun to arrive from the north, and frequently while at Ft. 
Vancouver their trumpeting call drew our attention to the long converging lines 



LATER HISTORICAL NOTES (1833-1925) 17 

of these magnificent birds, so large and so snowy white, as they came from 
their northern nesting places, and screaming their delight at the appearance of 
the broad expanse of water, perhaps their winter home, descended into the 
Columbia. 

This bird [whistler], considerably smaller than the last, is perhaps more 
common at the west. In California swans are much less common than on the 
Columbia, where during the winter season at least, they are exceedingly 
abundant. 

Dr. A. L. Heerman (1859 : 68) recorded the occurrence of the trum- 
peter in the Suisun and Sacramento Valleys of California, and in 
the San Francisco market. Since he made no mention of whistling 
swans, there may be some doubt about the accuracy of his 
identification. 

George Barnston, an official of the Hudson's Bay Company, verifies 
the general impression left by these observers as he relates (1862: 
7831-7832) : 

In the winter months all the northern regions are deserted by the swans, and 
from November to April large flocks are to be seen on the expanses of the large 
rivers of the Oregon territory and California, between the Cascade Range and 
the Pacific where the climate is particularly mild, and their favourite food 
abounds in the lakes and placid waters. Collected sometimes in great num- 
bers, their silvery strings embellish the landscape, and form a part of the life 
and majesty of the scene. 

Roderick MacFarlane was the next observer who made a significant 
contribution to our knowledge of the trumpeter as it existed in the 
days of long ago. MacFarlane was an experienced northern fur- 
trader, employed by the Hudson's Bay Company as a post and dis- 
trict manager for 22 years, from 1852-74, finally being appointed a 
Chief Factor of that firm in 1875. He was apparently one of the most 
qualified naturalists of "The Honorable Company" being an enthu- 
siastic and astute wildlife observer, collaborating with such other fa- 
mous early naturalists as Spencer F. Baird, Robert Kennicot, and 
Edward Preble, who were also keenly interested in the fauna of the 
Arctic. 

During the period 1862-66 MacFarlane was especially active in 
collecting mammals, birds, and eggs. He was then stationed at Fort 
Anderson, located at latitude 68°30' N., longitude 128° W., which 
served a portion of the lower Great Mackenzie Basin fur trade. He 
collected representative fauna in the approximate area bounded to 
the north by the Arctic Ocean, to the east by the coast of Franklin 
Bay, to the south by the 67° of latitude, and to the west by the lower 
Mackenzie River — roughly a radius of about 125 miles, all within the 
Arctic Circle (66°33' X. Lat.) . 

With MacFarlane's background in mind it is interesting to review 
his notes (1891:425) : 



18 



DISTRIBUTION AND STATUS 



^J ^ 

/* C Q DISTRICT HEADQUARTERS 



^^> 




• TRADING POST 



Fort Yukon 



/\ V •Fort,Anderson\Vr\ 

7IE v *£$y- 




MACKENZIE 
RIVER k 

Fort Simpson^ifc. <^S*rFort Resolution <^p 

9iv |it-.-^3&rr iFort Chipewyon 

ATHABASCA 17} * QKir>A / 

DISTRICT — M>* !Jr J ArFortChurch.il 

. *Jf )C — "^* #1 /OfSVork Factory 

Fort Dunvegan^tV^ . *] ' J Jp^/jT 

t&lsle a la CrbsserfV **j' ^nta*/ V 

v\i s ^<tJiS< ©V -^ V^ >Eos-tmain Fort ' 

ENGLISH RIVER'-; -P=^ iTOi YORK ^ . //- 

DISTRICT^ "--^.NorwayHouse^l DISTRICT^ Moos 



^g^gg^^lZfff 




Figure 1. — Locations of some Hudson's Bay Company posts which engaged in 
swan-skin trade, 1828-1884. 

Several nests of this species [trumpeter] were met with in the Barren Grounds 
[east of the Fort], on islands in Franklin Bay, and one containing six eggs was 
situated near the beach on a sloping knoll. ... It usually lays from four 
to six eggs, judging from the noted contents of a received total of twenty-four 
nests. 

MacFarlane was apparently able to distinguish between the nests of 
the trumpeter and those of the whistler, as he reported the following 
information under the heading Whistling Swan: 

The maximum number of eggs taken in the twenty nests of this swan which I 
find recorded, was five, while the nest itself was always placed on the ground, 
and several were also found on the coast and islands of Liverpool and Franklin 
Bays in the Arctic Ocean. 

Later MacFarlane added (Mair and MacFarlane, 1908: 324), "For 
some time back swans seem to be annually dwindling in numbers." 

With Richardson's earlier statements in mind, the following sum- 
mary by MacFarlane is particularly pertinent. Speaking of the 
Hudson's Bay Company's London sales, MacFarlane wrote 
(1905: 754) : 

We find 57 swan skins in the above summary [of London fur sale-offerings 
1888-1897], and they no doubt belonged to the Hudson's Bay Company. 
Although no skins of Olor columbianus or Olor buccinator appear in the fur 
catalogues for 1897, 1900, 1902, or 1903 yet for many years they never failed in 
having quite a number of swan skins for sale in London. From 1853 to 1877 
they sold a total of 17,671, or an average of nearly 707 a year. There were 
seven good years (1853 to 1856, 1861, 1862, and 1867), with sales ranging be- 



LATER HISTORICAL NOTES (183 3-1925) 19 

tween 985 and 1,312 in 1854 (maximum), and seven poor years (1870 to 1877), 
with returns varying between 338 and the minimum (122) in 1877. 

Continuing, MacFarlane throws further light on the origin of some 
of the swan skins in the fur trade : 

From 1858 to 1884, inclusive, Athabasca District turned out 2,705 swan skins, 
nearly all of them from Fort Chipewyan. Mackenzie River District, according 
to a statement in my possession, supplied 2,500 skins from 1863 to 1883. From 
1862 to 1877 Fort Resolution, Great Slave Lake, contributed 798 thereof. For 
1889 Athabasca traded but 33, as against 251 skins in 1853. In 1889 and 1890 
Isle a la Crosse, headquarters of the English River District, sent out two skins 
for each outfit [post?]. 

Unfortunately, MacFarlane makes no attempt to distinguish be- 
tween the two species of swans, so that Richardson's original range 
statement cannot be compared with this record. A statement by 
Thomas Nuttall (1834: 371) that the trumpeter furnished the bulk of 
these skins is quoted by H. K. Coale (1915 : 83), but as this statement 
is in the exact wording used by Richardson the latter was no doubt the 
original source. 

From this information it is possible to trace in a rough way the 
decline of the trade in swan skins by the Hudson's Bay Company over 
a period of nearly 100 years, from 1806 to 1903. Since this trade by 
the Hudson's Bay Company began before 1772 and (as John Rich- 
ardson said in 1832) was principally at the expense of the 
trumpeter, the effect of such exploitation on the far-flung breeding 
populations of this species for more than 125 years must have been 
devastating and largely responsible for its extermination over vast 
regions, particularly in the heart of its Canadian breeding range. 

The relatively high price asked for trumpeter swans' eggs during 
the last decade of the 19th century also indicates the scarcity of the 
birds during this period. "The Standard Catalogue of North Amer- 
ican Birds Eggs" (Lattin, 1892) lists the cost of a single eg<: at $4, 
compared with a whistling swan egg price of $2.50, heath hen — $3, 
and whooping crane — $3. 

Another brief note by George Barnston ( 1862 : 7831) gives a definite 
swan breeding record for Eastmain Fort on James Bay. He states 
that swans are generally scarce in the Hudson Bay region, but a con- 
siderable number hatch in this area. 

Since whistling swans have never been reported nesting as far 
south as 52° N. (the latitude of Eastmain Fort), this is presumably 
a valid trumpeter breeding record, and the easternmost to come to my 
attention. 

There were three ecologically distinct regions in the United States 
in which trumpeters could be said to have once been a more or less 



20 DISTRIBUTION AND STATUS 

common breeding species in areas of suitable habitat, These regions 
were — 

(1) the Red Rock Lakes- Yellowstone-Jackson Hole region of 
southwestern Montana, northeastern Idaho, and northwestern 
Wyoming, (2) the Flathead Valley in western Montana, and (3) 
southern Minnesota and northern Iowa. Elsewhere in the United 
States, the trumpeter was recorded as a breeding species only occa- 
sionally or from widely separated locations. The prairie pothole 
country in the provinces of southern Canada and the Great Plains 
marshes of the United States were of small importance in supporting 
the total continental breeding population. Thus, little of the original 
prime breeding range of this species extended to the United States. 

During the period 1850-1900 a great many observations of the 
trumpeter swan in the United States were recorded. It was during 
this time that the work of the scientific field naturalist began to show 
up prominently in the literature. This in turn awakened scores of 
other interested observers to the value of ornithological factfinding, 
and the number of reports increased correspondingly. Except for 
notes on the breeding range, there seems little point in listing the 
scores of single occurrence records, since the trumpeter can be so 
easily confused with the whistler, and apparently often was. State 
ornithological works cover these occurrence records adequately. 

Several records of false or questionable nature have appeared in 
the literature of the past. The note by D. E. Merrill (1932 : 460) re- 
porting a trumpeter shot near Mesilla Park, New Mexico, is appar- 
ently a case of mistaken identity (J. Stokely Ligon, correspondence), 
and no skin is now available for confirmation (W. A. Dick-Peddie, 
correspondence). According to J. Van Tyne (correspondence), B. 
H. Swales, a qualified critical judge, does not believe the J. C. Wood 
"record'' in the Auk (1908: 326), stating, "This record is worth- 
less — based entirely on memory. Wood did not know the swans or 
appreciate the value of accurate identification." Alfred M. Bailey 
(correspondence) reports that there is only one definite trumpeter 
record for the State of Colorado, that which Burnett reported 
(1916: 199) as being shot near Fort Collins on November 18, 1897, 
other reports notwithstanding. 

Enough acceptable records are available from the states of Wash- 
ington, Oregon, and California in the Pacific flyway; Montana, 
Wyoming, North Dakota, Nebraska, Kansas, and Texas in the Cen- 
tral flyway; Minnesota, Wisconsin, Iowa, Illinois, Missouri, and 
Louisiana in the Mississippi flyway; and Maryland, Virginia, and 
Nortli Carolina in the Atlantic flyway to demonstrate that the trum- 
peter still appeared as a migrant or winter resident in those states 
during the last half of the 19th century. Forbush (1912) cites a 



LATER HISTORICAL NOTES (183 3-1925) 21 

report from A. S: Eldridge of Lampasas, Texas, that flocks of 75-1000 
trumpeters were seen there in the 1890's but none had been seen since 
1909. 

The continuity of the occurrence of trumpeters in the Yellow- 
stone Park region can be traced from statements made, or specimens 
secured, by Elliot Coues (1874: 544) , Dr. C. Hart Merriam (1891: 91), 
and W. C. Knight (1902: 40), to establish this general region as 
ancestral breeding range, even though their status in the Park during 
these early days is not evident. 

After the early observations cited, M. P. Skinner's random sight 
record data from 1915 to 1921 sheds some light on the number of 
swans in the Park during this period. Skinner (1925 : 154) records: 

My records of Trumpeter Swans seen in Yellowstone Park are as follows : 



May 29, 1915 4 

May 31, 1915 4 

Aug. 16, 1917 1 

June, 1919 1 



Aug. 14, 1919 2 

Sept. 6, 1919 5 

July 4, 1920 2 

May 29, 1921 1 



Skinner found a swan's nest near Lewis Lake in 1919. This estab- 
lished that trumpeters bred within the Park— a fact previously un- 
known. During the same summer, Dr. H. M. Smith, an early fisheries 
worker in the Park, reported 6 cygnets on a lake near Delusion Lake. 

A report for March 1920 from Acting Superintendent Lindsley of 
Yellowstone Park stated, "There are 20 to 30 trumpeter swans winter- 
ing in the outlet of Yellowstone Lake where there is constantly open 
water; also two wintering on Lewis River near the bridge, and two on 
Bechler River." 

Although the original status of the early swan populations inhabit- 
ing the Red Rock Lakes area is obscure, their occurrence in these 
marshes can also be traced from early times. From the 1880's (Bent, 
1925: 298) to 1896 (Brower, 1897: 138) and 1910 (French, letter) 
the early existence of these birds in that area is outlined. Informa- 
tion from older residents of the Centennial Valley confirms and ampli- 
fies these records establishing successive seasonal residence of swans 
on the Red Rock Lakes marshes since the early 1890's. This also 
agrees with information collected by Wright and Thompson (1935: 
104), though again the actual level of any of these early populations 
was never recorded. A. C. Bent's source did report that he saw 
"quantities'' of swans and killed "many" young birds for food in the 
Centennial Valley, so they were by no means rare there. 

A later note regarding actual swan numbers in the Red Rock Lakes 
area is that left by C. S. Sperry when he surveyed these marshes as a 
waterfowl food-habits biologist for the 1". S. Biological Survey in 1922. 
Sperry noted "about 15 swans" were reported on the Lakes during 
that nesting season. lie further remarks that this species was 



22 



DISTRIBUTION AND STATUS 




Figure 2. — A day's has 



j&Sfcgi? 



of waterfowl in 1895 at Red Rock Lakes included a 
trumpeter swan. 



"frequently'' encountered during his week's work on these marshes in 
September of that year. 

The published notes concerning the early history of the trumpeter 
in Alaska before 1925 are both limited and brief. This is of course 
partly due to the fact that the United States did not acquire this vast 
region from Russia until 1867, but a search of the Russian records re- 
vealed little additional information. Swans do not seem to have been 
important in early Alaskan fur trade, although the taking of swans in 
arctic Russia for economic uses has apparently been practiced for 
years. 

The initial comment on the trumpeter in Alaska seems to be that left 
by Dr. Edward Adams, a competent English ornithologist, who made 
the following observation during the period 1850-51 (1878: 430) : 

Cygnus buccinator. This was the only species of Swan I met with at Michalaski 
[St. Michael]. The first appeared on the 30th. of May; but they were at no time 
numerous, from two to eight or ten keeping together. A few of them are said 
to breed here; but most of them go further north. 

Although this note was subsequently credited by Baird, Brewer, and 
Ridgway (1884 : 433), this has not been the case since that time, other 



LATER HISTORICAL NOTES (1833-1925) 23 

writers apparently overlooking this account or believing that Dr. 
Adams confused the trumpeter with the whistler. Subsequent egg 
records of trumpeters in the Norton Sound area strengthen Dr. 
Adams' original statement. 

Later, Dall and Bannister (1869: 294) stated that eggs of the 
trumpeter were obtained by a Mr. Lockhart at Fort Yukon, thus es- 
tablishing the first definite breeding record for this species in Alaska. 
One of these eggs, on deposit in the U.S. National Museum, was 
received in April or May of 1863. 

E. W. Nelson (1887 : 93) refers to Dall's note and remarks that both 
trumpeters and whistlers are to be found on the southeastern Alaskan 
coast during the migrations, and attributes the lack of knowledge re- 
garding this species in the Territory to the unexplored interior. 

In addition to these notes, there are two egg records, one in the 
Chicago Natural History Museum and another in the U. S. National 
Museum, both credited to trumpeters in Alaska and apparently un- 
published. The R. M. Barnes collection at the Chicago Natural His- 
tory Museum contains four eggs of this species which were collected 
June 28, 1902, 38 miles northeast of Cape Nome by Walter E. Bryant. 2 
The TJ. S. National Museum also contains an egg (one of two) col- 
lected by J. B. Chappel in Norton Bay (near Cape Denbigh) in 1867. 

There is also a clutch of 5 swan eggs in the National Museum at- 
tributed to the whistler but whose measurements, shape, and texture 
leave little doubt that they belong to the trumpeter. This collection 
is credited to A. H. Twitchell and was made June 4, 1915, at Bethel, 
Alaska. 

Table 2 outlines the former breeding range of the trumpeter on the 
continent, particularly in the United States and Alaska. The breed- 
ing range in Canada is shown in a general sense on the map, figure 3, 
based upon the preceding testimony of Richardson, MacFarlane, and 
Barnston as well as more recent information written later by J. A. 
Munro (1949 : 49), Brooks and Swarth (1925 : 38), J. D. Soper (1949 : 
240), and others. 

These records vary a great deal in value, but the fact that most 
questionable records apply to the same general region as records of 
higher caliber, or have been accepfed by earlier qualified observers, 
would appear to upgrade their value. The sparse and localized nest- 
ing population of trumpeters in the United States no doubt accounts 
for the comparative paucity of U. S. breeding records. 



7 U. S. Fish and Wildlife Service files refer to a set of four egps in the R. M. Barnes 
collection with a date of June 15, 1905, hut otherwise with the same data as these. Only 
one such set is in the collection, so the Service files must be In error on the date. Measure- 
ments of these etfjrs provided by Melvin A. Trnylor i letter i .ire average for the trumpeter, 
and there seems no reason to doubt the record. 

4U9660 O— 60 ;i 



24 



DISTRIBUTION AND STATUS 



Table 2. — Trumpeter swan breeding records in the United States and 

Alaska to 1925 



State and locality 



Washington: Cherry Lake 

(Whitman Co.). 
Montana: 

Near Flathead Lake (w 
Montana). 

Thompson River (w. Mon- 
tana). 

Clearwater drainage (Mis- 
soula Co.). 

Lake Rodgers (Flathead Co.) 

Swan Lake (Lake Co.) 

F'athead Lake (w. Montana) 

Centennial Valley (Beaver- 
head Co.). 

Flathead Valley (w. Mon- 
tana). 

Headwaters of South Fork of 
Flathead River. 

Swan Lake (Beaverhead Co.) 

Red Rock Lakes (Beaverhead 
Co.). 

Big Lake (Stillwater Co.) 

Big Lake (Yellowstone Co.) 
35 mi. northwest of Billings, 
Mont. 

Red Rock Lakes (Beaverhead 
Co.). 

Highland Lakes CFergus Co.) 

Idaho: 
Henrys Lake (Fremont Co.) . 
Grays Lake (Bonneville Co.)_ 

Icehouse Creek Reservoir 
(Fremont Co.). 
Wyoming: 
Jackson's Hole 

Lakes near head Green River. 

Near Lewis Lake (Yellow- 
stone Park). 

South of Delusion Lake in 
Yellowstone Park. 

Yellowstone (Valley) Region 
North Dakota: 

Island Lake (Barnes Co.) 

Rock Lake (Towner Co.) 

Along Red River of The 
North. 
Nebraska: 

Watt's Lake (Cherry Co.).... 

Swan Lake (head of the Little 
Blue; Adams Co.). 
Minnesota: 

Swan Lake (Nicollet Co.) 

Pike Lake (near Old Fort 
Snelling). 

Heron Lake (Jackson Co.) 

Everson Lake (Meeker Co.).. 

Along Red River of The 
North. 
Iowa: 

Near Sac City (Sac Co.) 



Date 



Oakland Valley (Pottawat 
tamie Co.). 

Near Hdwtrs. Des Moines 
River (Emmet Co.). 

Little Twin Lakes (Hancock 
Co.). 

Near Newton (Jasper Co.) 

Spirit Lake (Dickinson Co.).. 
Missouri: 

Lowland lakes near Alex- 
andria (Clark Co.). 

Northeastern Missouri 

Opposite Atchison, Kans. 
(Buchanan Co.). 



Until 1918 Old settler 



Apr. 15, 1842. 

1871 

1881 



1881 

1881 

1881 

1883-1888. 



Until 1886... 



June 10, 1896. 
1910 



1917. 
1920. 



1922... 
None- 



August 1877.. 
1923, 1924 

Early 1920's_. 



None. 
None. 
1919.. 



July 19, 1919... 
None 



Mid 1880's. 

1895 

None 



None. 
None. 



July 13, 1823. 
June 1853.... 



1883 

1884 or 1885 
None 



1859. 
1870. 



1871 

As late as 1875 - - 

As late as 1883.- 

None 

None 



None 



None 

July 4, 18C4- 



Authority 



Pierre Jean De Smet. 

E. S. Cameron 

E. S. Cameron 



E. S. Cameron. 
E. S. Cameron. 
E. S. Cameron- 
Ed Forbes 



E. S. Cameron-.- 
E. S. Cameron... 

Cecil French 



Rancher's report . 
G. B. Thomas ... 



C. C. Sperry 

P. M. Silloway (1903: 
15). 



C. E. Bendire 

B. Fordyce (MS.). 



S. A. Trude(MS.)... 



Reference 



M. P. Skinner. 
F. V. Hayden.. 



Newspaper report 
Alfred Eastgate... 



G. E. Beltrami 



Thomas Miller. 
L. O. Dart 



J. A. Spurrell.. 
J. A. Spurrell... 

W. C. Rice 

J. W. Preston.. 
J. W. Preston.. 



Old hunters 

Lewis and Clark. 



C. F. Yocom (1951: 17). 

R. G. Thwaites (1906). 

A. C. Bent (1951: 296). 

H. K. Coale (1915:87). 

H. K. Coale (1915: 87). 
H. K. Coale (1915:87). 
H. K. Coale (1915: 87). 
A. C. Bent (1951: 298). 

H. K. Coale (1915: 87). 

A. C. Bent (1925:297). 

J. V. B rower (1897: 138). 
U. S. Fish and Wildlife 

Service files. 
A. A. Saunders (1921: 42). 
U. S. Fish and Wildlife 

Service files. 

U. S. Fish and Wildlife 

Service files. 
A. A. Saunders (1921:41). 

C. Hart Merriam (1891: 91) 
U. S. Fish and Wildlife 

Service files. 
U. S. Fish and Wildlife 

Service files. 

W. C. Knight (1902:40). 
W. C. Knight (1902:40). 
M. P. Skinner (1920). 

A. C. Bent (1925: 297). 

E. Coues (1874: 544). 

R. Reid (correspondence). 
N. A. Wood (1923:23). 
W. W. Cooke (1887). 



J. M. Bates (1900: 16). 
J. M. Bates (1900: 16). 



T. S. Roberts (1936:204). 
G. Suckley (1859: 249). 

T. S. Roberts (1936:205). 
T. S. Roberts (1936: 205). 
W. W. Cooke (1887). 



U. S. Fish and Wildlife 

Service files. 
U. S. Fish and Wildlife 

Service files. 
Baird, Brewer, Ridgway 

(1884: 432). 
R. M. Anderson (1907: 192). 

R.M.Anderson (1907: 191). 

W. W. Cooke (1887). 
A. A. Mosher (1889:66). 

J. Blines (1888: 313). 

Otto Widman (1907). 
R. G Thwaites (1906). 



EARLY MIGRATION NOTES 



25 



State and locality 


Date 


Authority 


Reference 


Wisconsin: 






Qrundtvig (1895: 99). 








Kumlien and Hollister 




1842-1845 




(1903:31). 
Kumlien and Hollister 


Indiana: Kanakee marshes 

(Lake Co.). 
Alaska: 


None 

1850-51 


T. H. Ball 


(1903:31). 
A. W. Butler (1897:642). 

Dr. E. Adams (1878:430). 




Before 1863 

1867 


Mr. Lockhart 


U.S. Natl. Mus. (egg col- 




J. B. ChappeL 


lection). 
U. S. Natl. Mus. (egg col- 


Denbigh. 
Norton Sound, 38 mi. NE 
of Cape Nome. 


June 28, 1902' 


R. M. Barnes (egg 
collection). 


lection). 
Chicago Natural History 
Museum. 



1 See footnote, page 233. 

From all of the foregoing information it is evident that trumpeter 
swans were once an abundant and widespread species on the continent. 
Although both of the native swans were killed by the early colonists 
for food and plumage, the first substantial inroads into trumpeter 
populations occurred when the fur trade exploited this species over 
wide regions for more than a hundred years. The surge of western 
settlement during the latter part of the 19th century was also partly 
responsible. The white settlers not only killed and dispossessed these 
birds in the southern portions of their breeding range, but further 
reduced or extirpated populations breeding farther north as the in- 
creased hunting pressure to the south took its toll among migrating 
flocks. 



EARLY MIGRATION NOTES 

It is believed worthwhile to present here a number of brief state- 
ments by the early observers in order to document the migration 
habits of the trumpeter when many of the original flocks were more 
or less intact. 

SPRING MIGRATION (departure) 

In regard to departure times, John Lawson (1714) noted that the 
"trompeters" along the coast of North Carolina in 1700-1701 "stay 
. . . imtil February . . . when they go to the Lakes to breed." Also, 
Major Long corroborated this early movement of swans generally, 
reporting (James 1823 : 191) under date of February 22, 1820, "swans, 
geese, and ducks flying up the river" while on the Missouri River in 
the northwest corner of Iowa. Lewis and Clark (Coues, 1893: 915) 
noted great numbers of both swan species still on the lower Columbia 
River on the 29th of March, though whether these were the original 
winter residents or spring migrants enroute from points farther south 
is not mentioned. 



26 



DISTRIBUTION AND STATUS 




•* hypothetical eastern limit 
wintering range ^ 



Figure 3. — Former breeding and wintering range, trumpeter swan. 



In the Mississippi River drainage, John J. Audubon (1838: 537) 
corroborated the Lawson and Long; testimony implying that the nor- 
mal movement north commenced in February. Observations made at 
Red Rock Lakes confirm a statement of Audubon's that trumpeters 
move back towards their breeding grounds during the late winter upon 
the advent of moderating weather. 

A. C. Bent (1925: 301) supplies a couple of late departure dates 
as follows, "Arkansas, Helena, April 29, 1891; British Columbia, 
Osoyoos, April 25." 

SPRING MIGRATION (arrival) 

Several early observations agree that the trumpeter arrives on its 
northern nesting grounds among the earliest of any of the Arctic 
avifauna. The journal of Samuel Hearne (1795: 285, 435) under 



EARLY MIGRATION NOTES 27 

date of April 12, 1772, and latitude of about 60° when just south of 
the Great Slave Lake bears this entry : 

On the twelfth we saw several swans flying to the Northward ; they were the 
first birds of passage we had seen that Spring except a few snowbirds. 

******* 

In the interior parts of the country the larger Swan [trumpeter] precedes 
every other species of water-fowl, and in some years arrive so early as the 
month of March, long before the ice of the rivers is broken up. At those times 
they always frequent the open waters of falls and rapids, where they are fre- 
quently shot by the Indians in considerable numbers. 

Kichardson (Swainson and Richardson, 1832: 464) noted the early 
arrival of the trumpeter on its far northern breeding grounds, "It 
breeds . . . principally within the Arctic Circle, and in its migra- 
tion generally precedes the Geese a few days." 

Although both Barnston (1862: 7831) and Dr. Adams (1878: 430) 
agree that the trumpeter arrives on its breeding grounds in small 
flocks, the coastal arrival of trumpeters in the Norton Sound area of 
Alaska noted by Adams was preceded by both geese and ducks. 

A. C. Bent (1925: 301) lists some average dates of arrival for this 
species as follows, "Nebraska, March 16; South Dakota, April 2; 
Minnesota, Heron Lake, April 4; Saskatchewan, April 16; British 
Columbia, April 20." In the light of previous testimony, however, 
these would appear to be later than average arrivals. 

FALL MIGRATION (departure) 

Richardson (Swainson and Richardson, 1832: 438) furnishes the 
sole remark regarding this topic, writing, "Cygnus buccinator . . . 
remains later in the season [than the Geese]." This agrees with my 
observations at Red Rock Lakes where the trumpeters are con- 
sistently the last to leave the remaining patches of open water before 
the final f reezeup. 

FALL MIGRATION (arrival) 

R. G. Thwaites (1906, vol. 21: 336) presents a note from Town- 
send's narrative written at Fort Vancouver on the lower Columbia 
River, December 1, 1835, "The duck and geese, which have swarmed 
throughout the country during the latter part of the autumn, are leav- 
ing us, and the swans are arriving in great numbers." This agrees 
well with the observation by Dr. Suckley (1859: 249) in the Puget 
Sound and/or Columbia River regions, where both swans arrived 
from the north at the beginning of December. 

Dr. J. G. Cooper (1869: 83), writing of unidentified swans about 
the same period, stated, "Swans were seen in large flocks on the Co- 
lumbia River, in the Cascade Canyon, as early as October 29th, this 



28 DISTRIBUTION AND STATUS 

year (1860), and their migration southward seemed generally early. 
I saw them, however, on lakes of the Columbia Plain about the same 
time in 1853." Dr. Newberry (1857:100) mentions an early No- 
vember arrival on the Columbia. In the Mississippi flyway, Audubon 
(1838:537) reports late October arrivals usual on the lower Ohio 
River. 

A. C. Bent (1925:301) lists some fall occurrence dates as follows, 
"Minnesota, Spicer, October 8, 1913; Michigan, St. Clair Flats, No- 
vember 20, 1875; Washington, Douglas County, November 9, 1912; 
Colorado, Fort Collins, November 18, 1897, and November 15, 1915." 

Dr. Grinnell found trumpeter swans in October and November of 
1887 abundant at the extreme upper end of Lower St. Mary Lake near 
Glacier National Park (Bailey, 1918). 

RECENT OCCURRENCE, BREEDING, AND 
MIGRATION REPORTS, TO 1957 

Positive identification as to species, trumpeter vs. whistler, was not 
possible in most of the following reports, but they do constitute the 
opinion of trained or reliable wildlife observers and as such probably 
represent valid trumpeter records. 

Since the Red Rock Lakes Refuge was established in 1935, the in- 
formation from Montana, Idaho, and Wyoming is believed to be es- 
pecially pertinent. As might be expected from the resultant increase 
in the swan population following establishment of the Refuge, these 
birds may be moving about in this tri-State region more than is gen- 
erally realized and in some instances appear to be nesting in areas 
previously unoccupied. It is necessary to depend upon sight and/or 
sound observations in all these cases since, although over 300 trum- 
peters have been banded on the Refuge and stations of their introduc- 
tion, no band recoveries have yet been made outside the generally rec- 
ognized area of known use. (The banding data which have been 
gathered will be treated later under Management) . The known sight- 
ings of trumpeters since 1925, as well as the last previous occurrence 
report, are presented below by flyway for each State, Province, or 
Territory considered. 

PACIFIC FLYWAY 

California. Donald D. McLean (1937: 228), California Division 
of Fish and Game, gives a convincing description of a trumpeter 
which was seen in Lassen County and identified from its call, on 
November 8, 1935. The bird was seen between Grasshopper Valley 
and Termo, by Bailey Creek. 



RECENT OCCURRENCE, BREEDING, AND MIGRATION REPORTS 29 

The next previous California report seems to be that of A. L. 
Brown, who stated that the trumpeter was formerly a regular winter 
visitant to Lassen County (Honey Lake Valley) up to about 1910 
(McLean, correspondence) . 

Nevada. Frank W. Groves, present Director of the Nevada State 
Fish and Game Department, who was familiar with the trumpeter 
from his previous experience at the Malheur National Wildlife Refuge, 
reported by letter dated December 2, 1952, to the Fish and Wildlife 
Service that he found a swan while driving east from Carson City. 
The bird was larger than a whistling swan, and lacked the yellow 
spot at the base of the bill. Groves was convinced that its call, while 
not completely typical, was that of a trumpeter. 

This lone trumpeter, if such it was, must have been a stray from 
the groups which had been transferred to the Ruby Lake Refuge in 
Nevada or the Malheur Refuge in Oregon from the Red Rock Lakes 
Refuge. There is no earlier report of the trumpeter in Nevada. 

Oregon. The only report of trumpeters within the boundaries of 
Oregon since 1925 seems to be that of Gabrielson and Jewett (1940) 
who state, "On September 7, 1929, Oberholser, Gabrielson, and Jewett 
saw a single swan at Davis Lake that, judging from its huge size, 
might have been this species. This is the only recent record of even 
its hypothetical occurrence within the State." Earlier reports and 
records of this species in Oregon precede 1900. 

Washington. Allan Brooks (1926 : 129) states that a small number 
of trumpeters cross the International Boundary from British Colum- 
bia into Washington State each year (18 in 1924). Whether this is 
still true is not known, although J. A. Munro and Ian McT. Cowan 
(1947: 55) write, "In addition to the numerous wintering bands, that 
are widely distributed [in British Columbia], a smaller number is 
transient and apparently winters south of the Canadian-United States 
boundary. Migrating birds are met with both spring and fall in 
various localities in the extreme southern part of the Province." 

J. B. Lauckhart, Chief of the Division of Game Management. 
Washington Department of Game, advised (correspondence), "We do 
have some swan killed each year during the hunting season, but we 
have never identified one as a trumpeter." The occurrence of the 
trumpeter in a wintering status in Washington is thus obscure. 

On April 7, 1939, W. C. Ralston saw and heard 20-25 trumpeters at 
Othello, Washington. 

The next earlier reports are mentioned by Stanley Jewett et al. 
(1953 : 102) of a specimen taken at Moses Lake, Washington, in 1912, 
and the skin received by Edson in 1913 from a hunter who took the 
specimen at the mouth of Nooksack River, Bellingham Bay (Whatcom 
County ) . 



30 DISTRIBUTION AND STATUS 

Idaho. In addition to counts made in the winter range of the 
trumpeter in the Island Park area of Fremont County, Idaho, these 
great birds are occasionally noted farther down the Snake River 
drainage and more frequently elsewhere in eastern Idaho. David 
de Lancey Condon (MS), Chief Naturalist for Yellowstone National 
Park, noted : 

On April 17, 1937, I observed five swan on a slough on Marsh Creek which is 
a tributary to the Portneuf River, 30 miles south of Poeatello, Idaho, which, 
after careful examination with field glasses were felt to be trumpeter swan. 
On April 18, 1937, a pair of trumpeter swan were watched for some time on an 
oxbow lake in the Snake River bottoms near Roberts. 

Robert Salter (1954), Game Bird Supervisor of the Idaho State 
Fish and Game Department, also set down several occurrence records 
well outside the Island Park area in eastern Idaho : 

They normally do not go further downstream along the North Fork of the 
Snake River than St. Anthony which is approximately 30 air line miles south of 
the Island Park area. We have three records in recent years of trumpeter 
swan being found in Idaho outside Fremont county. In the fall of 1943 Mr. 
Hawley Hill, District Supervisor, positively identified by dissection a trumpeter 
swan which had been illegally killed on the Snake River near Burley in Cassia 
County. On March 30, 1951, Mr. E. L. Keppner, Conservation Officer, made a 
sight and "sound" record of five trumpeter swan on Elk Horn reservoir in 
Oneida County. On January 9, during the 1952 winter inventory, 11 swans were 
seen from the air on Spring Creek, which runs into American Falls reservoir in 
Bannock County. Mr. Winston E. Banko, Refuge Manager of Red Rock Lakes 
Refuge, was in Idaho Falls and went out the next day to observe these birds. 
We were able to approach within 75 yards of three birds which then flushed. 
Banko identified them as trumpeters [from their voice]. 

Swans, apparently trumpeters from the wintering flock at the Na- 
tional Elk Refuge in Jackson Hole, Wyoming, only rarely take a 
cruise downstream as far as Swan Valley on the South Fork of the 
Snake River in Bonneville County, Idaho. My field notes, under 
date of December 12, 1956, read : 

Arno Winterfield was contacted in Swan Valley [Bonneville County, Idaho] 
regarding the former and present status of trumpeter in that area. He ad- 
vised that he came to Swan Valley in 1915 and had never seen swans there 
until the winter of 1954 or 1955 when he saw 8 or 9 flying low downstream along- 
side the Snake River south of the community of Swan Valley. As he watched, 
the birds turned and headed back upstream. He did not recall that old-time 
residents of Swan Valley had ever mentioned wintering or breeding swans in 
that area. 

U. S. Fish and Wildlife Service files hold an earlier trumpeter 
breeding record for Idaho. R. F. James, in a game warden report 
dated November 23, 1932, reports a nest on an island in the Pend 
Oreille River just below the Idaho-Washington line. 



RECENT OCCURRENCE, BREEDING, AND MIGRATION REPORTS 31 

The next previous records for Idaho are breeding accounts given 
for Grays Lake, Idaho, in 1923 and 1924 (A. B. Fordyce, MS) as 
well as on Icehouse Creek Keservoir, Fremont. County in 1920 (S. A. 
Trude, MS), both brief manuscripts in Service files. 

In addition to these reports, R. H. Mackay (1957: 339) documents 
both sight record and band-recovery data establishing the presence 
of Alberta trumpeters among flocks of Montana birds in 1955 and 
1956 during the wintering period in the Island Park country of Idaho. 

British Columbia. Although reports of breeding trumpeters in 
British Columbia are rare, and for the most part unsubstantiated, 
hundreds of birds winter along the coast as well as in the interior. 
J. A. Munro (1949 : 709) states : 

It is not an exaggeration to say that trumpeter swans, at one time or another 
during the winter, visit most of the many lakes on Vancouver Island and along 
the mainland coast. The number fluctuates from year to year but probably 
exceeds 600 individuals. Thus, the winter population is believed to approxi- 
mate 1,000. . . . wintering populations of trumpeter swans are distributed 
over the western half of the province of British Columbia between north 
latitudes 49° and 55°. . . . Some of these frequent lakes and rivers at points 
distant from the sea ; others inhabit the lower reaches of coast streams ; and 
still others resort to the shallows and mud flats of sheltered estuaries. There 
are also interior populations, of which some winter on rapid stretches of river 
that remain open even in the coldest weather. 

Segments of the population wintering in British Columbia have 
been counted from time to time by Munro and others, but it is dif- 
ficult to secure anything like a true census due to the widely separated 
locations of wintering flocks and the relatively poor weather for 
operating aircraft which prevails over the entire region at this season. 
Also, the possible presence of whistling swans further complicates 
the matter. R. H. Mackay (correspondence, March 19, 1958) writes: 

Whistling swans winter in British Columbia to some extent. The largest 
group is a flock varying annually from 150 225 birds that winter regularly on 
the South Thompson River near Kamloops in the interior of the Province. 
Other irregular occurrences have been noted in the Lower Mainland region of 
the Fraser, on the Queen Charlotte Islands, and at Lonesome Lake wbere two or 
three whistlers have been recorded with the trumpeters on occasion. 

Although the breeding grounds of the trumpeters wintering in this 
Province are in the main still undiscovered, it is seen that easily half 
of the total North American population winters here. 

Alaska. For over 50 years following E. W. Nelson's (1887) state- 
ment that both species of swans were noted to occur "in migration" 
in southeastern Alaska, little was written to clarify the status of the 
trumpeter in that Territory, though collection of several clutches of 
eggs in the Norton Sound region confirmed Dal] and Bannister's 
(1869) breeding record. 



32 



DISTRIBUTION AND STATUS 



A report by E. L. Kepner found in U. S. Fisli and Wildlife Serv- 
ice files, and dated March 8, 1924, states : 

Camp Kora Kora : Lake Minchumina, Kantishna District. This low lying 
section of the interior is especially adapted to the waterfowl. . . . the great 
white Trumpeter Swan is the least plentiful of all the species, hut he is also 
in evidence in goodly numbers, and I have also noticed the hunters after it. 
... I believe the Treaty regulations between the U. S. and the Dominion of 
Canada afford them all the protection required. Lake Minchumina appears 
to be a favored spot for them to stop over and feed and rest on their northern 
and southern migration. 

This report implies that a remnant of the arctic breeding popula- 
tion still remained 35 years ago. Lake Minchumina is located in cen- 
tral Alaska at about latitude 64° N. If still in existence, this popula- 
tion may form a portion of those currently wintering in British 
Columbia. 

Ira K Gabrielson's (1946:102) note was the next pertinent oc- 
currence record. This confirmed E. W. Nelson's earlier remark that 
the trumpeter was to be found in southeastern Alaska at certain sea- 
sons including wintering populations, in common with British Co- 
lumbia. 

Subsequent swan census work in Alaska, accomplished during the 
annual January waterfowl inventory since that time, indicates that 
the number of swans which actually winter in southeastern Alaska 
varies greatly, but generally is fewer than indicated in Gabrielson's 
report, whose count of March (1945) probably included at least some 
northward-bound birds actually in transit. The swan census data 
gathered by the U. S. Fish and Wildlife Service in coastal Alaska 
during the period 1949-57 are presented in table 3. 

Table 3. — Swans censused, Alaskan waterfowl inventory, January, 1949 to 1957 

[U. S. Fish and Wildlife Service records) 



Year and location 


Number 
of swans 


Year and location 


Number 
of swans 


1949: i 


35 
4 
2 


1954: 

Ke tch ikan area 

Petersburg area 

Craig area -. 

Total 

1955: 3 


2 127 (+50) 


Petersburg area _. _ 

Sitka area . 


34 

2 56(+25) 


Total 


41 


2217(+75) 


1950: 


124 
2 


32 






16 






59 


Total 


126 




2 




Total 




1951: ' All areas 



37 

2 49(+30) 
12 


109 


1952: Ketchikan area 

1953: 


1956: Ketchikan and Petersburg areas 
combined (reduced coverage) ._ 


15 






82 








Total 


2 61(+30) 











1 Widespread and prolonged freezing of fresh-water lakes and protected bays. 

2 Figures in parentheses are estimated numbers in addition to swans counted. 

3 Mild winter noted, many inland lakes open, vessel survey. 



RECENT OCCURRENCE, BREEDING, AND MIGRATION REPORTS 33 

In addition to the southeastern Alaskan areas listed, swans have 
been reported from time to time wintering on the Alaska Peninsula, 
Kodiak-Afognak Islands, and Prince William Sound (W. A. Elkins, 
correspondence). Although the species of these birds has not been 
determined, it is believed that they represent trumpeters also. 

The census figures presented in table 3 are not directly comparable 
for many reasons. The exact habitat covered may not be the same 
from year to year even within a designated district, census observers 
and techniques (aerial, vessel, etc.) vary frequently, the weather no 
doubt affects distribution greatly and in unknown ways, and swans 
may not return to the same district each year. Also, the possible oc- 
currence of wintering whistlers in southeastern Alaska cannot be 
entirely dismissed at this time. 

Since small numbers of whistling swans have been known to pass 
the winter as far north as Washington, Idaho, and British Columbia, 
the data in table 3 may include some of the lesser species also, although 
there appears to be little doubt that the trumpeters are substantially 
represented here. 

Alda Orton's (1951:10) article reporting the presence of a small 
number of breeding trumpeters on the lakes of the Naha River Valley 
north of Ketchikan appears to be the first breeding record for this 
species in that area. In this instance it is interesting to note that 
the breeding and wintering range overlap as they do in the Red 
Rock Lakes and the Yellowstone Park areas to some extent. 

The first indications of a substantial breeding flock of trumpeters 
in Alaska was brought to light as a result of field work in the lower 
Copper River Basin by Melvin A. Monson (1956: 444-445). Flying 
the area comprising the convergence of the Tasnuna and Bremner 
River Valleys with that of the Copper River on August 11, 1955, Mon- 
son censused 69 adult swans and 5 broods totaling 15 cygnets. Identi- 
fication of several of this group as trumpeters had previously been 
made on the ground from voice calls, bill characterist ics, and egg speci- 
mens obtained. 

Trumpeter swan investigations are currently underway by U. S. 
Fish and Wildlife personnel at the Kenai National Moose Range on 
the Kenai Peninsula, Alaska. The following information was 
gathered in the preliminary studies by David Spencer (Refuge Super- 
visor), Jim Johnson (Refuge Manager), and Jim Branson (Game 
Management Agent), and furnished by Spencer (correspondence, 
August 30, 1957). I have summarized it as follows: 

Swans have been known to nest on the northern part of the Kenai Peninsula 
over a long period of years. From time to time a few birds have been shot by 
waterfowl hunters. Two of tbcse which were recovered in 1951 and 1956 were 
identified as trumpeter swans. It appeared likely these were Kenai nesting 



34 



DISTRIBUTION AND STATUS 




Figure 4. — Aerial view of trumpeter breeding grounds in lower Copper River 
Basin, Alaska, at confluence of Tasnuna, Bremner, and Copper Rivers. 



birds. Investigations in 1957 were aimed at determining the identification of 
the Kenai nesting swans and to estimate the nesting population. 

The first birds, one pair and one juvenile, were noted on the east fork of 
Moose River on April 2. The main group of swans arrived on the nesting ground 
about the third week in April. A flock of 48 adult swans observed April 30 were 
believed to be migrating birds as there was no evidence that this flock re- 
mained in the area. 

Approximately 20 pairs of swans nested on the Kenai Moose Range this year. 
An additional 10 nonbreeding birds appeared to be in the area. Three clutches 



RECENT OCCURRENCE, BREEDING, AND MIGRATION REPORTS 35 

of eggs had measurements within the trumpeter size range. The male of a nesting 
pair which was collected was identified as a trumpeter. 

The fact that only a single juvenile bird was observed to return in the spring 
suggests considerable loss among the first-year birds. The single swan (speci- 
men) collected had been previously shot. Banding is indicated as an initial 
step in management, since it will be necessary first to determine the wintering 
area of the Kenai population before steps are taken to analyze losses. 

CENTRAL FLYWAY 

Utah. At least two sight records of swans believed to be trumpet- 
ers have been made by well-qualified wildlife observers in Utah during 
the period 1925-57. While positive identification was not made in 
either of these cases, it is not believed likely that both are in error. Dr. 
Clarence Cottam (correspondence) reported that A. V. Hull, formerly 
a Service employee at the Bear River Refuge, observed a trumpeter on 
that area on June 14, 1932 ; also that in July 1940 Dr. D. I. Rasmussen 
and Leo K. Couch reported an immature trumpeter on Strawberry 
Reservoir. 

There is apparently no record that the trumpeter has ever bred 
within the State of Utah, although several early occurrence records do 
exist before 1925 (1 in 1923, 1 in 1907 or 1908, and 6 specimens captured 
in 1901 — Cottam, correspondence) . 

Wyoming. Vernon Bailey (1930: 188) mentions a few early random 
Park trumpeter occurrence records, among them 2 breeding pairs seen 
in 1926, 1 pair on Bridger Lake and the other near Yellowstone Lake. 
George Wright and Ben Thompson (1935: 104) add, "prior to 1929 
a pair of trumpeters had been known to make unsuccessful nesting at- 
tempts at Trumpeter Lake in Lamar Valley." Wright and Thompson 
sum up the early situation : 

Early superintendents' reports have mentioned the presence of swans in the 
Park. . . . but we have not been able to ascertain whether there was a period 
of interruption when the birds did not breed in the Park at all, or whether they 
simply became so scarce as to be generally overlooked. The latter is probably 
the case. 

It is a fact that in recent years there has been an increase in the number of 
trumpeter swans breeding in the Park. To a degree this increase may be more 
apparent than real, inasmuch as more attention has been focused on the swans 
than before and nesting stations recently reported may have been previously 
overlooked. 

Other recent records are given under Annual Swan Census, 1929-57. 

Two recent Wyoming reports of the trumpeter's occurrence outside 
the Yellowstone-Jackson Hole area have been made. The first is 
especially interesting. Robert L. Patterson (correspondence) fur- 
nished this as follows : 

Of . . . interest is a report of a pair of wild swans and five cygnets seen in 
September, 1953, on a small lake in the vicinity of Pathfinder Migratory Bird 



36 DISTRIBUTION AND STATUS 

Refuge in central Wyoming. We rather assume that this observation was of 
trumpeter swans although, of course, it is not verified. The observation was 
made by George Wrakestraw, one of our wildlife biologists. 

The second record is that of 2 trumpeter cygnets, banded on Lowe 
Lake in the Grande Prairie region of northwestern Alberta in the 
summer of 1956 by Canadian Wildlife personnel. The birds were 
found dead, apparently shot, near Cody, Wyoming, on or before 
October 27, 1956 (R. H. Mackay, 1957 : 339). 

Montana. In this state no reports of trumpeters occurring outside 
their known range during the early part of the 1925-57 period are 
known. There are several interesting reports since 1950. 

K. F. Roahen (correspondence), U. S. Game Management Agent, 
reported a trumpeter found dead in poor flesh (weight 27 pounds) 
at Freeze-out Lake, Fairfield, Montana (35 miles west of Great Falls), 
on October 10, 1950. 

Henry Lentfer, taxidermist in Livingston, Montana, furnished this 
note (correspondence, January 1,1956) : 

A Mr. Hansen who works for the Montana Power Company told me about a 
pair [of swans] that evidently were about to nest on a small lake near Mystic 
Lake on the Rosebud last spring or early summer as he saw them for quite a 
while and then one flew into the powerline and was killed . . . (weight 22 V 2 
pounds). 

Ralph L. Hand, retired U. S. Forest Service official, also furnished 
an interesting note of a flight of about 30 swans believed to be trum- 
peters seen over Missoula, Montana, on October 31, 1953. 

Besides the winter movements of the trumpeters in the Madison 
Valley northwest of Yellowstone Park, birds occur there as far north 
as Ennis, Montana, during the spring, summer, and fall months. A 
pair or two are usually found nesting on Ennis Lake. 

Trumpeters have been reported at various places along the Beaver- 
head Valley as far north as Twin Bridges, Montana, over 100 airline 
miles northwest of the Red Rock Lakes Refuge. A pair of breeding 
swans have occasionally been reported near Twin Bridges; however, 
this report has never been verified. A number of late fall and early 
spring occurrences of trumpeters near Dillon, Montana, .have been 
reported in recent years by Joseph H. Buck, former Red Rock Lakes 
Refuge employee. 

During the winter months the occurrence of a trumpeter or two 
along the Yellowstone River outside the Park between Gardiner and 
Livingston is also occasionally observed by Park Service personnel; 
however, such sightings indicate only sporadic use of that area. 

More recent records are given under Annual Swan Census, 1929-57. 

Nebraska. During the 1956 fall hunting season a trumpeter family 
of 5, which included 3 cygnets banded in the Grande Prairie region of 



RECENT OCCURRENCE, BREEDING, AND MIGRATION REPORTS 37 

northwestern Alberta (Lowe Lake), were all shot in western Ne- 
braska. Two of the cygnets were killed on October 27 — one at 
Schoolhouse Lake and one at Shoup Lake near Valentine (Cherry 
County) — while the third was found dead November 2 on the Loup 
River 12 miles west of Fullerton (Nance County), having previously 
been shot. One of the adults was shot and crippled October 30 
near Fullerton while the other adult was captured wounded near 
Shelton (Buffalo County) on November 2. The crippled adults were 
taken to Grand Island where they could be cared for. No other re- 
ports for this species in Nebraska appear to have been made since the 
November 11, 1929, Holt County record (Haecker, Moser, and 
Swenk, 1945: 5). 

North Dakota. Information received from J. F. Cassel, Chairman, 
Department of Zoology, North Dakota Agricultural College, indi- 
cates that a pair of trumpeters in company with 125 whistling swans 
were observed on Slade Lake near Dawson, North Dakota, by Lee 
Pettibone on April 25, 1928. 

Eussell Reid, Superintendent of the Historical Society of North 
Dakota, wrote (correspondence), "During October 1930, I observed 
two swans flying over Lake Isabel south of Dawson, North Dakota. 
These swans appeared to be exceptionally large but . . . identifica- 
tion could not be positive." 

There do not appear to be any reports from this State in the last 
25 years. 

Alberta. The presence of a breeding group of trumpeters in north- 
western Alberta in the Grande Prairie district has been known for 
some time. J. D. Soper (1949 : 240) reported 64 adults and 14 cygnets 
in this area. These birds have been under seasonal observation by 
the Canadian Wildlife Service since that time. 

A breeding pair of trumpeter swans was reported in the Cypress 
Hills region of southeastern Alberta by Robert Lister (1951: 157). 
These were observed without young in 1948 but were accompanied 
by cygnets in 1949 and 1950. These presumably winter somewhere 
in the United States. 

MISSISSIPPI AND ATLANTIC FLYWAYS 

A field report (U. S. Fish and Wildlife Service files, Patuxent 
Refuge) by B. J. Shaver dated August 31, 1937 noted two trumpeter 
swans on a small marsh lake in Beltrami County, Minnesota. These 
birds were reported to have been there all summer, but no young birds 
were seen. No other records show trumpeter occurrence east of Al- 
berta or North Dakota. 



HABITAT 




BREEDING HABITAT 

LIFE ZONE CHARACTERISTICS 

The trumpeter swan originally nested over a wide latitudinal range, 
roughly 1,700 miles at the greatest distance. Although the prin- 
cipal breeding grounds were reported to be mainly within the north- 
ern portions of the continent, it is apparent that this fowl formerly 
nested from at least as far east as the eastern shore of James Bay 
west to coastal Alaska. This species thus once occupied a variety of 
different ecological environments. 

Established breeding records of the trumpeter document nesting 
in the following life zones of North America : 1 

1. Arctic-Alpine Zone (Mackenzie Bay, Norton Sound). 

2. Open Boreal Forest Zone (lower Mackenzie Basin, Kenai 
Peninsula). 

3. Closed Boreal Forest Zone (upper Mackenzie Basin, Grande 
Prairie region, Yellowstone region [including Red Rock 
Lakes] ) . 

4. Aspen Parklands Zone (Cypress Hills, Alberta). 

5. Montane Pine Zone (Yellowstone region). 

6. Pacific Rainforest Zone (Naha Valley, Alaska). 

7. Eastern Deciduous Forest Zone (northeastern and northwestern 
Missouri, south central Minnesota, southern Wisconsin). 

8. Short Grass Prairie Zone (Flathead Valley, Montana; north- 
western Nebraska). 

9. Tall Grass Prairie Zone (northern Iowa, southern Minnesota). 



1 Life zone names based on unpublished information in U. S. Fish and Wildlife Service 
files. 

38 



BREEDING HABITAT 



39 



While the range of life zones occupied by various groups of breed- 
ing trumpeters in the past has been great, the fur-trade records would 
seem to confirm that the trumpeter has been found breeding more 
typically in the Open Boreal Forest than in any other life zone. As 
the species existed near the southern limits of its breeding range in 
the United States, it was to be found nesting chiefly in the Closed 
Boreal Forest, Montane Pine, Eastern Deciduous Forest, Short Grass 
Prairie and Tall Grass Prairie Life Zones. 

PHYSICAL CHARACTERISTICS 

Although trumpeters originally lived in many different major 
groups of environments, as embraced by the life-zone concept, there 
is much evidence that this species is far more limited in the variety 
of habitat it will accept as actual breeding grounds. Its ecological 
niche may therefore be said to be as confined as its life zone range 
was generous. This characteristic would be expected in such a spe- 
cialized waterfowl. 




■^r breeding populations 

wintering range 
Q breeding and wintering range 



Figure 5. — Presently known breeding and wintering range, trumpeter swan. 
469660 O— 60 4 



40 



HABITAT 




Figure 6. — Red Rock Lakes Migratory Waterfowl Refuge. 

The following statement outlines some of the specific physical fea- 
tures of the trumpeter's breeding-habitat requirements: 

1. Stable waters possessing a relatively static level, not exhibiting 
marked seasonal fluctuations. 

2. Quiet waters of lake, marsh, or slough, not waters subject to 
obvious current or constant wave action. 

3. Shallow waters of lake or open marsh, not so deep as to pre- 
clude considerable digging and foraging for lower aquatir 
plant parts, roots, tubers, etc. 

RED ROCK LAKES REFUGE 

Perhaps the best way to outline the characteristics of the trumpeter's 
present breeding habitat in the United States is to describe the 
principal nesting grounds of this species in the Red Rock Lakes 
Migratory Waterfowl Refuge. This area was acquired by the United 
States Government in 1935 and is now administered by the Bureau of 
Sport Fisheries and Wildlife principally for the perpetuation of this 
species. This splendid mountain-marsh system is located in the 
Centennial Valley (Beaverhead County) in southwestern Montana. 
Comprising about 13,000 acres of shallow lakes, productive open 
marsh, and extensive sedge meadows, it is a biotic complex not dupli- 
cated elsewhere in this country on such a grand scale. Its elevation 
of 6,600 feet, the relatively stable water supply which flows from 
numerous springs and creeks sustained by a dependable snow run-off, 
plus the exceptionally gradual gradient of the entire drainage are 
physical features which combine to perpetuate a stable virgin marsh 
of high quality, a rare feature of such generous proportions in these 
modern times. 



BREEDING HABITAT 



41 




Figure 7. — The Red Rock Lakes owe their stable waters to the Centennial 
Mountains which tower above them to the south, trapping abundant snows 
that feed the numerous creeks and springs entering the marsh system. 

Geologically speaking, the Red Rock Lakes in the Centennial Val- 
ley of southwestern Montana lie in a broad trough bounded on both 
the north and south sides by two major faults. South of the lakes 
a continuous series of en echelon faults form the north face of the 
Centennial mountain range. The north side of the trough in which 
the lakes lie is marked by a series of faults along the front of the 
Gravelly range; thus the lakes lie in a down-dropped basin which 
comprises most of Centennial Valley. The gradient of the valley 
floor of Centennial Valley is extremely slight, and erosion is not down- 
cutting the exit of the Red Rock Lakes at any great speed. There- 
fore there seems little likelihood that within the next few hundred 
years there will be any marked change in the lakes themselves; they 
will neither be filled in nor drained by erosion, though many higher 
stands of the lake shore can be seen around the margins of the valley. 
These higher stands of the lakes probably correspond to wetter cli- 
matologic periods rather than any marked difference in drainage, and 
may perhaps be correlated with the various advances of the Wisconsin 
ice sheet and the extensions and retreats of the valley glaciers into the 
bottom of the valley floor. 

Records of much dryer periods in the recent geologic past are also 
preserved. Immediately west of the Red Rock Lakes area are many 
square miles of anchored sand dunes, barchans; these dunes are now 
covered by vegetation and are nearly stationary. Their form and 
outline indicates that they were active moving dunes in the recent 
geologic past, and in a sense are now fossil dunes, testifying to a 
period of much lower rainfall than now occurs. 



■HP! 







Figure 8. — Aerial view of Red Rock Lakes. Lower Lake in foreground is 
dotted with beds of bulrush. The marsh system is at the upper left, and the 
Upper Lake is in the center background. 



The Red Rock Lakes and marsh were the subject of a formal flora 
survey, with transect control, in 1955 and 1956 by Biologist Watson 
E. Beed of this Bureau. His work, together with that of other in- 
dividuals, forms the chief basis of present knowledge regarding the 
identification, distribution, and quantity of both submerged and 
emergent vegetation in this marsh. The following description is 
based on Mr. Beed's report. 

All of the Red Rock Lakes bottoms are composed of a mucky 
matter, being a mixture of decaying vegetation, plankton, and mineral 
soil. Because of the relative low water temperatures, seldom exceed- 
ing 50° F., decomposition is slow and the deposit of decaying material 
relatively greater than the annual rate of deposition would indicate. 
It is this residual fertility of the bottoms, which combines with favor- 
able water temperatures and levels during the short summer months, 
that produces the tremendous abundance of aquatic plants found in 
the Red Rock Lakes marsh. 



BREEDING HABITAT 



43 



The water itself, except for a stained condition in some of the bog 
bays, is normally clear except when disturbed by wind, feeding water- 
fowl, or by water movement during the spring run-off. The abun- 
dance of aquatic plants indicates a medium hard water with perhaps 
20 to 30 ppm. of bound C0 2 . The actual pH of four samples taken 
was 8. 

With the exception of the north shore of the Upper Lake, which is 
subjected to considerable wave action, the shorelines of all waters are 
vegetated to the water's edge, chiefly with beaked sedge (Carex ros- 
trata) 2 , and exposed mud flats are absent. Shorelines are open rather 
than timbered except the south shore of Upper Red Rock Lake, which 



2 Botanical nomenclature, which follows Beed's report, was hased on Norman C. Fassett's 
Manual of Aquatic Plants, Albert S. Hitchcock's Manual of the Grasses of the United 
States, and W. E. Booth's Flora of Montana, Part 1, as well as identifications supplied 
by Loran C. Anderson, Acting Curator of the Intermountain Herbarium, Logan, Utah. 



f~$8&& 




FIGURE 9. — Trumpeter swan nest located on an old inuskrat house on a cattail- 
sedtfe island in Lower Red Rock Lake. In the background the Centennial 
Mountains wear a snow mantle normal for June. 




Figure 10. — Numerous channels, sloughs, and potholes set in a bog-mat environ- 
ment of beaked sedge typify the Red Rock Lakes marsh. Darker shoreline 
vegetation is bulrush, cattail and rushes. 



is bordered by a fairly continuous belt of aspens (Popuhis tremu- 
loides). Along the higher better-grained soils, Engelmann spruce 
(Picea engelmanni) in a bog environment with willows (Salix spp.) 
along the immediate lake shore exist in certain locations about Upper 
Red Rock Lake. 

Arrowhead (wapato, Sagittaria I at? folia) and spikerush (Eleo- 
charis macrostachya) are the principal emergent plants found in the 
Lakes and marsh between the normal sedge shoreline and deeper water. 
The stable low water levels explain the abundance of these plants in 
certain locations. 

As might be expected, animal life flourishes in the water and around 
the shoreline. Frogs, toads, and polliwogs are extremely abundant 
locally in season, while snails and the fry of several fish species are 
also present in numbers. Water beetles, caddis flies, and rat-tailed 
maggots are also common in their appropriate ecological strata, while 



BREEDING HABITAT 



45 



the production of small Crustacea and plankton in maximum abun- 
dance is truly astounding, the water being literally alive during the 
summer season. 

Swan Lake is a small but important shallow marsh of roughly 400 
acres lying to the north of Upper Eed Rock Lake and connected with 
it only by means of its drainage. Elk Springs Creek, which emerges 
from Swan Lake near the east end only a short distance from where 
it enters the Lake, is its principal source of water. The water table 
in this lake is very stable, though having no flow. Numerous emer- 
gent islands of spikerush and beaked sedge occur in Swan Lake, and 
several rather prominent beds of cattails (Typha latifolia) are also 
present. Water depths are extremely shallow, varying from a few 
inches to only about a foot in the deepest area of any size, and averag- 
ing about 6 to 10 inches over the entire floor of the lake bed. 





#*& 




Figure 11.— A trumpeter nest located in the predominant sedge environment 
of the Red Rock Lakes marsh. Stem and Leaf parts of both sedge and cat- 
tail form the bulk of the nest material both for the muskrat lodge nest 
foundation and the nest proper. 




Figure 12. — Swan Lake is a shallow marsh sealed off from Upper Red Rock 
Lake by a natural sedge-willow anchored dike. Islands and peninsulas are 
chiefly sedge bog-mat while many extensive beds of spikerush also occur in 
these stable shallow waters. 

Because the shallow, static nature of the water causes higher water 
temperatures than in the other areas of the Lakes, algae are con- 
spicuous, especially during the late summer months. In spite of algal 
shading, the lake bottom is very fertile and supports a great profusion 
of aquatic plants. The following plants predominated in Swan Lake 
in 1955 and 1956. Percentages of area occurrence are : water milfoil 
(Myriophyllum exalbescens) , 35; bare, 23; sago pond weed (Pota- 
mogeton pectinatus), 13; clasping-leaf pondweed (P. richardsonii) , 
12; leafy pondweed (P. foliosus), 7; slender pondweed (P. pusillus), 
4 ; and miscellaneous, 6. 

A glance at figure 6 will show that Upper Red Rock Lake is the 
largest lake on the Refuge; it is about 2,880 acres in expanse. It 
contains no "islands" of emergent vegetation, and even peripheral 
plants, such as bulrush or cattail, are not so prevalent as elsewhere. 



BREEDING HABITAT 47 

Water depths in the Upper Lake vary from a few inches to over 5 
feet, but almost all of the lake is less than 4 feet deep. The main 
water supply is furnished by Red Rock Creek, though the Elk 
Springs Creek-Swan Lake drainage, Tom Creek, and numerous fresh 
springs along the south side of the lake are also important and add 
a considerable flow, especially during the runoff season. Drainage 
of this lake is westward into the main marsh system. 

The very fertile bottom of the Upper Red Rock Lake supports an 
almost unbelievably abundant and luxuriant growth of aquatic plants. 
In 1955 and 1956 the following tabulations of species percentages were 
recorded: waterweed (Elodea canadensis), 41; muskgrass (Chara 
spp.), 22; bare, 12; leafy pondweed, 5; sago pond weed, 4; and mis- 
cellaneous (chiefly Potamogeton spp.), 16. 

The marsh surrounding Swan Lake and extending between Upper 
and Lower Lakes comprises the largest single habitat unit within 
the Refuge, over 8,000 acres. Of this area only about 10 percent is 
open water, most of the balance being nearly pure stands of sedge in 
a bog meadow community. Water depths vary greatly but outside 
the main channels are uniformly shallow. Current in the main stream 
is very slow and even less perceptible when divided into more than 
one channel. Many isolated potholes are found within this river 
marsh area. Most of these are small but a few are of considerable 
size. 

The best of this river-marsh habitat, from a food-producing stand- 
point, is found along the stream beds of the slow-moving river and 
extensive shallow sloughs which border these outlet channels. Aquatic 
plants in the channels and sloughs of the main stream bed were found 
to occur in the following approximate order of abundance, with a 
high percentage of the area surveyed being covered: clasping-leaf 
pondweed, water milfoil, muskgrasses, sago pondweed, and arrowhead. 

Common emergents in this area include at least two species of bur- 
reed (water burreed, Sparganiu/m fiuctuans, and S. multipeduncvla- 
tuin), hardstem bulrush {Scirpus acutus), and cattail. Ecologically, 
this unit is the most diversified of any on the Refuge, with the great- 
est variety of plant life. 

The Lower Red Rock Lake is 1,540 acres in size and is supported 
chiefly by the dependable waters of Odell Creek, which arise in the 
mountains to the south. Several permanent sedge islands are found 
near the north side of this lake, while many prominent beds of bulrush 
are scattered over the lake at large. Water depths vary generally 
from 1 to 2 feet, placing this lake in an intermediate position between 
shallow Swan Lake and the moderately deep Upper Lake. The lake 
bed was covered by plants in the following percentages : waterweed, 



48 HABITAT 

39; bare, 19; algae, 12; clasping-leaf ponchveed, 9; arrowhead, 5; sago 
pondweed, 2 ; and miscellaneous species, 14. 

Several species of rushes (Juncus balticus, J. parryii, J. longistylus, 
etc.) and sedges (Garex festivella, G. kelloggii, and G. laeviculmis) 
are found most frequently on firmer ground between the marsh proper 
and upland meadows. 

The northern slopes of the Centennial Mountains, which form the 
ramparts to the south of the Lakes, are covered with timber, prin- 
cipally Douglas-fir (Pseudotsuga taxifolia) and lodgepole pine (Firms 
contorta) with a lower slope apron of aspen and willow (SaJix, spp.). 
The slopes of the Gravelly Kange which stretch away to the north 
of the Lakes are characterized by a more arid climate and sandier 
soil where numerous grasses and sages, principally big sagebrush 
(Artemisia tridentata) , threetip sagebrush (A. tripartita), and silver 
sagebrush (A. cana) thrive. 

By far the most common waterfowl associated with the swans in the 
Red Rock Lakes marsh are the lesser scaup (A thy a afjinis), many 
hundreds of which are produced annually. Other common marsh 
nesting birds include the long-billed marsh wren (Tehnatodytes pal- 
ustris), a sandhill crane (Grus canadensis) , and coot (Fulica ameri- 
cana). 

YELLOWSTONE NATIONAL PARK 

In contrast with the Red Rock Lakes area, where the nesting terri- 
tories are contained in a single marsh system, breeding swans in 
Yellowstone Park usually exist as isolated pairs on widely separated 
waters. Without exception, each of Yellowstone's swan lakes is oc- 
cupied by only one breeding pair of birds. 

The swan lakes of Yellowstone also differ physically in many ways 
from the rather uniform Red Rock marsh nesting habitat. In the 
Park, shorelines are often timbered, feeding areas are much more apt 
to be peripheral due to deeper water areas toward the center of the 
lakes, and lake elevations are generally greater. So the breeding 
grounds of the trumpeter in Yellowstone are a more marginal habitat 
than the vast uniform marshes of the Red Rock Lakes. This is appar- 
ent in the following description, based on a letter from Condon, of 
four Park swan waters found outside the plateau region. 

The lakes of Yellowstone occupied by swan as nesting areas are 
pronouncedly different, each from the other, in their geological 
origin as well as in the general ecology of the area surrounding them. 
Trumpeter Lake, at an elevation of about 6,050 feet and with a surface 
area of about 20 acres, owes the origin of its basin to glaciation ; it is 
surrounded only by a grassland-cinquefoil-sagebrush plant associa- 
tion. The waters are shallow, and one end of the lake provides cover 













*l* r 



.*-»• «''* 




Figure 13. — A trumpeter pen on her nest in a shoreline stand of pure sedge, 
Upper Red Rock Lake. The Centennial Mountains escarpment forms a chilly 
backdrop. 



50 HABITAT 

for nesting birds in the cattails, bulrushes, and sedges. A detailed 
study of the vegetation within the lake has not been made, but its 
composition is very different from the vegetation in the lakes at high 
elevations, secluded in the evergreen forests of the plateau section of 
the park. There are no large beds of wokas, (yellow pondlilies, 
Nuphar polysepalum ) . Associated with the swans on Trumpeter Lake 
are found: ruddy ducks, coots, redwinged blackbirds, yellow-headed 
blackbirds, spotted sandpipers, mallards, soras, Canada geese, long- 
billed marsh wrens, muskrats, and a variety of smaller animals. 

The Beach Spring Lagoon, with a surface area of about 29 acres, is 
off Mary Bay on Yellowstone Lake at an elevation of about 7,740 feet. 
It owes its basin to water impoundment behind a bar formed along the 
lake shore. Like Trumpeter Lake, this body of water is surrounded 
by a grassland-sagebrush vegetative complex. It does not have so 
much cover in the form of cattails, rushes, and sedges for concealment 
as does Trumpeter Lake. There are no large beds of wokas. The 
waters are shallow, and during the summer months are commonly 
visited by California gulls and white pelicans. Canada geese, buffle- 
heads, mallards, scaup, and coots are commonly seen with young on 
its waters. Marshy areas are much more extensive around this lake 
than at Trumpeter Lake. The vegetative growth in the marsh areas is 
not sufficiently tall to provide cover for swans but does provide con- 
cealment for smaller birds and mammals. 

Swan Lake, at an elevation of about 7,250 meet, owes its basin to 
glacial action. It is surrounded by a grassland-cinquefoil-sagebrush 
and sedge-marsh vegetative complex. Canada geese, coots, mallards, 
green-winged teal, scaup, goldeneyes, and buffleheads are seen with 
young on this lake. Yellow-headed blackbirds, spotted sandpipers, 
long-billed marsh wrens, and Wilson's phalaropes nest there. Musk- 
rats are common, and otters are seen at times. The waters are rela- 
tively deep with extensive marsh areas on the northern end. Sedges 
and rushes predominate on the north end. Some small clumps of 
willow are present. Wokas beds are absent. 

Geode Lake is a small lake at an elevation of about 6,150 feet with 
open rocky shores and virtually no plant cover. The waters are rela- 
tively shallow, impounded by an old beaver dam. This has silted over 
and thus established itself as a barrier which will probably retain 
water in the basin for many years to come. Very few other birds or 
animals use this lake. The absence of cover apparently discourages 
ducks and other waterfowl. There is undoubtedly overland movement 
of swans from this lake to ponds about %-mile distance under Crescent 
Hill. 

The lakes secluded in the evergreen forests of the plateaus of the 
park are, in most instances, larger in size than the open-country glacial 




Figure 14. — A female trumpeter, on her nest after returning from a feeding 
period in the Lower Lake, shakes the water from her plumage. The nest is 
located on a muskrat house behind a protective screen of bulrush. Note 
elevation of nest in tall, dense cover, and discoloration of swan's head and 
neck from contact with ferrous organic matter. 



lakes. Their exact geological origin is somewhat obscure in some 
instances, but the majority of them were caused by the damming of 
old drainage basins or courses with glacial debris. Some are residual 
lakes remaining in a depressed area of a once much larger Yellowstone 
Lake. Virtually all of these lakes have beds of wokas in their shallower 
waters. In most instances there is an absence of rushes and cattails. 
This is not true of Tern Lake, Riddle Lake, or the small lake below 
Madison Junction. In some lakes beavers are present and occasionally 
their old lodges have provided a base for a nest site. Many of these 
lakes have a fringe of meadow around them consisting of grasses and 
sedges. Canada geese, mallards, goldeneyes, buhMeheads, green- winged 
teal, and scaup are seen with young on most of these lakes although 
they are not present in any appreciable number. Grebes and coots 
are also found on some lakes. The sora nests at White and Tern Lakes 



52 



HABITAT 



YELLOWSTONE 
NATIONAL PARK 



Beach Springs 
^Yellowstone Lake 




SCALE OF MILES 
20 40 
i 1 I 



,V\* NATIONAL ELK REFUGE 



WYOMING 



Figure 15. — Geographical features of the trumpeter swan breeding and winter- 
ing areas in the United States. 

and also at Riddle Lake, while the common loon has been observed 
nesting at Riddle Lake in association with the trumpeter swan. 

COPPER RIVER BASIN, ALASKA 

Notes on the Copper River area were furnished by Melvin A. Mon- 
son, U. S. Fish and Wildlife Service, who discovered the trumpeters 
there in 1951. I condensed his remarks as follows : 

The Chugach Mountains, through which the lower Copper River passes, 
effectively divide the climate of the Copper River Basin into two categories. 
The south side of the range bordering the Gulf of Alaska lias a climate maritime 
in nature with heavy precipitation and relatively mild temperature. . . . North 
of the Chugach Mountains the climate is colder and considerably drier. Some- 
where in between these two general categories are the climatic conditions exist- 
ing in the Bremner and Tasnuna River valleys. 



BREEDING HABITAT 



53 




Figure 16. — Trumpeter swan nesting site at Grebe Lake in Yellowstone National 
Park. Note exposed situation of sedge sod nest. Beds of wokas appear in 
the background, moulted feathers in the foreground. 



Because of rugged topography of the region the deep Copper River canyon 
acts as a wind funnel so that high wind velocities are common in the lower 
Bremner and Tasnuna valleys. . . . During the summer the wind blows up- 
stream . . . these strong winds pick up sand and silt from the valley floor of 
the Copper River below the confluence of the Bremner and Tasnuna Rivers' and 
deposit this material as the wind divides and fans into the Bremner and Tasnuna 
Rivers. Such deposits are so great that the shallow lakes show evidence of 
Ailing up. 

The Bremner River has a drainage area of 1,000 square miles and enters the 
Copper River 40 miles upstream from its mouth. . . . Only in the lower portion, 
the last 23 miles, does the river bed broaden into :i relatively wide flat valley 
floor. Here there is evidence of great deposits of gravel and silt which have 
been carried down from the upper reaches. ... In this stretch, the river does 
not possess a well-defined channel. Within this lower section small shallow- 
lakes are scattered through the valley floor. It is in these small individual lakes 
that considerable nesting of swans occurs. 

The Tasnuna Basin assesses characteristics similar to those described for 
the Bremner River. It has a drainage area in excess of .'">(»(» square miles and 
enters the Copper River from the west 10 miles above the mouth of this stream. 
. . . Here, as in the Bremner River, there is evidence of considerable deposits 
of gravel and silt laid down in the valley by retreating glaciers. . . . The river 
has no well-defined channel, and during high water much of the valley floor is 
flooded. Throughout the lower 10 miles are numerous shallow lakes where 
aesting swans have been observed. 

Spruce is the only valuable timber in the two valleys. It is found up to 
elevations of about 2,500 feet above sea level. Above the timherline the moun- 
tain slopes are covered with a dense growth of alder. . . . 

In the flat valley floors there are abundant growths of both willow and alder. 
which appear to he the dominant species. Also scattered throughout the area are 



54 



HABITAT 




Figure 17. — Aerial view of trumpeter nesting habitat in lower Tasnuna River 
Basin, Alaska. Trumpeter nest was found in small restricted slough in the 
lower right-hand corner of photo. 

limited stands of Cottonwood and birch. Grasses are abundant throughout 
much of the area, and in shallow lakes and along the lake shores in the valley 
floors there are luxuriant growths of horsetail (Equisctum spp. ). 

WINTERING HABITAT 



Within the greater Yellowstone region of southwestern Montana, 
northwestern Wyoming, and northeastern Idaho, there are five prin- 



WINTERING HABITAT 55 

cipal swan wintering districts. These are listed below in the order 
of importance, the first two being more vital to the United States 
segment of the continental trumpeter population than all the rest 
put together : 

1. Island Park area, which includes Henrys Fork of the Snake 

River and its upper tributary waters (Idaho). 
± Eed Rock Lakes Migratory Waterfowl Refuge (Montana). 

3. Yellowstone National Park (Wyoming). 

4. National Elk Refuge, Jackson Hole (Wyoming). 

5. Madison River, and its tributary waters above the Meadow 
Lake Dam (Montana). 

All of the areas listed contain shallow-water lake, stream, and pond 
habitat with varying amounts of aquatic vegetation. Because of 
warm springs these waters do not freeze over entirely during the long 
periods of cold winter weather which normally prevail. Forays by 
trumpeters outside the greater Yellowstone region described are occa- 
sionally observed, though probably these are chiefly exploratory 
flights. Most, if not all, of the trumpeters inhabiting the United 
States are believed to winter on suitable waters within the limits of 
the districts outlined. 

These wintering grounds may be roughly divided into two main 
groups, being either spring- fed streams, or lakes and ponds which also 
receive warm water from some source. So far as streams are con- 
cerned, water movement alone is a factor of considerable importance 
in keeping such waters open during moderately cold weather, but some 
source of warm water is a necessity because prolonged periods of cold 
are common during the winter, with daily minimum temperatures 
well below zero. In such weather, water movement alone will not 
keep solid ice from forming completely across fairly active cold livers. 

This role assumed by warm-water springs in providing winter swan 
habitat in the greater Yellowstone region is all-important. For in- 
stance, on the main stem of Henrys Fork of the Snake River the 
abundant warm waters of Osborne, Harrinian, Elk, and Big Springs 
are essential. On the Madison River within Yellowstone Park the 
warm waters from numerous geysers and springs collect in the famous 
Firehole River to keep both it and the Madison River free of solid ice 
for many miles downstream, and numerous other examples could 
be cited in the Park. Warm spring impoundments on the Red Rock 
Lakes Refuge provide the only swan wintering habitat in that area. 

Without exception the numerous large warm springs within the 
greater Yellowstone region are primarily responsible for whatever 
winter waterfowl habitat is available; without the effect of their com- 
bined warm flow, the trumpeter as well as thousands of lesser water- 

4«96(H1 () (JO — ") 



56 HABITAT 

fowl would be forced to migrate elsewhere, and this whole section of 
the Rockies would be nearly barren of wintering water birds. These 
warm springs provide wintering habitat for trumpeters conveniently 
near to suitable breeding grounds, a fact principally responsible for 
saving this species from extinction in the United States, sparing 
them the long dangerous migrations down heavily gunned flyways. 

Besides open water, good swan wintering habitat contains a certain 
amount of level and open terrain allowing these large birds to loaf or 
fly without restriction of visibility or movement. On the smaller 
streams this becomes especially important since the air space over 
such water is limited, and trumpeters, perhaps more than any other 
waterfowl, require ample and unrestricted air space for take-off. Too, 
the presence of timber growing thickly along watercourses or around 
spring ponds provides convenient perches for avian enemies (eagles), 
cover for mammalian predators, and formidable obstacles to flight. 
Unobstructed snowfields on meadows adjacent to open streams or 
ponds are regularly used as loafing sites, especially later in the winter 
when the snow hardens with settling. During this season trumpeters 
are prone to convene in large flocks and become more active socially. 

Because of these factors, the heaviest use of even a comparatively 
large open stream occurs in those areas which are not timbered or con- 
fined to a narrow canyon, and those portions of waters so restricted, 
even though containing an abundance of food at easily available levels, 
do not support their proportionate share of use. 

ISLAND PARK 

The waters of Henrys Fork of the Snake River, together with those 
of its upper tributaries, arise in the Island Park country (Fremont 
County) of northeastern Idaho along the west boundary of Yellow- 
stone National Park. Here the terrain, physical characteristics of the 
stream, and warm waters from many contributing springs combine 
to produce hundreds of acres of shallow and productive riverbed and 
pond habitat, some of which does not freeze over even in the coldest 
weather. 

The heart of this wintering area is located on or adjacent to the 
Railroad Ranch. This ranch with its adjoining lands contains the best 
and most intensively used trumpeter wintering area for its size on the 
continent. Old timers say that originally the preferred swan winter- 
ing area in this district was located on Shotgun Creek several miles to 
the north. When the desirable features of that area were eliminated 
by the completion of the Island Park Reservoir Dam in the 1980's, 
which flooded this Creek, the swans were forced to rely more heavily 
on the waters of Henrys Fork proper. (Likewise according to old 
residents the impoundment of Jackson Lake Reservoir in Jackson 



WINTERING HABITAT 



57 




iifcn 1 1 \i\ II kL 



Figure IS. — Aerial view of Henrys Fork (North Fork i of the Snake River 
below the Railroad Ranch, Island Park, Idaho. This stretch of river offers 
habitat to wintering trumpeters. The warm Harrinian Springs keep these 
waters open even below —W V. 



Hole destroyed open-water areas caused by warm springs. This for- 
merly constituted a wintering area of considerable importance to 
trumpeters.) 

In the vicinity of the Railroad Ranch, the Henrys Fork is a mod- 
erately large, clear, shallow stream of relatively stable flow which 
meanders through open meadows. .Several hup' springs and spring- 
fed tributaries provide the necessary warm water in strategic loca- 
tions to keep tit least some stretches of the stream open even in the 
severe winter weather. Beds of marestai] (Hippuris vulgaris), leafy 
pondweed, and sago pondweed cover the stream bed in profusion, and 
with clasping-leaf pondweed no doubt form the bulk of the i rumpeters' 
winter diet in this area. 



58 



HABITAT 




Figure 19. — Aerial view of trumpeters wintering on Henrys Fork of the Snake 
River below the Railroad Ranch. Gray birds are cygnets-of-the-year. Trum- 
peters from the Grande Prairie, Alberta, region have wintered in this area. 

RED ROCK LAKES REFUGE 

Wintering habitat on the Red Rock Lakes Refuge is confined to two 
warm spring impoundments, MacDonald Pond, where the multiple 
Elk Springs furnish a plentiful supply of warm (58° F.) water, and 
Culver (Widow's) Pond where the equal but colder (41° F.) flow of 
the dual Picnic Springs is confined. At these two areas, located about 
2 miles apart at the east end of the Refuge, a combined area of from 5 
to 10 acres is normally open during the winter. Although these waters 
never freeze over entirely, the average open-water area may be reduced 
by half or less during the prolonged occurrence of —30° F. or colder 
nightly temperatures. 



YELLOWSTONE NATIONAL PARK 

Although regular counts are not taken owing to winter isolation 
factors, five main areas in Yellowstone Park are known to be regularly 
frequented or occupied by wintering trumpeter swans. A brief de- 
scription of these winter habitats follows : 

1. The Yellowstone River from the outlet of Yellowstone Lake north 
to its junction with Alum Creek normally furnishes winter quarters 
for a number of Park trumpeters as well as groups of Canada 
geese, mallards and goldeneyes. Various areas along about 2 miles 




Figure 20. — Aerial view of SO trumpeters in east Culver Spring. Red Rock Lakes 
Refuge. January 1!)."»<». Air temperatures —20° F. Note moose tracks in 
willow growth. 



of this stream furnish natural aquatic food at available depths as 
they remain open owing to thermal activity. 

2. The Firehole and Madison Rivers offer dependable food supplies 
in open waters for the greater distance of their existence in the Park. 
A number of swans are regularly observed on the courses of these 
streams, even in midwinter, along with a number of mergansers, 
goldeneyes, mallards, and Canada geese. 

3. Shoshone Lake geyser basin contributes enough warm water to the 
west bay of that lake to create a ID-acre expanse of open water there. 
Here a pair or so of trumpeters have been known to pass at least 
part of the winter, sometimes in company with a few Canada geese. 

4. A 5-acre expanse of water normally remains open at the north end 
of Heart Lake near the entrance of Witch ("reek. These waters 
usually support a pair of swans during most of the winter along 
with a few goldeneyes. 

5. At the south end of the Park the Snake and Lewis Rivers, plus the 
open waters of Polecat Creek together with an adjacent slough. 
provide open water and aquatic food at an available depth to the 
small flock of trumpeters normally found wintering in this area. 
Mallards, geese, and mergansers are also found here with the 
trumpeters during this season. 



60 HABITAT 

NATIONAL ELK REFUGE 

Several generous warm springs on the National Elk Refuge assist 
in keeping Flat Creek open during the winter months. This habitat 
is located for the most part within the Refuge and but a short distance 
from the town of Jackson, Wyoming. It has witnessed a rather re- 
markable increase in the numbers of trumpeters which have wintered 
here during the past decade. Together with other local warm spring- 
fed water areas in Jackson Hole, the National Elk Refuge promises 
to become a wintering area of major importance to the trumpeter in 
the future, particularly if some development of warm water areas 
could be accomplished without defeating other wildlife objectives. 

MADISON RIVER 

This drainage, below Park boundaries but above Ennis Lake Dam 
and including Cliff and Wade Lakes, normally winters several small 
flocks of trumpeters. These groups trade back and forth within the 
area or visit adjoining areas as the occasion demands. Specific areas 
containing winter habitat in this district are O'Dell Creek near Ennis, 
Montana, the upper Madison River near the head of Hebgen Reservoir, 
and spring- fed portions of Wade and Cliff Lakes located to the west 
of the Madison Valley proper. 

WINTER COUNTS 

Because of the poor winter flying conditions and the isolated char- 
acter of the country, no true aerial census over the entire greater 
Yellowstone region has been made during the midwinter months. 
Fairly complete aerial or ground counts have been made as the oppor- 
tunity arose in some of the districts listed. These observations have 
been made by rangers of the National Park Service on winter patrol, 
biologists of the Idaho Fish and Game Department, U. S. Fish and 
Wildlife Service personnel, and other local observers. 

These count data are presented in table 4 in order to provide an 
index of relative use. 

Small numbers of whistling swans have been observed (voice iden- 
tification) during the midwinter months in the Island Park area. 
I have heard whistling swans on winter patrol trips in the vicinity 
of the Railroad Ranch, and Ed Kroker, foreman of the Ranch, has 
confirmed the regular occurrence of a few wintering birds in this area. 
The maximum number of the lesser species which has been noted 
is 8. These were reported by Frank Kennedy, winter keeper of the 
Elk Springs Ranch in the Island Park area. So although whistlers 
have been observed to winter in this area regularly, they are appar- 



WINTERING HABITAT 



61 



ently never present in great numbers and the data in table 4 are there- 
fore believed to represent trumpeters almost entirely. 

Table 4. — Winter swan counts, Greater Yellowstone region, 1950 to 1957 



Time of observation 


Swans observed 


Count method 


Observer 


Island Park Area 
(Idaho) 
Feb. 3-7, 1950. 


262 (208) ' 






Feb. 7, 1951 


257 


do 


Fish and Game Department. 
Do. 


Jan. 10, 1952 


330 (222)1 


. do 




Feb. 2, 1953 


356 


do 


Department. 
Misseldine, Shaw, and Nielson, 


Jan. 6, 1954 


419 (333) 1 


Aerial and ground. 


Idaho Fish and Game De- 
partment. 
Salter, Idaho Fish and Game 


Jan. 6, 1955 


271 (141)L 


Department. Cromwell, U. 
S. Fish and Wildlife Service. 


Feb. 16, 1956 


318 (288) 1 . 


do 


and Game Department. 


Jan. 10, 1957 


323 (250)1 


do 


Department. 


Red Rock Lakes Refuge 
(Montana) 2 
Dec. 1949-Mar. 1950 


105-80-200-150 




Fish and Game Department. 
U. S. Fish and Wildlife Service 


Dec. 1950-Mar. 1951 . 


31-47-100-120 


do 


station personnel. 
Do. 


Dec. 1951-Mar. 1952 


18-50-50-150 


.. do 


Do. 


Dec. 1952-Mar. 1953.. 


35-61-75-100 


do 


Dc. 


Dec. 1953-Mar. 1954 a 
Dec. 1954-Mar. 1955 


12-90-146-250 

147-140-135-250 


do 

.. do 


Do. 
Do. 


Dec. 1955-Mar. 1956 


55-154-325-280 


do 


Do. 


Dec. 1956-Mar. 1957 


?-95-209-230- . 


.. do 


Do. 


National Elk Refuge 
(Wyoming) * 
Season 1949-50 


10 


do 


Do. 


Season 1950-51 


13 


do 


Do. 


Season 1951-52 


13 - 


.. do 


Do. 


Season 1952-53 


13 . - 


do 


Do. 


Season 1953-54 


24 - . 


.. do 


Do. 


Season 1954-55 . 


30- 


.... do 


Do. 


Season 1955-56 


33 


do 


Do. 


Season 1956-57 


34 (56) 4 


.. do 


Do. 


Madison River Drainage 
(Montana) 
Dec. 1955 


30-50 (Cliff Lake) 
20-30 (Cliff Lake) 


do 


Philip L. Wright, Montana 


Jan. 1956 


do 


State University. 
Monte Neelv, local resident. 


Jan. 1956 


6-8 (Wade Lake) 

11 (O'Dell Creek 

52 .- 


.. do 


Do. 


Jan. 1956 .. 


.. do 


II. W. Baker, U. S. Fish and 


Yellowstone Xationai. 
Park 5 
Jan. 10-13, 1950 


do 


Wildlife Service 
I'nknown. 


Jan. 8-12, 1951 




.. do 


Do. 


Jan. 1952 


n; 


do 


Do. 


Jan. 13-15, 1953 .. 


33 


.. do 


Do. 


Jan. 3-18, 1954... 


56 


.... do 


Do. 


Jan. 7-18, 1955 


18 .. 


...do 


Do. 


Jan. 9-13, L956 


14 . 


.. do 


Do. 


Jan. 4-9, 1957 


20 


do .. 


Do. 


(Madison River Only) 









i Number in parenthesis represents numbers of swan on or adjacent to Henrys Fork through the Rail- 
road Ranch or tlic immediate vicinity and upstream to I. P. dam. 

- Highest count or estimate of numbers of birds seen during December, January, February, and March, 
in that order. 

:1 MacDonald Pond winter-habitat development completed fall of 1953. 

* Figure corresponds to maximum number of swans seen about Flat ("reek feeding ground during winter. 
Average number accommodated each year is probably only slightly lower except for winter of 19 
when maximum number was present only a short time, hence is shown in parenthesis. Some of the maxi- 
mum number shown in parenthesis may have been whistlers, though none were identified as such at the 
time, identification of all individuals in entire flock of 56 was not possible. 

5 No concerted effort has been made to gather wintering trumpeter data in the Park. These figures 
represent swans seen while conducting the annual winter waterfowl inventory. 







LIFE CYCLE 



DESCRIPTION 

The large size and general waterfowl conformation, white color, 
and prominent long necks of our native swans identify them whether 
seen on the water or in flight. Except for the occurrence of feral mute 
swans (Cygnus olor) along the eastern seaboard in the general vicinity 
of the lower Hudson River Valley or in Michigan (Grande Traverse 
County and vicinity), only the two native North American species are 
likely to be encountered in the wild. A detailed description of the 
external appearances of both species follows. For comparison, a 
number of weights and measurements of mute, whooping, and 
Bewick's swans can be found in Hilprecht (1956: 51-54). He also 
describes the appearance, flight, and voice of these foreign swans 
(1956: 19-31). From these we may conclude that the trumpeter is 
the largest swan in the world. 

SPECIES DESCRIPTION 

Trumpeter swan, Olor buccinator (Richardson), adult (sexes 
alike) : entire plumage white, head and neck commonly with a rusty 
stain from ferrous waters; iris brown: bill black, rarely with small 
grayish or yellowish spot immediately posterior to nostril ; bill usually 
longer and broader terminally than in Olor columbianus; front edge 
of nostril usually 50 mm. or more from tip of culmen; four outer 
primaries emarginated terminally; and feet usually black or gray but 
sometimes tinged with brownish, yellow, or olive. 

Juvenile (sexes alike) : Gray Phase (common). Brownish-gray 
especially on the head, neck, and upper back, lighter gray ventrally; 
forehead, crown, occiput, nape, and upper cheeks light rufescent 
brown ; plumage sometimes rust-stained as in the adult ; feet yellowish 
or olive gray-black; bill becoming black but with basal portion of cul- 
menary ridge behind nostril still salmon or light pink color; tomia of 
mandible dull flesh color. White Phase (rare). White down of 
young replaced directly by white feathers, identical to adult. Color 
of feet and bill as in gray phase. 

62 



DESCRIPTION 63 

Downy Young (sexes alike) : Gray Phase (common). Head and 
neck uniformly mouse-gray; body mouse-gray dorsally, lighter gray 
to white ventrally; feet yellowish; bill pinkish basally, dark gray 
terminally. White Phase (rare). Entire plumage white, feet yel- 
lowish, bill flesh colored. 

Adult Male: 1 Wing 545-680 (618.6) ; tail 173-191 (182) ; culmen 
from tip of frontal feathering 104-119.5 (112.5); tarsus 121.5-126 
(122.9) ; middle toe without claw 135-145 (141.1 mm.). 2 [Adult male 
(Kenai) : total length 59 in., wingspread 87.5 in., weight 27 lb. 6 oz. ; 
(Yellowstone Park) : total length 60 in., wingspread 96.5 in., weight 
27 lb. 9 oz.] 

Adult Female: Wing 604-636 (623.3) ; tail 185-207 (196) ; culmen 
from tip of frontal feathering 101.5-112.5 (107): tarsus 113-128.5 
(121.7); middle toe (w/o claw) 138.5-148 (143.3 mm.). 3 [Adult 
female (Yellowstone Park) : total length 58 in., wingspread 74 in.] 

For comparative purposes the external appearance of the whistling 
swan is also presented here : 

Whistling Swan, Olor columbianus (Ord), adult (sexes alike) : 
Entire plumage white, head and neck sometimes with a rusty stain 
from ferrous waters: iris brown; bill black when not with usual yel- 
low or orange-yellow spot in front of the eye, front edge of nostril 
usually less than 50 mm. from tip of culmen: four outer primaries 
emarginated terminally; feet black or gray. 

Juvenile (sexes alike) : Entire plumage ashy gray, usually dark- 
est on the head and palest on the ventral portions of the body, some- 
times plumbeous to sooty, brownish instead of pale gray duo to stain- 
ing from ferrous waters, bill basally flesh-colored with the nail and 
gape border black; iris hazel : tarsi and tors flesh color, livid to dusky. 

Downy Young (sexes alike) : Plumage white, tinged with car- 
tridge buff to ivory yellow especially on the head, neck, and breast; 
bill, tarsi and toes yellowish. 

Adult Male: Wing 501-569 (538); tail 162-181 (170.8); culmen 
from tip of frontal feathering 97-107 (102.6); tarsus 105-117.5 
(111.9) ; middle toe without claw 120-133 (126.4). 4 

Adult Female: Wing 505-561 (531.6); tail 146-186 (165.3); cul- 
men from tip of frontal feathering 92.5-106 (99.9); tarsus 99.5-115 
(107.2) ; middle toe without claw 110-126.5 ( lis).' 



1 Measurements in millimeters, giving the smallest and largest of the birds examined, 
with the average in parentheses i2.">.4 mm.=l inch). 

-Five specimens, from Idaho, Wyoming, Wisconsin, and Michigan. 

3 Three specimens, one from Montana. 

1 Ei^'lit specimens from Alaska, Maryland. Virginia, and North Carolina. 

"• Fifteen specimens from Alaska. California. Maryland. Virginia, Xortli Carolina, and 
captivity. 



64 



LIFE CYCLE 



Table 5. — Overlapping weights and dimensions of small trumpeter and large 

whistling swans 





Olor buccinator — Minimum weights 


Olor Columbian us— Maximum 


veights 






and measurements 




and measurements 










From tip 








From tip 




Age and sex 






of bill to 


From tip 






of bill to 


I- rum tip 




Number 


Body 


anterior 


of bill to 


Number 


Body 


anterior 


ofhillto 




of speci- 


wt. 


edge of 


axis of 


of speci- 


wt. 


edge of 


axis of 




mens 


(lbs.) 


nostril 


eyes 


mens 


(lbs.) 


nostril 


eyes 








(mm.) 


(mm.) 






(mm.) 


(mm.) 


2+ years: 




















8 
14 


20 
16 


50 

50 


140 
133 


7 
21 


19.5 
19 


48 
49 


125 


Female 


138 


1+ years: 


















Male 


8 


18 


47 


131 


2 


17 


41 


123 


Female 


4 


15 50 


135 


/ 


17 


44 


118 



EXTERNAL APPEARANCE 

If certain external characteristics are lacking or nnobservable, it is 
easy to see why it is virtually impossible to distinguish these species 
positively without a postmortem examination. Richardson pointed 
out that the trumpeter tracheal route along the sternum detoured 
dorsally into the body cavity whereas the tracheal routes of other 
closely related swans did not. This detail is also naturally expressed 
in the pertinent adjacent portions of the trumpeter's anatomy, such 
as the sternum and furculum where structural modifications are neces- 
sary to accommodate the really unique dorsal tracheal detour which 
extends so prominently into the body cavity. More lately, Condon 
(MS) has focused attention on the syrinx and has been able to show 
significant differences between the trumpeter and whistling swans in 
the specimens he studied. The empirical anatomical differences be- 
tween these two species are shown graphically in figures 21 and 22. 
Since a diagnostic autopsy may be impractical from many standpoints, 
even with the specimen in hand, the means of separating trumpeters 
from whistlers solely by external means will be explored briefly here. 

The search for a valid external characteristic other than voice has 
perplexed both the field observer and the systematic scientist for well 
over a century. 

Some of the points used in the past for species differentiation are 
taken up in some detail here to provide an understanding of the facts 
involved. On this basis a positive solution of the problem may some 
day be worked out. 

With the exception of the voice criterion, 3 methods of identifica- 
tion based solely on external characteristics have been used in the 
past. These are the tail-feather count, bill coloration, and the meas- 
urements of various bill features, the last method being dependent 
upon size. A brief discussion of these 3 methods follows. 



DESCRIPTION 65 

Tail-feather count. Many writers picked up John Richardson's 
remark that the trumpeter possessed a tail of 24 feathers, and have 
perpetuated a method of identification of such obviously limited value 
that it should, in my opinion at least, never have received more than 
passing attention in the first place. This was probably all that Rich- 
ardson intended anyway, judging by his casual note. Leonhard Stej- 
neger's early statement on this method should have pointed out once 
and for all the negative value of tail-feather counts when positive 
species determination is desired. He stated ( 1882 : 216-217) : 

It has often been stated as a good criterion that buccinator has twenty-four 
tail feathers in contradistinction to columbianus, which only has twenty. Inde- 
pendent of the inconvenience of this character, when the birds moult their 
rectrices. I may confess that I only in a few cases have been able to count 
twenty-four tail feathers: and the inconstancy of the number of these feathers 
I have found pervading the whole group, this character changing individually, 
so that it is not at all to be depended upon. 

Bill coloration. Most of the references of previous writers re- 
garding this method of speciation refer to the area of the upper man- 
dible (bill) immediately in front of the eyes, known as the "lores." 
Though the whistler is usually characterized by a yellow or orange- 
yelloAv spot on the lores, apparently this color is sometimes lacking and 
the entire bill is black. 

On the other hand, the bill of the trumpeter is almost invariably 
black, though again this rule is not absolute. Dr. Kay Erickson, U. S. 
Fish and Wildlife Service biologist formerly at the Malheur Refuge, 
said that trumpeters kept in captivity at that Refuge sometimes ex- 
hibited an olive-yellow spot in the loral region. Apparently the 
abrasive or scuffing action given the bill when rooting out food from 
comparatively hard pond banks caused the underlying color to appear. 

In 1957, I noted that the wild trumpeters at Red R<x'k Lakes some- 
times exhibit a small indistinct gray spot of irregular shape behind 
the nostril. In two cases this was tinged with yellow, and in one 
instance the yellow could be discerned witli the naked eye from a dis- 
tance of over 50 feet. This specimen was collected and confirmed as 
a trumpeter by a postmortem examination of the sternum. 

In conclusion it may be stated that while a completely black bill 
can represent either species, a prominent bright yellow or orange- 
yellow spot on the lores indicates a whistler. 

F. H. Kortright (1943: 77) raises another point in bill coloration, 
writing of the trumpeter, "bill, black, with narrow salmon-red streak 
on edges of mandibles, lacking in "Whistling Swan." My experience 
not only demonstrated that the salmon-red streak on the trumpeter 
was confined almost wholly to the basal section of the lower mandible 
edge, but that there was great variation in the degree to which it is 



66 



LIFE CYCLE 




Figure 21. — Trachea and sternum of whistling swan. 



present. This variance ranges from the quite prominent "grinning 
streak'' normally seen to a few very faint specks of vestigial salmon 
coloration which could be observed only upon minute and critical ex- 
amination, the preponderant color for all practical purposes being 
completely black. 

Furthermore, I have noted that some whistling swans complete 
with prominent yellow lores also exhibit the characteristic salmon- 
red "grinning" streak along the basal segment of the lower man- 



DESCRIPTION 



67 




Figure 122. — Trachea and sternum <>f trumpeter swan. 



dible edge, though not enough specimens have been examined in this 
regard to furnish a general rule. So, for all practical purposes, the 
salmon color usually present on the dorsal portion of the basal edge 
of the lower mandible cannot furnish a positive indicator of either 
species, since overlapping characteristics are commonly observed. 

Bill measurement. From a comparison of considerable anatomi- 
cal-measurement data on the subject, Stejneger correctly concluded 
that size alone is not sufficient to separate the two species since enough 



68 LIFE CYCLE 

overlap exists to confuse the issue. This is true even though the 
trumpeter, the largest species of swan in the world, is on the average 
much larger than the whistler. He does state (1882: 217) : 

The position of the nostrils, those being situated more backwards in the 
Trumpeter than in the Whistling Swan, is thus the only mark by which it is 
possible to express in a short, diagnosis, and which I have found constant and 
easily perceptible. 

Measurements of the bills of a number of trumpeter specimens were 
made on the Red Rock Lakes Refuge during the summer molt period. 
With the cooperation of various Fish and Wildlife Refuge person- 
nel at the Tule Lake and Sacramento Refuges, comparable data 
on whistling swans were also gathered. This information is sum- 
marized in table 5. These statistics demonstrate that, owing to the 
possibility of overlap, bill measurements alone cannot provide an ab- 
solute method of separating the species in question, though with the 
proper qualifications in mind an excellent rule of thumb can be dem- 
onstrated. Of course, in order to show overlap to the best advantage, 
maximum extremes of the weights and measurements of whistling- 
swan features and minimum extremes of the weights and measure- 
ments of the pertinent trumpeter characteristics in the appropriate 
age and sex groups were those listed. 

When the voice and bill color characteristics of a given swan are 
missing or in doubt, any swan over 1 year of age, of either sex, which 
measures 50 mm. (2 in.) or more from the tip of the bill to the front 
edge of the nostril is probably a trumpeter. If the subject measure- 
ment is less than 50 mm., identification of the species as whistling 
swan is most likely to be correct. 

VOICE 

The voices of our two species of swans differ distinctly in the adult, 
doubtless owing to the extra loop of the trachea in the sternum of the 
trumpeter. Once heard, the trumpeter's call notes should not easily 
be confused with that of any other bird, least of all that of the whis- 
tling swan, whose voice resembles at a distance a high-pitched barking 
of "wow, wow-wow.'' Close at hand, as described by Lewis and 
Clark (Coues, 1893: 885), who gave to this species the common name 
of whistling swan, the "kind of whistling sound" can be heard. This 
noise "terminates in a round full note, louder at the end," the dis- 
tantly audible wow. 

Trumpeters are an expressive fowl, and their voices are often em- 
ployed to show their feelings and attitudes. During the nesting and 
brooding seasons the mated pairs are fairly mute, though individuals 
in the nonbreeding flocks remain relatively communicative all sum- 
mer. Through the fall and winter seasons the vocal natures of all age 



DESCRIPTION 69 

classes begin to be more fully expressed. During these months most 
of the swans are loosely bound into large informal flocks, and vocal 
expression is common, individually and in an occasional synchronized 
flock effort. Though they are perfectly capable of loud hissing, this 
has only been heard from cornered flightless trumpeters. 

During the months of March and April, just before the occupation 
of the breeding grounds by the restless mated pairs, vocal efforts 
reach a climax. At this season the swans on the Refuge are still at- 
tracted to the open-water spring-heads at feeding time, though the 
pull of the breeding grounds must be growing stronger daily. The 
approach of twilight finds the large flock usually resident about 
the open water announcing with loud trumpet calls each flight of 
swans as they return from their daily visits to the still ice-locked 
lakes and marshes which will soon become their summer home. 

It is difficult, if not impossible, to describe phonetically the notes 
of the trumpeter. E. H. Forbush (1929 : 305) credits E. S. Cameron 
with the Kootenai Indian name for a swan, Ko-hoh, which when 
pronounced with a gutteral intonation is a very good reproduction 
of the notes of a trumpeter swan. The call has a definite hornlike 
quality over a wide vocal range and may be uttered from one to a 
number of times, at widely spaced intervals or in staccato fashion. 
The trumpeter gives voice perhaps most often in flight but also 
commonly while on land or floating on the water. 

In general, the warning notes of the adult are sharp and terse, 
uttered infrequently; the decoy calls are longer and more apt to be 
repeated. Voices associated with simultaneous behavioral displays 
are much more conversational and when indulged in by more than 
two sw r ans are apt to build up rapidly in participation and volume, 
finally reaching a crescendo and then ending in longer wailing notes. 
Since the range of an adult trumpeter's calls is well over a mile, the 
combined voices of noisy flocks can be heard at a distance of several 
miles if atmospheric conditions are favorable. 

Flocked trumpeters especially may be heard after dark, and in all 
seasons, particularly on moonlight nights. At such times and when 
softened by distance their wild trumpeting calls heard afar over lake 
and marsh furnish musical reminders of their wilderness world. 

If the call notes of the adults can be described as resembling a 
horn instrument, then the immature birds have the tone of a toy 
trumpet. Higher pitched and uncertain in overall quality, they 
bear the unmistakable characteristics of adolescence. By January, 
however, in place of the high-pitched fluting of the downy and post- 
downy periods, the birds utter a hoarse off-key imitation of the adult 
trumpeter. 



70 LIFE CYCLE 

PLUMAGES AND MOLTING 

Cygnets and immatures. Young trumpeters emerge as downy 
cygnets in either of two color phases, gray and white (not albino). 
In the case of the gray individuals, by far the most common, the 
head, neck, and back are mouse-gray with the underparts quite 
white. Much the same situation prevails in the mute swan (Delacour, 
1954 : 63) except that the white phase has only been reported in captive 
birds (Hilprecht, 1956: 107-8) apparently as a result of inbreeding. 

Although white cygnets have never been seen at Red Rock Lakes, 
they are regularly observed in Yellowstone Park, where broods with 
both colors occur. Condon (MS) reports: 

Of the cygnets recorded during the period 1937-40. the following count of 
gray and white ones was secured: 1937, 23 gray and 6 white; 1938, 3 gray 
and 1 white: 1939, 16 gray and 1 white: 1940, 16 gray and 1 white. 

Thus, over a 4-year period in the Park, 13 percent of the cygnets 
were those of the white phase. Moreover, Condon has said that the 
white down in these birds is replaced by white feathers, instead of 
those of the usual brownish-gray, so that when they have reached 
flight age they can only be told from their parents by their slightly 
smaller size, pinkish bill, and yellowish legs, which are becoming 
darkened with gray. 

Only one record of white cygnets occurring in the wild outside of 
Yellowstone Park exists, that of thre« cygnets censused on the Ice- 
house Reservoir (Fremont County), Idaho, in 1956. 

F. E. Blaauw (1904: 73), a Dutch aviculturist who bred the trum- 
peter in captivity at Gooilust (Holland) for more than 25 years, 
provides a good general description of the normal gray-colored young 
from his day-to-day familiarity with these birds, stating: 

The chicks are white with a grey tinge on the back. The cere is covered with 
pure white down. The bill is flesh-coloured. The down of these chicks is very 
short and dense, quite different from the longer and more fluffy down of the 
chicks of Cygnu8 nigricollis and C. atratus [black-necked and black swans]. 
The result is that the chicks look much smaller in comparison. ... At the 
age of about six weeks, the first feathers appear, and the birds then begin to 
grow very quickly. The first feathers are brownish-grey, without any markings 
as a rule, but one of this year's birds is remarkable for having transverse mark- 
ings on the shoulders and greater wing coverts. After the birds are feathered the 
bills gradually acquire the black colour, the black beginning at the point and at 
the forehead, and gradually increasing. Later, the middle part, which is still 
pink, gets spotted with black, and in the course of the February following the 
first summer the whole of the bill usually becomes quite black. The legs by that 
time have also gradually darkened into dusky grey, which becomes black after 
the birds are a year old. About March white feathers begin to replace the grey 
plumage, except for some fine grey spots, which are still visible on the back of 
the neck and on the head. 



DESCRIPTION 



71 




Figure 23. — A pair of trumpeters on Grebe Lake. Yellowstone National Park, 
with 3 cygnets of the normal gray color phase and 2 cygnets of the uncommon 
white phase. 

Usually the pinkish color of the cygnet's bill has become predomi- 
nantly black by the time the individual is about a year old, though a 
close examination of the upper mandible will usually still show traces 
of the typical flesh-colored pigment at least until the individual's first 
flightless molt. By the time the bird has entered its second flightless 
molt, the bill is black. 

During 1955 and 195(5 Peter Ward, of the Delta "Waterfowl Research 
Station, Delta, Manitoba, noted the general molting pattern of the 
young trumpeters furnished that station by the IT. S. Fish and Wild- 
life Service in 1955, writing (correspondence) : 

Although their exact age on arrival was not known, they were assumed to be 
four weeks old, this being based on our familiarity with growth rates of other 
waterfowl. This would have given them the first feathering of scapulars and 
flanks at six weeks. Body feathering was externally complete by the tenth 
[week]. The young birds seemed very conscious of the large wings and unable 
to hold them indefinitely at their sides. 

The first juvenal plumage was a dark grey-brown and remained thus until 
early in January when a gradual moult set in. Within the month this has 
changed the neck and breast to an off-white and is still in progress. Some evi- 
dence of the same change was visible in both scapular and wing coverts at this 
time where new feathers are appearing. 

Adults. All of the closely related circumpolar species of swans are 
strictly white-plumaged birds in their adult plumage, except when a 
reddish coloration has been imparted to the head and neck feathers by 
ferrous organic compounds in the marsh or lake bottom they habitually 

469660 O— 60 — —6 



72 LIFE CYCLE 

frequent. At the Red Rock Lakes Refuge, swans feeding principally 
in shallow water during the summer months possess this distinctive 
reddish coloration to a much greater degree than those which custom- 
arily seek their food in deeper water. 

During the winter, this coloration is much less evident on their 
heads and necks. Then the swans are feeding primarily in flowing 
spring and river waters where relatively clean (organically) rock, 
silt, or sandy bottoms prevail. Even during that season some rusti- 
ness is invariably observed upon a close examination of the feathers 
about the head, and I have never seen a wild trumpeter entirely 
devoid of the stain. With swans living principally in very shallow- 
water marsh areas, the whole neck and head and even some of the 
ventral plumage may be startlingly reddish. 

While the leg color of most adult trumpeters can accurately be 
described as black, an off-black to distinctly gray color is also common. 
Various degrees of olive-yellow pigmentation are occasionally noted 
on the skin of the legs and feet of the adult trumpeter, but only rarely 
to the extent that the whole extremity could be said to have a yellowish 
appearance. The incidence of yellow pigment was noted on the skin 
of the legs, feet, and webs of the 102 nonbreeding swans captured 
during the summer of 1956 for fluoroscopic examination. Thirty- 
four of this group had at least some subdued olive-yellow tones in 
various skin areas. Frequently the yellow coloration was discernible 
on the skin of all three parts — legs, feet, and webs — with the most 
noticeable cases commonly found in the yearling age-class, and to 
some extent in individual birds of the 2-years-or-older age group. 

Francis D. LaNoue (MS) implied that such coloration may be 
seasonal or local in nature in Yellowstone Park swans, as he records 
an unusual instance in this regard : 

Early last spring 11 swans were seen possessed with yellow legs and feet. In 
addition all three of the dead mature birds [referred to] show the same color. 
Later in the season this color was not observed. 

Immature and adult swans regularly undergo an annual molt dur- 
ing the summer period during which time they are unable to fly 
because of a more or less simultaneous loss of primary flight feathers. 
This molt most commonly occurs among the swans at Red Rock Lakes 
during the month of July, but may be completed during June in 
some cases or be delayed until August, September, or even October. 
This flightless molting period is important from a management 
standpoint since these birds can then be conveniently captured 
for examination and banding. 

Several phases of this annual molt are as yet poorly understood. 
While the flocked nonbreeders molt more or less simultaneously, nest- 



I T 



/ 



~* 




,*&»■ 







Figure 24. — Six trumpeters circle the open water at Culver Pond on the Red 
Rock Lakes Refuge in southwestern Montana. Seldom more than 6 or 8 of 
these birds fly together in local flights unless a large flock flushes together. 

ing pairs do not usually follow such a regular molting pattern, on 
the Red Rock Lakes breeding grounds at least. Molting of the 
breeders appears to extend over a much longer period than that of the 
nonbreeders. Molted primary wing feathers are sometimes observed 
about the nest site in early June, and individuals of mated 
pairs have been captured for banding while in a flightless condition 
as late as October. During the summer of 1954, when it was desired 
to obtain pairs of known breeding capability intact with their young 
for transfer purposes, only the pen (female) and cob (male) of 6 
pairs were simultaneously flightless and could be captured. Approxi- 
mately '25 pairs were periodically checked for flight capabilities during 
the period of July 14-2N that year, and only :'> pairs were obtained on 
each of those dates. One member of each pair was able to fly in every 
other instance. 

In the following '2 years, l'.».V> and 1956, even poorer luck was 
experienced. The mated-pair swan transfer program was suspended 
during those years chiefly because no more than a single known pair 
could be captured during any given attempt. 

During the early part of the molting season, where only one of a 
pair was flightless it usually has been the pen. while most late-molting 
birds checked have been cobs. Peter Scott and James Fisher 
(1953:210) observed similar conditions among the wild whooper 
swans in Iceland. 



74 LIFE CYCLE 

Molting; information on Yellowstone trumpeters which is contained 
in Park reports agrees generally with that from Red Rock Lakes, 
except for sex, which was not determined. The opportunity to check 
on the duration of the flightless molt of individual birds is somewhat 
greater in the Park, however, and Condon (MS) mentions in this 
respect, "The fact that some swan have been seen in flight as late as 
July 1 and as early as August 2 indicates that the interval of time 
when they are unable to fly is in some instances rather brief, probably 
not exceeding 30 to 40 days." 

Oberhansley and Barrows (MS) record two exceptionally long 
molting periods in 1938 for the pair of trumpeters on Swan Lake : 

The female remained flightless from May 14 to October 9, a period of 
148 days, while the male was not seen in flight from June 11 to October 0, a period 
of 120 days. . . . Moulting in the pen occurred largely on or near the nest 
during the time of sitting. Most of the flight feathers were found in close 
proximity to the nest. A very small quantity of down was found on the nest 
eight days after hatching. The majority of the primary feathers were shed by 
the cob at a later date, many of them on or near the resting sites on the west 
hank of the lake. 

FLIGHT 

It is difficult to imagine a more beautiful and stirring sight in the 
whole waterfowl kingdom than a typically small flight of trumpeter 
swans as they cleave the air against a wilderness setting of dark 
conifers and the rugged Rocky Mountains. With the regular beat 
of their powerful wings and long necks undulating slightly from the 
exertion of each thrust, sometimes calling in flight but more often 
silent, they usually pass directly to their destination over the shortest 
route. If they chance to pass close to the observer, the clatter of 
their great flight quills can be heard distinctly above the usual rush- 
ing sound of moving air. 

Local flights are usually low. This is especially true over familiar 
flat marsh or water where their wing tips sometimes appear to touch 
the sedge tops, or if they are over water, to pluck small jets of water 
into the air with each powerful lift of the wing. On longer flights 
over rugged mountain country, they are to be seen at much greater 
altitudes, gaining this height with considerable effort. Once they 
approach their destination, they may descend rapidly with a roar of 
cupped wings much in the usual manner of the more agile and air- 
worthy smaller waterfowl, but their descent is usually slower and more 
gradual. 

The trumpeters prefer to fly about their Rocky Mountain en- 
vironment in small flocks, apparently family groups for the most 
part. Even when a large flock of trumpeters is roused suddenly, take- 




Figure 2.">. — A pair of trumpeters show the 2 ways of carrying "landing gear" 
during flight. The normal method is by folding them back under the tail, but 
in sub-zero weather cold feet may be tucked up forward and he quite invisible 
in the warm feathers and down. 




Figure lit;. — The normal and ■•exerting*' neck attitudes are shown by - trum- 
peters. Most commonly bent in this peculiar attitude during take-off, the 
neck straightens out in full (light. 



76 LIFE CYCLE 

offs are intermittent and by loosely formed groups. Upon becoming 
airborne they make their way in loosely knit small groups or flocks, 
though often to a common destination. 

Their flying formation varies greatly, sometimes being on the order 
of an offset line, sometimes nearly abreast, or otherwise irregularly 
formed in an informal staggered formation. Even a pair in flight may 
follow no particular flight pattern. I have never observed a true 
V-formation of trumpeters. This flight formation is probably em- 
ployed on certain occasions, especially on long flights when larger 
flocks would be the rule. A high V-flight of swans, apparently trumpe- 
ters, was seen by Ralph L. Hand, as previously noted. 

H. F. Witherby et al. (1939 : 169) note of the whooper swan, "When 
travelling far flocks frequently fly in oblique lines or V's, but in 
[Outer] Hebrides parties rarely adopt any definite formation." This 
seems to apply to what is known of the trumpeters' flights as well. 
Audubon (1838:540) notes also, "If bound to a distant place, they 
form themselves in angular lines."' 

To my knowledge, the flight speed of the trumpeter has never been 
recorded. Though the swans generally have been credited with most 
astounding speeds by some writers, it is doubtful whether the 
trumpeter can, without a tailwind, fly much faster than the speed 
recorded for the whistling swan by C. S. Weiser (1933 : 92). Weiser 
estimated the full speed of the latter species at from 50 to 55 miles 
an hour, when tracked by a light airplane on several passes. With a 
strong tailwind, the trumpeter can probably approach or exceed a 
ground speed of 80 miles an hour with little difficulty. 

Their legs and feet are normally carried in a streamlined manner 
tucked under the tail, nearly reaching its end. During the winter sea- 
son, if the weather is very cold, they have been observed to fold their 
feet and legs forward in flight, carrying them quite buried in a 
warm "muff" of thick breast and down feathers (figure 25). 

The feet with their great webbed area are usually employed both 
as an aid in gaining speed on the take-off and as an effective brake 
in alighting. After sufficient flight speed is gained following the 
take-off, the required distance for which varies greatly according to 
the wind, the feet are retracted into the customary position. In 
landing, the huge webbed feet are thrust prominently forward, act- 
ing like aircraft flaps to reduce flying speed and becoming effective 
hydrofoils as the swan contacts the water, skims briefly along the 
surface, then toboggans to a swimming position. 

The long neck is often curved somewhat with the great effort re- 
quired during the take-off and flight, apparently because of abnormal 
exertion. In normal flight position, however, it is carried fully ex- 
tended, undulating slightly with the beat of the wings. 




Figure 27. — Six trumpeters landing "flaps down" on Culver Pond, Red Rock 
Lakes Refuge. The feet are thrown forward before the moment of impact to 
ski the bird to a stop. Note various web positions guiding birds into landing. 

F. E. Blaauw (1904: 74) mentions, "Young trumpeter swans when 
fully fledged are very active birds. They fly with great ease, rising 
directly from the water into the air, without running over it first 
with flapping wings as so many of the large waterfowl do." I have 
never seen this occur among trumpeters of any a<re class, though 
Richard Rodgers, the assistant manager al the Red Rock Lakes Refuge 
for several years, reported seeing an adult trumpeter rise directly 
into the air from the firm hank of MacDonahl Pond. This was no 
douht possible because of the great springing power of the powerful 
leo;s of these birds, hut it is difficult to see how a similar take-off 
could be performed from the water unless it were very shallow over 
a hard bottom. 



BEHAVIOR AND RELATED CHARACTERISTICS 

Studies of swan behavior, per se, have never been reported, and as 
a result only a few fragmentary and scattered notes are available. 
Far from being a subjecl of only academic interest, certain actions 
of behavior of any species can be valuable indicators of inherent basic 
requirements. This subject should be studied by the wildlife man- 
ager in order to learn lx>th the normal characteristic expressions of 



78 LIFE CYCLE 

the species and those made under duress so that their management 
may be guided accordingly. 

ESCAPE-DISTANCE 

This topic, borrowed from H. Poulsen as it applies specifically to 
the swans, has been generally commented upon by some observers 
under other subject headings. The term, however, is aptly descriptive 
and so is adopted here. Poulsen (1949: 196) sums up some escape- 
distance characteristics of two Eurasian species of swans, stating: 

The escape-distance ... of Whooper Swan and Mute Swan in winter in 
shore marshes was about 300 metres. In open lanes in the ice in winter in the 
harbor of Copenhagen the escape-distance is much less, that is they have then 
got used to human beings and have become tame. This does not influence the 
escape-distance in their breeding places. The Danish resident Mute Swans 
have a small escape-distance towards man and often breed close to habitations. 
But in the great Swedish lakes as for instance Takern the escape-distance of 
the Mute Swan is about 1,000 metres according to B. Berg (1926). The Whooper 
Swan is a more shy bird. According to Rosenberg (1946) the escape-distance 
in its breeding places in northern Sweden is about 1,500 metres. In enclosures 
the swans gradually become tame, the escape-distance gradually decreasing. 

The escape-distance of trumpeters also varies, depending upon cir- 
cumstances and the conditioning to human activity experienced by any 
given individual. Munro (1949: 712), speaking of wild trumpeters 
in British Columbia, relates : 

On many occasions in winter I have approached within 100 yards of a group of 
trumpeter swans standing on the snow-covered ice of a river margin. . . . When 
the trumpeter swans stand on some lake beach, it is usually possible to approach 
them within easy observation distance provided some caution is used. Thus at a 
small marshy slough near Vanderhoof a single immature bird remained standing 
on a muddy shore long after a flock of whistling swans, alarmed at my approach, 
had taken wing. Again, on a slough in the Cariboo region, two young of the 
previous year were observed at close range as they fed among a scant growth of 
dead rushes, 20 to 30 yards from shore. When two of us walked towards the 
slough the swans swam to the beach, walked up on it, and began dressing their 
plumage. At our closer approach they walked again into the water and swam 
slowly towards the centre of the slough. Many such instances could be related. 

Supporting this testimony, the experiences of Frank Groves and a 
companion in "walking up to" a single trumpeter in Nevada and that 
of Donald McLean in approaching to "within 30 feet" of a trumpeter 
in California, previously related, should be recalled. Gwen Colwell 
(1948) also approached to within less than 50 feet of 5 wild cygnets of 
flight age on the Klinaklini River in British Columbia. 

The escape-distance of trumpeters on the Red Rock Lakes, where 
these birds are captured periodically for banding and examination, is 
conspicuously great, even though they are fully protected at all times 
and fed regularly through the long winters. A long escape-distance 
is also prevalent in Idaho on the swan wintering area where some 



BEHAVIOR AND RELATED CHARACTERISTICS 79 

shooting occurs. In either locality alarm is shown at the first sight of 
man at whatever range, and the distance of their departure, whether 
by swimming or flight, probably averages well over 300 yards. Even 
in Yellowstone Park, infrequent molestation by tourists, fishermen, 
and photographers has apparently contributed to the great escape- 
distance noted there, in some instances. 

While escape-distance has a measurable value for birds on the 
ground, it seems to lose some of its meaning when airborne individuals 
are considered. For instance, trumpeters which have flushed beyond 
300 yards may fly back over the disturbing person well within 100 
yards and even approach another person much closer if he happens to 
be in the path of flight. Other waterfowl frequently act in a similar 
manner. Unfortunately the usual low-flying habits of the trumpeter 
are not greatly affected by the fright factors which contribute to a long 
flushing range, and because of this they often provide tempting targets 
to waterfowl hunters who are strategically located, practically "flying 
down the gun barrel" if the hunter is partly hidden. This characteris- 
tic, coupled with their apparent inability to profit from learned wari- 
ness, which they practice on the ground, makes them especially 
susceptible to gunfire. 

H. Poulsen (1949: 196) notes that, "The swans do not show inten- 
tion movements when they are going to fly up such as the geese and 
ducks. But the neck is held erect and the call notes are emitted 
preparatory to taking wings. "' Alarmed trumpeters hold their necks 
stiffly erect, with perhaps a slow nervous pumping action if flight 
is delayed, and emit single, terse, trumpetlike warning notes hinting 
of the intended escape. These short warning calls may be repeated 
while the escaping swan is taking off and for a short while in flight. 
Although the preflight behavior of swans does not include the striking 
head movements of geese and ducks, it is still a characteristic pattern 
that tells the observer that the bird is about to fly (Lorenz, 1937). 

INTERSPECIFIC TOLERANCE 

Some phases of this subject are of course closely related to the pre- 
ceding topic, and its definition as applied to the trumpeter for the 
purpose of this discussion is simply learned escape-distance, or inher- 
ent escape behavior as it may be modified by remembered experience. 
Where interspecific behavior action is related to other birds, it will 
be discussed under the more appropriate topic of territorialism. 

Condon (MS) furnishes a good general picture of the variability 
of learned escape-distance under various conditions among the Park's 
trumpeter population, under the topic "reaction to molestation or 
interference with normal solitude." He concludes, "Unless swan are 
in constant contact with man, they show a pronounced tendency to 



80 LIFE CYCLE 

be alarmed by his presence and keep at what they deem a safe dis- 
tance from him." The degree to which the normal (predator) aware- 
ness of these birds in wilderness surroundings contributes to this 
caution, or is learned by individuals from previous molestation at the 
hand of man, is of course not known. 

Condon (MS) also points out that while trumpeters within Yellow- 
stone Park are principally considered birds of wilderness character, 
this species has, in certain instances, accepted man and his activities 
to the extent necessary to incubate and raise its young successfully 
in spite of considerable human activity (photographers, fishermen, 
etc.). In some cases man's activity is not introduced into the breed- 
ing habitat to any extent until after incubation has been completed, 
and in others the adjustment to molestation apparently could not be 
made and the blame for the loss was laid on man-caused activity. 

Duane Featherstonhaugh (1948: 375,379) also notes that the trum- 
peter swan is to be found successfully living and raising its young 
on waters near active farmsteads in its northwestern Alberta environ- 
ment. He even observed one pair nesting in a slough near the Grande 
Prairie airport, a principal stop on the Alaska-Edmonton run, where, 
he records, the roar of engines went unnoticed by the birds. 

At the National Elk Refuge too, where breeding trumpeters were 
successfully established by the Fish and Wildlife Service, Aimer 
Nelson, the former Refuge Manager, states (correspondence) : 

In 1944 the pair nested in the Flat Creek Marsh about 600 feet from the 
Jackson-Moran Highway. . . . one of the cygnets ventured through the woven 
wire game fence onto the highway and was killed by an automobile. In 
1948 . . . one pair nested within 400 feet of the highway. This pair of swan 
left the nesting site two days following the hatch . . . [and] on July 1 the 
birds [parents] moved their young down Flat Creek to near the Flat Creek 
bridge at the edge of town within 50 feet of the Jackson-Moran Highway, and 
in showing off their family they caused a traffic jam on the highway which 
became crowded with tourists who stopped to see them. . . . This pair managed 
to raise three of the five young. 

In summary, human activity may be tolerated within distances 
ordinarily considered within trumpeter nesting territory, certainly 
much closer than intruding swans would be permitted. (The latter 
trait will be treated later when the spatial requirements of breeding 
trumpeters are discussed.) The critical factors involved in the 
toleration of man's activity on or near the breeding territory seem 
to be not so much the actual presence of man, or even the relative 
distance at which this is experienced, as it is the degree and regularity 
of molestation. 

At the Red Rock Lakes Refuge, these birds live in quite isolated 
wilderness surroundings at a considerable distance from humanity. 



BEHAVIOR AND RELATED CHARACTERISTICS 81 

On occasion they are disturbed by census activities on the marsh as 
well as by capturing for banding, examination, etc. This apparently 
occurs infrequently enough so the "conditioning" does not occur. 
Hence, on the Refuge the swans are extremely wary and will avoid 
any approach by man. 

Wild trumpeters, especially the young which have apparently never 
been molested or frightened by man, have been found to be very 
tolerant of man, sometimes almost unbelievably so. Featherston- 
haugh (1948: 376) provides an interesting statement in this regard, 
telling of two stranded cygnets rescued and raised by Joe Tomshak 
in the Grande Prairie country, as he writes, "When we saw them [the 
yearling trumpeters] they were as tame as domestic fowl. They would 
waddle up to the kitchen door to beg for bread and drink from the 
rain barrel." 

An even more remarkable example is provided by Gwen Colwell 
(1948) as she describes an unusual visit of five wild trumpeter cygnets 
one winter to the meteorological station at Kleena Kleene, British 
Columbia : 

Peter, our goose, was fed his breakfast that morning on the ice ledge along 
the river bank. In no time the swans showed interest and were soon literally 
shovelling in mouthfuls of wheat. . . . They became so tame that they would 
scramble onto the ice when they saw us coming. ... At the end of the first 
week they had found their way to the house door. . . . Upon several occasions 
we had all five huge birds in the telegraph office at once. They literally filled 
the room. Indeed, one felt that if they became alarmed and decided to take to 
the air, the roof would in all likelihood be carried off on their backs. 

In captivity, trumpeters have lived for long periods and even bred 
regularly in favorable environments, so the presence of man or human 
activity, in itself, cannot be said to be inimical to their existence. 
When not molested, trumpeters can tolerate considerable human ac- 
tivity and actually thrive if other factors prove favorable. This 
tolerance may decrease as the birds acquire a certain amount of general 
predator wariness, which increases with age. 

Trumpeters nesting in a wilderness environment are alert to any 
change in the appearance of the landscape within their nesting terri- 
tory. Any such action as the erection of a blind is regarded warily. 
Nevertheless, Marshall Edson, photographer for the Idaho Depart- 
ment of Fish and Game, reports no difficulty in having breeding 
trumpeters accept a canvas blind located at no great distance from their 
nest, but these birds were familiar with man-made activity. My 
experience on the Red Rock Lakes Refuge wilderness breeding 
grounds is to the contrary, with one nest desertion resulting when I 
moved a blind from approximately 80 yards away, where it had been 
accepted during the incubation period, to only about 40 yards distant. 
Scott and Fisher (1953: 208) report similar extreme wariness in the 



82 LIFE CYCLE 

whooper swan on its isolated breeding grounds in central Iceland, 
stating: 

Most females left the nest as soon as the intruder tame into sight. . . . Two 
pairs of swans showed extreme shyness when a photographic hide was erected 
more than sixty minis from their nests. One pair deserted and in the other 
case the hide was removed only just in time. 

On one occasion a pen left a nest as a result of hearing the alarm note of a 
pinkfoot [goose], while the intruders were out of sight over a ridge. She 
apparently left in a hurry as the eggs had not been covered. 

The high degree of tolerance displayed by trumpeters toward the 
presence and activity of other birds and animals persists even in the 
case of possible predators. Referring to their studies of the trumpeter 
in Yellowstone Park during the summer of 1938, Oberhansley and 
Barrows relate (MS) : 

Little concern was shown by swans at the approach of elk. moose, beaver, bear, 
or coyotes in observed cases and in no instance were they seen to be molested 
or greatly alarmed by any bird or animal other than man, at whose approach 
they were always alarmed. The first sight of a fisherman approaching Riddle 
Lake, for instance, would drive the swans from the small islands at the nesting 
site to the extreme north and east shore of the lake nearly a mile distant. At 
other lakes reactions were similar. Cover was resorted to if sufficiently distant 
from the intruder, while on larger lakes the swans swam rapidly away from 
the shore. 

R. W. Patrick (1935 : 116), observed a pair of mute swans attacking 
a bullock twice, finally driving it away. Statements by other ob- 
servers indicate that mute swans, especially in captivity, are generally 
more pugnacious than the swans of the genus Olor, though reportedly 
this trait is much less apparent in wild mutes (Witherby et al., 1939 : 
175). 

MEMORY 

The memory characteristics of trumpeters seem to play an important 
role in such actions as escape-distance. From the standpoint of the 
wildlife manager, at least the fundamentals of the trumpeter's memory 
traits should be understood so that human activity can be planned ac- 
cordingly, as this characteristic is unusually keen in this species. 

Smith and Hosking (1955: 116-117), in their experimental studies 
of the aggressive displays of some birds in the laboratory, found that : 

Birds possess to a remarkable degree, a high retention of visual images, 
which become deeply "imprinted" on the bird's consciousness. . . . for birds 
are above all animals "eye-minded," and dominated by visual stimuli. 

This is certainly true of the trumpeter. One characteristic which 
has impressed observers who have worked with this species has been 
its ability to remember visual experiences which have frightened it in 
the past and to govern its actions accordingly. For example, in the 
year 1950 I moved a small shed from Refuge Headquarters to the 
swan wintering grounds and placed it at the water's edge to serve 



BEHAVIOR AND RELATED CHARACTERISTICS 83 

as a swan observation post and photographic blind. During the fol- 
lowing winter or two the swans became accustomed to this rough 
shelter, and having no reason for mistrust, accepted it as a part of the 
landscape and fed on occasion practically within its shadow. During 
the winter of 1951-52 I departed from this blind in full view of a 
large flock of trumpeters without first arranging for another party 
to preflush the flock as was customary, thinking that no harm would 
be done since it was the last observation of the season and any harmful 
effects would soon wear off. This abrupt action of stepping out of the 
blind directly into the full view of a hundred or more nearby swans 
naturally startled the flock, which, after a moment's hesitation and 
warning calls, took flight. 

This event was apparently remembered in succeeding years, at least 
until the 1955-56 season, since they were never observed to "trust" 
the small building to the original extent again, always moving off in 
a wary attitude if they inadvertently fed or moved too close. Though 
the distance to which they would approach the blind decreased steadily 
as time went on, some mistrust was still evident during the spring of 
1956, 30 feet being about as close as they would come in to feed, even 
when attempts to bait them closer were made. Apparently, the older 
birds which remembered the event communicated their feelings to 
others unconsciously by not approaching this shed too closely, for 
there must have been a considerable turnover in population during 
this 4-year period. 

Erickson has mentioned that the trumpeters held in captivity at 
the Malheur Refuge remembered their capture and subsequent 
blood tests for avian tuberculosis, being much warier and more difficult 
to capture and handle the following season. 

Leland Stowe (1957: 223) also noted, apparently from the testi- 
mony of the Ralph Edwards family of Lonesome Lake, British Co- 
lumbia, that though wild wintering trumpeters at "The Birches" had 
taken grain from the hand of Trudy Edwards for years, after they 
observed the capture of several of their number which had been lured 
by grain into a trap, they would not accept hand-fed grain again 
during four subsequent winters. 

Trumpeters are very alert to events, and recall detail well. John 
Holman (1950) quotes Ralph Edwards of British Columbia as writ- 
ing, "The swans are very sensitive to any changes in routine, to any 
change in feeders, or even to any change in the garments worn by the 
feeder." Similar characteristics have been recognized in Canada 
geese (Hochbaum, 1955 : 43) . 

SENSORY PERCEPTION 

While no special work has been done on this subject, it has been my 
experience that their sense of sight and hearing are very keenly de- 



v^ - ; * 




Figure 28. — Trumpeters on Culver Pond display the 2 methods of plumage-shak- 
ing, 1 employing the wings. The elevated position necessary for either posi- 
tion is attained by rapidly treading the water. 

veloped. Foreign sounds, such as the click of a camera shutter, are 
heard at considerable distances and may even cause an escape move- 
ment. Sight is also extremely acute, especially at great distances. 
Its long neck enables the swan to see above low forms of marsh vege- 
tation far out over the water, and its keen eyesight can detect even 
a cautious approach by an observer. 

SOME GENERAL BEHAVIOR ATTITUDES 

Submerging and Diving. When hard pressed in close pursuit and 
unable to fly, all age classes will dive to avoid capture. The older 
cygnets as Avell as the immatures and adults are frequently surpris- 
ingly adept at this, and once submerged are often capable underwater 
swimmers. 

Sometimes adults also display the curious ability to submerge almost 
their entire bodies in the water while the head and neck remain upright 
in a normal position. This is apparently accomplished by changing 
the web action, thus literally pulling themselves downward in the 
water while swimming. I have seen this phenomenon employed 
occasionally by flightless Refuge swans when they were attempting to 
avoid capture by boat in deep water. After diving a number of times, 
followed by extensive swimming under water, they become winded, 
and upon successive approaches by the boat they sometimes submerge 
their buoyant bodies gradually in this manner in order to avoid diving 
until the last possible instant. 

Oberhansley and Barrows (MS) also note this behavior by swans 
in the Park, writing, "In some attempts at concealment they appeared 
to become less buoyant and drew their heads down to the level of the 
sedges in which they were hiding . . . becoming almost invisible." 

Resting. All the various postures of relaxation appear to be 
assumed most commonly while out of the water. When in the water, 
individuals usually are moving about feeding, swimming, or en- 
gaging in some other definite activity. Even during the cold winter 




Figure 29. — A small flock of trumpeters feeding with goldeneyes at Culver Pond, 
Red Rock Lakes Refuge. Typical drinking attitude is shown by swan with 
outstretched neck, right of center. 

weather, when they are not actually feeding, most of their time is 
spent loafing or sleeping on the ice and snow. 

In sleeping, whether prone or erect, the trumpeter curves its long 
neck to the rear, resting its head on the back between the wings and 
with the tip of the bill usually tucked under a wing up to the nostrils. 
I have never seen the trumpeter sleep floating in the water, although 
Condon has observed this in the Park. 

Oberhansley and Barrows (MS) record of the Park swans : 

Resting attitudes observed consisted of lying on the breast on land or in 
shallow water, floating on the water, and .standing on either one or both legs 
with the neck usually recurved back across the body and the head tucked under 
the wing. Two swans at Geode Lake were each observed to stand continu- 
ously upon the left leg while alternately sleeping and preening for a period 
of 54 minutes. During most of this time the right leg of each was alternately 
trailed to the rear and downward at an angle of about 15 degrees, then drawn 
into the body or used to scratch the head and neck. In each case during sleep 
the neck was curved to the right across the body and back with the head tucked 
under the right wing. The more profound sleeper completely concealed the 
eyes, while the other one was more restless, never concealing the eye and fre- 
quently raising the head to a watchful position for a short time. It required 
much more care to approach swans when resting than when they were feeding. 

Plumage-shaking. When swimming or feeding in the water, or 
shortly after coming ashore, the trumpeter commonly shakes the wa- 
ter from its feathers by one of two methods. When this action does 
not include the wings, the statement of II. Poulsen (1040: 196) ap- 
plies, "When a swan is going to shake its plumage, the movement 
starts at the tail, which is swung rapidly side to side, and then the 
movement is spreading all over the body ending at the head." If 
this is accomplished by the trumpeter while still in the water, the 
whole body is first elevated by rapid treading. In any case the neck 
is held more or less in an outstretched position. 

This method is not seen so commonly as a similar action which 
employs a. full beat or two of the outstretched wings. The primary 



86 LIFE CYCLE 

feathers are also frequently adjusted following this shaking, which 
is accomplished with the neck bent in a typical "exertion" attitude. 

Attitude of Head. Erickson has noted with the captive trum- 
peters at the Malheur Refuge that the male commonly held its head 
in a nearly level position whereas the female often carried its head 
with the bill tilted slightly downward. If this holds true in wild 
flocks, it might aid the determination of sex in the field. 

Drinking. The trumpeter drinks water in the general manner of 
other fowl, the water being first drawn into the mouth by submerg- 
ing the bill and then transferred to the lower regions by elevating the 
head and neck. The latter movement is accompanied by a fairly 
rapid movement of the mandibles, a swallow of water visibly moving 
down the neck as a mobile swelling. 

Foot Attitude. Some of the swans have the curious habit of occa- 
sionally holding one foot outstretched backwards, as if drying this 
appendage. This may be done either while on the water or when 
standing on the land, and is a much observed trait of the mute swan. 
A. C. Bent (1925: 282) records an observation of this habit in the 
whistling swan, but I have only rarely seen it practiced by the wild 
trumpeter (figure 43) . 

Carrying Young. Delacour and Mayr (1945 : 9) state of the swans 
generally, "They seem to be the only Anatidae which have the habit 
of taking their downy young on the back when the young are tired 
or cold. This is the usual practice with Mute and Black-necked 
Swans. It is exceptional in the other species." To my knowledge 
this trait has never been observed in the trumpeter. 

DISPLAY 

Even in a group of birds noted for their display behavior, the 
trumpeter is an expressive species. Some of this reputation of swans 
comes from the frequent "threat'' attitudes of the common mute swan 
of park and zoo. While the trumpeter does not exhibit this particu- 
lar display, both its voice and prominent physical features are often 
employed in other ways to show its various feelings about aggression, 
recognition, territory, sex, etc. These emotions are expressed prin- 
cipally by the action and attitude of the wings, head and neck, gen- 
eral body demeanor, and voice, with many variations possible. But 
the true "courtship" or "nuptial" displays so prominent in the lesser 
waterfowl are notably lacking in the swans. 

An attempt might be made to classify the fundamental behavior 
postures as expressions of "recognition," "triumph." "aggression," 
etc., but since these all have a common root in their display appear- 
ance, in which the voice is an integral part, such an appraisal should 
await that time when extensive recordings of their vocal efforts have 



•• % 




I \ 




Figure 30. — A typical mutual display of 2 wild trumpeters on wintering waters, 
Red Rock Lakes Refuge. This basic display invariably is accompanied by 
vocal expression. It is used with variations in "recognition" and "aggression", 
and may have nuptial and other connotations. 



been made in synchronization with motion pictures of their various 
actions. When these are available to the researcher for detailed com- 
parison and analysis, we may begin to understand the behavior mech- 
anism of these unique fowl. Without this, a fundamental knowledge 
of the species is lacking. 

The most common display attitude is one in which the quivering 
wings are raised horizontally and partly extended. This posture, 
when accompanied by the pertinent vocal effort and extended posi- 
tion of the head, neck, and body, is used with some variation on 
greatly different occasions. In the water or on solid footing, the 
exact position and movement of the wings may vary considerably. 
The angle of the head at the end of a usually fully extended 
upright neck is nearly level in this basic display, contrasted 
with the definitely upward-inclined head and bill of the whooper 
swan as shown during its '•mutual greeting ceremony" by E. A. Arm- 
strong (1947: 192,142). 

4i;!MitiO O-60 7 



LIFE CYCLE 




•*p*z*--~" 




Figure 31. — Trumpeters face each other in mutual display (right foreground) 
and a swan indulges in a wing-flapping plumage shake (center background) 
while an adult bald eagle watches from ;i background snowbank in March 
on Red Rock Lakes Refuge. 

This basic display attitude has only been seen exhibited as a mutual 
action. It is shown on occasions when aggressiveness is involved 
among flocked birds that are socially active, or during the breeding- 
nesting-brooding season when a member of a breeding pair flies back 
to its mate after successful defensive action towards another swan 
trespasser. It may also be employed first by a single adult and result 
in mutual action when aggressive tactics are employed within the 
territory. During such times, both birds apparently recognize each 
other as foes and rush together with loud staccato trumpeting, exhibit- 
ing with outstretched quivering wings and extended head and neck 



BEHAVIOR AND RELATED CHARACTERISTICS 89 

as they plunge in to do battle, or turn to escape. O. Hilden and P. 
Linkola (1955: 524) report very similar behavior in the whooper 
swan, as do Witherby et al. (1939: 170). 

Essentially the same display behavior, but with some notable varia- 
tions, commonly occurs among the individual members of late-winter- 
ing flocks as they gather about the chosen feeding areas or on their 
extensive loafing grounds of snow, which at that season has become 
packed and hardened. This attitude appears to arise from less justi- 
fied reasons than territorial protection. Commencing with bobbing 
heads and gradually increasing wing action, it develops into positive 
aggression, apparently as the result of self-assertive tendencies which 
seek expression before territorial establishment. It also occurs to 
some extent whenever large flocks of nonbreeding trumpeters gather 
together, and so may be a result of population pressure. 

One variation of this display may involve as many as 4 or 5 birds, 
if the efforts of 1 or 2 are successful in getting action started. In this 
group action, which may occur either on land or on water, the body 
position is more erect than in the simple mutual display, and the 
wings are also usually slightly more extended and are apt to be held at 
a higher angle, thus showing off the underside of the wing primaries 
to a greater extent. Treading increases their stature in the water, 
while wing movements are much more active as each swan strives to 
maintain or improve his performance in the circle of displaying indi- 
viduals. After the preliminary head-bobbing procedure, the bird 
holds its neck quite fully extended with the bill about level, facing 
its fellow demonstrators in voluble expression. 

The trumpetings of the group exhibitors are truly remarkable, even 
from the start, but especially so when they rapidly increase in tempo 
and intensity as they are joined by other swans. When the climax 
has been reached, it usually ends in lowered-head aggressiveness as 
various individuals shoot rapidly in pursuit of others in a regular 
free-for-all amid a noteworthy outburst of trumpeting from the 
always interested onlookers. It is impossible to say whether these 
exhibitions are made up principally of any particular sex or age group 
since those observed have been of unknown sex and in the white dress 
of the adult. 

This performance is, in general, the usual aggressive expression of 
these birds, which they may assume either in defense of their breeding 
territory or in pursuit of personal victory in a spontaneous dispute. 
In the case of breeding birds on the territory, a warning display 
and calls by one or both of the resident pair usually suffices to turn 
approaching strangers away. Occasionally an intruder alights in 
an active territory of a pair, or more rarely mates from pairs in 
adjacent territories come to blows. 



90 



LIFE CYCLE 








■ .7 



r %\ 




Figure 32. — Two trumpeters landing on Culver Pond are greeted by displaying 
swans. Band on left leg of lower bird marks it as a pen (female). Both 
Barrow's and common goldeneye ducks are present in this scene. 

Aggressive action on land or water begins when an individual 
with head lowered for action propels itself decisively by wing 
or web in the direction of the trespasser. In the air the pursuing swan 
closes the distance to the trespasser by rapid flight. The victim, 
perceiving its predicament after a losing race, usually turns steeply 
upward and is followed for a brief time by the pursuer, after which 
the action is abruptly terminated by the pursuer turning back. In 
the water, actual feather pulling and wing pummeling may occur 
before one is successful in routing its opponent. Such punishment 
seldom lasts more than a few moments, but it can nevertheless be 
formidable and effective and seems always to result in the defeat of 
the trespasser. Invariably the returning victor is met in the home 
territory by its mate which joins in a mutual display of quivering 
wing, bobbing head, and staccato trumpeting, ending with reclining 
neck and wings and wailing notes. This is comparable to the 
"triumph ceremony" described by Heinroth and Lorenz for the geese 
and shelducks. 

The aggressive attitude may also be assumed by any flightless 
trumpeter when it is confronted suddenly or is pursued by man and 



BEHAVIOR AND RELATED CHARACTERISTICS 91 

is unable to escape. It is usually displayed in such cases when an 
individual is captured in a confined location or cornered on solid 
footing in an unfamiliar environment, when the aggressive posture 
or action is accompanied by considerable hissing. Swans on water 
have never been reported to take an aggressive action toward man. 
Possibly the bird feels that it is in its native element and escape is 
possible until the moment of capture. 

From the foregoing remarks it might be concluded that the trum- 
peter is a pugnacious and quarrelsome bird. This is not generally 
true, however, at least in the wild population with which I have been 
acquainted. Minor emotions are usually expressed initially by voice, 
and many times these feelings are not further developed. Hours 
have been spent observing these birds on their breeding grounds when 
not, a single aggressive action was noted. During the fall months 
when the breeding birds and their families rejoin the nonbreeding 
flocks, the pair formation which apparently occurs then among ma- 
turing individuals (Delacour and Mayr, 1945: 8) adds to the general 
unrest resulting from the change of season and impending migration, 
and more frequent emotional displays take place. This is also true 
when early spring unlocks their traditional nesting marshes, since the 
birds are still confined to limited feeding areas about the few warm 
springs. The approach of the breeding season, with its sexual stim- 
ulation and welcome seasonal change after the winter's hardships, 
ushers the population into its greatest social season. At this time 
display attitudes are commonly observed among flocked birds. As 
soon as the marshes open up and the birds disperse, the display activity 
shifts to the nesting territory and is less frequent. 

Delacour and Mayr ( 11)45: !)) describe the precopulatory display of 
swans : 

Swans, «eest\ and whistling ducks (tree ducks) have essentially the same pre- 
copulatory display, both birds of a pair repeatedly dip the whole head and neck 
until finally the female flattens herself out on the water and sinks deeper with 
the neck half extended. 

On several occasions a similar display, but without the dipping cere- 
mony, was observed on an open-water area while the birds were still 
on their wintering grounds during March. In these cases, the postur- 
ing was not followed by copulation, and perhaps expressed some other 
mood or was not even a formal display attitude. A description of 
copulation by trumpeter swans provided by Frank McKinnev (corre- 
spondence) reveals that this act does not differ from that noted with 
other large species of waterfowl. 

Intraspecilic strife and display among the confined trumpeters at 
the Malheur Refuge is described by Erickson, who relates (corre- 
spondence) : 



92 



LIFE CYCLE 




Figure 33. — "Solo" display, trumpeter swan on Culver Pond. Red Rock Lakes 

Refuge. 



A pecking order is established with each group of swans in the pond. With 
the very young cygnets, size seems to be the main factor determining the position 
of each bird in the order, but as the smaller individuals approach the previously 
larger ones in size, vigorous tussles ensue as members of the order attempt to 
maintain or improve their positions. The scuffling usually is most noticeable 
during feeding when the swans are grouped more closely. 

In an evenly matched light, the swans will approach and attempt to intimidate 
the adversary by carrying the head and neck low. If the opponent stands his 
ground, the aggressor will drive in and each will grasp the neck or feathers of 
the head, neck, or anterior part of the body of the other swan, both birds thrash- 
ing against each other, breast to breast, and each attempting to tread the other 
one under the water. This may last as long as two minutes, though usually 
the outcome is forthcoming within a few seconds, and the weaker or less experi- 
enced member of the match turns and flees, the victor grasping the rump or 
tail feathers of the loser and being towed for some distance around the pond, 
accompanied by much splashing and flailing of wings. 

The wings are less commonly used in striking the opponent, but the loser 
always uses them in running from the fight. When the loser reaches the cover 
of the willows or races up on shore, the winner will turn and face an apparently 
admiring group of other swans who have been watching the performance, will 
draw its head far back on its back, half spread its wings on each side, and 
promenade back towards the flock in an extremely pompous and swaggering 
fashion. 

The cygnets appear more interested in these engagements than the older 
swans, and will gather along the fence in their part of the enclosure and pay 
tribute to the winner in the form of rapt attention and juvenile "trumpeting" 
as the winner slowly swims by in full display. Sooner or later after the 
match, both participants will rise on the water and flap their wings. 

If the winner is a member of a mated pair, he then will rush forward, and be 
met in like fashion by his mate, both facing each other closely with quivering 
wings partly outstretched and trumpeting their congratulations in staccato 
fashion, usually ending these expressions in a longer wailing sound. 



BREEDING 



93 




Figure 34. — Rear view of "solo" display (left) . 

Judging from my observations of wild trumpeter populations, 
Erickson's report indicates that behavior becomes much more formal 
and stylized in captive birds, where certain features may be more fully 
practiced and developed. Though strikingly similar, they do not 
appear to be truly representative of similar actions among a wild 
population. A fertile field for further study in this direction awaits 
tine research worker. 

BREEDING 

Although a basic knowledge of breeding characteristics and habits 
is essential to a grasp of population dynamics, very little on this 



m.-^^ri 




Figure 35. — While a pair of trumpeters engages in mutual display (left center), 
4 gather in a group exhibit (right). Mallards and pintails in the irregular 
foreground. 



94 LIFE CYCLE 

subject is now known about the trumpeter in its breeding habitat in 
the United States. Only from detailed observations by various in- 
dividuals over a period of years, coupled with notes on similar char- 
acteristics of better-known species of swans, can we throw light on 
the important aspects of reproduction. 

The breeding biology of mute, whooping, and Bewick's swans, in- 
cluding notes on pair formation, courtship, territorial traits, nesting, 
and hatching success, is treated in Hilprecht (1956: 55-89). 

PAIR FORMATION 

Literally nothing is known of the ages of wild swans in their pre- 
paring associations. 

The behavior of captive trumpeters should provide clues regarding 
the formation of pairs as it occurs in the wild, and Erickson furnishes 
an interesting observation in this regard, writing (correspondence) : 

Although the cygnets form friendships during their first year of life, they 
seem to serve no sexual function, and it is as common to see three associating 
amicably with one another as it is with pairs. The first mated pairs develop 
during the third year, when they seem to resent intrusion by other single or 
paired birds. 

Writing in a more general sense of the swans as a group, Delacour 
and Mayr ( 1945 : 8) state : 

Pair formation, which occurs in the fall in all temperate zone swans, takes 
place without elaborate displays. According to Heinroth (1911), birds that 
are in the process of pairing swim in close proximity, press the plumage close 
to the body, and hold the neck in a peculiar position, the head appearing 
thickened. 

BREEDING AGE 

Assuming that the ages of both birds are equal, pairs do not 
appear to become firmly mated until well along in the third 
year of life. Possibly the earliest breeding of trumpeters may be 
accomplished as the pair enters the breeding season completing their 
fourth year of life. It is conceivable that if one of the paired birds is 
older, or has had previous breeding experience, successful pairing 
and nesting may be initiated somewhat earlier than would otherwise 
be the case. (W. H. Watterson [1935: 238] reports mute swans 
nesting at 2 years of age. ) 

Referring to captive trumpeters again, Erickson furnishes another 
pertinent statement on the earliest ages at which copulation was 
observed among trumpeters in the Melheur flock, writing: 

No pairs were observed copulating until in the five-year-old class, although it 
may well have occurred unobserved. One three-year-old pair, which was sepa- 
rated from the others, made a rather listless attempt at nest construction, but 
the effort was abandoned before the "nest" bad passed the "platform" stage. 
This same pair again attempted nest construction and were seen copulating two 



BREEDING 



95 




Figure 36. — Aggressive action of trumpeter following group display. Culver 

Pond wintering waters. 



years later. However, the female developed a lameness and did not continue 
nest-building, dying about three months later. 

Whatever the average minimum breeding age of trumpeters may 
be, the initial age at which a wild pair comes into breeding mood and 
nests may be influenced somewhat by the quantity of unoccupied ter- 
ritory located in suitable nesting habitat, Delacour's statement 
(1954: 72), on the four closely-related circumpolar species of swans 
may apply to the trumpeters of the Red Rock Lakes: 

Although the adult state is assumed in the third year, it seems that most of 
these swans do not breed until the fifth or sixth year, perhaps because it is 
often difficult for young birds to appropriate a nesting territory. 

We do not know if a high breeding population of swans occupying 
a limited area has any effect in postponing the initial breeding age of 
nesters. It will be shown later that while the number of breeding 
swans at Red Kock Lakes has increased in proportion to the whole 
population, it is breeding success which has declined markedly during 
these years. 

Examples of the nesting of :'> pairs of trumpeters of known ages 
may throw some light on the subject. In the first case, a pair of 
trumpeters, forming from 3 cygnets-of-the-year, which were taken 
from Red Rock Lakes to the National Elk Refuge in 1938, nested 
successfully in 1944 when they were entering their sixth year of life. 
Though these, individuals were established within easy flight range of 



96 LIFE CYCLE 

the Yellowstone swan population and had the ability to fly unre- 
stricted during this period, they were seen so consistently on the Ref- 
uge following their transplanting, where none had been observed for 
many years previously, that the identity of the pair is assured. It is 
also interesting to note here, in reference to Jean Delacours remarks, 
that while these were the only swans in the habitat, they did not 
nest until practically 6 years old. 

Two pairs of trumpeters have since bred several times in the limited 
marsh area available on the Elk Refuge. The second pair nested first 
in 1948. Since only 1 cygnet was produced in the original nesting at- 
tempt in 1944, the second pair (if natives of the Elk Refuge) must 
have been mated either from a combination of brood members of the 
1944-45 hatches, or that of 1945 when 3 cygnets were produced. In 
either case at least one of the mated pair would have bred at its hypo- 
thetical minimum breeding age, when just completing its third or 
fourth year of life. Of course, there is no proof that either of the 
mates comprising the second nesting pair were native Elk Refuge 
birds, but in view of the general tendency of the Anatidae to return 
to their natal breeding marshes following the wintering period, at 
least one and probably both mates of the second pair were Elk 
Refuge-bred birds. 

In the third instance, a pair of trumpeters which formed from 
several cygnets-of-the-year transferred to the Ruby Lake Refuge 
from Red Rock Lakes in 1949 were seen on nearby Franklin Lake 
in their third year of life, during an October 1952 aerial water- 
fowl census. On October 7, 1953, another aerial census revealed 
a pair of swans with a lone cygnet, again on Franklin Lake. 
Because identification of this pair was not confirmed by a ground 
check, and because whistling swans have arrived from the north at 
Ruby Lake as early as mid-October and no nesting swans were noticed 
on an earlier spring flight over Franklin Lake on April 16, this record, 
like the others, can be classed only as hypothetical. If it is a valid 
trumpeter nesting record, as the refuge manager assumed, these birds 
would also have begun nesting at a minimum breeding age, just com- 
pleting their fourth year. Thus the only evidence at hand, which is 
admittedly sketchy, indicates that nesting may begin as early as 
the fourth year of life (3 years, 10 months) or as late as the sixth year 
(5 years, 10 months) . 

MATING FIDELITY 

The oft-repeated truism that "swans mate for life" has been estab- 
lished more by a lack of evidence to the contrary in semidomesticated 
captive birds than by a thorough study of the facts with wild swan 
populations. While a general rule of life-mating appears to be valid 



BREEDING 



97 



Mfo*i 




Figure 37. — Aggressive pursuit terminating a group display of 5 trumpeters. 
Red Rock Lakes Refuge. 



for swans, it is reasonable to suppose that a wild swan which loses its 
mate early in life may remate. 

H. Poulsen (1949: 197) furnishes an interesting general statement 
on the mating fidelity of swans among those pinioned in the zoological 
gardens of Copenhagen, Denmark, writing: 

The Mute Swan is strictly monogamous. Among the 60-100 tame (hand ampu- 
tated) Mute Swans kept in the parks of Copenhagen, each pair always sticks 
together for life. In the cases in which it has been attempted to pair a swan 
with a new mate instead of the dead one, no success has been achieved in contrast 
to the statement of HEINROTH (1911) that the re-pairing is not difficult. 

There is a real attraction between particular individuals of the opposite sex. 
Unfaithfulness between the mates is rare. During the last ten years only three 
cases have occurred among the tame swans in Copenhagen. Thus a wild male 
had paired with two tame females. Just as mentioned by PORTIELJE (1936) 
the pairing with the second female occurred when the first one was sitting on 
the eggs. 

In captivity, bonds of naturally monogamous species sometimes 
break down, and the trumpeter apparently is no exception. Dr. G. C. 
Low (1935: 147) records that in England: 

Polygamy in the Mute Swan is very rare indeed, and I have only heard of one 
instance, in addition to one case of a female Swan that paired with two males, 
all three living together on harmonious terms. There was for many years at 
Woburn Abbey a breeding trio of Trumpeter Swans, but I was never able to 
discover whether the odd bird was male or female. . . . Many years ago a 
ludicrous instance occurred at Abbotsbury. where two male swans (mutes] not 



98 LIFE CYCLE 

only associated together, but even built a nest every year, upon which they took 
turns in sitting! 

Dr. J. M. Dewar (1936 : 178) published a short but interesting paper 
in which he outlined some aspects of the mating infidelity of captive 
mute swans as it has been observed in certain rare instances over the 
years in England and Europe. In his article Dr. Dewar proposes 
the apt phrase "menage a trois" to describe "the association of three 
individuals of a bird species for the purpose of nesting." Dr. Dewar 
continues his explanation of the term and its pertinency to the mute 
swan as follows: 

As a label, menage a. trois is preferred to its synonym, bigamy, because 
menage k trois implies the setting-up of an establishment, which bigamy does 
not necessarily do. . . . 

Menage a trois has to be distinguished carefully from homosexuality and 
other sexual relations. Homosexuality, which has been recorded several times 
in the Mute Swan, is an association of two individuals of the same sex, leading to 
pairing and nest-building, and in the case of females the laying of eggs which are 
necessarily infertile. 

Altogether I have been able to collect from the literature six examples of 
menage a trois in the Mute Swan and to add a seventh case coming under per- 
sonal observation. 

John Ellis (1936:232), commenting upon Dr. Dewar's paper, es- 
tablishes at least one and possibly two apparently valid cases of 
menage a trois among mute swans on an English park lake. 

A similar aberrant relation existed among three trumpeters living 
south of the Red Rock Lakes Refuge on a small reservoir in Fremont 
County, Idaho. I noticed them while flying the summer census on 
August 29, 1956, in the Island Park area. Three adult swans were 
together with three cygnets on the Icehouse Creek Reservoir. All six 
birds formed a typical family group which did not break up in spite 
of repeated low flights directly over them in the pond. Conversation 
with a rancher familiar with the swans on this Reservoir later con- 
firmed that observation, and further established the fact that these 
three adult birds spent most of the spring and summer together, 
from breeding season until fall, although one departed for about a 
month during this period only to return later and remain until autumn. 
In 1957 the three adult swans returned to the Reservoir and one female 
again nested successfully. This trio was broken up later in the summer 
by the death of one of the adults. The sex of the extra bird was never 
determined. As far as is known, only one nest was built each season 
and only one brood was ever seen. Of the hundreds of pairs of wild 
trumpeters I have observed with cygnets in their breeding territories 
during the period 1948-57, this was the only record in which more 
than two adults were seen with young. 



BREEDING 99 

PRENESTING HABITS AND BEHAVIOR 

Long before the winter season lias ended, sometimes 3 months 
before any open water appears, pairs or small groups of trumpeters 
may be found loafing about their still-frozen breeding habitat on the 
Red Rock Lakes Refuge. This bleak, wintry landscape is 6 or 8 
miles from the nearest open water at the spring-fed ponds. Water is 
not generally open in the Red Rock Lakes and marsh until after mid- 
April. But both paired birds and small flocks have been seen far out 
on the vast snowfields which overlie the breeding habitat as early as 
February 2 (in 1949) and February 21 (in 1950). This practice be- 
comes commoner as the season advances. By the time the ice on the 
Lakes is ringed with run-off water from the surrounding meadows 
in April, it is immediately occupied by the swans, which then 
no longer need return to their winter feeding waters. 

Early occupation of the breeding grounds is apparently instinctive, 
as several Yellowstone Park observers have testified to the same be- 
havior pattern. In Yellowstone these early visits to breeding habitat 
may occur considerably later than at Red Rock Lakes, since early 
April is the earliest that swans have been seen visiting their still-frozen 
Park breeding habitat. Perhaps before April other loafing areas in 
Yellowstone are more convenient to winter feeding waters, and at 
Red Rock Lakes the breeding habitat may first be occupied coinci- 
dentally as loafing grounds during the late winter months, with no 
special territorial significance. With only one exception, the early 
literature states that the trumpeter was invariably the earliest water- 
fowl to arrive on its Arctic breeding grounds in the spring, preceding 
even the geese or whistling swans. 

Whether a given pair occupies in the late winter the area to be 
claimed as a territory later lias not been determined. While pairs 
often occupy the same snowfields, more consistently as the season 
advances, their positive identity as the same pair was not established 
then, or related later to the breeding pair which nested in that area. 
It would appear logical to assume that in the last few weeks pre- 
ceding the advent of open water some territorial claims are being 
staked. Specific observations of the beginning of territorial defense 
actions are lacking. At first, just the pair's presence in an area is 
enough to show that the territory is occupied. 

During the period just before the spring breakup, especially on the 
warmer days and nights, vocal efforts and flight activity reach a 
climax. The long winter with its hardships and severe cold is draw- 
ing to a close and the excitement of the breeding season is at hand. 
Singles, pairs, and small groups move frequently about from one 



100 LIFE CYCLE 

open patch of water to another, spending long periods feeding or loaf- 
ing on the ice in the warm spring sunshine. The successively later 
twilight increases this activity, and vibrant sonorous trumpetings 
from the marsh are then audible far into the night. 

TERRITORY AND TERRITORIAL BEHAVIOR 

Territorial behavior in the trumpeter is characterized by the defense 
of the "mating, nesting, and feeding ground for young," the "type 
A" territory classification of Margaret Morse Nice (1941: 471). 
Territorial defense of areas other than that concerned essentially 
with reproduction is apparently unknown in wild swan populations; 
hence, the discussion of territory here will be confined to this defini- 
tion of the term. 

Many observers writing from firsthand experience have agreed that 
SAvans as a group are among the most territorially minded of any 
birds commonly kept in captivity, setting up wherever possible 
relatively large areas of habitat where various other forms of com- 
peting bird life, especially other swans, may not be tolerated during 
the breeding season. It also appears that paired swans, wild or 
"kept," differ a great deal in degree of territorial behavior, both inter- 
specifically and intraspecifically. 

H. Poulsen (1949:195, 198), writing of swans both in the wild 
and in the Zoological Gardens of Copenhagen, says : 

In the Mute Swan the well known threat display (imposing posture, Im- 
poniergehaben, HEINROTH) serving to intimidate intruders in its territory 
was observed chiefly in the adult male, but also in the female when I ap- 
proached the nest at a time when it had left it in search of food. . . . but 
never in the Whooper Swan. . . . Outside the breeding season the swans are 
sociable birds, and outside their territories they even in the breeding season 
agree well. A strange female, which settled in a territory, was seen to be 
chased off by the owning male in threat display, whereas outside the territory 
he dropped this attitude, the feathers now being close to the body. Thus a 
strange female may have two different valences (TINBERGEN, 1942). Inside 
the territory : enemy, outside the territory : female to copulate with. 

Intolerance in the mute swan is apparently modified by captivity. 
H. F. Witherby et al. ( 1939 : 175) remark On this : 

Mute swan, much more than Bewick's and Whooper, is naturally predisposed to 
association with man and easily tamed. O. Heinroth found that behavior of 
wild-caught birds from the Black Sea differed in no respect from that of semi- 
domestic swans. Usually aggressive and vicious towards other birds in the 
semi-artificial conditions in which it often lives, but both Naumann and E. 
Christoleit stress that this trait is less noticeable in fully wild birds. 

******* 

In wild state usually nests on islets in swamps or in shallow water in reed 
grown lagoons, but in semi-domesticated state almost anywhere near water, 



BREEDING 101 

sometimes in colonies of great size. In protected areas of this kind, the nests 
may be only a few yards apart. 

******* 

The swannery at Abbotsbnry (Dorset) is not only the largest individual con- 
gregation of Swans in this country, but is unique. Though foot-marked and 
living under conditions to some extent artificial, the birds are all fully winged 
and virtually wild. Dependent to some extent on annual fluctuations of food- 
supply, numbers vary between under 200 and over 500 pairs. 

The interspecific relationships of mute and whooping swans are 
also noted in Hilprecht (1956: 89) to vary from "extremely tolerant" 
in captivity to "far more tolerant" in the wild. 

Erickson makes an interesting comment on the trait of interspecific 
intolerance among the confined trumpeters at the Malheur Kefuge, 
stating (correspondence) : 

The trumpeters are intolerant of intrusion by whistling swans and several 
whistlers have been seriously injured when they attempted to mingle with the 
larger birds and had to be rescued or they would have been killed. Trumpeters 
seem to disregard ducks and geese. 

E. A. Armstrong (1947: 284) notes yet another aspect of territorial 
behavior in swans, writing, "Where a pair of territorial birds, such as 
whooper swans, are constrained to remain on a lake dominated by an- 
other pair they do not breed." 

Wild trumpeters usually show territorial aggressiveness toward 
their own kind by a combination of loud calls, tremulous movements of 
half -raised wings, and general hostile body attitude. In most cases, 
the defending resident pair is located on the water when the possible 
trespasser is spotted in flight some distance away. If the distant flyer 
approaches, one or both of the swans occupying the territory assume 
the aggressive posture with their wings while trumpeting with ex- 
tended head and neck their unmistakable staccato warning notes. 
If this display is ignored by the approaching swan and a close 
passage or landing appears likely, no time is lost by the defender 
in getting into the air in immediate pursuit. 

In flight, the pursuer always seems able to overtake the departing 
intruder, though if both territorial defenders take to air, only one, pre- 
sumably the male, approaches the trespasser closely. When with 
great effort the defending bird has succeeded in overtaking the fleeing 
invader, the latter invariably climbs sharply upward, only to be fol- 
lowed closely by its pursuer. This seems to be the signal for the 
conclusion of the chase, for the successful defender, now far from its 
territory, turns and heads homeward, announcing its return with 
triumphant trumpeting. Gliding downward, it splashes into the 
water near its waiting mate where both birds approach each other 
trumpeting their mutual staccato congratulations with outstretched 



102 



LIFE CYCLE 




Figure 38. — Observations on the territorial traits of trumpeters can be made 
by a single observer over several thousand acres, since the high mountains 
provide ideal vantage points. Here the birds on Lower Red Rock Lake are 
studied from an observation post on the northern flank of Centennial Moun- 
tains. 



tremulous wings, ending with a dipping motion of their head and 
neck and longer prolonged wailing notes. A display of the whooper 
swan on similar occasions has been reported by E. A. Armstrong 
(1947:142). 

Sometimes the defending resident bird is on solid footing when a 
flying intruder draws near. In this case the wings of the hostile de- 
fender are held in an even more outstretched drooping attitude than 
is possible when it is on the water. Here, since the extending of the 
neck appears more pronounced and the body is visibly erected, an 
even more threatening attitude results than when the displaying bird 
is on the water. In either case a direct attack by air follows shortly 
if the warning is ignored. 

Though both sexes usually partake in aggressive warning displays 
toward a trespassing swan, usually only one departs from the territory 
if pursuit or eviction is necessary, but both swans may take wing when 
prompt action is made necessary by an overt violation. 



BREEDING 103 

Some territorial demonstrations occur from before the time that 
the nest is constructed in the spring until late in the summer when the 
cygnets are half -grown, though they are not shown uniformly during 
this period. They begin sometime after territories are taken, are most 
common during nesting and early brooding, and then taper off. 

Even during the height of the breeding-nesting season, however, 
aggression and discord are not common. When breeding populations 
have been highest on the Refuge, paired swans appear to spend the 
vast majority of their time feeding, loafing, incubating eggs, caring 
for young, etc., actually geting along quite harmoniously with 
neighboring pairs if territorial boundaries are respected, as they 
usually are. Too, the large flock of nonbreeders scatter out on 
the vast shallow expanses of Upper Red Rock Lake, feeding far 
out from shore on the extensive underwater aquatic pastures or loafing 
along the shoreline wherever breeding territories are not established, 
and seldom venture into the established breeding territories. 

At the other extreme, I observed a lone trumpeter, apparently a 
""lonesome" nonbreeder, warned or actually evicted from five different 
territories within the space of an hour. In some cases this individual, 
which appeared to be seeking the company of its kind, would be 
allowed to settle in a distant corner of an occupied territory for a few 
moments; however, the hostility of the residents would increase visibly 
with each passing minute until cob or pen, or both, would fly at the 
trespasser in a show of aggressive eviction. 

This is not the general rule, as mated pairs seem to learn neighbor 
relations quickly, just as the nonbreeders are apparently impressed 
with the importance of staving clear of the breeding areas. By the 
time of the flightless molt in July, few acts of aggression are observed. 
Movement is naturally more restricted at this season, but even after 
the molt, when flight activity picks up, aggression never appears to 
regain its former level, though it is displayed on occasion by breeders 
throughout the rest of the summer. 

During the incubating period, mated swans rarely leave their terri- 
tory unless one makes a short aerial inspection or defensive flight. 
Sometimes the departing bird may land some distance away in a "neu- 
tral" area where either alone, or congenially with others, it feeds or 
loafs, returning to the territory some time later. Breeding pairs 
nesting along the line of flight usually make aggressive warning dis- 
plays upon seeing the commuter in flight, and this usually causes 
the vagrant mate to move on. Except for such short absences, 
the mated pair usually remains resident within its nesting territory 
until late summer or early fall. Towards the end of summer, terri- 
torial bonds definitely become weaker; this is especially true of brood- 
less pairs which may desert their home area altogether. 
4(;!h;ooo— 60- s 



104 LIFE CYCLE 

On one occasion a mated pair, together with their brood, deserted 
their territory, travelling about 2 miles across Upper Red Rock Lake 
to settle along the opposite shore. Before this change of territory, 
the brood had been reduced from 6 to 2 from unknown causes, so it is 
possible that the parents wished to move from the cause of mortality 
and/or molestation. The area selected for the new home was the shore- 
line of a rather exposed bay about midway between two other active 
but distantly spaced territories. The season being well advanced 
and the site well separated from adjacent territories, the shift of 
residence was a successful move and permanent for the season. 

Some variation of territorial behavior is evident among individual 
pairs, depending upon their familiarity with each other. Also, the 
size of the territory defended, and the subsequent spacing of nests, 
indicates the appeal of a given habitat. Once the territory is estab- 
lished, adjacent resident pairs recognize their neighbors and modify 
their aggressiveness accordingly. The pursuit distance at which the 
defenders will take aggressive action is much greater when a stranger 
has been sighted than when a mate from an adjoining territory is 
observed. 

In one unique case of tolerance, 2 pairs nested for several successive 
years a measured 885 feet from each other on the same shoreline of 
a large widening of the Red Rock River. However, the nests were 
hidden in a dense growth of bulrush and the areas used in common 
were at a minimum, each pair keeping to its end of the opening and 
the adjacent stretch of narrower river channel. The distance be- 
tween nests is usually much greater. 

Interspecific aggressive behavior by trumpeters on their nesting 
territory appears to be directed chiefly against the larger birds. 
Usually, territorial aggressiveness is not shown towards the larger 
mammals, including man. When such an intruder approaches nest 
or young, even at a distance, trumpeter pairs discreetly desert. Trum- 
peters generally disregard the ducks. Both ducks and coots swim 
unmolested among trumpeters in close association and perfect har- 
mony. Ducks and coots feed intimately within the trumpeter "family 
circle" in the territory, where they compete with cygnets for surface 
food stirred up by the parent swans. When ducks and swans are 
present in large numbers and compete excitedly for grain in the 
restricted areas of open water of the Refuge wintering areas, a trum- 
peter may take an annoyed jab at some passing duck that gets in the 
way, but this is infrequent. 

In Denmark, K. Paludan and J. Fog studied the effects of in- 
tolerance displayed by wild mute swans against ducks. This study 
was made in response to the claim by many sportsmen that the 
swans in that country interfered with the reproductive success of 



BREEDING 105 

wild ducks. While testimonies of swan intolerance with ducks were 
noted on small and restricted sites, the swan, mallard, and gray-lag 
goose bred close together without inimical effects in other instances. 
Paludan and Fog (1956: 44) concluded, "Under no circumstances 
can the Mute Swan be of any importance to the Danish duck popula- 
tion in general.'' 

The trumpeter is not so tolerant of the larger water and marsh 
birds. While Erickson (correspondence) mentions that nonnesting, 
captive swans held in an enclosure at the Malheur Refuge ignore these 
lesser companions, this may not always be the case with wild pairs on 
their breeding territory. Featherstonhaugh (1948:379) writes of 
trumpeters : 

The swans also drive off any geese (in addition to other swans) that may land 
in the vicinity of a nest, but they pay no attention to ducks or other marsh birds. 
We found nests of the mallard, the ruddy duck, the lesser scaup, and the Ameri- 
can coot within a few feet of swans' nests. 

In observations made between May 11 and August 30, 1949, 1 noted 
11 instances of territorial defense, 8 against other swans and 1 each 
against a white pelican, a great blue heron, and a Canada goose. 
Charles Hotchkiss, ranger-naturalist of the National Park Service at 
Teton Park, reported to me seeing a swan chase away a sandhill crane 
which came close to the swan nest. 

Interspecific intolerance involving muskrats has been observed in 
at least two cases. W. Verde Watson, a Park Service naturalist in 
Yellowstone Park, furnishes an account of a trumpeter swan killing 
a muskrat, supposedly in defense of its cygnet brood, writing 
(1949: 49) : 

The pair of adults were lazily swimming about off shore sounding rather 
plaintive, deep toned "words" of instruction to some of the cygnets. These 
youngsters had just given some heed to the old folks and were making way 
toward them when one of the adults, with a great flurry of feathers and beating 
of the water, half-flying and half-running upon the water, bore down upon 
the muskrat intruder which was apparently swimming past some 2"> to 50 feet 
farther out in the lake. Arriving at the spot where the 'rat must have been she 
beat the water furiously with both wings, seeming literally to walk about on 
the water as she darted very quickly from side to side and round and round 
following the quarry. All the while she hissed loud and angrily and periodically 
pecked vigorously at the object of her wrath. ... A quick look through the 
telephoto tinder of the Leica revealed that the animal was a muskrat, and 
observations during the succeeding couple of minutes or so indicated that it 
was probably done for. . . . Thus we were really amazed when it emerged 
again and swam almost directly at the same swan that had abused it so badly 
shortly before. . . . The old bird saw it coming and with determined bearing 
swum to meet the muskrat. This time the initial shock was delivered as a 
vigorous and meticulously aimed peck followed by the same unmerciful wing 
beats and much loud hissing. . . . This encounter probably did not last over 



106 LIFE CYCLE 

30 seconds, and then when the bird sailed away from the scene and the water 
settled down the unfortunate 'rat came up and lay motionless on the surface. 
. . . Subsequent autopsy . . . revealed a considerable bruised and bloody 
area in the neck, and it was thus considered likely that the fatal blow may have 
been the first well aimed hammerlike peck delivered at the opening of the second 
round. 

R. O. Hart, a District Ranker in Yellowstone Park, furnishes 
(1952: 56) a similar eye-witness account of an encounter between 
a swan and a muskrat. This time, however, the skirmish did not 
end in a fatality. 

The presence of pelicans, cranes, herons, geese, or muskrats, does 
not necessarily arouse aggressiveness in swans, even mated birds within 
their breeding territory. Most of these species have often been seen 
in close proximity to swans with no territorial action or other aggres- 
sive behavior resulting. Swans with young are most apt to take 
offensive action against such species. 

Despite the variations and flexibility in the defense of territories 
such action is the main factor regulating the distribution of pairs in 
an area of breeding habitat. There is no direct evidence yet that 
territorialism limits breeding numbers in all cases, although it is 
a factor in determining nesting success. 

In the complex pattern of the Red Rock Lakes marshes, territories 
are generally established where they existed the previous year, often 
with exactly the same nesting site occupied. Various observers agree 
that breeding pairs remain attached to their territories year after 
year. Oberhansley and Barrows (MS) state of their 1938 Yellow- 
stone Park observations, "At each nesting site studied, old nests were 
used and the actual time devoted to their repair was brief."' Condon 
(MS), Yellowstone Park, stated, "In nesting, pairs have in most in- 
stances returned to their previous year's nests and repaired the old 
nests for re-use." 

In the contiguous marshes of the Refuge, the desirable features of 
these territories with a long breeding history are apparently recog- 
nized by other pairs who quickly appropriate areas unclaimed by 
former owners. As Albert Hochbaum (1944:78) found in his 
studies of the canvasback on prairie marshes, "I believe that 
... a delicate arrangement of terrain, if it remains relatively 
unchanged from year to year, is recognized by any individual duck 
as desirable and thus is occupied." This is apparently true of the 
trumpeter as well, since a normal population turnover would dictate 
at least some change if the selection of territories were not governed 
by inherent instincts. What appears as desirable nesting habitat to a 
human observer may remain barren of breeding swans year after 
year, even in the face of a rising population of breeding swans, while 
territories which appear similar may be occupied. 



BREEDING 107 

During years of increasing numbers of breeding pairs at Red Rock 
Lakes, expansion has occurred chiefly into less desirable (previously 
unoccupied) habitat, not in the compression of the additional breeders 
within previously occupied territories. This may contribute to the 
low reproductive success which characterizes the years of high breed- 
ing population, but just how it does is unknown. 

If the former nesting site is missing or unusable for any reason, the 
swans select another location within essentially the same territory. 
For several years a pair nested on a bit of shallow marshland which 
protruded from an otherwise open lake shore unoccupied by other 
sw T ans. One season this small area was destroyed by the winter's ice 
action, and with the loss of the only suitable nesting site, the otherwise 
acceptable territory has not been occupied since. 

Whatever determines the trumpeter's selection of territory, the most 
obvious result is the distant spacing of nests. For four successive 
years, during the nesting seasons of 1954-57, swan nest locations 
were plotted on aerial maps showing about 6,000 acres of water and 
marsh, about 50 percent of the nesting habitat in the Red Rock Lakes 
marsh. The Upper Red Rock and Swan Lake areas are shown in 
figure 39, and the Lower Red Rock area in figure 40. 

This nesting distribution data is highly accurate, since the incubat- 
ing swans are very conspicuous when viewed with a 20 X spotting 
telescope from lookout posts on nearby hills. Most of the nests shown 
were subsequently checked by boat, and no errors were found in the 
plotting data. Any errors would probably be those of omission. A 
total of 109 nests were thus plotted during the month of June in the 
1954—57 period considered. 

Of 74 nests observed on the Upper Red Rock and Swan Lakes 
in the 4 seasons, 57 (77 percent) were located on or within a 
few feet of previously or subsequently used sites. Three (4 per- 
cent) were occupied during all 4 seasons. Much the same situation 
prevailed on the Lower Red Rock Lake where a total of 35 sites was 
checked, with 25 (71 percent) located on substantially the same bit 
of marsh used the previous year. Here only 1 site was used all 4 years. 

Shorelines are not selected in the same proportion for nesting ter- 
ritories as is island habitat, and relatively straight shoreline is almost 
totally ignored. Whenever territories are established on compara- 
tively open shorelines, the pursuit -distance at which one of the mated 
pair will take aggressive action against an intruder is noticeably 
greater than if a bay or island is occupied. The highest concentration 
of nests per acre is found on shallow Swan Lake where the irregular 
shoreline combines with numerous stable sedge islands to provide the 
greatest variety and interspersion of water and marsh habitat. In 
1957, for instance, approximately 500 acres of water, island, and 



108 



LIFE CYCLE 




1954 = 3 1955-Q I956=Q I957=£) 

Figure 39. — Nest locations, 1954-57, Upper Red Rock Lake and Swan Lake 
marsh. (Approximately 8,000 acres in map.) 



peripheral habitat of Swan Lake supported 7 pairs of nesting swans, 
or about 70 acres of territory per nesting pair; on deeper Lower Lake, 
where nesting sites are most frequently located atop bulrush muskrat- 
house sites, only 10 pairs nested on the 1,500 acres, or about 150 acres 
per nesting pair. The relation of shoreline to interspersed nesting 
habitat will be shown later under Population Mechanics. 



BREEDING 



109 




I954=(5 I955 = Q 1956=0 1957*© 

Figure 40. — Nest locations, 1954-57, Lower Red Rock Lake. (Approximately 

3,000 acres in map.) 

The amount of territory claimed by a mated pair of trumpeters 
may seem to be related to the quantity of food available at a given 
distance from the nest. On an open shoreline, the territory defended 
is normally greater than that of an island-nesting pair in shallow- 
water territory where a great deal of food may be available within a 
short radius of the nest. A shoreline nesting pair will, however, fre- 
quently select a small bay for the nest location where territorial de- 
fenses are limited principally to the confines of the bay itself, and in 
spite of the comparatively smaller amount of food available, the 
pursuit-distance is found to approximate that of island-nesting swans. 
So, quantity of feeding area alone does not necessarily determine either 
the size or the appeal of any given area as nesting territory. The 
arrangement of the various terrain features within the area, as well 
as the number of potential nesting pairs, are also important factors. 

The area of marsh or lake required to support a pair of trumpeters 
and their brood adequately must he but a fraction of the size of the 
territory claimed, and depends upon the quality of food produced 
as well as the quantity and availability. For instance, trumpeters 



110 LIFE CYCLE 

have nested along; very narrow but productive water channels where 
food was abundant and where travel to larger waters for food would 
not appear to be necessary. They do not prefer to nest on closed 
channels or ponds of a size equal to or even larger than the channel 
if egress by swimming to larger waters is restricted, though the food 
supply within such an area may appear adequate to support a good- 
sized family. M. M. Nice ( 1941 : 469-470) , speaking generally of song 
birds, states : "Many birds, like the Song Sparrow and House Wren 
. . . , at first claim far more land than they really need; under 
pressure of competition they decrease their holdings bid not beyond 
a certain jioint. In other cases, territorial behavior adapts itself to 
circumstances, and the type changes, so that many more pairs are 
accommodated on a certain area than would otherwise be possible." 
This may also apparently be true of the trumpeter to a limited 
extent. 

A certain amount of water space, presumably to meet flight take-off 
requirements, appears necessary within each territory, and the large 
number of potholes over the Refuge which often produce considerable 
food are not an important segment of the breeding habitat because 
of such restrictions. The marsh next to these potholes is heavily 
vegetated; thus, landing or take-off near the nest is difficult or 
impossible. 

Condon (MS) found in Yellowstone Park that: 

Of the 29 lakes used by trumpeter swan during the past 10 years, only 4 are 
smaller in size than 16 acres, and of these 4, all are 9 or more acres. This 
tendency to choose lakes of 9 or more acres indicates the need for a reasonably 
large territory for the rearing of young. . . . none of the 29 lakes used have 
harbored more than one nesting pair of trumpeter swan. Many of the lakes 
have adequately cared for several nonnesting adults, but only one nesting pair 
has been found to utilize a lake. 

Mated pairs sometimes guard territories but have never been 
observed to nest. This situation may be noted in the same territory 
from year to year, when the same pair apparently returns. It is not 
known whether these pairs have been shunted by competition to areas 
in which breeding may be inhibited for some reason, or merely 
are incapable of breeding. There does seem to be some cor- 
relation between the areas occupied in this manner and their spe- 
cific location. Too, the percentage of nonnesting pairs appears to 
increase when the breeding population is high, but no figures are avail- 
able to support this generalization. In 1957, there were 3 pairs of non- 
nesters in addition to the 10 nesting pairs on Lower Red Rock Lake, 
while the Upper Lake contained '2 pairs of nonnesters in addition to 
the 6 pairs of nesting swans. 



NESTING 111 

NESTING 

NEST SITES 

Muskrat houses furnish the great majority of swan nesting sites at 
Red Rock Lakes. On the Lower Lake where bulrush beds are plenti- 
ful, the trumpeters prefer to nest on muskrat lodges located in this 
growth, and few nests are placed on the shoreline proper. On the 
Upper Lake where bulrush is found only occasionally, all of the nests 
are located by necessity along the shore proper. 

Even while the breeding marsh remains frozen, the tops of muskrat 
houses which protrude from the snow are visited by swans and used 
as loafing sites. Whether their attraction at this season is due to their 
potential as nesting sites or to their convenient location as observation 
posts is not known, but their prebreeding season appeal is certainly 
more than just casual. 

Nests are usually located so that all or part of the site is bounded 
by a moat of water. During a year with an abnormally high spring 
water table, one swan nest was located on a solid sedge meadow, a 
measured 298 feet from the nearest waters. The dried remains of 
algae at the base of the nest, however, showed that the nest was 
actually built in a few inches of water during the runoff. The great 
majority of nests on the Refuge are placed on muskrat houses located 
on semi-floating sedge bog-mats. 

Any suitable feature located somewhat above the general level of 
the marsh terrain may be used as a nesting site. Oberhansley and 
Barrows (MS) mention in their Yellowstone report: 

Old muskrat houses furnish excellent nesting sites, and in one instance at 
Little Robinson Creek, an old beaver house was used. At Riddle Lake, beavers 
were observed in the act of converting an old swan nest Into a home for them- 
selves by piling limbs and dead tree sections over it. On the other hand, old 
beaver houses form islands which were used by swans. 

Condon (MS) adds to the subject of nest locations in Yellowstone 
Park by stating: 

In some instances, small islands removed from the mainland are used as nest- 
ing sites, and islands visited at Riddle and White Lukes afforded sites for nests 
made of reeds and grasses winch were piled into small mounds hollowed to 
accommodate the clutch of eggs. . . . Many nests are built on the lake shores 
in open unconcealed areas, with very little vegetative cover for concealment and 
with the nest itself consisting of only a small mound of grasses, reeds, twigs, 
and rushes. Such nests and nest sites were used at Geode, Grebe, and Madison 
Junction Lakes. 

NEST BUILDING 

Nest-building activities are shared by both sexes, though the female 
probably contributes the bulk of the effort. Nest materials on the 
Refuge consist chiefly of sedge sod and plant parts, though any ma- 



112 LIFE CYCLE 

terial nearby may be used. These materials are not moved farther 
than a neck-length away. In one instance, a pair of swans in Upper 
Red Rock Lake was observed in what seemed to be nest -construct ion 
activities. Both birds remained prone on a small sedge island near 
the mouth of Shambow Creek and busily picked up vegetative debris, 
rootstocks, and plant parts with their bills, stacking these in a mound 
to the rear. This continued for perhaps 5 minutes with vigorous 
enthusiasm. Then one of the swans departed and began feeding 
some distance away, completely ignoring the activities of the other 
bird. The mate remained and continued to tug and wrestle with de- 
sirable bits of tough sedge and fibrous matter, adding these materials 
to the small heap already accumulated to the rear. It was still at the 
task when the observer left the observation post some 15 minutes 
later. 

This particular nest foundation was begun late in the season and 
was never completed. The pair of swans" which were so intent on 
its construction were not observed engaging in this activity again, 
nor did they nest at all that season, although they remained in the 
territory and defended it against other swans. 

An observation in Yellowstone Park of a pair of trumpeter swans 
engaged in nest-building activities is given by Oberhansley and Bar- 
rows (MS) : 

In repairing the nest at Swan Lake the cob and pen cooperated. The old 
nest material was rearranged by adding material from the sides of the nest 
to the top. Some of the submerged portions of the nest were brought above the 
water and other materials (chiefly sedges) near at hand were gathered and 
added. As the swans gathered sedges they would throw them to the rear in the 
general direction of the nest to be added later. This particular nest is located 
upon an old muskrat house and has been used for several years. It has a fi- 
brous, mucky base and gradually becomes coarser toward the top where the 
fibrous material blends with sedges and a few scattered leaves of willow and 
birch in the nest proper. The nest is partially surrounded and supported by 
several clumps of mountain bog birch (Betula glandulosa) and a few willows 
(Salix, sp. ) which [formed] a rather poor screen until the surrounding sedges 
had grown tall enough to serve better. All approaches are well guarded by 
water to a depth of about four feet, gradually sloping to a width of approxi- 
mately 10 feet at the bottom of the pond. The total height of the nest was 61 
inches, with top protruding 22 inches above the water line. 

Swan nests constructed on the Red Rock Lakes Refuge average 
somewhat smaller than the nest just described but the general account 
is typical. Condon (MS) records, writing again of his observations 
in Yellowstone Park : 

The type of nest constructed by trumpeter swan in Yellowstone Park varies 
greatly and the material from which it is made is governed entirely by the type 
of cover and vegetation near the nest site. . . . where an abundance of 
grasses, sedges, reeds, and rushes is available, nests of large proportions are at 
times built. Such nests have been built at Swan and Trumpeter Lakes. Their 



NESTING 113 

large size is, in all probability, due to the necessity of keeping a dry nest and 
the desire to have the nest removed from dry land by a strip of water. Nests 
of this type have been constructed only where vegetative cover and water depths 
have been favored with suitable sites. 

MacFarlane (1891 : 425) gives a general description of the nests of 
Arctic trumpeters which were observed near Fort Anderson (east of 
the Mackenzie River delta) , stating : 

Several nests of this species were met with in the Barren Grounds, on islands 
in Franklin Bay, and one containing six eggs was situated near the beach on a 
sloping knoll. It was composed of a quantity of hay, down, and feathers 
intermixed, and this was the general mode of structure of the nests of both swans. 

Only a trace of down and a few molted feathers have been observed 
about the nest areas of trumpeters on the Red Rock Lakes area. The 
material of which the nest bowl proper is constructed differs little 
from that of which the upper part of the nest is fashioned, the finer 
leaf and stem parts of the sedges being the usual material used there. 

For a month, more or less, after the eggs are hatched, the nest, 
becomes a favorite site for the brooding of the cygnets at night and 
loafing by day. By midsummer, as a result of these activities, the 
nest is an odoriferous mound of decaying vegetation and defecation. 
The hatched egg shells and unhatched eggs, if any, are buried to a 
depth of several inches with fecal deposits in addition to the vegetative 
material which has become mashed down from the nest bowl or 
piled on the site by muskrats. Of course the nest by this time 
is unrecognizable, with usually only a few molted white feathers 
nearby to indicate that the unattractive heap was once a tidy swan's 
nest. 

EGG DESCRIPTION 

Trumpeter eggs are somewhat granular in texture, elongated ovoid 
in shape, and off- white in color when freshly laid, becoming nest- 
stained a brownish color a short while after incubation. 

In 1955, 109 egos representing the complete clutches of 21 nests 
were measured for length and greatest diameter (see appendix 
3). Longitudinal measurements ranged from 123 mm., which was 
the longest and which had a diameter of 74 mm., to the shortest, 
which measured K>4 mm., there being 4 of the latter (2 in a clutch 
of 6, 1 in a clutch of 5, and 1 in a clutch of 4) which were ('>!> mm., 
71 mm., 7<>.r> mm., and 7<>.r> nun., respectively, at their greatest 
diameter. 

The ego- of greatest diameter measured 77. 5 nun. and was 1<>'.> mm. 
long, being one of a clutch of •'., while the ego- ( ,f shortest diameter 
was 68 nini. and measured 113 mm. long, being one of a clutch of 8. 

The average length of the 109 eggs checked was 110.9 mm., while 
the average diameter was 7'2A mm. It is interesting to note that 



114 LIFE CYCLE 

the average trumpeter eo«- from the Red Rock flock is noticeably 
smaller, 110.9 x 72.4 vs. 121.3 x 77, than the average measurements 
of 3 eggs (from 2 nests) obtained from the Copper River, Alaska, 
flock by Melvin Monson (1956: 415). The smaller egg-size ratio of 
the Red Rock Lakes trumpeters also holds true when compared with 
that reported from the Kenai trumpeter flock (Dave Spencer, cor- 
respondence). The average size of the eggs obtained at Red Rock 
Lakes compares very closely with that reported by A. C. Bent 
( 1925 : 297) in the measurement of 25 trumpeter eggs. 

CLUTCH SIZE 

Sizes of completed clutches of eggs in various trumpeter nests on the 
Red Rock Lakes Refuge show this annual variation : 1949, 12 nests 
containing 3 to 9 eggs each held a total of 61 eggs for a mean of 5.1 
eggs to the nest ; 1951, 13 nests containing from 4 to 7 eggs held 73 
eggs for a mean of 5.6 ; 1952, 17 nests containing from 2 to 7 eggs held 
88 eggs for a mean of 5.2; 1955, 32 nests containing from 4 to 8 eggs 
held 157 eggs for a mean of 4.9. The 74 completed clutches observed 
over an intermittent span of 7 years contained a total of 379 eggs, the 
mean being 5.1 eggs to the nest. 

These figures agree well with the clutch size noted by MacFarlane 
( 1891 : 425 ) among Arctic-breeding trumpeters, as he states, "It usually 
lays from 4 to 6 eggs judging from the noted contents of a received 
total of 24 nests." 

EGG LAYING 

The rate at which eggs are laid and the length of the incubation 
period were not studied on the Refuge since gathering such data on 
a single nest would unnecessarily disturb several nesting pairs. 
Other observers have made some pertinent notes. 

H. F. Witherby et al. (1939: 177) state of the mute swan, "Accord- 
ing to O. Heinroth, eggs laid on alternate days; confirmation de- 
sirable ;" which H. Poulson ( 1949) obligingly furnished, writing, "The 
female Mute Swan in the Zoo laid 5 eggs in 1947 and 4 eggs in 1948 on 
alternate days." 

Witherby et al. also report that whooper swans in confinement laid 
eggs on alternate days (1939: 170). For lack of specific information 
on the subject, the production of about 1 egg every 48 hours is assumed 
to be normal for the trumpeter also. 

INCUBATION 

Although Witherby et al. (1939: 177) report that in the case of 
the mute swan the male assists the female in incubating the eggs, 
this has never been observed or reported in the trumpeter. Poulsen 



NESTING 115 

(1949) corroborates Witherby's mute-swan statement but adds that 
in the case of the whooper swan the male did not participate in 
incubation duties. 

Several records have been compiled on the length of the incubation 
period. Dr. Ward Sharp, writing of 5 trumpeter swan eggs which 
were set under bantam hens, records in a Bureau report: 

The little hens could not keep the eggs warm, faithfully as they tried. One 
end of the egg was always cool. A few days before the [other] eggs hatched 
(about 3 or 4) two eggs became warm and hatched soon afterward. The 
incubation period was about 33 days. 

Oberhansley and Barrows (MS) in their Yellowstone Park obser- 
vations also report an incubation period of 33 days, but Aimer Nelson, 
formerly Refuge Manager at the National Elk Refuge, writes of a 
period of 36-37 days. Inasmuch as the incubating period lasts more 
than 4 weeks, the variation of a few days' time would be expected 
under the varying conditions found in the wild. A normal incubation 
period of from 33 to 37 days seems reasonable. 

Again referring to the much-studied mute swan, "Witherby et al. 
(1939: 177) state, "incubation begins before completion of clutch in 
some cases.' ? This tendency may also be present in the trumpeter to 
some extent, as unhatched eggs containing well-developed embryos 
are sometimes found in nests from which the female has departed 
with her first-hatched cygnets. 

HATCHING DATA 

The Red Rock Lakes- Yellowstone region has short, cool summers. 
Thus the average hatching date is important, since the nesting lakes 
and marshes freeze over rather early, dooming any late cygnets which 
are still flightless. 

Of 12 nests closely watched in 1949, 9 had produced broods between 
June 15 and 21. The first brood was seen on June 15, and the last 
nest under observation apparently hatched about June 26. 

In 1952 hatching was much later. On 7 nests checked that year, 
only 1 had produced young by June 17, 3 more had hatched by June 
28, and the remainder had hatched by July 3. The average hatching 
date in 1952 was later than at any time during the period 1948-52, 
presumably because mating was delayed by abnormally high water 
levels during the initial spring breakup period. Fortunately a long, 
unusually warm autumn followed, and no cygnet mortality seemed to 
result from this late hatch. Normally, hatching on the Red Rock 
Lakes marsh occurs between June 15 and June 25. 

In 1946 Sharp reported seeing the first cygnets on June 10, and 
earlier A. Y. Hull mentioned, '"The first egg date that we have is April 
26." Roth of these records indicate unusually early nesting. 



116 LIFE CYCLE 

Condon (MS) records a late-nesting case in Yellowstone Park in 
1940. The trumpeters Avere not seen on the lake until May 30, and no 
cygnets appeared until July 18, probably too late to survive the fall 
freeze. 

Judging from the egg-laying rate, average clutch size, period of 
incubation, and the knoAAm hatching dates of many nests, egg-laying 
normally commences on Refuge marshes shortly after May 1 and most 
clutches are completed by May 15. Thus, nesting is underway in many 
cases before the ice has disappeared. This is many AA-eeks before 
the ducks commence to nest in earnest. 

David Spencer (correspondence) states that on the Kenai National 
Moose Range in Alaska in 1957 most of the hatching was completed by 
June 25. This indicates that the nesting seasons on the Kenai and in 
the Red Rock Lakes marshes are coincidental to a surprising degree, 
the great difference in latitude (16°) apparently being well compen- 
sated for by the contrast in elevation (sea level vs. 6,600 ft.) 

RENESTING 

All the white northern swans raise a single brood each year, if 
successful in nesting. No instance Avas found in the ornithological 
literature to the contrary, either in the Avild or in captivity. In cap- 
tivity, both the black swan and the black-necked swan AA T ill produce 
2 or even 3 clutches of eggs in a single year if the eggs are removed 
successiA^ely after each clutch is completed. If a brood is raised by the 
parents from the first clutch of eggs laid, this precludes a second nest- 
ing for that year. 

An unsuccessful attempt, sponsored by outside interests but per- 
mitted by the Service, was made in 1944 to increase trumpeter swan 
production artificially at the Red Rock Lakes Refuge. In this case 
a clutch of 5 eggs AA'as removed from a Avild trumpeter nest on the 
Refuge and incubated artificially. Jean Delacour (1944: 135-136) 
states of this attempt, "We had hopes that the robbed pair of SAA-ans 
Avould nest again, but they refused to do so, and the only supposed 
advantage of taking eggs rather than cygnets was thus denied." 

One A 7 alid case of renesting may have been found. While on a 
routine inspection of swan nests in Refuge marshes, I encountered 
2 fresh nests within 25 feet of each other. In one nest, which Avas 
deserted, there AA-ere the broken pieces of 5 eggs, which had apparently 
been destroyed not too long previously, while the active nest located 
nearby held 2 eggs. The smaller clutch was being incubated, and in 
addition 3 eggs were floating near the neAA- actiA r e nest. 

Presumably when the eggs in the first nest were destroyed, possibly 
by predation, the clutch AA'as in the process of completion, and the 
pair promptly renested close at hand. The 3 floating eggs may have 



CYGNET DEVELOPMENT 117 

been lost in the interval between the destruction of the first clutch and 
the completion of the second nest to the point of being able to hold 
eggs. Thus, a total of 10 eggs was apparently laid by the one 
female, as an association of 3 breeding swans has never been observed 
on the Refuge, and territorialism would prevent the nesting of 2 
pairs so closely. 

In the case of the failure of a trumpeter pen to renest, as reported 
by Jean Delacour, the eggs may have been removed from the nest 
after egg laying had stopped and incubation was actually under way. 
If the eggs had been quietly removed as they were laid, leaving one 
or two in the nest to restrain the inclination to desert or nest else- 
where, a much greater production by the female may have resulted. 

CYGNET DEVELOPMENT 

In common with other birds, the young of the trumpeter are 
equipped with an egg tooth believed to help in breaking out of the 
shell. Oberhansley and Barrows (MS) noted, "This sharp point is 
a special adaptation designed only for pipping the shell and dis- 
appears sometime after hatching. . . . The shells average 1 milli- 
meter in thickness and are very strong." 

Only one record of the weights of newly hatched cygnets seems to 
have been made. Regarding this, Sharp, referring to the cygnets 
artificially incubated, states, "The two cygnets weighed 7 and 7V& 
ozs. respectively when hatched on June 10, 1044." No other figures 
are available, but these data are believed representative. 

How much time is spent by the wild pen brooding the newly hatched 
cygnets on the nest before leading them to water is not known. The 
presence of unhatched eggs or cold inclement weather might prolong 
brooding, while a complete hatch and warm weather might shorten it. 

F. E. Blaauw (1004: 74) made a note regarding the persistence of 
brooding in his captive trumpeters, stating, "During the first days of 
the life of her chicks, the old female trumpeter often retires to her 
nest for hours together, warming them under her, and she continues to 
do this during the night for a long time." 

Much attentiveness is shown the young cygnets by the parents, with 
both adults usually present. How aggressively the parents might 
defend their young from predators is not known. The treatment of 
muskrats by aroused trumpeters suggests that very vigorous action 
is possible. But the parents' close supervision of the young gives very 
few opportunities to predators. 

When the presence of humans threatens the swan family, the adults 
will usually desert their young without protective action, with little 
if any reduction of the normal escape-distance. If time and oppor- 



118 



LIFE CYCLE 



tunity allow, the adults try to lead their young into dense growths of 
emergent aquatic plants, leaving the scene unobtrusively shortly after 
hiding their cygnets. The cygnets will then usually remain quiet and 
well hidden, though sometimes flushing from their hiding place when 
deliberate search is commenced in the immediate vicinity. Scott and 
Fisher (1953: 209) report that among wild Icelandic whooping swans: 

Older cygnets would feign death when handled, having their necks in a lifeless 
attitude. This was particularly noticed in a brood estimated to be about two 
weeks old, and again in one of about four and a half weeks. . . . 

The behavior of parent whoopers with cygnets was also variable. Some 
deserted their brood and flew away at a range of several hundred yards. Others 




Figure 41. — Newly hatched trumpeter cygnet. Lower Red Rock Lake; egg in mid- 
foreground being pipped. 



CYGNET DEVELOPMENT 



119 




Figure 42. — Close-up of trumpeter cygnet showing fine, grayish-white down. 



remained to protect their young and were photographed at less than thirty 
yards. 

When not disturbed, parent trumpeters spend most of the time 
swimming, feeding, or loafing, with the more active cygnets busily 
moving between or immediately around them. Close family ties 
result in a tightly knit family formation which reduces vulnerability 
to predators. 

This characteristic, coupled with a pair's territorial proclivities, 
virtually eliminates the possibility of two or more broods combining, 
especially in the younger age classes when both factors are more 
strongly expressed. On one occasion, however, during the August 29, 
1955, aerial census of the Refuge, a single pair was seen accompanied 

469660 O— 60 9 



120 LIFE CYCLE 

by 10 cygnets. Specific nest checks in that vicinity earlier in the year 
to determine clutch size establishes that in this instance the abnormal 
size was due to an association of at least 3 broods. The actual circum- 
stances surrounding this unusual case are unknown. (Earlier ob- 
servations of the 4 broods nearest this occurrence had revealed that 
hatching originally produced broods of 5-3-3-1.) Sharp, in a trum- 
peter census report in Refuge files dated June 28, 1943, also reports a 
brood of 7 cygnets which he believed was a compounding of 2 broods 
of 4 cygnets seen in the same general area 12 days earlier, so such 
cases apparently do occur. 

Although swan brood amalgamation appears to be rare, older broods 
of preflight age sometimes contain individuals of marked size differ- 
ences. These cases probably represent variations in individual growth 
rates rather than examples of brood combinations, though the latter 
may occur to a limited degree. Hochbaum (correspondence) notes 
that the two Montana cygnets raised at Delta showed marked differ- 
ences in size from the start. The larger bird proved to be male, the 
smaller, female. 

The rapid growth rate of this species is assisted by the long day- 
light hours of summer which the young spend feeding in their fertile 
marsh environment. It was previously noted that the two cygnets 
hatched in captivity on the Refuge on June 19 weighed 7 and 7y 2 
ounces. On September 2 these same birds weighed 15V4 and 15% 
pounds respectively, a thirtyfold increase in 75 days. In the wild, 
growth must be at a comparable rate, as I have weighed 19-pound 
cygnets of preflight age captured for banding in early October. 

Because of the early freeze-ups on their breeding grounds, the 
average age at which cygnets are capable of flight is important. 
Oberhansley and Barrows (MS) report that in one case a cygnet 
hatched June 23 was observed on its initial flight on October 9, a 
period of 109 days. James R. Simon (1952:462) checked the flight 
capabilities of 3 trumpeter cygnets, hatched on June 16, 1951 in 
Grand Teton National Park, from October 4 to 16. Two cygnets 
could fly by the 14th, and 2 days later, 122 days from hatching, the 
whole family departed the pond on the wing. The cygnets transferred 
from the Red Rock Lakes Refuge to the Delta station in 1955 made 
initial flights when about 13 weeks old, a period of 91 days. A de- 
velopment period of from 100 to 120 days would apply to the average 
Red Rock Lakes cygnet, as young hatched about June 20 are fre- 
quently seen in flight before October 10, though seldom before Sep- 
tember 20. There is considerablevariation in the individual develop- 
ment so that some cygnets, though hatching on time, might be flightless 
and vulnerable at the final freezeup. This has occurred as early as 












Figure 43. — Swan family at loafing cite. Grebe Lake. Yellowstone .National Park. 
The special foot position of the adult is commonly seen with mute swans. This 
brood is approximately a month old. 



October 28 for the Red Rock Lakes and marsh, though the 16-year 
average final freezeup date compiled during the 1938-53 period, is 
November 8. 

Though family ties remain strong, the "apron strings" of the par- 
ents tend to loosen as the young grow older. On one occasion, a brood 
of cygiiets was left alone for about :'>o minutes while the parents moved 
briefly to another part of the lake. This occurred on August •"><>. when 
the young were half grown. 

Only two notes exist regarding the duration of family ties after 
the offspring's first winter. I once noted two immature trumpeters, 
in their initial flightless molt during July, closely together when a 
large loosely scattered nonbreeding flock was approached. These 
two individuals were so attracted to each other that the long pursuit 



122 LIFE CYCLE 

by boat did not separate them, as usually occurs among 1 unrelated 
swans. Both were subsequently captured for banding, and were 
found to have been banded the previous autumn when they were pre- 
flight cygnets of the same brood. 

This observation suggests that associations of brood mates may 
persist for some time after the offspring are left by their parents 
upon the approach of the breeding season, at least until their first 
flightless molt. This period would appear to be confirmed and even 
extended by R. H. Mackay (1957: 339), who reported that three 
brood mates banded in 1955 were shot virtually together in Nebraska 
in late October 1956. Family ties in the trumpeter are apparently 
strong. 

FOOD 

Swans spend long hours in their endless quest for food and consume 
enormous amounts of succulent green vegetation when given an op- 
portunity, all parts of the various aquatic plants being taken. With- 
erby et al. (1939) mention that pondweeds, buttercups, mannagrass, 
eelgrass, waterweed, muskgrass, and clover, besides others, constitute 
the food of the Eurasian species of swans. Hilprecht (1956 : 96-100) 
also mentions their foods and feeding habits. Many of these plant 
forms are an important part of the diet of our native swans as well. 

The findings from several unpublished food studies of the trumpeter 
in its Yellowstone and Red Rock Lakes environment, plus the labora- 
tory analysis of stomach contents of trumpeter casualties and pertinent 
notes by other observers are combined here to furnish a summary of 
the food of this species. Much more remains to be learned, partic- 
ularly of their winter food habits and requirements. 

FEEDING HABITS AND FOOD OF YOUNG 

From the beginning, downy cygnets are much interested in food, 
and are very active in their quest for it. For a long period follow- 
ing hatching, the swan family feeds in a tightly knit group, the adults 
usually remaining near each other in the shallow water while the 
cygnets swim busily about between them, frequently with coots or 
ducks intermixed, seeking the morsels which are stirred up by their 
parents. 

Writing from close-hand observations of swan families feeding 
on lakes in Yellowstone Park, Oberhansley and Barrows (MS) 
describe these early feeding activities : 

The first food of the cygnets was presented [brought up] to them on the sur- 
face of the water by the adults and consisted principally of aquatic beetles, 
with some insects and crustaceans, together with small quantities of the white, 



FOOD 123 

tender basal part of sedge. The young birds were very adroit in snapping 
up morsels that floated to the surface near the parent birds as they fed from 
the bottom or scratched food loose. Droppings in each case studied averaged 
over 95% animal matter for the first three weeks. Plant life became increas- 
ingly important with age and varied from sedges to water milfoil, pond weed 
and other aquatic plants as the season progressed. Beginning in August 
snail shells (Lymnaea stagnalis jugulahs, Say) began to appear in the cygnet 
droppings. These snails are abundant near the east shore of the lake. 

Condon (MS) reports: 

The cygnets that have been observed during their first two weeks after 
hatching were seen to feed in very shallow waters of six inches to one foot in 
depth, and when feeding where the water was deeper, they were gathering the 
food stuffs brought to the surface from the bottom by their parents while feed- 
ing. In shallow water, where they can reach the bottom or the vegetation 
growing up from the bottom, their feeding is carried on by the simple process 
of stretching their long necks down and securing the food by working over the 
plant and animal matter at hand and selecting those desired. 

That swan cygnets tended to cut down on the animal matter in their diet 
after about five weeks was noted by their tendency to feed in deeper waters 
and to be feeding primarily on vegetative foods. Droppings collected at Grebe, 
Riddle, Geode and Swan Lakes all gave evidence of a preponderance of vegetable 
foods and very little animal. Those animal forms eaten were undoubtedly of 
the softer forms, for evidence of them did not appear in the droppings collected 
at resting areas. 

These observations agree generally with the feeding habits of the 
cygnets at the Red Rock Lakes Refuge, though close observations 
of feeding families of swans are impractical in the vast marsh sys- 
tem. On one occasion five Refuge cygnets from a single brood and 
one cygnet from another brood were recovered soon after they 
had died, presumably of exposure, and a determination of their 
stomach contents was made by the Fish and Wildlife Research 
Laboratory in Denver, Colorado. These data, as well as information 
concerning the stomach contents of a predator-killed cygnet in Yellow- 
stone, are presented in the Appendix, part 4. In the case of the 
Refuge cygnets, practically no animal matter was present, with leaf 
and stem fragments making up from 80 to 100 percent of the stomach 
contents, and the seeds of sedge and spikerush also present, In the 
single Yellowstone cygnet of comparable age, fresh water fairy 
shrimp (Eubranchipus sp.) were represented as well as sedge frag- 
ments. 

The young of the trumpeter have been successfully raised in cap- 
tivity in at least two instances, without natural parental care, and 
under varying conditions. This indicates that their early food habits 
or requirements are not critical or fixed. The first case was demon- 
strated on the Red Rock Lakes Refuge when two were raised by 
Sharp, as mentioned previously, while a pair of month-old cygnets 



124 LIFE CYCLE 

were reared at the Delta Waterfowl Research Station after having 
been transferred from their Red Rock Lakes Refuse natal en- 
vironment. 

In the case of the Refuge cygnets artificially raised by Sharp, 
bantam hens served as both the method of incubation and source 
of parental care. This attention inspired no apparent attachment to 
the foster parent, nor to the humans helping care for the cygnets. 
Initial foods fed in this case were broiler chow, milk curd, and dande- 
lion leaves. Wheat and lawn clippings were added to the diet later. 
Development of these birds appeared comparable to those in the wild 
except for a weakness of the legs, which became apparent after each 
weighed about 10 pounds, and from which they subsequently 
recovered. 

At the Delta Station the month-old trumpeters were successfully 
started on a ration consisting of duck grower pellets, with a constantly 
available supply of lesser duckweed (Lemna minor) serving as the 
green vegetation supplement. Later the leaves and stalks of arrow- 
head were introduced and were much relished, as much as a bucketful 
being consumed by a single cygnet in a day. Upon the exhaustion 
of the local supply of arrowhead, the leaves of cattail were substituted 
with equal success. 

The young developed normally at Delta except again for an ap- 
parent weakness of the leg bones, which supported the body with 
difficulty out of water as the birds rapidly gained weight before the 
bone structure hardened. This weakness was eliminated by per- 
mitting the cygnets access to a supply of swimming water, where 
their body weight was supported much of the time by water instead 
of the individual's legs on the hatchery's cement floor. 

FEEDING HABITS AND FOOD OF OLDER CYGNETS, 
IMMATURES, AND ADULTS 

Even before the development of contour feathers changes the ap- 
pearance of the wild downy cygnets, they seem to rely progressively 
less on food material provided by the adults and become more in- 
terested in obtaining it by their own efforts. At this stage any em- 
phasis on the high protein diet of aquatic insect and crustacean life 
shifts to vegetable foods. Feeding is still accomplished very much 
as a family unit, and after the cygnets are 2 or 3 months old their 
food-gathering actions indicate that their diet is approaching that 
of their parents. 

While the feeding of the cygnets appears to be confined solely to 
water, that of the immature and adult, though predominantly aquatic 
in nature, may include a limited amount of feeding or grazing upon 
land. Audubon (1838: 540) noted, "This swan feeds principally 



FOOD 125 

by partially immersing the body and extending the neck under 
water. . . . Often, however, it resorts to the land, and then picks 
at the herbage, not sidewise, as Geese do, but more in the manner of 
Ducks and poultry."' Swans have rarely been observed feeding on 
land on the Refuge. 

Trumpeters most frequently feed in shallow-water areas where 
they are able to use their long necks to the best advantage, or if deeper 
water is encountered they may "tip up"' in the manner of puddle 
ducks. Although they are quite capable of diving and swimming 
under water, they apparently resort to diving solely to escape when 
flightless. 

Oberhansley and Barrows (MS) contribute an interesting note on 
the feeding of a pair of trumpeters within Yellowstone Park, writing, 
"A typical observation on September 18 of a pair of swans feeding on 
a small lake near Madison Junction showed 2 birds suspending 15 and 
13 times respectively in 30 minutes. . . . There was no system of 
timing, sometimes both birds submerged alternately and again simul- 
taneously; neither appeared to be on guard." This description also 
typifies the feeding of trumpeters in the shallow water areas of the 
Refuge. 

Tubers and rhizomes of the various aquatic plants are a staple food 
item, along with the stems and leaves of such plants, and the swans 
spare no effort in excavating for these starchy plant parts. Their 
powerful legs, large webs, and prominent toes are especially efficient 
in stirring up the soft mud of their shallow marsh environment. 
Great holes, sometimes over a foot deep and several feet in diameter, 
on the shallow bottoms of the Red Rock Lakes marsh bear witness to 
this method of exposing food materials. 

Erickson describes the feeding of the Malheur captive flock 
(correspondence) : 

Swans are also disposed to feeding along the shorelines and river hanks, where 
they gouge out and undermine the hanks in search for roots and shoots. Their 
stout, muscular necks and heavy bodies aid them in performing major ex- 
cavations when undercutting the hanks. In the swan pond they have heen 
successful not only in eliminating much of the hardstem bulrush growth, hut 
also in the destruction of the tough root stocks of the tule. 

Many references to the food habits of the native swans are to be 
found in the early literature. It will be recalled that I,e\vis and 
Clark noted that both species of swans fed much on the root of the 
"wappatoo" in the Columbia. River. 

Later observers confirmed Lewis and Clark's statement 
that the swans fed much on the root of the wapato or duck 
potato. George Barnston of the Hudson's Hay Company noted that 
(1862: 7831), "In the scarcity of their favorite food, the tubers of 



126 LIFE CYCLE 

the Sagittaria sagittifolia [probably S. lati folia], they have recourse 
to the roots of other plants, and the tender underground runners of 
grasses in the higher latitudes." J. C. Hughes (1883:283) also 
recorded that along the Columbia River the favorite food of the 
trumpeter was the wapato, listing the species as Sagittaria variabilis 
[probably S. latifolia], stating that a Mr. Allard observed a trum- 
peter which had been strangled by a large tuber of this plant which 
had become lodged in its throat. 

A. C. Bent (1925: 286) quotes Major Bendire as stating that about 
"20 small shells, perhaps half an inch in length" were found in a 
stomach of a whistling swan, while E. S. Cameron was noted to have 
observed this species to feed, presumably in Montana, as follows : 

The swans were engaged in feeding upon the soft-shelled fresh-water snails 
which abound in this lake and explain its great attraction for them. During the 
several days that I watched the swans I never saw them eat anything else, but 
doubtless they pick up vegetation as well, being accustomed to walk about in the 
grass at the mouth of Alder Creek. Marsh Lake is so shallow (only 2 feet deep 
over most of it, and 4 feet in the deepest part) that the long-necked birds can 
generally reach the mollusca without much tilting of their bodies in characteristic 
swan fashion. 

In a recent study of the food habits of whistling swans wintering 
in the Chesapeake Bay region, Robert E. Stewart and Joseph H. 
Manning (1958: 209-210) examined the gullet and stomach contents 
of 49 birds. They report : 

In the series studied, submerged aquatic plants furnished 100 percent of the 
food in fresh estuarine waters, 60 percent in brackish waters, and 47 percent in 
estuarine marsh ponds. Mollusks [chiefly long clams and Baltic macomas], 
although comprising 31 percent of the food in brackish estuarine waters, were 
not listed for other types, while rootstalks and stems of emergent marsh plants 
were important only in the estuarine marsh ponds. 

Witherby et al. (1939: 177) mention that the mute swan has been 
noted to eat "small frogs and toads, tadpoles, worms, fresh-water 
Mollusca, occasionally small fish (Alburnus) and insects with their 
larvae" in addition to its more staple diet of plant foods. Fish were 
also recovered from the gullets of several trumpeters which died at 
the Kellogg Bird Sanctuary in Michigan (Dr. Miles Pirnie, corre- 
spondence), but it is doubtful that these represent a part of their 
customary diet. 

From this, and data to be presented later, it appears that the 
trumpeter will eat a variety of vegetable foods. Mollusca and 
vertebrates do not occur as a staple fare but are apparently eaten 
when readily available. 

Several observers have contributed to the knowledge of the specific 
foods of the trumpeter in Yellowstone Park. Oberhansley and Bar- 
rows (MS) state: 



FOOD 127 

Identification of two principal plant foods (from small lake near Madison 
Junction) was positive and later determined as pond weed (Potamogeton fili- 
formls) and water milfoil. . . . The droppings of adult birds consist almost 
entirely of vegetable matter, with an occasional large quantity of grit. . . . 
Four species of sedges used as food have been identified from Swan Lake, the 
most important of which is Carcx rostrata, which serves also as an excellent 
cover. . . . Seeds of various aquatic plants, principally sedges, were found 
in the stomach of the swan that died on Trumpeter Lake. One small snail shell 
and traces of crustaceans were also present. 

Condon (MS) gives a more detailed list for the swans in Yellow- 
stone Park : 

The principal plant types on which the trumpeter swans have been observed 
to feed as identified by examination of plants taken at various places feeding 
occurred are: Pondweed (Potamogeton, sp. undet.), Water Milfoil (Myriophyl- 
lum, sp. undet.), Musk grass (Chara, sp. undet.), Waterweed {Elodea cana- 
densis), Duckweed (Lemna trisulca), Tules (Scirpus, sp. undet.), Spatterdocks 
( Nymphaea polysepala [Nuphar polysepalum]) , Bur-reeds (Sparganium augusti- 
folium), Wapato (Sagittaria cuncnta). 

In watching the trumpeter swan feeding it was found that they eat the foliage 
of each of the above-named plants. The opportunity to examine the stomachs of 
the adult trumpeter swan for food content has been limited and only one has 
been secured in the past 2 years. This contained all vegetative matter, parts of 
which were identified as being: Muskgrass (Chara), Waterweed (Elodea), and 
Duckweed (Lemna). This stomach contained an ample quantity of quartz and 
obsidian sand grit. 

Collections of droppings . . . from Geode, Grebe. Swan, and Madison Junc- 
tion Lakes . . . were so nearly 100 percent vegetative in character that no 
animal matter was discerned. . . . 

Another interesting item was the abundance of the seeds of the spatter- 
dock ... in the droppings collected from Grebe and Madison Junction Lakes 
where large beds of these plants abound. . . . From one dropping taken at 
Grebe Lake on September 21, 1939, a total of 272 seeds of the spatterdock were 
secured and 497 small seeds from an unidentified plant. All the droppings at 
resting areas at Grebe Lake gave evidence of heavy seed eating. The failure 
to digest many of these seeds was of interest. All seeds were highly polished. 
That the preponderant percentage of the foods eaten by swans are of plant origin 
was evidenced in droppings examined at resting areas on all lakes visited. 

Dr. O. J. Murie, former U. S. Fish and "Wildlife Service biologist, 
collected 17 samples of swan droppings from the shores of Grebe Lake 
on September 2, 1943, and analyzed them. Prominent plant parts in 
these remains included filamentous green alga, sedge spikes, pond 
weeds, and wokas, with traces of animal matter (Tricoptera). 

In 1938, A. V. Hull, who was manager of the Red Eock Lakes Refuge 
at the time, found the fresh carcasses of two trumpeters on the Refuge 
in December and June and sent the stomachs to the Service's Denver 
Wildlife Research Laboratory for analysis. In both, the tubers of 
sago pondweed dominated. In the December-taken bird, with the 
fragments of rootstocks, they comprised 100 percent of the contents 



128 LIFE CYCLE 

(443 tubers) while in the case of the June-taken bird 597 tubers con- 
stituted 90 percent of the contents, with leaf and stem material of the 
same plant bringing the total up to 96 percent. (See appendix 4 for 
an analytical breakdown of data.) 

Earlier, Hull submitted 3 trumpeter swan stomachs taken from 
lead-poisoning fatalities at Culver Springs April 3-7, 1937, on 
the Red Rock Lakes Refuge. White water buttercup {Ranunculus) 
and mosses (Amblystegium and Fissidens) were the most prominent 
plants represented in the 100-percent vegetable contents. (See appen- 
dix 4 for further details.) 

Most of the foregoing information has concerned the food habits 
of the trumpeter other than during the months when they are restricted 
to the limited areas of open water in winter, about which little is 
known. 

An aquatic plant survey along portions of Henrys Fork of the Snake 
River used by wintering trumpeters indicates that the following plants 
are available (in the probable order of their importance to the 
swans) : Sago pondweed, leafy pondweed, water milfoil, white water 
buttercup (Ranunculus aquatUus), marestail, water moss (Fonti- 
nalis), clasping-leaf pondweed, and mannagrass (Glyceria elat-a). 

Munro (1949: 712) notes that in British Columbia their winter 
diet includes the following items: 

From observations of feeding trumpeter swans, it has been determined that 
the following foods are attractive to them, namely, the seeds of yellow pond 
lily, Nuphar poli/scpala, and water shield, Brascnia Schreberi; the tubers of 
sago pondweed, Potamogcton pectinatus, and the stems and foliage of similar 
species. Late in the season, when the supply of more desirable foods is low, 
the birds eat water moss, Fontinalis sp., the stems and roots of sedges, Sci?-piis 
sp., and whatever other aquatic vegetation can be secured. The gullet of an 
adult male that died from lead poisoning at Itatsoo Lake, Vancouver Island, in 
February 1938, was packed with stems of grasses and sedges ; the stomach 
contained 12 seeds of Ceratophyllum demersum. In an examination of the 
stomach contents of seven adults and two juveniles, killed by lead poisoning on 
Vancouver Island in January 1946, Dr. I. McT. Cowan identified the following 
items, namely, stems, leaves and roots of grasses, sedges (Carex sp.), and rushes 
(Juncus sp. ), seeds of Polygonum sp., Carer sp., and wild cherry (Prunus 
cmarginata). Another from Steveston, at the mouth of the Fraser River, had 
eaten grass roots, and seeds of a spike rush l Eleocharis sp. ). 

Swans kept in captivity adjust their food habits to whatever is 
available. Their bulky-green-food requirements usually cannot be 
entirely met with the limited supply of aquatics available, and some 
sort of supplementary feeding becomes necessary. At the Malheur 
Refuge, where a number of trumpeters were kept for several years on 
a fairly large spring-fed pond, a daily ration of barley and wheat 
supplemented their natural green foods, which they obtained either in 
the pond or by gouging roots and rhizomes from the banks. 



FOOD 129 

At the Delta Waterfowl Research Station, the green-food require- 
ments of the trumpeters in summer are met largely from the endless 
supply of duckweed which floats through the pens, as well as the 
occasional addition of the leaves and stalks of arrowhead. Their main 
diet requirement is provided in the form of wheat, soaked and fed in 
automatic dispensers. In the winter they are fed wheat, duck pellets, 
and lettuce trimmings. 

Bulk green foods fed in quantity may be important when reproduc- 
tion is desired in captive birds. This point was stressed by Mr. C. L. 
Cunningham, a successful breeder of swans at Woodinville, Wash- 
ington, who advised that his captive swans, including the whooper, 
mute, black-necked, and black, daily consumed enormous quantities of 
fresh lawn clippings before the egg-laying season and that this 
plentiful supply of bulk green food was all-important in bringing 
his birds to a breeding condition. In this regard, the Heinroths 
(1928 : 149-150) also mention that whooper swans in zoos rarely pro- 
duce fertile eggs. They cite Blaauw's success in propagating trum- 
peters, giving them abundant greens in the form of watersoldier 
{Stratiotes) before the nesting season. Similar results were obtained 
with whoopers in Berlin by feeding cabbage and other greens. The 
nutritional requirements of the swans are unknown. This may ex- 
plain in part the generally poor breeding success experienced more 
recently with the trumpeter in captivity. 

A number of swan studies have been conducted by various govern- 
ments over the years at the insistence of fishermen and sportsmen who 
accused these birds of interfering with livelihood or sport.. In Ger- 
many, a food habits investigation of mute swans was conducted by the 
Reich Health Administration before World War II (Hilprecht, 1956 : 
96). In 1954, Danish sportsmen instigated a study of mute swans in 
their country, claiming wild duck production was being adversely 
affected by the aggressive behavior of the swans on mutual nesting 
habitats (Paludan and Fog, 1956). 

In the United States, several swan studies have been carried out 
from time to time as the result of complaints to the Federal Govern- 
ment. As early as 191!), W. F. Kubiehek conducted a field survey in 
Currituck Sound, N.C., for the U. S. Biological Survey, investigating 
charges that the large number of whistling swans which winter in this 
area were consuming most of the natural aquatic foods, leaving little 
or none for the ducks. A study with a somewhat similar objective is 
currently in progress on the Bear River Migratory Bird Refuge, Utah, 
under the direction of the Cooperative Wildlife Research Unit at 
Logan. The study of the food habits and status of whistling swans 
in the Chesapeake Bay area by Stewart and Manning ( 195s : 203-212) 
was undertaken in pari to obtain information to answer the charges 



130 LIFE CYCLE 

by sliellfishers that these birds were making inroads in the commercial 
clam beds. 

In all cases, either in this country or abroad, the swans were sub- 
stantially cleared of these charges, although in certain instances some 
inimical relationships were noted. 

LIMITING FACTORS 
EGG FAILURE 

The hatching success of trumpeter swan eggs on the Red Rock 
Lakes nesting marshes has been low compared with that of 
lesser waterfowl. In 1949 for instance, 30 of 61 swan eggs laid 
in 12 nests failed to hatch — a loss of 49 percent. In 1951, the 
loss was 34 percent in the 13 nests checked, when 25 eggs remained 
in the nest from a total of 78 incubated. Examination of ITS eggs in 
36 nests in 1955 revealed that 36 percent failed to hatch for one reason 
or another. Thus, in the limited number of cases studied, hatching 
varied from. 51 to 66 percent. In Denmark the hatching rate of the 
eggs of wild mute swans was about 60 percent as reported by Paludan 
and Fog (1956: 44). In studies of the trumpeter on the Kenai 
Peninsula, Alaska, Spencer (correspondence) reports about a 65- 
percent hatching success in a limited number of clutches. 

For various reasons, the roles played by infertility and mortality of 
the embryo in the trumpeter egg are not known. Often the embryo 
has died after it was well developed. In such cases, incubation 
may have begun before egg laying was completed, or the eggs failed 
to hatch together for other reasons. The trumpeter pen then ap- 
parently departed with the cygnets which hatched first. Other causes 
of egg failure are even more obscure. These undoubtedly include 
cases of infertility or physical handicap, fatal chilling of the embryo 
after incubation has commenced, or abandonment of the nest before 
incubation has been completed. Loss of productivity due to egg fail- 
ure is a major factor in the present low production of cygnets on 
the Refuge. 

Predation is not important to hatching success on the Refuge. In 
the data presented, for a total of 61 nests observed in 1949, 1951, and 
1955, not a single case of predator-caused egg loss was observed. Only 
4 nests containing predator-destroyed eggs have been found in the 7 
seasons during which swan nests have been examined. Furthermore, 
eggs which failed to hatch remained exposed but unmolested in the 
nest long after incubation had been terminated. 

In Yellowstone Park, however, a number of random studies and 
observations made through the years show that egg destruction by 
predators apparently occurs to a significnnt degree. Joseph Dixon 
(1931:454) writes: 



LIMITING FACTORS 131 

The pair of swans which Mr. Wright and Mr. Thompson watched at Tern Lake 
on June 11, 1030, were not successful in driving off the marauding ravens, for 
when the mother left to feed, a raven appeared and was observed to fly directly 
to the nest. . . . Mr. Wright recorded in his notebook what took place, as 
follows, "At first the raven just poked about in the nest with its beak. . . . 
It stuck its head down once more and pulled from an egg in the nest a long 
pink and whitish object, apparently an embryo from one of the swan eggs, and 
started to fly away with it just as the parent swans rushed back and drove it 
away from the nest." 

Condon (MS) records an incident of nest destruction by a bear, and 
George M. Wright and Ben H. Thompson (1935: 34, 35) furnish an- 
other account : 

A black object loomed by the swan nest. With field glasses glued to our eyes, 
we saw that it was an otter stretching its full length upward to peer down into 
the nest. From one side it reached out toward the center and pushed aside the 
material covering the eggs. Then the commotion started. With rapt interest, 
the otter rooted around in the dry nest material, heaving up here and digging 
in there, until it was moi-e haystack than nest. Then the otter started to roll, 
around and around, over and over. This went on for a number of minutes. At 
frequent intervals its long neck was craned upward, and the serpentlike head 
rotated around to discover (we supposed) if the swans were returning. At 
last the otter seemed to weary of this play. It climbed from the nest to the 
outer edge, then slid off into the water. ... It never turned back, and was 
finally lost to sight. . . . Seeing that the damage was already done, and another 
year's potential swan crop for the Mirror Plateau lost irrevocably, we saw no 
further reason for caution. So we stripped off our clothes and waded out across 
the shallows. We were amazed to find all five eggs intact. There they were, 
all togethe", rolled to one side, but perfectly whole. . . . We covered the eggs 
and hurried away in confusion as huge hailstones pelted our bodies. We hoped 
that the parents would return to protect the eggs from chill. The storm ob- 
scured the scene, obliterating the next chapter in the story. Later we learned 
from ranger reports that no cygnets were raised on Tern Lake that year. Which 
meddler should shoulder the blame, the otter or the scientist? 

Even in Yellowstone Park, the low hatch is due principally to causes 
other than predation. Observers agreed that human intrusion was 
the most significant known cause of v^ failure in the Park. 

PREFLIGHT CYGNET MORTALITY 

Although the relative paucity of predation records on swans of 
flying age indicates that predation is of little consequence in determin- 
ing overall swan population levels, it may be an important cause of 
death to preflight cygnets. Swan broods sutler serious losses in both 
the Red Rock Lakes and Yellowstone Park breeding populations. 
While casualties of preflight youngsters may approach or possibly 
exceed 50 percent during some years, very little is known regarding 
causes of such mortality. 

The information in table 6 is believed representative of the overall 
cygnet mortality on the Refuge during 1040. Since some of these ob- 



132 LIFE CYCLE 

serrations were accomplished at distances over 2 miles with a 20 X 
spotting scope, counts may not be absolutely accurate for any given 
count and brood. A high degree of accuracy was achieved by frequent 
observations over a period of 3 months, and as the cygnets became 
larger and moved in a less compact brood, tabulation was easier and 
more accurately made. The habit of swan families to remain in the 
nesting territory until the approach of flight age, plus the characteris- 
tic of each family to remain apart from other similar groups, makes 
the accurate tally of cygnet mortality by individual brood possible. 

In the broods under consideration, mortality was widespread and 
significant, with losses heavier among the newly hatched cygnets than 
among those approaching flying age. The causes of these losses are 
undoubtedly varied but unknown. Perhaps because the remains of a 
small cygnet resulting from a kill are few and inconspicuous and may 
be entirely consumed by predator or scavenger, few records are avail- 
able regarding specific predation on young cygnets in Red Rock's 
marshes. 

In 1949, 1 saw a large gull kill one cygnet and wound another after 
the young were separated from the parents. The old swans were dis- 
tracted by my presence in the boat, and failed to defend their young. 
Normally, the young cygnets remain very close to their parents, and 
without my presence, the attack would not have been made, or the 
parent swans would probably have repelled it. 

In Yellowstone Park the opportunities for discovering the remains 
of dead cygnets are greater than in the large marshes of the Red Rock 
Lakes. Condon (MS) furnishes a specific account: 

Those cygnets on Swan Lake, however, are thought to have been killed by 
a large male otter, whose presence there was discovered on July 10, 1989, when 
a thorough survey of this lake area was made in an endeavor to locate the lost 
cygnets, and the cause for their disappearance. One cygnet was found dead and 
floating in the lake near the northwest bank within ten yards of the swan nest- 
ing site. This cygnet, upon examination, revealed a crushed sternum, ribs, and 
two tooth punctures. . . . The otter den was located on the east bank of the 
lake and at several sites anmnd the lake otter droppings were collected that 
contained down, bones, leg and foot skin. These fragments were examined in 
the laboratory and compared with the down and leg skin from the cygnet found. 
The comparison revealed that these undoubtedly came from a swan cygnet, and 
it is felt that in this instance the otter was responsible for the loss of part, if not 
all of the family of five cygnets from Swan Lake. 

Although otters have only rarely been reported from the Red Rock 
Lakes Refuge, minks have at times been suspected of cygnet preda- 
tion. Sharp relates in a Refuge report : 

A family of mink worked at the Idlewild boat pier during late July. I counted 
36 coots and 31 ducks and 1 young muskrat that were dragged upon the pier 
along the edges of tall overhanging sedges. A family of three cygnets that used 
this area disappeared during this time. 



LIMITING FACTORS 
Table 6.— Cygnet mortality at Red Rock Lakes Refuge, 1949 



133 





Eggs 
hatched 






Number of cygnets observed per 


brood 




Nest 


June 


July 


August 




21 


30 


6 


14 


21 


28 


6 


15 


19 


30 


No. 1 


3 
3 

5 
3 

4 
4 
4 
1 
3 
1 


3 

3 

2 
4 
1 







3 
3 

5 
2 
4 
1 
4 

2 



2 
3 


3 
4 


4 

2 



2 
3 
3 
3 
4 

4 





2 
3 
3 
3 

2 

4 

2 



2 
3 

3 
3 
1 
1 
4 

2 




3 

3 
3 

1 
3 

2 



2 
3 
3 

1 
1 
2 

3 



2 
3 
3 
3 
1 
1 
2 





2 


No. 2 


3 


No. 3 


2 


No. 4 


3 


No. 5 


1 


No. 6 


1 


No. 7 


2 


No. 8 





No. 9 


3 


No. 10 









Total 


31 




















17 




5 
3 






1 
1 


2 
1 


2 

1 


1 
1 


1 
1 


1 
1 












1 






1 









With the exception of minks and skunks, no mammalian predators 
of any consequence are to be found in the dense, sedge-covered, soft 
bog-marshes of the Red Rock Lakes. Though dead cygnets are occa- 
sionally discovered on the. water areas, they are. invariably intact, with 
no evidence of predation. The densely vegetated shores preclude a 
systematic search. 

Although gulls, falcons, eagles, and ravens are occasionally sighted 
over the marsh during the summer, they have never been seen molest- 
ing the swans, either young or old. Presumably, the usual close 
swimming and feeding formation of the swan family presents little 
opportunity to the predator, with the size and potential defense 
capabilities of the adults an obvious deterrent. Although great 
horned owls have been mentioned as possible predators, no record 
exists. 

MORTALITY OF IMMATURES AND ADULTS 

Except for man, trumpeters in the wild appear to have few impor- 
tant natural enemies after Hying age is reached. Roth golden eagles 
and coyotes may take swans of any age class under certain local con- 
ditions which present favorable opportunities. Even in such cases 
it is doubtful whether the trumpeter is a normal prey of either 
eagles or coyotes with any degree of regularity. Some of the 
captive trumpeters at Malheur and Ruby Lake Refuges have been 
lost to bobcats on several occasions. The following instances outline 
the circumstances under which losses have occurred among unconfined 
trumpeters. 

The natural enemies and causes of mortality, especially parasites 
and diseases, of other swans arc discussed in detail in Hilprecht 
(1956:101-107). 



134 LIFE CYCLE 

Avian predation : Probably the only winged predator capable and 
willing to tackle a full-grown swan in flight is the eagle. Apparently 
even these great raptors will attempt this only occasionally. 

On several occasions, eagles have been observed to knock trumpeters 
out of the air and kill them. Sharp (1951 : 225) witnessed the follow- 
ing cases of eagle predation on cygnets of flight age concentrated on 
their Red Rock Lakes winter feeding waters, writing: 

On one occasion in late November of 1044 the writer observed one of the eagles 
[golden] make three stoops over a flock of swans on a snow covered meadow. 
The swans stood motionless and apparently had no fear. This eagle was ap- 
parently sporting over the swans as no kills had been made up to this time. . . . 
A cygnet was killed at Culver Pond on December 2b", 1944, and another was struck 
in the air and killed on January 1, 1945. ... A total of three cygnets was 
killed during this winter. 

A local rancher in that area, James F. Hanson, reports occasional 
harassment of the trumpeters by eagles, but only rarely a killing. 

Henry W. Baker, Jr., Superintendent of the Federal fish hatchery 
near Ennis, Montana, provides an eyewitness account of eagles kill- 
ing a swan in the Madison Valley (correspondence) : 

When first observed, the encounter was approximately 1,000 feet elevation. 
The two eagles worked together, first one would hit the swan and then the other 
until they brought it to the ground, at which time they both attacked it . . . 
killing it in the matter of a couple minutes. I was approximately 600 to 700 
yards distant at the time. 

Ralph Edwards (Holman, 1933: 169-211), the early settler of 
Lonesome Lake, British Columbia, relates, "I have noticed during the 
hard winters that the grey ones fall prey to the eagles and starvation 
before the white ones. This winter I have seen two cases of eagles 
killing swan. The eagles do not seem to be able to catch the swan 
when they are stronger or on a straightaway flight." 

Though eagles can and apparently do kill adult swans on occasion, 
the effect on overall trumpeter numbers is believed insignificant. To 
my knowledge, no other winged predator has ever been observed to 
prey upon adult swans. 

Mammalian predation: Swans may occasionally be molested by 
coyotes, but direct evidence that they have actually killed swans still 
is lacking. Even in Yellowstone Park, where coyote populations exist 
at natural levels, reports of actual kills are nonexistent. Condon 
(1950: 1, 2) reports some ineffective coyote molestation: 

During the fall of 1947 after Swan Lake had frozen over it was common to 
see a lone pair of trumpeter swans resting on the ice. . . . The tracks in the 
snow showed that their siesta was interrupted by a coyote which . . . appar- 
ently was either persistent, hungry, or just playing a game, for it had each time 
approached cautiously to some point where it was screened by a cinque-foil 



Limiting factors 135 

bush or clump of grass at the ice's edge and then had made a dash toward the 
resting swan. Each time failure was its lot. 

Dr. Adolph Murie (1940: 135), after a thorough study of coyote 
prey relations in Yellowstone Park, wrote : 

At some of the lakes where swans have been raised, coyotes are concentrated. 
At Trumpeter Lake, where seven cygnets were raised in 1936 and again in 1937, 
coyotes and coyote signs were frequently noted at the lake. . . . The only evi- 
dence of waterfowl predation consisted of some remnants of a green-winged teal 
found on the bank and in one dropping. 

Dr. Murie concluded his field study and a review of available infor- 
mation on the subject within the Park by writing, "It was rather un- 
expected to find that the coyote in Yellowstone exerts no appreciable 
pressure on the trumpeter swan population. . . . The data avail- 
able at the present time indicates that the coyote does not represent an 
important mortality factor for the trumpeter swan." 

At the Red Rock Lakes Refuge, too, no definite coyote kills of 
swans have been recorded, though Hull (1939: 381) states, "During 
the winter coyotes have been known to capture adult swans in deep 
loose snow before the birds were able to get into the air or open water." 
Sharp also reported, "Ranchers hauling hay off the refuge near 
Upper Red Rock Lake reported seeing coyotes on two occasions 
flush swans off the ice or snow 7 . In both cases, the swans were too alert 
and agile in the take-off to allow the coyote to come close to a catch." 

From the foregoing evidence it is concluded that the coyote is not 
an important predator of trumpeters, either in Yellowstone Park or 
on the Red Rock Lakes Refuge. 

Condon (MS) also relates a case where circumstantial evidence 
pointed to a bear as the suspected killer of an adult swan in Yellow- 
stone Park, writing: 

a dead male was found floating near the northwest shore of Fern Lake. ... A 
thorough examination of this bird revealed a transverse cut straight across the 
breast region 6 inches long and 1*4 inches deep. . . . After inspecting the area 
around Fern Lake where this swan was found, I concluded that a bear was, in 
all probability, responsible for its death. There were abundant fresh signs of 
bear around the lake and the extensive damage done the swan seemed greater 
than that which any other animal might inflict. 

From the foregoing testimony it would seem that 4-footed pred- 
ators are even less effective than their avian counterparts in preying 
upon swans of flight age. 

Hunting. From the earliest times on this continent swans have 
been taken by the native peoples by whatever method was available, 
snare, arrow, or gun. Though the primitive peoples presumably 
killed principally for food, the white man also killed the swan in 
great numbers over wide regions of its range not only for domestic 

4(»!»GG0 O— 60 10 



136 LIFE CYCLE 

needs but also because of the ready commercial market established 
for its down and quills. Man is, by far, the greatest enemy with 
which they have had to contend. 

Although the enactment of the Migratory Bird Treaty Act by the 
United States Congress in 1918 made it illegal to kill either species of 
our native swans, shooting and lead-poisoning still account for more 
casualties, in the case of the trumpeter at least, than the aggregate of 
all other known causes of adult mortality. 

During the last 20 years, illegal kills of trumpeter swans have oc- 
curred chiefly during the open waterfowl season in Idaho along 
Henrys Fork of the Snake River and its tributaries, and to a lesser 
extent in Montana and Wyoming. Since trumpeters commonly fly 
along the water courses at a low level, they furnish a conspicuous tar- 
get well within range of waterfowl hunters, many of which cannot 
resist the temptation to shoot. The kill is believed to have increased 
in the past decade with the appearance of greater numbers of nimrods 
afield. 

Fifteen years ago, Condon recognized this danger to the swan pop- 
ulation in the Yellowstone region, stating (MS) : 

That there is a definite mortality among the swan due to shooting by hunters 
during the open season on waterfowl is evidenced not only by the above in- 
cident [that of finding a swan containing shot in the Park] but by the arrest 
and conviction of hunters in Idaho and Montana for killing trumpeter swan. 
Many instances of this type have come to light and undoubtedly many are shot 
that no one knows about. . . . Adults known to have lost their lives at the 
hand of man far exceed the records that we have of death due to natural causes. 

In an effort to determine the gunning pressure to which the trum- 
peters are subjected while on their comparatively unprotected winter 
ranges, the U. S. Fish and Wildlife Service arranged with the Illinois 
Natural History Survey to make a fluoroscopic examination of a num- 
ber of swans during their flightless molt on the Red Rock Lakes 
Refuge. Frank Bellrose of that survey supervised this investigation 
in the summer of 1956, using a portable fluoroscope borrowed from 
the Delta Waterfowl Research Station, Delta, Manitoba. 

During the period July 20-28, 100 trumpeters from the Refuge's 
nonbreeding population were examined fluoroscopically by Bellrose 
to determine the presence of lead shot. In addition to this sample, 
I subsequently examined 3 birds in August. 

Of the 103 trumpeters thus inspected, a total of 15 (14.6 percent) 
were found to be carrying lead shot. Numbers of shot present in 
any individual bird varied from 1 to 9 and included shot sizes ranging 
from 7y 2 ' s to BB's with 2's and 4's most common. Of 4 swans banded 
in 1951 or earlier, 2 were carrying lead. Owing to the large size of 
these birds and the difficulty of locating the shot on the dimly il- 



LIMITING FACTORS 137 

himinated fluoroscopic screen, some may have been missed. Thus, 
it is probable that the actual percentage of swans carrying lead shot 
was somewhat greater. 

The actual number of trumpeters killed each year in their United 
States range is unknown, but it probably exceeds 25. The number 
of known swan casualties was 17 in 1933 (Beard et al., 1947 : 140) and 
19 in 1939 (Condon, MS). The average number of swans known to 
have been lost to hunting during later years continues to be serious. 
The known loss was reported to be 23 in 1951, IT in 1952, and only 9 
in 1953. In 1955, Eddie Linck, the Idaho State Fish and Game 
Officer covering the Island Park area, estimated a total of 25 trum- 
peters illegally killed in that area alone, with 12 casualties known 
for certain. According to Walton Hester, conservation officer for the 
Island Park district in 1956, a known loss of 15 hunter-killed swans 
occurred with at least another 5 estimated as being taken. Mr. 
Hester also expressed the thought that some of the cygnets may be 
selectively shot for food, since the adults are noted for their general 
unsavoriness. Evidence supporting this view is lacking. 

The concern of those interested in the welfare of the trumpeter 
resulted in the appointment of a new U. S. Fish and Wildlife Service 
enforcement agent in eastern Idaho in 1956, principally to cope with 
this illegal killing of trumpeters while on their main wintering 
grounds in the Island Park area. Increased local publicity in the 
past few years via radio, TV, newspapers and posters has focused 
attention on the problem. It is hoped that the increased attention 
will serve to stop the indiscriminate killing of these birds. 

Lead poisoning. This factor is irrevocably related to hunting and 
causes mortality among swans that feed, even for short or intermit- 
tent periods, in habitat shot over in previous years. Hull recovered 
4 trumpeters which died on their Refuge feeding grounds at Culver 
Pond during late March and early April, 1937. Material from these 
birds was sent to the Denver Research Laboratory where E. R. Kalm- 
bach diagnosed the fatalities of 3 as due to lead poisoning. The 
gizzard pads of all 3 exhibited the characteristic greenish coloration 
and hardening, with the contents containing 3, 11, and 17 pellets 
respectively (0.248, 0.498, and 0.857 grams of lead). In the fourth 
case, Hull made a similar diagnosis, with 19 pellets in the gizzard of 
the dead bird lie examined. Xo other trumpeter cases have been re- 
ported in the United States. No hunting has been permitted on the 
wintering waters of the Refuge since it was established in 1935; 
hence, the possibility of further losses is lessened. 

In British Columbia, the problem of lead poisoning among winter- 
ing flocks of trumpeters has presented a recurring threat. J. A. 
Munro (1949) documented the loss of at least !> trumpeters of the 



138 LIFE CYCLE 

Vaseaux Lake wintering: population in 1925. These birds were forced 
out of their regular winter quarters by ice and used other open waters 
which were heavily contaminated with lead shot. The stomach con- 
tents of 1 of these victims contained 451 shot. More of this group 
were believed to be subsequent victims of ingesting lead shot on this 
occasion, as only 6 of the original group of IT returned to Vaseaux 
Lake the following winter and the flock later disappeared completely. 
Munro also records the loss of at least 13 trumpeters from a flock 
of 15 wintering on Vancouver Island in 1946. The stomach tracts 
of these victims held from 2 to 29 pellets each. 

On Idaho's lower Coeur d'Alene River, a form of metallic poison- 
ing diagnostically similar to lead poisoning has resulted in irregular 
but substantial mortality in the waterfowl over the years. Whistling 
swans, stopping in migration, have occasionally suffered heavy losses 
in this area, but as contamination is local these losses have never 
involved trumpeters. 

Weather and mortality. Unseasonally cold weather undoubtedly 
affects hatching success and survival of trumpeter cygnets. These 
effects are not completely known, but some influences have been 
observed and are cited here. 

Cygnet Development vs. Weather. Uneven development rates 
of cygnets are not uncommon and, when combined with late hatching, 
result in some loss when the ice forms earlier than usual. The 
average hatching date on the Red Rock Lakes Refuge is about June 
20. Over 100 days is normally required for a cygnet's development 
to flight age, and the Refuge has become icebound as early as October 
28 (twice) with November 8 the 16-year average (1938-1953). 

Final freezeup is invariably preceded by a period when ice is 
prevalent over the marsh and lakes, so development may be retarded 
in the critical preflight stage of the growing cygnet through food 
shortage and injury to the wing from hitting the ice during 
flight attempts. Although it is possible occasionally to rescue such 
birds, as well as unharmed individuals which have simply not ma- 
tured sufficiently to fly, it can hardly become a regular practice, since 
travel conditions on the new ice over the vast river and marsh area 
are often treacherous by foot and impossible by boat. 

In 1949 at least 20 cygnets on the Refuge were still incapable of 
flight by October 15. Fortunately, the final freezeup did not occur 
until November 18 that year. This additional time may have allowed 
all of these particular cygnets to develop sufficiently to fly. 

Condon raises a point about some other hazards, found in Yellow- 
stone Park : 

One factor that may contribute to cygnet mortality after they reach flying 
age is that many of the lakes on which the swans establish themselves are small 



LIMITING FACTORS 139 

and may not offer sufficient space for them to learn to fly well, and when the 
families leave these lakes they must fly for some distance over land before 
reaching water upon which to alight and on such occasions cygnets may become 
fatigued, fall to earth and may not again get into the air. It is felt that 
such was the fate of one of the cygnets from Geode Lake in early October 
1939 and that such mishaps may occur more often than we think where lakes 
are small and separated by rough canyons and timbered areas such as exist 
on the north side of Yellowstone Park. 

Mortality of Grown Birds. The formation of ice over normally 
open wintering waters, as a result of very low temperatures, may pre- 
vent adult swans from feeding in these traditional locations. When 
this ice remains for a prolonged period, starvation may result rather 
than movement out of the region to where food may be available. 
Such instances seem to be rare within the United States however, 
judging from the lack of evidence or reports. Dr. Olaus J. Murie 
documents such an occurrence (correspondence) : 

A number of years ago (March 22, 1932) I found two dead swans north of 
Moran in Jackson Hole, where they had been wintering in a small piece of open 
water on a stream (Second Creek) near Jackson Lake. They had evidently 
starved to death since they had eaten all the available food in that little piece 
of water. . . . The male weighed 18 lbs. 4 oz. The female 16 lbs. 12 oz. 

As a general rule in the major Island Park-Eed Rock Lakes- 
Yellowstone wintering habitat, at least some open water and food are 
available to swans wintering in these warm spring-fed water areas. 
This is true even during prolonged periods of winter weather where 
nightly minimums drop below — 20°F. Though food supplies are un- 
doubtedly short until moderating weather arrives, they never fail 
entirely, and I know of no other cases of trumpeter starvation in this 
country. 

In British Columbia, starvation has caused greater losses of 
wintering trumpeters. Munro (1949:713) records: 

The number of trumpeter swans dying from starvation in winters of more 
than average severity probably is a significant factor in population reduction. 
Many swans winter in sub-marginal territory where food is not abundant at 
the best of times and may become completely inaccessible at times of sub-zero 
weather, or at periods of high floods. In such times the swans stay on. in what 
probably is their ancestral wintering ground. to starve or to become, in their 
weakened state, victims of predators, rather than seek feeding grounds else- 
where. The situation is being met to some extent by artificial feeding, as has 
been noted, but winter populations in remote and inaccessible territory cannot 
be helped in this way. 

Swan mortality resulting from the icing up of swans' plumage by 
severe winter weather has also been reported from Canada, though 
never to my knowledge from the United States. The notes of O. J. 
Murie record this instance related to him by Dave Hoy, a river 
freighter familiar with wintering trumpeters: 



140 LIFE CYCLE 

Fort St. James, B. C, June 13, 1934, Mr. Hoy says that a number of years 
ago the trumpeter swans numbered 250 or more but they winter killed. He 
says the water does not freeze over for long but the short period of freezing 
may be fatal. About three years ago a number got frozen into the ice. They 
were found in that condition on a number of occasions, eaten by coyotes. Slush 
ice would gather on their wings so they could not fly. 

The icing of swans' plumage has never been reported from the Island 
Park area where slush ice is seasonally common on the streams fre- 
quented by wintering trumpeters. The water-shedding capacity of a 
swan's plumage is definitely related to the overall health of the indi- 
vidual, so it is difficult to see how the plumage of a healthy adult swan 
could collect ice, or how such an individual would allow itself to 
become frozen into the ice no matter how severe the weather might 
become. Low food supplies may play the determining role in such 
cases. 

Disease. Trumpeter swans within the United States exhibit the 
alertness and vigor associated with most wildlife populations. Dead, 
sick, or weak birds are rarely observed without reason for their 
condition being obvious, and disease does not appear to contribute 
significantly to mortality in the wild. 

While disease has apparently never been reported in adult wild 
trumpeters, small cygnets occasionally possess deformities of their 
feet, Sharp stated in a Service report : 

Three nests did not hatch and a fourth failed due to feet deformities of the 
cygnets. The latter nest, when checked on the Upper Lake, had three dead 
cygnets and another alive on the nest. Careful study revealed that the living 
cygnet could not stand. An examination of its feet showed that they were 
pitifully deformed. Then the dead cygnets were examined, and their feet were 
deformed in a similar manner. 

A cygnet which I rescued from a gull's attacks possessed a deformed 
foot as described by Sharp. On the other hand, the broodmate of 
this cygnet, which was killed by the gull, had normal-appearing feet. 
This abnormal condition may be a cause of some mortality in 
preflight age classes, since it has not been noted with the older 
trumpeters. 

The incidence of several diseases has been reported from trumpeters 
in captivity. Confinement often increases the opportunities for sick- 
ness and infection, and facilitates the observations of afflicted birds. 
One of the adult trumpeters at the Delta Station died during the win- 
ter of 1955-56 after displaying signs of weakness and sickness, one of 
which was trouble in keeping its plumage dry and free of ice. A 
thorough postmortem examination was not possible at that time, 
though symptoms of both aspergillosis and fowl cholera were appar- 
ently present. 

Dr. E. M. Dickinson of the Veterinary Department of Oregon State 
College found and cultured bacilli typical of avian tuberculosis from 



LIMITING FACTORS 141 

a captive trumpeter at Malheur Refuge which exhibited the lesions 
of this disease, dying there apparently of this cause. Several other 
losses in the Malheur trumpeter flock had these symptoms, although no 
successful testing for this disease was developed. Three casualties 
listed for the Ruby Lakes trumpeter flock were attributed to avian 
tuberculosis. The greatest incidence of loss in these cases seemed to 
occur in the younger age groups, especially those less than a year old, 
with a reduced rate of loss as the birds grew older. A more recent 
trumpeter loss at Malheur in 1956 was diagnosed by Dr. Dickinson as 
having aspergillosis. 

Of the captivity record of the trumpeters which have been kept at 
the New York Zoological Park, William G. Conway (correspondence) 
advised, "Four specimens are said to have died of aspergillosis ; . . . 
two, probably, from botulism." Since the natural conditions neces- 
sary for botulism contamination do not normally occur in the Red 
Rock Lakes-Yellowstone region, this sickness has never been reported 
in the native trumpeter flock, but in late October 1957 two cygnets in 
Malheur's captive flock apparently died from botulism. In one case 
the diagnosis was fairly certain, while in the other the evidence was 
only circumstantial (David Marshall, correspondence). 

Dr. T. T. Chaddock (1938: 25) examined 8 wild whistling swans 
postmortem, from April-June carcass recoveries in "Wisconsin, report- 
ing the presence of aspergillosis (in 4), pneumonia (in most), silicosis 
(in 2), "dropsy" (in 2), besides parasites (in 5) plus other pathological 
factors. 

Parasites. Trumpeter swans, in common with other wild species, 
are frequent hosts to various parasites. Judging from the occurrence 
of parasites in other fauna, the level of any given parasite population 
is usually determined more by the general health of the host than by 
any other single circumstance. Healthy birds normally support, low 
numbers of parasites, while sick or weak birds frequently exhibit 
heavy infestations. In the latter instances, while parasites may com- 
bine with other factors to hasten death, they are usually considered 
only a contributing cause of mortality. Thus, there seems sufficient 
justification to document several cases in which parasites were either 
believed to have caused mortality or were present in such numbers 
that they probably contributed substantially to the reported sickness 
or death. 

Dr. Ian McT. Cowan (1946: 248, 249) stated that the death of a 
wintering British Columbia trumpeter found in a weakened condi- 
tion near Vanderhoof, B. C, was due to gross multiple parasitism. 
He relates, "Both the cestode Hymenolepis and the filarial nematode 
Eurycerca were present in numbers apparently sufficient to induce 
pathological changes in the host, and it is not possible to determine in 
this case which of the two was most harmful." 



142 LIFE CYCLE 

In another instance Cowan found the white swan louse Ornithobius 
cygni abundant in the plumage, and 3 specimens of Eurycerca in the 
heart muscle of a trumpeter which apparently died of lead poisoning, 
as 30 pellets of lead shot were found in the gizzard of this swan. 

Parasites were noted in 5 of the 8 whistling swan carcasses exam- 
ined in Wisconsin by Chaddock (1938 : 25-27). Five cases exhibited 
pediculosis (lice infestation) around the fluff of the vent, the pres- 
ence of gizzard worm (Spirotera hamulosa) was demonstrated, and 
the eggs of common poultry roundworm (Ascaridia liniata) were 
found when a fecal examination of the 5 internally parasitized indi- 
viduals was made. 

Leeches are common to abundant during the summer months in 
most of the waters inhabited by the trumpeters in their United States 
range. As one might expect with waterfowl accustomed to seeking 
their food in the soft mud and vegetation of such areas, leeches fre- 
quently become attached to their bodies. While these blood suckers 
apparently possess little more than nuisance value on the larger swans, 
they may be a contributing cause of mortality with small cygnets. 
Sharp reports that on one occasion : 

Cygnets taken from the north side of the Lower Lake revealed that their under 
parts had from a dozen to fifty small leeches crawling over their wet feathers. 
Swanlets on two occasions taken from this area when placed in the boat within 
a few minutes shook their heads violently and finally threw out a leech ; the 
latter were gorged with blood. These leeches were from one-half to three- 
quarters of an inch in length, and when crushed were filled with blood, as much 
as could be held without apparently bursting. One cygnet on the Upper Lake 
also disgorged a large leech. 

One of 3 cygnets transferred from the Red Rock Lakes Refuge to 
the Delta Research Station in 1955 died after only 3 days. The post- 
mortem examination was conducted by the Ontario Veterinary College 
at Guelph, Ontario, and revealed that the cygnet had died from an 
infestation of thornyheaded worms (Polymorphic baschadis) . These 
worms require crustaceans as an intermediate host and are fairly 
pathogenic, causing anemia and cachenia (Peter Ward, correspond- 
ence). The cygnet probably was infested at Red Rock Lakes, and 
this may be a cause of some mortality there. 

Trematodes are occasionally observed in the cloaca of Red Rock 
Lakes trumpeters when they are being examined to determine the sex. 
Two of these parasites were identified as Echinostoma revolutum. 
Feather lice (Mallophaga) are also commonly observed. Determina- 
tions of the specific identity of these parasites was made through the 
office of Dr. William Jellison, Parasitologist, National Microbiological 
Institute, at Hamilton, Montana, 

In 1950 and 1951 blood smears from various Refuge trumpeters 
were prepared and forwarded to Dr. Carlton M. Herman, Wildlife 



LONGEVITY 143 

Pathologist, Patuxent Research Refuge, for a routine examination for 
leucocytozon, but no positive report was received. 

Hilprecht (1956: 103-101) reports that swans in Europe become 
infested with parasites, the tape worm Hymenolepis aequabiUs and 
the leech Protoclepsis granata. The latter becomes especially 
abundant during summers of low water levels when it is thought to 
contribute to mortality on a large scale. 

Accidents. As one might expect from such large, specialized 
fowl, trumpeters appear to be "accident prone" under certain circum- 
stances. In confinement at the Malheur Refuge, death of several swans 
resulted from drowning when their heads and necks became caught in 
an underwater section of fence while trying to obtain grain beyond 
easy reach. In the New York Zoological Park a trumpeter was 
reported to have died of injuries sustained when it was caught in a 
gate. 

In the wild state, the known accidents seem to be confined largely to 
striking power, telephone, or fence wires in flight. At least 3 cases of 
known trumpeter fatalities have been reported for the Island Park 
area from such causes, as winter fog is common along open water- 
courses. Besides these, 2 other similar cases, 1 on the Refuge and 1 in 
southeastern Montana, have occurred. In 4 of the 5 known cases the 
accident was fatal. 

LONGEVITY 

From earliest times swans were known to be very long lived. The 
ancient naturalists of Greece bore testimony to this (Evans 1903 : 121 ) 
as well as early English ornithologists who presumably wore writing 
of the mute swan in captivity (Swann 1913: 164). Some age data 
of other species of captive and wild swans are furnished by Hilprecht 
(1956:100-101). 

The Refuge swan banding project is comparatively recent and may 
eventually contribute valuable data on the longevity of wild trumpet- 
ers. Despite the considerable success of F. E. Blaauw and others in 
breeding the trumpeter over a long period in Europe, specific records 
of longevity appear to be lacking. The Philadelphia Zoological 
Garden had eight trumpeters on display from 1895-1939, one of which 
lived for 29 years. F. H. Kortwright (1943: 80) noted that a 
trumpeter lived for 321^ years, presumably in Canada. This seems 
to be the present record for this species in captivity. 





POPULATION 

Little information was uncovered regarding the status of the swan 
population which existed in the Rocky Mountains of Montana, Wy- 
oming, and Idaho, before the specific swan surveys were initiated by 
the National Park Service in 1929. The few breeding pairs and 
immatures which then inhabited this vast region were even more 
thinly dispersed over their widely scattered mountain lake environ- 
ment than they are today. (See "Distribution and Status" for a few 
clues to precensus status of swans in Yellowstone Park and Red Rock 
Lakes Refuge.) The important general conclusion to be drawn from 
the scattered data available seems to be that this species was not 
abundant in this region since the turn of the century, and by the 
1920's must have nearly disappeared from its last breeding grounds 
in this country. 

ANNUAL SWAN CENSUS, 1929-57 

The life history studies in the Park and Refuge have progressed 
only sporadically in the three decades since the National Park Serv- 
ice's trumpeter swan survey began in the fall of 1929. Fortunately, 
the annual census which was initiated in 1931 has been effectively 
conducted during most of this period. When properly qualified, this 
accumulation of data offers a remarkably complete 27-year record of 
population levels. The large size, prominent white color, sedentary 
habits, and use of only a comparatively few water and open-marsh 
habitats combine to make these birds an ideal species to locate and 
census accurately. Too, with few exceptions, census methods and 
coverage were generally expanded in time to keep abreast of the grow- 
ing swan population. For these reasons I believe the census data 
which follow are exceptionally reliable and representative. 

144 



POPULATION DYNAMICS 145 

Although it is assumed that little or no interchange has occurred 
between the trumpeters living in this tristate region with other popu- 
lations in Canada and Alaska, this possibility has never been thor- 
oughly explored. But in view of the attraction the waterfowl show 
for their natal marshes generally, and the absence of banding data 
to suggest the possibility of populations mixing, it is concluded that 
the factor of interchange has been insignificant thus far. 

The results of the 27 years of swan-census effort, first solely by the 
National Park Service and then with the cooperation of the Fish and 
Wildlife Service, are presented in detail in table 7 and in appendix 5. 
The distribution of the swans during their 1954 peak year census, 
and the pertinent references, are given in appendix 2. 

Not all of the census data in table 7 will be found to agree exactly 
with figures released for news publication by the Fish and Wildlife 
Service over the years. A few discrepancies were subsequently dis- 
covered in the field and corrected but were not released as a news 
followup owing to the small difference in numbers involved. In each 
case, the data in table 7 are the most comprehensive and representative 
which could be found. 

POPULATION DYNAMICS 

The rise in trumpeter numbers in the United States which began a 
quarter century ago is closely correlated with the establishment of the 
Red Rock Lakes Refuge and the increased protection and attention 
which then became possible. The relatively few departures of the 
annual census numbers from uniform rates of change can be explained 
by incomplete censuses, departures of sizable segments of the popula- 
tion, and actual variations in productivity. 1 Information obtained 
from the annual trumpeter censuses is presented in tables 7 to 12 and 
shown graphically in figures 44 to 50. 

As related earlier, ground counts conducted from 1931 through 
1945 were made under great handicaps of personnel and equipment 
compared with the coordinated aerial censuses which were developed 
later. Since a complete coverage of areas occupied by trumpeters 
was not accomplished during the earliest years, 1931-35, it is likely 
that the actual populations were somewhat larger than were located, 
but the numbers recorded then are believed to be highly representative. 

Since 1936, when more complete ground coverages of the trumpeter- 
occupied areas were begun, only two complete censuses, in 1950 and 
1957, produced results which did not compare well with counts made 
during the preceding and following years. The low count of im- 



1 For purposes of this discussion, "productivity" is measured by the number of cygnets 
censused annually. 



146 



POPULATION 



Table 7.— Swan census data, 1931 to 1957 





Red Rock Lakes Refuge 


Yellowstone Park 


All other areas 


Total, all areas 


Year 




























Adults 


Cyg- 


To- 


Adults 


Cyg- 


To- 


Adults 


Cyg- 


To- 


Adults 


Cyg- 


To- 






nets 


tal 




nets 


tal 




nets 


tal 




nets 


tal 


1931... 


(') 


(') 


(') 


18 


12 


30 


2 


3 


5 


20 


15 


35 


1932... 


19 


7 


26 


29 


2 


31 


9 


3 


12 


57 


12 


69 


1933... 


15 


9 


24 


27 


8 


35 


7 





7 


49 


17 


66 


1934... 


16 


26 


42 


16 


17 


33 


16 


6 


22 


48 


49 


97 


1935... 


30 


16 


46 


16 


11 


27 


(') 


(') 


(') 


46 


27 


73 


1936... 


31 


26 


57 


38 


13 


51 


7 


2 


9 


76 


41 


117 


1937... 


34 


51 


85 


38 


26 


64 


9 





9 


81 


77 


158 


1938... 


28 


42 


70 


40 


4 


44 


25 


9 


34 


93 


55 


148 


1939... 


50 


59 


109 


47 


17 


64 


26 





26 


123 


76 


199 


1940. _. 


58 


48 


106 


39 


14 


253 


26 


6 


32 


123 


68 


191 


1941... 


52 


44 


96 


44 


15 


59 


47 


10 


57 


143 


69 


212 


1942... 


45 


43 


88 


(') 


(') 


(') 


53 


10 


63 


98 


53 


151 


1943. _. 


88 


25 


113 


(') 


(') 


(') 


49 


9 


58 


137 


34 


171 


1944... 


106 


58 


164 


41 


8 


49 


60 


6 


66 


207 


72 


279 


1945... 


113 


50 


163 


(') 


(') 


(') 


67 


5 


72 


180 


55 


235 


1946... 


124 


46 


170 


43 


8 


51 


122 


18 


140 


289 


72 


361 


1947... 


131 


49 


180 


45 


8 


53 


116 


3 


119 


292 


60 


352 


1948.-- 


121 


73 


194 


49 


13 


62 


142 


20 


162 


312 


106 


418 


1949... 


132 


61 


193 


54 


21 


75 


162 


21 


183 


348 


103 


451 


1950... 


106 


40 


146 


57 


16 


73 


140 


17 


157 


303 


73 


376 


1951... 


170 


76 


246 


63 


11 


74 


184 


31 


215 


417 


118 


535 


1952... 


184 


55 


239 


58 


10 


68 


236 


28 


264 


478 


93 


571 


1953... 


211 


38 


249 


51 


10 


61 


216 


51 


267 


478 


99 


577 


1954— 


352 


28 


380 


64 


23 


87 


144 


31 


175 


560 


82 


642 


1955... 


242 


41 


283 


58 


10 


68 


195 


44 


239 


495 


95 


590 


1956... 


293 


39 


332 


48 


9 


57 


166 


33 


199 


507 


81 


588 


1957— 


159 


45 


204 


44 


16 


60 


196 


28 


224 


399 


89 


488 



1 Xo census. 

2 Incomplete census. 

matures and adults in 1950 was followed by an increase in these 
combined age-classes in 1951 which was much greater than could be 
accounted for by cygnet production. It remains to be seen whether 
the same lack of agreement will occur between the 1957 census and 
that of 1958. 2 These census disparities apparently resulted from the 
movement of a substantial segment of the population out of the region 
censused (about 120 in 1950 and 100 in 1957). 

The annual aerial census covers all possible trumpeter habitat in 
portions of three States, but not the many remote areas outside this 
region to which they conceivably might fly. Specific knowledge of 
any such outward migration is lacking at this time. Furthermore, 
no clue to their time of departure, return, or destination is now at 
hand. Their absence most likely began as a northward movement 
with the spring migration. After summering at a new location, re- 
joining the resident flocks on the traditional wintering grounds dur- 
ing the fall migration would be expected. But this is merely 
speculation. 

Since banded trumpeters from northern flocks have never been 
found among the many handled in the United States during the 
summer molt, and United States-banded swans have not been recov- 
ered outside their expected range in this country, I assume that the 

2 A total of 703 trumpeters, 565 immatures and adults and 138 cvgnets, was tallied in 
1958. 



POPULATION DYNAMICS 



147 



Table 8. — Nonbreeding trumpeter swan populations at Upper Red Rock Lake, 
Lima Reservoir, and other important areas, 1939 to 1957 

[Nonpaired (nocked) immatures and adults (cygnets excepted)] 



Year 


Upper 
Red 
Rock 
Lake 


Lima 
Reser- 
voir ' 


Island Park 
Reservoir, 
Sheridan 
Reservoir, 
and other 
waters 


Malheur 

and Ruby 

Lake 

Refuges 


Total 


1939 . 


11 

19 

18 

12 

42 

52 

66 

62 

51 

49 

50 

63 

99 

120 

135 

248 

150 

162 

77 


2 


10 

9 
10 
16 
15 
27 
26 
37 
74 
69 
83 
136 
112 

7 
11 

7 
35 


20 
3 
17 
22 
12 
11 
8 
35 
32 
54 
26 
11 
39 
43 
10 
32 
87 
37 
39 




31 


1940 


22 


1941 


3 


49 


1942 


43 


1943 


64 


1944 


18 

34 

27 

24 

27 

24 

17 

10 

8 

7 

1 

26 

40 


79 


1945 


107 


1946 


159 


1947 


136 


1948 

1949 


164 
177 


1950 


167 


1951 


239 


1952 


310 


1953 


266 


1954 


294 


1955 


249 


1956 


233 


1957 


181 







1 Lima Reservoir was dry during 1954-1956 inclusive. Most of the resident summer population on these 
waters apparently moved to Upper Red Rock Lake during this period as the latter area shows an abnor- 
mally large population during the summers of 1954-1956. 

2 No count was made in 1939. 

missing birds moved out of the region before the annual census and 
then returned in time to be included in the following year's count. 

Having mentioned the major departures from the otherwise fairly 
uniform population curves for the period 1931-57, let us look at the 
overall trend in the numbers of this species during this period. The 
main references for this discussion are tables 7 and 9. Disregarding 
the years 1935, 1942, 1943, and 1945 when complete counts were not- 
secured in the Park, the two categories for which comparable informa- 
tion is available in table 7 are (1) total swan numbers and (2) cygnets. 
The data in table 9 are graphed in figure 44 to show the rates of 
change for certain segments of the population. 

In figure 44, the total population curve shows a steady and rapid 
climb (about 10 percent annually) until 1954, when 042 swans were 
counted. This peak was followed by two slightly lower counts, in 
1955 and 195(5. The sharp decline in 1957 was explained earlier. The 
numbers of immatures and adults increased at a similar rate. Judg- 
ing from these rates, mortality in the immature and adult age classes 
is low. 

Surprisingly enough, the cygnet production rate has not kept pace 
with that of the mated pairs. The rising cygnet production curve 
mirrors some, but significantly not all, of the increases in breeding 
birds censused each year through 1951, when a. population of approxi- 
mately 90 mated pairs was reached. After 1951 the continued rise 
of breeders was followed by a decline in cygnet production when it 



148 POPULATION 

Table 9. — Trumpeter swan production data, 1931 to 1957 



Year 


Mated 

pairs 

censused 


Cygnets 
censused 


Cygnets 

per mated 

pair 


Immatures 
and adults 
censused 


Cygnets: 
immature- 
adult ratio 


1931 




15 
12 
17 
49 




20 
57 
49 
48 


75 


1932 






.21 


1933 






.35 


1934 






1.02 










Mean ... . .. _ 




23.25 




43.50 


.58 








1935 . 




27 

41 

77 
55 




46 
76 
81 
93 


.59 


1936 . 






.54 


1937 






.95 


1938 






.59 










Mean. .. _. . _ 




50.00 




74.00 


.67 










1939.- 


46 


76 

68 
69 
53 


1.65 


123 
123 
143 

98 


62 


1940 


.55 


1941 

1942 


47 


1.47 


.48 
.54 










Mean_ 


46.50 


66.50 


1.56 


121.75 


.55 


1943 




34 

72 
55 

72 




137 

207 
180 
289 


.25 


1944 

1945 


64 


1.12 


.35 
.31 


1946. 


65 


1.11 


.25 






Mean 


64.50 


58.25 


1.12 


203.25 


.29 


1947 

1948 

1949 

1950 


78 
74 
85 
68 


60 
106 
103 

73 


.77 
1.43 
1.21 
1.07 


292 
312 
348 
303 


.21 

.34 
.30 
.24 


Mean 


76.25 


85.50 


1.12 


313. 75 


.27 


1951 


89 
84 
106 
133 


118 
93 
99 

82 


1.33 
1.11 
.93 

.62 


417 

478 
478 
560 


.28 


1952 

1953 

1954 


.19 
.21 

.15 


Mean -. 


103.00 


98.00 


1.00 


483. 25 


.21 


1955 

1956 


123 
137 

108 


95 
81 
89 


.77 
.59 
.82 


495 
507 
399 


.19 
.16 


1957 


.22 


Mean 


122. 66 


88.33 


.73 


467.00 


.19 







1 Numbers of mated pairs approximate and not available for periods 1931-38, 1940, 1942-43, and 1945. 

dropped from 118 young in 1951 to 93 in 1952, following which the 
annual production varied between about 80 and 100 cygnets. 

Another characteristic shown in figure 44 is the much greater pro- 
portion of mated pairs which existed in relation to nonbreeders dur- 
ing the early years of the census for which data are available (1939- 
41). This is contrasted with the ratio which existed later during 
the general population rise 1950-54. This suggests to me that the 
greatly increased proportion of flocked nonbreeders which existed 
after 1950 apparently resulted from the incapability of mated pairs 
to reduce territorial claims within limited breeding habitats to the 
degree necessary to accommodate the rising numbers of potential 
nesters. Table 8 exhibits the growth of the two main flocks of non- 
breeders which inhabit Upper Red Rock Lake and Lima Reservoir. 



POPULATION DYNAMICS 



149 



Because production is relatively stable and the period of imma- 
turity comparatively long, it is difficult to trace with certainty the 
impact of any year's production on later populations of the immature 

Figure 44. — Trumpeter swan productivity rates, total population, 1931-57. 1 




1955 



O GROUPED AVERAGES (SEE TABLES 7 AND 9) 
DOTTED LINES = LEFT SCALE, SOLID LINES=RIGHT SCALE 



1 Complete data unavailable, 1931-38, 1940, 1942-43, and 1945 ; mated pair data 
1931-57 approximate only. 



1 50 POPULATION 

and adult ago classes. However, the near-peak production years of 
1948, 1949, and 1951 apparently acted, possibly in concert with other 
factors, to cause the pronounced upward trend of nonbreeders in 1951, 
1952, and 1954. This, in turn, appears to have resulted in the marked 
rise in numbers of mated pairs in 1953, 1954, and 1956. If cause and 
result relationships exist here, a 5-year breeding; age is indicated, at 
least during periods of high breeding populations. 

Although the rate of increase was previously higher, production 
reached a high plateau during the 1948-52 interval when a average 
of 80 pairs produced 99 cygnets annually by census time. This con- 
trasts sharply with the 5-year period which followed, 1953-57, when 
an average of 121 pairs produced only 89 cygnets yearly. In this case 
an increase of 151 percent in breeders was followed by a cygnet pro- 
duction decrease of 10 percent. This hints that the higher popula- 
tions of breeders may have depressed productivity. 

When the related ratios are graphed, that is, cygnets to mated pairs 
and cygnets to immatures and adults, the apparent inverse relationship 
between the population level and productivity becomes clearer. The 
data for 1955, 1956, and 1957 are shown separately, to bring out the 
direct relationships suggested by the grouped averages, though, of 
course, there is much more possibility for the factor of chance to enter 
in these individual cases. The element of chance in the grouped 
average curves is, for all practical purposes, insignificant. 

In figure 44, a number of other productivity relationships are also 
apparent. The grouped averages of immatures and adults combined 
are shown increasing at a constant rate from 1934 to 1954, after which 
a leveling off or decline is evident. The number of mated pairs cen- 
sused increased at a rate comparable, but not equal to that of the im- 
matures and adults. This suggests to me that a shortage of unclaimed 
breeding habitat may have caused potential mature breeders to remain 
in a flocked nonbreeding status somewhat longer, or to a somewhat 
greater degree, than would otherwise have been the case. 

Data relating to the production dynamics of the two most apparent 
United States population segments are handled under separate cate- 
gories: Red Rock Lakes Refuge populations and Yellowstone Park 
populations. (Due to a lack of comparable census data breakdowns 
for populations outside the Federal sanctuaries, it is not possible to 
study the dynamics of these populations.) It is realized that the ac- 
tivities of one population segment may affect the others, as shown by 
the following example, but it will also be demonstrated that the pop- 
ulation mechanics of the Refuge and Park flocks manifest some char- 
acteristics separately. 

A good example of the interaction existing between population 
segments is exhibited in fijmre 45. This shows that nonbreedine: 



POPULATION DYNAMICS 



151 



Figure 45. — Nonbreeding trumpeter swans censused at Upper Red Rock Lake 
and Lima Reservoir, 1 1940-57. 




1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 

1 Lima Reservoir practically dry 1954—56 summer season. 

trumpeters which had habitually occupied the Lima Reservoir moved 
into Upper Red Rock Lake during the low water conditions in the 
Reservoir storage pool during 1954, 1955, and 1956. With the return 
of higher water conditions in the Reservoir in 1957, the census revealed 
an increased number of swans there. 

RED ROCK LAKES REFUGE POPULATIONS 

Since the breeding swans inhabiting the Red Rock Lakes Refuge 
play a major role in determining the status of the total population in 
the whole region, the census data for this area during the period 
1932-57 were broken down insofar as possible, compiled in table 10, 
and shown graphically to arithmetic scale in figure 46. Semilog 
curves are shown in figure 47 for all cases where data breakdowns 
were possible. 

Interestingly, the consistent inverse ratios expressed by breeder 
numbers in relation to production in the total population (figure 44) 
are shown to be even more pronounced for the Refuge population 
(figure 47). 

It should be explained that while a certain proportion of paired 
swans inhabiting Refuge marshes each year apparently do not nest, 
the ratio of these pairs to known nesting birds is small. It is prob- 
ably less than 10 percent for the whole marsh most years. Since so 
few nonnesting pairs were apparent in the initial phases of the study, 
their numbers were not recorded, but later, when the numbers of 
mated pairs were much higher, it is recalled that nonnesting pairs 
were more regularly observed. I therefore suspect that the numbers 

169660 O — 00- 11 



152 



POPULATION 



of nonnesting pairs may increase at a disproportionate rate during 
years of high breeding population. If true, this may significantly 
affect the rate of production which I attributed to mated pairs. How- 
ever, the great majority of pairs on the Refuge nest and lay eggs, even 
in years of high population density, so the production rate decline so 

Figure 46. — Trumpeter swan census, Red Rock Lakes Refuge. 1932-57. 




1932 1934 



Table 10. — Trumpeter swan production data, Red Rock Lakes Refuge, 1936 to 

1957 1 



Year 


Mated 

pairs 

censused 


Broods 
censused 


Cygnets 
censused 


Broods 

per mated 

pairs 


Cygnets 

per mated 

pair 


Cygnets 
per brood 


1936 

1937 

1939 


14 
14 

19 


9 
12 
15 


26 
51 
59 


0.64 
.86 
.79 


1.86 
3.64 
3.11 


2.89 
4.25 
3 93 






Mean _ 


15.66 


12.00 


45.33 


.76 


2.87 


3.69 


1940 


19 

16 


12 
13 


48 
43 


.63 

.81 


2.53 
2.69 


4 00 


1942 


3.31~ 


Mean 


17.50 


12.50 


45.50 


.72 


2.61 


3 66 






1951 


31 

31 
34 

54 


20 
20 
14 
15 


76 

55 
38 
28 


.65 
.65 
.41 
.28 


2. 45 
1.77 
1.12 
.52 


3 80 


1952 

1953 


2.75 
2 71 


1954 


1 87 






Mean 


37.50 


17.25 


49.25 


.50 


1.47 


2 78 






1955 


44 

63 
36 


12 
16 
17 


41 
39 

45 


.27 

.25 

.47 


.93 
.62 
1.25 


3 42 


1956 


2 44 


1957 


2 65 






Mean 


47.66 


15.00 


41.66 


.33 


.93 


2.84 



1 Data grouped to correspond with comparable information in table 12; unavailable prior to 1936 and for 
1938, 1941, and 1943-50. 



POPULATION DYNAMICS 



153 



evident during the years of high populations is due principally to the 
failure of eggs to hatch and young to survive. Many possible theories 
for such failures could be advanced, but the underlying causes have 
not yet been systematically investigated. 



Figure 47. — Trumpeter swan productivity rates, Red Rock Lake Refuge, 1936-57. 1 



100 




1931 



1935 



1940 



1945 



1950 



1955 



O GROUPED AVERAGES (SEE TABLE 10) 
DOTTED LINES = LEFT SCALE, SOLID LINES = RIGHT SCALE 



1 Data unavailable before 1936, and except for 1938, 1941, and 1943-50. 



154 



POPULATION 
Table 11. — Variations in Refuge swan nesting density 





Paired swans observed 2 , 3 


Year' 


Upper 

Lake; 2,880 
acres 


River 

Marsh; 

8,000 acres 


Swan Lake; 
400 acres 


1937 

1939 

1940 

1941 * 


6 (9) 
8 (12) 
6 (10) 

(8) 


6 (13) 
12 (26) 
12 (18) 
10 (14) 


2 (8) 
6 (8) 
2 (0) 
2 (0) 


Mean 


6.7 (9.75) 


10 (17.75) 


3 (4) 


1954 

1955 

1956 

1957 


Hi (3) 
12 (14) 
12 (17) 
12 (6) 


56 (16) 
46 (14) 
54 (9) 
48 (27) 


14 (6) 
12 (0) 
18 (3) 

15 (ti) 


Mean 

Percent change . 


13 (10) 
+94 (+2) 


51 (16.5) 
+410 (-7) 


15.5 (3.75) 
+416 (-6) 







1 Census data for 1938 not available in habitat breakdown form. 

2 Paired swans observed at census time (August) for the period 
1937-41. Swans actually observed nesting (June) during the 1954- 
57 period, except for River Marsh data which are obtained from 
(aerial) census figures, as part of the marsh cannot be seen from 
lookout posts. Comparable data for Lower Red Rock Lake are 
not available because habitat boundary lines are not clear. 

3 Cygnets censused are shown in parentheses. 

4 Breakdown for Upper Lake population not available. 

It will be noted from table 10 that the averages of pertinent cygnet 
production data between the two periods of 1936-42 and 1951-57 
differ markedly. For instance, during the period of comparatively 
low breeding population (1936-42), 74 percent of the paired swans 
censused were seen with young, while broods averaged 3.7 cygnets 
each. During the 7-year period of comparatively high breeding pop- 
ulation (1951-57) the percentage of paired swans censused with young 
dropped to 39 percent and the average brood declined 24 percent, from 
3.7 to 2.8 cygnets per brood. Stated another way, a 250-percent in- 
crease in the average numbers of mated pairs censused on the Refuge 
between the periods 1936-42 and 1951-57 resulted in virtually no 
change in average annual cygnet production, being 45.4 cygnets dur- 
ing the 1936-42 period and 46.0 cygnets in 1951-57. Considering the 
percent of pairs with broods for the period 1936-42 versus 1951-57, 
there is a highly significant difference between the means, the odds 
being more than 2 million to 1 against a difference as great due to 
chance; the odds against a difference as great due to chance for the 
period 1957 versus 1951-56 are 2.6 to 1. 

Table 11 shows the numbers of breeding swans which were attracted 
to each of the major habitat units when the total Refuge-paired swan 
population increased about 300 percent, from the 28-40 level to that of 
86-104 magnitude. The numbers of mated swans are shown to have 
increased by different ratios on the two characteristic habitat units 
during the periods considered. On the shoreline of the Upper Lake, 
a large open-water body where nesting is restricted to the perimeter, 



POPULATION DYNAMICS 155 

the increase in breeding pairs averaged only 94 percent, while in the 
River Marsh and Swan Lake units, where potential nesting sites occur 
more frequently and uniformly, the increase was 410 percent and 416 
percent, respectively. This points up the relative importance of habi- 
tat composition and arrangement to breeding swans when a high 
breeding population is present. 

In figure 47, the numbers of mated pairs have shown an increasingly 
rapid rise from 1936 to 1956. The number of broods increased ini- 
tially at a rate comparable to that of mated pairs, but this trend 
shows progressively greater signs of leveling off. The total number 
of cygnets produced annually rose only slightly from 1936 to 1954, 
but. declined markedly during 1955 and 1956 when the numbers of 
mated pairs were highest. 

The related productivity ratios, broods to mated pairs, cygnets to 
mated pairs, and cygnets to broods all declined at a similar rate, 
though in the opposite direction, from the increasing rate shown for 
mated pairs. When all curves are compared for 1955, 1956, and 1957, 
a strong inverse relationship between population density and produc- 
tivity is apparent. Although the element of chance may enter to some 
degree in the case of the individual years, it is outside the realm of 
expected possibility in the cases of grouped averages. 

YELLOWSTONE NATIONAL PARK POPULATIONS 

As one might expect, a breakdown of Yellowstone Park's trumpeter 
census statistics over the 1931-57 period reveals that factors similar 
to those manifest in the Refuge also have influenced populations there. 
This is evident even though the breeding habitat in the Park is much 
more varied and discontinuous than in the Refuge. 

As figure 48 shows, the Park's swan numbers during the past 27- 
year period have been characterized by several features. One has 
been the relatively constant population of paired swans supported 
prior to about 1949, considering the inadequacy of the very early 
census coverages. Another characteristic is the fairly constant rate 
at which cygnets have been produced during this long period. For 
most years since about 1949 the greater numbers of paired swans 
censused also coincided with a somewhat depressed productivity, 
though this relationship is not as strong as for the Refuge. 

Figure 49, graphed from data compiled in table 12 in a form 
similar to the preceding Refuge population study, throws further light 
on these different expressions of population dynamics. From these 
statistics it is evident that the average number of paired swans cen- 
sused in the Park during the periods of L931-39 and 1940-50 rose only 
slightly, from 10.25 to 11.75, whereas from 1951 to 1957 the average 
rise was much more pronounced, to 15.9. This is an increase of about 



1 56 POPULATION 

Figure 48. — Trumpeter swan census, Yellowstone Park, 1931-">7. 



-i r 



-i 1 1 1 r 



IMMATURES AND ADULTS 
(CHIEFLY PAIRS) 





CYGNETS 




1931 1932 1934 1936 

O INCOMPLETE CENSUS 



1940 1942 
■NO CENSUS 



35 percent from the lowest pair population in the Park to the highest, 
compared with an increase of paired swans on the Refuge of over 250 
percent from 1939 to 1957. It should be noted, however, that the 
average number of cygnets per brood censused in the Park also 
dropped, from 3.0 during the 1931-39 period to 2.5 during the 1951-57 
interval, a decline of 17 percent. This is compared with a similar 
drop of 21 percent on the Refuge, from 3.6 to 2.8 cygnets per brood. 

In figure 49, the decline in the number of cygnets per mated pair 
in the Park also closely parallels a downward trend of similar pro- 
portions which occurred substantially during the same period in the 
Refuge (figure 17). While table 12 shows the average number of 
cygnets per mated pair in the Park to have declined only slightly, 
from 1.20 to 1.10, between the periods 1931-39 and 1940-50, it dropped 
to 0.72 cygnet per brood during 1951 to 1957 when the number of 
mated pairs was highest. For the Refuge, table 10 lists 5 years' data 
collected from 1936 to 1942 showing an average of 2.77 cygnets for 
each pair, this average dropping to 1.24 for the period 1951-57. 

Although the ratio of broods to mated pairs in the Park did vary 
for the periods 1931-39 versus 1940-50, there is no significant dif- 
ference between the means. For the period 1940-50 versus 1951-56, 
however, the odds against a difference as great due to chance are 18 
to 1; while for 1957 versus 1951-56, the odds are 13 to 1. 

Unlike the situation at Red Rock Lakes, the decline in average 
number of cygnets per pair in the Park has been compensated for by 



POPULATION DYNAMICS 



157 



a gradual rise in the average number of pairs having broods. These 
factors have almost exactly balanced, with the result that the average 
annual production of cygnets in the Park has remained practically 

Figure 49. — Trumpeter swan productivity rates. Yellowstone Park, 1931-57. 1 



1.0 
0.9 
0.8 
0.7 
0.6 

0.5 

0.4 

0.3 



0.2 



0.1 



! 










1 












1 




















































| CYGNE" 
1 PER BR 

1 o~ _ 


rs 

OOD 




,^ 










— -^ 




S 

s 
* 




( \ 




; CYGNE - 
MATED 

w 


rs PER 
PAIR 






\ 


\r CYG 

f MAT 

/r 


YETS 
ED PAIRS 


° y 








X 


\J 1 












^ 


1 












\ 


\ 




\ BROODS 


i TO 






\ 
\ 


, 1 BROODS 


1 MATED 

I \ 


PAIRS 








/ 1 






/''°~' ~~ " 


v 


>. 




/I 




! / 






>o- — 


---9 
\ 
\ 


\ /' 
\/' 












\ 

\ 
\ 
\ 
\ 


1 

1 
1 




1 1 1 1 1 


i i i i 


i i i i 


1 1 1 1 


i i i i 


k 4 


i i i i 



100 
90 
80 
70 
60 

50 
40 

30 



20 



1931 



1935 



1940 



1945 



1950 



1955 



o GROUPED AVERAGES (SEE TABLE 12) 
DOTTED LINES = LEFT SCALE, SOLID LINES = RIGHT SCALE 



'Data unavailable for 1942-4.''., 1945; incomplete 1940; for mated pairs. 1931-57 ap- 
proximate only. 



1 58 POPULATION 

Table 12. — Trumpeter swan production data, Yellowstone Park, 1931 to 1957 ] 



Year 


Mated 

pairs 

censused 2 


Broods 
censused 


Cygnets 
censused 


Broods 

per mated 

pairs 


Cygnets 

per mated 

pair 


Cygnets 
per brood 


1931 


9 
7 
9 
8 


4 
1 
2 
5 


12 
2 

8 
17 


0.44 
.14 
.22 
.63 


1.33 
.29 
.88 

2.13 


3.00 


1932 _ 


1933 




1934 


3.40 


Mean_. _. 


8.25 


3.00 


9.75 


.36 


1.16 


3 10 






1936 


10 
10 
12 

17 


5 
6 

4 
5 


13 

26 
4 

17 


.50 
.60 
.33 
.29 


1.30 
2.60 
.33 
1.00 


2 60 


1937 




1938 




1939 


3 40 






Mean.__ .. . 


12.25 


5.00 


15.00 


.43 


1.31 


2 83 






1940 


8 
10 
12 
13 


6 
6 
4 
3 


14 

15 
8 
8 


.75 
.60 
.33 
.23 


1.75 
1.50 
.66 
.62 


2 33 


1941 


2 50 


1944 


2 00 


1946 


2 66 






Mean.. 


10.75 


4.75 


11.25 


.48 


1.13 


2 37 






1947 


14 
10 
12 
15 


3 

4 
6 

5 


8 
13 
21 
16 


.21 
.40 
.50 
.33 


.57 
1.30 
1.75 
1.07 


2 66 


1948 


3 25 


1949 


3 50 


1950 


3 20 






Mean 


12.75 


4.50 


14.50 


.36 


1.17 


3.15 


1951 


13 
10 
18 
19 


5 
6 
4 

7 


11 

10 
10 
23 


.38 
.33 
.40 
.37 


.84 
.55 
1.00 
1.21 


2 20 


1952 

1953 

1954 


1.66 
2.50 
3.29 


Mean 


15.00 


5.50 


16.00 


.37 


.90 


2.41 


1955 

1956 


20 (28) 
17 (21) 
14 (14) 


4 
3 

7 


10 

9 
16 


.20 
.18 
.50 


.50 
.53 
1.14 


2.50 
3 00 


1957 


2 29 






Mean. 


17.00 


4.66 


11.66 


.29 


.72 


2.60 



1 Data unavailable 1935, 1942-43, 1945; incomplete 1940. 

2 Approximate number 1931-57; exact data 1955-57 in parentheses. 

constant over the 27-year period ; namely 12.4 cygnets annually from 
1931 to 1939, 12.9 cygnets annually from 1940 to 1950, and 12.7 young 
annually from 1951 to 1957. 

Figures 47 and 49 allow close comparisons of Park and Refuge swan 
productivity characteristics. For instance, the numbers of mated 
pairs in the Park increased at a much lesser rate than in the Refuge 
until about 1946, after which they accelerated and then fell off to a 
degree comparable with that characterizing the Refuge population. 

The total number of cygnets produced in the Park until 1954 in- 
creased at a slightly greater rate, though more irregularly, than on 
the Refuge, after which a similar leveling off is indicated in both 
environments. The number of broods censused in the Park decreased 
at only a slight rate until 1950, after which it dropped at a rate com- 
parable to that shown for the Refuge. 

As would be expected from the slower rate of increase of mated 
pairs in the Park, the productivity ratios of broods to mated pairs, 



POPULATION DYNAMICS 



159 



Table 13. — Characteristics of some Yellowstone Park lakes and their record of 
use by swans, 1931 to 1957 1 



Lake 



Acres 



Remarks 





Total 


Total 


Years of 


number 


number 


record 2 


years 


broods 




occupied 


produced 


24 


24 


13 


18 


18 


10 


23 


20 


9 


24 


17 


10 


20 


16 


9 


19 


15 


9 


24 


19 


3 


24 


18 


4 


23 


16 


3 


22 


14 


5 


22 


13 


4 


17 


7 


1 


20 


3 


2 


23 


19 





13 


10 





18 


12 





17 


11 





18 


9 





22 


2 






Maximum 
number 
adults 

occupying 
lake dur- 
ing years 
of record 



Tern 

Madison Junction. 

Riddle 

Trumpeter 

Geode 

Grebe 

White 

Shoshone 

Heart 

Beach Spring 

Swan 

Obsidian 

Lewis 

Fern 

Wolfe 

Grizzly 

Lily Pad 

Delusion 

Lake of the Woods 



66 

9 

109 
20 

13 
90 

439 

8,475 

2,730 
29 

19 

14 

2,926 

97 

20 
232 

64 
659 

40 



Adequate cover. Good food 
production. 

Cover rather poor. Food 
abundant. 

Ideal. Good food and cover.. 

Adequate cover. Abundance 
of food. 

Poor cover but ample food 

Visited by too many fisher- 
men. 

Adequate cover. Good food 
production. 

West end highly favorable for 
waterfowl. 

Often disturbed by fishermen 

Limited cover. Near high- 
way. Good food supply. 

Frequented by too many 
people. 

Seems suitable. Water level 
low in Fall. 

Visited by too many fisher- 
men. 

Cover limited. Otherwise 
lake is fine. 

Seems suitable for swans 

Seems suitable. Cover lim- 
ited. 

Large shallow areas dry up_ _ 

Limited feeding areas 

Seems suitable for swans 



i Data obtained from Condon's (1941) MS plus annual Park and Refuge swan census reports since 
that time. 
2 Period 1931-57 except for 1942, 1943, and 1945. 

cygnets to mated pairs, and cygnets to broods, held fairly constant 
from 1934 to 1950 with much lesser expression of definite trends than 
that exhibited by the Refuge population. After 1950, however, all of 
the Park's productivity indicators declined when mated pairs in- 
creased further, though this is shown not to have occurred as consist- 
ently or at as rapid a rate as in the Refuge. 

A comparison of the Park and Refuge productivity data suggests to 
me that environment factors in the dissimilar habitat of the Park, 
other than population density, are more variable and influential in 
regulating annual production there. 

In order to illustrate the variable capacity of the Park lake habitats 
to support swan broods, a sample of counts on breeding habitats was 
chosen from those areas on which swans have been censused for a 
period of 10 years or over. This information is shown in table 13. 
An examination of these data points up the limited capability of the 
lake habitat in the Park to support broods regularly, the upper limit 
actually being about 55 percent of the time over a long period (Madi- 
son Junction and Tern Lakes). On some other waters, in spite of 



160 



POPULATION 



regular records of swan occupancy, not a single brood has been pro- 
duced. The brief "remarks" column does not entirely explain why 
breeding pairs select certain lakes and leave others unoccupied, nor 
why certain nesting waters are consistently more productive than 
others. 

POPULATIONS OUTSIDE RED ROCK LAKES REFUGE 
AND YELLOWSTONE NATIONAL PARK 

The annual swan tallies made over the years covering scattered 
areas contiguous to Yellowstone and Red Rock Lakes have not been 
quite as complete or consistent as on the federally administered areas. 
As a result, these data are not so reliable, especially before the aerial 
methods were employed in 1946, although they are believed to be 
highly representative. Furthermore, since census figures prior to the 
1950's were generally "lumped," it is not possible to prepare a table or 
graph of productivity data as was done in the case of Red Rock Lakes 
and Yellowstone Park populations. 

Figure 50 has been prepared from the most comprehensive infor- 
mation available in Park and Refuge tiles to show the increase in these 
"outside'' populations. An especially rapid population rise is shown 
for the areas outside the Refuge and Park in 1946. This particular 
increase is believed to have been more apparent than real, reflecting 
the greater accuracy and coverage of the aerial census method which 
was employed for the first time. The apparent rise in population 
numbers was greater on the "outside" areas mainly because the large 



Figure 50. — Trumpeter swan census outside Red Rock Lakes Refuge and Yellow 

stone Park, 1931-.77. 




1950 1952 1954 1956 1957 



POPULATION DYNAMICS 161 

reservoirs outside the Park or Refuse boundaries were covered effi- 
ciently and completely for the first time. 

The most significant feature of figure 50 is the tendency of areas 
outside the Park and Refuge not only to hold increasingly greater num- 
bers of swans but at the same time to produce a generally rising 
number of cygnets as well. This is in contrast with the trend in Yel- 
lowstone Park and the Refuge where production recently declined. It 
is plain that habitat outside the two Federal sanctuaries is becoming 
increasingly important as the total number of swans in protected 
areas rises. 

SUMMARY, POPULATION DYNAMICS 

Total Population: 

1. The population increased at a constant rate from about 1935 until 
1954 (about 10 percent annually). Beginning in 1955 a definite 
leveling out became evident, 

2. The rates of change for the total population reflected the survival 
rate of the immature-and-adult age class to a much greater extent 
than the progressively declining cygnet production rate. Popula- 
tion turnover (mortality) in the immature and adult age classes is 
thus shown to be low. 

3. Mated pairs increased at a rate approaching, but not equal, that 
of the immature-and-adult age class. This suggests that a shortage 
of desirable unclaimed breeding territories may prolong the non- 
breeding status of potential nesters. 

4. During periods of increasing populations at high levels, cygnets 
were produced at a rate progressively less than during periods of 
increasing populations at low Levels. 

5. During low levels, mated pairs comprised a much greater propor- 
tion of the total population than at high levels. 

6. There is an indication that mated pairs initially occupied breeding 
territories as 5-year-olds, at least during periods of high popula- 
tion levels. 

7. Cygnet production reached a plateau from 1948 to 1952. 

8. An inverse relationship between population levels and productivity 
is shown. 

Yellowstone Park Population: 

1. Considering the inadequate coverage of the early years, the number 
of mated pairs remained nearly constant from 1931 to about L952. 
A definite increase occurred beginning in L953. 

2. Broods were produced at a nearly constant rate from 1931 to 1957. 

3. Cygnets were produced at a nearly constant rate from 1931 to 1953, 
and in ratio to the number of mated pairs present : titter 1953 the 



162 POPULATION 

number of mated pairs increased and the production of cygnets 
declined. 

4. The ratio of broods to mated pairs increased at a constant rate 
from 1931 to 1945 and then changed, but generally decreased at an 
irregular rate from 1946 to 1954. After 1954 the rate of decline 
accelerated, coincident with the further increase, in mated pairs. 

5. The rate at which cygnets were produced per brood remained 
nearly constant from 1931 to 1950; a decline occurred after 1950 
with a further increase in mated pairs and the number of cygnets 
produced per brood remained low until 1957. 

6. The rate at which cygnets per mated pair were produced was nearly 
constant from 1931 to 1950 and roughly proportional to the number 
of mated pairs present ; after 1950 the cygnets per mated pair rate 
changed inversely with the change in number of mated pairs 
present. 

7. Breeding habitats are "saturated" when occupied by about 15 pairs, 
greater breeding populations appear to depress productivity. 

Red Rock Lakes Populations: 

1. The number of mated pairs increased at a substantially constant 
rate during the 1936-57 period. 

2. From 1936 to 1954, the increasing rate at which broods were being 
produced slightly outweighed the consistent declines in the ratios 
of cygnets to broods and broods to mated pairs. The result was a 
slight increase in the cygnet-production rate. 

3. In 1955 and 1956, when populations of mated pairs were highest, 
cygnet production declined. The falling ratios of broods to pairs 
and/or cygnets to broods during this period resulted in the pro- 
duction drop. In 1957, when the number of mated pairs dropped, 
the production rate went up due to an increase in these same 
productivity factors. Thus, cygnet production is shown to be in- 
versely related to the number of mated pairs when high popula- 
tions are present, 

4. Breeding habitats are "saturated'' when occupied by about 40 pairs, 
greater breeding populations appear to depress productivity. 

Population Outside Federal Sanctuaries: 

1. The census data for this segment does not lend itself to the detailed 
analysis possible with other populations. 

2. The total population, and cygnet production, show consistent 
through different growth rates. 

Red Rock Lakes versus Yellowstone Park Populations: 

1. The point of diminishing productivity was reached about the same 
time (1955) in both of these habitats. In view of the long period 



CONCLUSIONS 163 

when relatively constant numbers of mated pairs occurred in the 
Park, during which they increased about 300 percent on the Refuge, 
some interaction between these populations is suggested. It ap- 
pears that at ''supersaturated" levels, Refuge pairs may overflow 
to Park habitat, depressing the productivity rate there. The simi- 
lar drop of mated pairs in the Refuge and Park between 1955 and 
1957 leads to the same conclusion — that interaction may occur at 
high levels but not necessarily at low. 
2. Where breeding territories are contiguous, as within the Refuge, 
increasing breeding populations at "saturation'' levels or below 
exert a depressive effect on the potential production rate. This 
is apparently not true in isolated habitats, as in Yellowstone Park 
where the cygnet production rate tends to change directly with the 
number of mated pairs present, unless a "supersaturated" breeding 
population is sustained when the rate declines. 

CONCLUSIONS 

1. Trumpeter swans in the tristate region of Montana, Wyoming, and 
Idaho should no longer be considered an endangered species; this 
population has increased at a constant rate for 20 years, and it now 
exhibits signs of leveling off at the maximum level this environ- 
ment will support. 

2. The rate of population change in the total population varied in- 
versely with changes in population density. This change occurred 
in two habitats of varying capacity, Red Rock Lakes and Yellow- 
stone Park, and during periods of low and high populations, hence 
the phenomena is relative and probably occurs to some degree in 
all swan-occupied habitat, 

3. The dynamics of the change in population are tied to the rate of 
productivity of mated pairs, which varied inversely with changes 
in population density. 

4. The rate of increase approached zero about 1954 when the popula- 
tion peak was reached. After that, except for 1957 when an exodus 
apparently occurred, the population fluctuated around 590, ap- 
parently nearly the maximum population which can regularly be 
sustained. Continued population and production increases on areas 
outside Federal sanctuaries will raise this estimate if further ex- 
pansion of their range occurs or more isolated breeding habitats 
within the existing environment are successfully occupied. 

DISCUSSION 

Howard and Fiske (1911) were the first to show that natural popu- 
lations tend to vary inversely with population density, and Nicholson 



164 POPULATION 

(1933: 132-178) and Smith (1935: 873-898) also pointed out that the 
comparative stability of natural populations is controlled dynam- 
ically, meaning that the farther that numbers rise or fall, the stronger 
is the tendency to return to the previous level (Lack, 1954). 

Lately Christian (1957 : 443-62) has shown that numerous field and 
laboratory studies involving mice support a theory that the growth 
of populations may be regulated and limited by sociopsyehological 
factors, (social competition) through the production of stress in some 
proportion to population density. This possibility has not been as 
thoroughly studied in wild avian populations, presumably because of 
few hints in this direction and difficulties inherent in making accurate 
censuses of entire populations; nevertheless, there are clues to such a 
theorem. Working with great tits in Holland, Kluijver (1951) 
found that both the average clutch and the proportion of pairs raising 
second broods were lower at high than low population densities; but 
it was concluded by Lack (1954) that the diiference was too small 
to have any important effect on subsequent numbers. Errington 
(1945), discovered that the summer gain in Wisconsin bobwhites 
(young and adults surviving autumn) varied inversely with the num- 
bers present in April. The foregoing study, though concerned only 
with swan populations, parallels Errington's findings. 

Since by far the great majority of paired swans on Refuge marshes 
complete nests and lay eggs, population density-dependent variations 
in the number of cygnets produced may be substantially attributed to 
the hatching and survival rate. Just how the number of cygnets 
raised may be regulated by the density of mated pairs is not under- 
stood, but it seems clear that the deterioration of habitat, usually 
associated with the population declines of some wildlife species, does 
not play a major role. 





MANAGEMENT 

PROTECTIVE LEGISLATION 

The farsighted Congressional legislation which originally provided 
for the protection of wildlife in Yellowstone National Park, the Lacey 
Act of May 7, 1894, furnished essential protection for the ancestors of 
the few pairs of trumpeter swans which were discovered breeding in 
this famous Park in the summer of 1919. The early protective wild- 
life regulations which grew out of this initial National Park legisla- 
tion were forerunners of continentwide laws which first applied 
specifically to waterfowl and later to waterfowl refuges. Each link 
of legislation which protected the trumpeter was forged as part of a 
greater plan to perpetuate portions of the representative native fauna 
in their natural environment. 

Unfortunately, the passage of the second Lacey Act in 1900, the 
Weeks-McLean Law in 1918, and the Migratory Bird Treaty Act in 
1918 arrived much too late to prevent the extirpation of the trumpeter 
over most of its United States breeding range. For two decades after 
1900, a number of prominent American scientists interested in the 
problems of species survival commented on the fate of the trumpeter 
swan. William T. Hornaday (1913: 19) reported that in 1907 these 
swans were regarded as so nearly extinct that a doubting ornithologi- 
cal club of Boston refused to believe on hearsay evidence that the 
New York Zoological Park contained a pair of the living birds, 
and a committee was appointed to investigate in person and report. 
Edward Howe Forbush (1912: 475), an eminent ornithologist, 
lamented : 

The trumpeter has succumbed to incessant persecution in all parts of its 
range, and its total extinction is now only a matter of years. . . . The large 
size of this bird and its conspicuousness have served, as in the case of the 

165 



166 MANAGEMENT 

whooping crane, to make it a shining mark, and the trumpetings that were 
once heard over the breadth of a great continent, as the long converging lines 
drove on from zone to zone, will soon be heard no more. 

Passage of the Migratory Bird Treaty Act 6 years later placed a 
closed season on both species of native swans for the first time when 
it became effective in 1918. This was the first aid to survival of the 
few trumpeters which still existed outside Yellowstone Park bound- 
aries and which were to be so important in the eventual restoration of 
the species. 

In 1929, the Migratory Bird Conservation Act authorizing the 
acquisition of land for waterfowl refuges was passed by Congress. 
When supported with funds in 1934, this basic waterfowl legislation 
was as important in providing for the future increase of the United 
States trumpeter flock as the Migratory Bird Treaty Act was in 
protecting the remnant populations. 

Under the Migratory Bird Conservation Act, the Red Rock Lakes 
Migratory Waterfowl Refuge in southwestern Montana was 
established by Executive Order in 1935. This area, containing thou- 
sands of acres of historic trumpeter swan breeding habitat, was sub- 
sequently staffed by the Biological Survey, a predecessor of the 
United States Fish and Wildlife Service. • The 22,682-acre area 
originally set aside under this Order was enlarged in September of 
the same year, when about 18,000 additional acres were included in 
the Refuge in order to complete the breeding-ground acquisition and 
to bring under management certain warm spring-water areas im- 
portant to the swans during the winter months. Although several 
management problems remained, the establishment of this Refuge 
provided the upward turning point for this species in the United 
States. While the status of the trumpeters in Yellowstone Park 
before the establishment of the Refuge was marginal, it was ap- 
parently improving slowly. But the existence of this species outside 
the Park was actually in jeopardy by the early 1930's. 

Later, since it was discovered that irresponsible waterfowl hunters 
were killing swans under the claimed pretext of shooting snow geese, 
the hunting seasons on snow geese were closed in those States within 
the trumpeters' winter range. Service regulations, stemming from 
authority in the Migratory Bird Treaty Act, closed the snow-goose 
season first in the State of Idaho in 1941, and were modified about a 
decade later to exclude the counties where swan shooting was not a 
problem. In Montana the snow goose closure has been in continuous 
effect in Beaverhead, Gallatin, and Madison Counties from 1942 until 
the present. Similar Federal closures were initiated as a statewide 
measure in Wyoming in 1946 because of the threat posed to the newly 



CAPTIVITY RECORD 167 

established trumpeter flock introduced to the National Elk Refuge in 
Jackson Hole; however, these regulations were modified in 1955 to 
include only the pertinent areas of Teton and Lincoln Counties. 

Unless these protective measures had been taken by the Federal 
Government, this large and conspicuous bird would surely have dis- 
appeared from its native breeding grounds in this country. 

CAPTIVITY RECORD 

The history of the trumpeter in captivity is long, varied, and 
interesting. It is valuable as avicultural history, for information 
on the traits this bird displayed in captivity, its breeding record, 
and the success which was attained by some of the various individuals 
or organizations which kept it in confinement. 

Audubon (1838: 537, 541) has left us with an early note or two 
on the subject, writing : 

I have traced the winter migrations of this species as far southward as the 
Texas . . . where I saw a pair of young ones in captivity, and quite domesti- 
cated, that had been procured in the winter of 1836. 

******* 

I kept a male [trumpeter] alive upwards of two years, while I was residing 
in Henderson in Kentucky. It had been slightly wounded in the tip of the 
wing, and was caught after a long pursuit in a pond from which it could not 
escape. . . . Although at first extremely shy, it gradually became accustomed 
to the servants, who fed it abundantly, and at length proved so gentle as to 
come to my wife's call, to receive bread from her hand. "Trumpeter" . . . 
now assumed a character which until then had been unexpected, and laying 
aside his timidity became so bold at times as to give chase to my favorite 
Wild Turkey Cock, my dogs, children and servants. Whenever the gates of 
our yard happened to be opened, he would at once make for the Ohio, and it 
was not without difficulty that he was driven home again. ... in the course 
of a dark and rainy night, one of the servants having left the gate open, 
Trumpeter made his escape, and was never again heard of. 

The next record of the trumpeter's history in captivity seems to be 
that left by Baird, Brewer, and Ridgeway (1884: 432), as they state : 

A nest of this species was found by Mr. W. C. Rice at Oakland Valley, la., 
in the spring of 1871, and the Cygnets taken from it. Three of these were 
successfully raised, and were purchased for the Mount Auburn [Iowa] Cemetery, 
where they were received in December. They bore their transportation, in a 
week of unparalleled severity for the season, without injury, and were remark- 
ably docile and tame. In the summer months when at large they would leave 
their pond and seek the companionship of their keeper, whose occupation as 
painter occasionally required his presence on the grounds near their place of 
abode. If permitted, they would spend the day in his company rather than 
remain in their pond. They were perfectly and completely domesticated and 
showed no fear of any person, feeding from the hands Of any stranger. This 
swan has also been domesticated in the cemetery in Cincinnati, a pair of the 
409660 O— 60 12 



168 MANAGEMENT 

progeny having been sent to the London Zoological Gardens, and another to 
Mi mnt Auburn. 

Jean Delacour (1954: 78, 79) provides a recent synopsis of both the 
foreign and domestic captivity record of this species. He begins 
with the arrival of the first specimens in Europe in 1866, which were 
apparently the progeny shipped from the Cincinnati cemetery just 
mentioned : 

Trumpeter swans do very well in captivity. They soon become tame, prove 
completely hardy, easy to feed, and they breed readily. The first specimens 
to reach Europe arrived at the London Zoo in 1866, and the earliest breeding 
success in captivity took place there in 1870 when three cygnets hatched on 
July 6 and were reared on the Three-Islands Pond. Other successes followed. 
The species reached Paris, at the Jardin des Plantes, in 1873, but not until 
1880 were eggs laid, and these proved infertile. In 1885, however, five eggs 
hatched and four cygnets were reared. 

Later on, Trumpeters bred regularly in Europe, but since the beginning of 
this century, only the Duke of Bedford, in England, and F. Blaauw, in Holland, 
seemed to have possessed and raised any. 

******* 

Blaauw reared Trumpeters at Gooilust almost every year until his death 
in 1936. There were then sixteen birds left, old and young, and they all went 
to Woburn Abbey, as they had been bequeathed to the Duke of Bedford, who 
still possessed four. Unfortunately, all these birds died through lack of food 
during the 1939—45 war. . . . 

We kept only one pair at Cleres [France], in 1920 and 1921. They were two 
years old when they arrived from Gooilust, and they were placed on the lake. 
They swam and walked all over the park, at great speed. Very soon they 
became quarrelsome and attacked large birds, particularly white Rheas, which 
they pursued relentlessly over the hills. It became impossible to keep them 
at large, and as all suitable pens were already occupied, we sent them away 
to the London Zoo. 

Trumpeters kept at liberty at Woburn did not molest other birds in the huge 
park. Each pair established a territory and nested, but the young were often 
lost. At Gooilust, each pair was kept on a comparatively small pond, and bred 
regularly. 

As a result of the breaking up of F. E. Blaauw's waterfowl collec- 
tion in Holland in 1936 after his death, the disastrous results of 
World War II upon the Woburn Abbey flock of trumpeters in 
England, and Delacour's earlier abandonment of his Cleres trumpeter 
raising efforts, it is doubtful whether any of these birds remain in 
Europe or England today, except of course for the trumpeters which 
were presented to the Queen of England by the Canadian Govern- 
ment. 

Trumpeters were also apparently kept successfully in captivity in 
or near Washington, D. C, in the early days. The Patuxent Re- 
search Refuge records note that 5 sets of trumpeter eggs were in the 
collection of J. P. Norris, Jr., tagged "D. C. (captivity)" under the 



CAPTIVITY RECORD 169 

date of May 3, 1893. No other data are furnished except that this 
report was received from A. C. Bent. 

The National Zoological Park in Washington, D. C, exhibited 
trumpeters for over 22 years, from May 24, 1900, until June 14, 1922, 
involving a total of 8 birds. The trumpeters at the Philadelphia. 
Zoological Garden have been noted under "Longevity." 

The New York Zoological Society kept trumpeters for over 20 
years, commencing in 1899 and lasting until 1921 (W. G. Conway, 
correspondence) . A total of 22 specimens were received as purchases, 
deposits, or exchanges during this time, having been obtained from 
such States as Idaho (3 in 1889), Utah (6 in 1901), and Maine (1 in 
1901), as well as from the collections of L. C. Sanford of New Haven, 
Connecticut (4 in 1909), and F. E. Blaauw of Holland (4 in 1921). 
Apparently none of these trumpeters bred in New York. 

H. K. Coale (1915 : 89, 90) reported that, at the time of his writing, 
live Montana-originated trumpeters were in the collections of Dr. L. 
C. Sanford of New Haven, Connecticut, and Mr. John E. Thayer of 
Lancaster, Massachusetts; also that Judge R. M. Barnes of Lacon, 
Illinois, had written that he possessed 5 of the 10 trumpeters then 
known to be in captivity, though he had been unable to breed any. The 
origin of Judge Barnes's flock is unknown. 

Before the days of the enforcement of the Migratory Bird Treaty 
Act in 1918, some traffic existed in live trumpeter swans between per- 
sons able to obtain them, and those interested in their propagation or 
exhibition in captivity. 

Dr. T. S. Roberts (1936: 206) stated that an old-time resident of 
Heron Lake, Minnesota, related that pre-flight cygnets were rounded 
up and captured there for shipment to the East, presumably sometime 
after the 1850's. 

Mr. Cecil Wetmore, presently the proprietor of the Summit Hotel 
in Monida, Montana, and the oldest living pioneer of the Red Rock 
Lakes marshes, told me that about the turn of the century, when he 
was but a boy, his family captured young trumpeter cygnets for sale 
to zoos, municipal gardens, or interested individuals. The price, at 
least at one time during this period, was $50 a pair and all birds which 
remained unsold at the season's end were liberated in order to ensure 
ample breeding stock for future years. Mr. "Wetmore recalled that 
several pairs were disposed of to the Columbia Gardens in Butte, Mon- 
tana, but other purchasers had been forgotten and the pertinent 
records lost during the intervening years. 

At least one other pioneer Valley resident, Mr. Fred Hanson, cap- 
tured Red Rock Lakes swans for the live-bird trade during this period 
(Alta Hanson, correspondence). From the diary record of Lillian 
Culver it is clear that Mr. Hanson was active in supplying birds to 



1 70 MANAGEMENT 

the live-swan trade during the period 1896-1914, shipping them to 
various unnamed buyers located at unspecified destinations: 

1SDG. August 20. Fred has 15 swans and will ship tomorrow. 

September 17. Fred and Henry [Hackett, her brother] have gone after 

swan. They made $50 apiece clear on the last shipment. 
September 21. Henry left home with 12 swan this morning, he left 2. He 

has 5 at Collins and will take them. 

1897. September 12. Fred and Henry have 35 swan now. Fred expects to go 

with them soon now. 
September 19. Henry went Friday with 2 swan for King in Ohio. 
September 24. Well, Fred and Henry started at 2 p. m. with 32 swan in 

the hay rack. I hope they will not have any trouble. 

1898. August 29. Fred has 17 swan. 
November 10. Fred left with six swan. 

1899. July 25. Fred went for swan. 

1900. July 20. Home about 4 p. m. Fred and Emma gone after swan. 
September 25. Fred shipped 17 ducks. He has only 8 swan left. 

1901. October 31. Been hunting Fred's swan all day. They got out last nite. 

One died and one flew away so he has only 6 left. 

1902. October 5. Fred is ready to take swan in the morning. 
1906. October 15. Fred went to Monida with the swan after dinner. 

1908. October 20. Matt [Reis] tore up boxes to make the swan crate and 
packed them over. He will go with the swan Friday. 
November 26. The boys got their check for swan today, $66.00. 

1911. August 31. Henery came with 10 swan and put them in the stable. We 
had dinner and I went to feed and water the swan when Fred came 
with one more. 

1914. August 31. Fred and Chester got 3 more swan. 5 new swan now. [James 
F. Hanson, son of Fred Hanson, adds that these were the last swan 
taken. Fred could not sell them and they stayed around Culver's 
pond for years.] 

Apparently one of the early day "swan-brokers'" who obtained some 
of the Red Rock trumpeters was Dr. Cecil French of Victoria, B. C, 
who wrote to the Kellogg Bird Sanctuary in 1934 (a copy was 
furnished by Dr. Pirnie), stating : 

I have had quite a bit to do with native wild swans in my time. Until the 
days of the War [WW I] I was located in Washington, D. C, and off and on 
for several years had been engaged in collecting various birds and animals for 
Zoological institutes throughout the world. Until about the year 1913 I received 
annually, from a party in the State of Montana, from 2 to 6 young Trumpeter 
Swans, taken from the nests. These went to a collector in Boston, Mass., to the 
Duke of Bedford in England, and to a Mr. Blaauw at Hilversum, Holland. 

Patuxent Research Refuge records hold an entry that Dr. French 
reported in a letter of October 18, 1910, that trumpeter swans nested 
at Lakeview, Montana, the former postoffice address for residents of 
the Red Rock Lakes area. So apparently at least some of the early- 
day Red Rock Lakes trumpeter population found its way via Dr. 
French to the East and thence abroad to foreign aviculturists. 



CAPTIVITY RECORD 



171 




Figure 51. — Trumpeter swan cygnets captured on the Red Rock Lakes by the 
Wetinore family for the live swan trade about 1900. 

As any information regarding the whereabouts or availability of 
these rare fowl in the days before they were protected by the Migra- 
tory Bird Treaty Act could be turned to personal profit, such informa- 
tion was rarely published. No doubt the files of Dr. French and other 
early aviculturists such as F. E. Blaauw and the Duke of Bedford 
could reveal a wealth of information along these lines. 

Dr. Miles D. Pirnie (correspondence) reported that the Kellogg 
Bird Sanctuary in Michigan, with which he was formerly associated, 
purchased 10 or more young trumpeters from F. E. Blaauw in Hol- 
land between 1927 and 193] at a cost of about $500 apiece. According 
to Dr. Pirnie, copulation occurred seasonally among paired indi- 
viduals but they made no attempts at nest building. The last 
pair was broken up when the male died about L938. The sur- 
viving pen was then moved to the Chester K. Brooks estate near Cleve- 
land where a cob trumpeter was available. This attempt at breeding 
trumpeters in captivity also ended in failure when the pen was killed 
by a dog. Dr. Pirnie indicated that extreme emaciation due to un- 
known causes resulted in the deaths of several trumpeters at the Kel- 
logg Sanctuary. Human interference, intraspecific strife due to 
crowding, nest desertion, and malnutrition were believed to be prin- 



172 MANAGEMENT 

cipally responsible for low breeding success among the various other 
species of swans (whooper, whistling, and mute) which did breed on 
that sanctuary. 

The following statement by Dr. J. M. Derscheid (1989: 94) has 
apparently led to some speculation in the past regarding the original 
source of the trumpeter swans in Yellowstone Park. 

Mr. Blaauw told me then [upon the occasion of Derscheid's visit to Holland in 
1924] that he was not only slowly but regularly increasing the strength of that 
[trumpeter swan] stock, but that he had had much satisfaction in sending 
some of the Trumpeter Swans bred at his place to the United States Federal 
Government, with the object of restocking some American National Parks with 
this species, formerly living there, but then practically extinct. 

In spite of inquiries at the field headquarters of Yellowstone Na- 
tional Park, the likely recipient if any trumpeters had been sent, noth- 
ing could be learned which would verify this alleged transplanting. 
Regardless of Dr. Derscheid's statement, it is highly improbable that 
a Government project possessing so much inherent public interest was 
actually consummated at that early date without the usual publicity 
and deliberate recording of the facts involved. It is more likely that 
Blaauw's remark refers to the trumpeters which he shipped to the 
Kellogg Bird Sanctuary. Trumpeter swans (-1) were noted in Yellow- 
stone Park as early as 1915 (M. P. Skinner, 1925: 154), but the first 
breeding trumpeters were not reported until 1919, when 2 pairs were 
discovered. No special efforts to save them from extinction were made 
by the Park Service until a decade later. 

C. G. Sibley (1938: 329) reported the hybridization of the trum- 
peter swan while confined in captivity with several other species of 
Anatidae. Drawing upon the testimony of other breeders as well 
as his own experience, Sibley lists hybrids of the trumpeter cross- 
breeding with the mute, whooper, and whistling swan and the Canada 
goose. What is perhaps of even greater significance is the indication 
that hybrids between the rather distantly related swans are some- 
times fertile, this characteristic being noted in a whistling-mute cross 
(male). The young of a whistling- whooper hybrid were also said to 
be fertile. 

NATIONAL PARK SERVICE INVESTIGATIONS 

In 1929 the National Park Service launched a comprehensive 
series of biological studies which were needed to outline the most 
pressing wildlife problems which existed in the National Parks. 
Early attention was given to determining the status of the trumpeter 
in Yellowstone Park, with the aim of saving it from extinction. 
While M. P. Skinner (1925: 153-155) had outlined the precarious 



NATIONAL PARK SERVICE INVESTIGATIONS 173 

early status of the trumpeter in the Park during the period 1915-21, 
no special attempt had been made to assure its welfare since. 

Dr. Joseph Dixon, then economic mammalogist at the University of 
California, served as the field observer during the initial phase of the 
new Park Service program and conducted the preliminary swan sur- 
vey in Yellowstone Park during the fall of 1929. In the course of 
these investigations he learned that although a pair of trumpeters had 
nested every season since 1925 on a small lake near Junction Butte, 
known locally as Trumpeter Lake, they had never been known to 
raise their young to flight age. The need for study of egg loss and 
cygnet mortality was thus indicated and plans were made to do this the 
following season. 

In the spring of 1930 Dr. Dixon returned to Yellowstone Park as 
planned, reinforced by National Park Service naturalists George 
Wright and Ben Thompson. Two nesting pairs of swans, one pair 
located at Trumpeter Lake and the other at Tern Lake, were placed 
under surveillance in order to determine the causes of egg loss and 
juvenile mortality, while a preliminary general survey of other swans 
in the Park was carried out as time and opportunity permitted. 

At the end of the 1930 nesting season, only 3 cygnets were success- 
fully raised from the total of 4 nesting pairs of trumpeters found in 
the Park that summer. The 6 cygnets which hatched at Trumpeter 
Lake were all lost, dropping out 'from unknown causes by ones and 
twos over the whole span of the breeding season in spite of several 
periods of dawn-to-dusk surveillance. The only cause of mortality 
actually observed all summer was a raven which was seen to pilfer 
the contents of a swan egg at the Tern Lake nest. Plainly, heavy 
losses of eggs and juveniles were holding the swan population in the 
Park at precariously low levels. Further investigations, coupled with 
localized predator control, were planned again for the following year. 

About this time, the Park swan restoration program came to the 
attention of some of the local residents of the nearby Red Rock Lakes 
area, where these rare fowl were still commonly killed every year 
by hunters during the waterfowl season despite the Federal law. 
Letters from at least two ranchers in the Red Rock Lakes marshes, 
Mr. Clarence Hunt and Mr. A. Hayden, protested to Park authorities 
the unnecessary shooting and killing of swans in the vicinity of their 
marshland ranches. In one of these letters Mr. Hunt reported to 
Park Ranger Frank Anderson that 7 trumpeters were killed during 
the 1930 season alone. Mr. Hayden advised the Park that the num- 
bers of swans were so reduced by hunters on the Red Rock and 
Henrys Lakes that their numbers probably totaled less than 15. Both 
ranchers made separate recommendations that something be done for 
the protection of these rare birds in the Red Rock Lakes area. 



1 74 MANAGEMENT 

From 1931 until the Bed Rock Lakes Refuse was established in 
1985 the Park Service spared no labor in promoting the welfare of 
the trumpeter. To the everlasting credit of that Service this was 
true not only within the Park but in the important Red Rock Lakes 
area as well. During this critical period George Wright was placed 
in charge of the program, and he, together with his associates, Dr. 
Dixon and Ben Thompson, worked tirelessly with Park Superin- 
tendent Roger W. Toll on management measures designed to protect 
and increase the trumpeter population in the whole Yellowstone 
region. 

When George Wright was specifically assigned to the trumpeter 
problem by the National Park Service in 1981, he accepted the chal- 
lenge with characteristic enthusiasm and dedication. That summer 
he initiated the first annual swan census. The life history studies 
were also commenced at this time under his supervision. These led 
to such important discoveries as the recognition of the Red Rock 
Lakes area as a major breeding grounds of the species and the fact 
that the trumpeter wintered in Yellowstone Park, a fact apparently 
not recognized before 1932. Mr. Wright also wrote letters to officers 
of the various duck hunting clubs located about the Red Rock Lakes, 
stressing the lamentable status of the trumpeter and otherwise publi- 
cizing the problem locally. Acting in the light of Mr. Wright's 
publicity of the trumpeter's plight, the effort of Mr. Frank Conley 
of Deer Lodge, Montana, resulted in the Montana State Fish and 
Game Department's becoming interested in the swan killing problem, 
and in 1933 the Commission offered a $50 reward for information 
leading to the conviction of anyone found guilty of shooting a 
trumpeter in Montana. 

Dr. Joseph Dixon also played a key role in the early restoration of 
the trumpeter. Besides his early survey work he later served as a 
consultant. It was Dr. Dixon who originally kindled public interest 
in this species by his now historic article which appeared in the August 
1931 issue of American Forests. This not only authoritatively out- 
lined the precarious position of the trumpeter during this period but 
did much to arouse public opinion in support of the progressive Park 
program, of which little was then known. 

Ben Thompson served in the early swan restoration program chiefly 
by assisting George Wright and Dr. Dixon in the field, and later by 
outlining the trumpeter's survival problems at the first North Ameri- 
can Wildlife Conference (1936: G39-41). 

In Yellowstone Park, management measures were taken by 
Superintendent Roger Toll as a result of recommendations based 
on field investigations by Messrs. Wright, Dixon, and Thompson. 
Local predator control of coyotes and ravens was practiced, fishing 



NATIONAL PARK SERVICE INVESTIGATIONS 175 

waters were closed to prevent molestation of nesting swans, at least 
two small nesting islands were constructed to reduce the chances of 
predation, and the life history studies were continued. In one case 
Superintendent Toll decided to relocate a main Park road that was 
being constructed in order to furnish a space "buffer zone" to prevent 
undue disturbance of nesting swans by curious visitors. 

The climax of Park Service efforts came when J. N. "Ding" 
Darling, then chief of the Biological Survey, impelled by the Park's 
swan restoration program and favorable reports, visited the Red Rock 
Lakes area in 1934 and subsequently recommended that these lakes and 
marshes be included within the Federal waterfowl refuge system which 
was then just getting underway. Twelve years previously, in the fall 
of 1922, Charles S. Sperry, a waterfowl food-habits biologist, of the 
Biological Survey, had inspected the isolated Red Rock Lakes area 
and, though he reported these marshes a wonderful breeding ground 
for all kinds of wild fowl including the trumpeter, recommended 
against acquisition owing to opposition from hunting-club interests 
which had been entrenched in that area since the turn of the century. 
In 1934, following "Ding's" recommendations, these differences were 
resolved under the urgency of the swan restoration program, and in 
the following year Red Rock Lakes Migratory Waterfowl Refuge was 
created. 

After the Refuge was established and management was undertaken 
in earnest by the Biological Survey, the Park Service did not con- 
sider the swan restoration program a finished matter. Wright, then 
Chief of the Wildlife Division of the National Park Service, and 
Superintendent Toll were both killed in a tragic automobile accident 
in 1936, but the new Superintendent, Edmund B. Rogers, established 
a firm liaison with the succeeding Red Rock Lakes Refuge managers. 
Rogers' interest led to a number of progressive swan projects during 
the next 20 years. 

Several important studies of the trumpeter were made in Yellow- 
stone Park during Rogers' tenure as Superintendent. In 1938 
Frank Oberhansley, Assistant Park Naturalist, and Maynard 
Barrows, Assistant Chief Ranger, completed a season of important 
observations resulting in their ID.") 1 .) manuscript. In 1941 David Con- 
don, now Chief Naturalist of Yellowstone National Park, finished 
his manuscript on the trumpeters in the Park. Shortly afterwards 
Condon was in a position, along with refuge manager Dr. Ward 
M. Sharp, to stand in united opposition against the establishment of 
a U. S. Army mountain training and artillery center at Henrys Lake, 
Idaho. Construction of this base had actually begun before conserva- 
tionists rallied behind recommendations made by Condon and 
Sharp in order to safeguard the breeding population of trumpeters at 



1 76 MANAGEMENT 

Red Rock Lakes, which was only a few miles to the west of Henrys 
Lake, and almost within the proposed artillery-target sector. 

The significant annual loss of swans to waterfowl hunters along 
Henrys Fork of the Snake River in Idaho was also brought to light 
for the first time as a result of Condon's investigations. To re- 
duce this unnecessary mortality a cooperative educational project was 
organized in which the Park Service furnished film and information, 
and the Emergency Conservation Committee, headed by Rosalie Edge 
of New York City, supplied funds for an extended series of lectures 
throughout eastern Idaho. These were presented by George Marler, 
a seasonal Park Service naturalist. This 2-year series of lectures 
reached a total of 24,687 people, and its beneficial effects continued 
long after the project had ended. 

Park Service cooperation continues to the present time. The annual 
swan census, now accomplished by aerial methods, is carried out with 
Park Service cooperation. Park Biologist Walter Kittams has served 
as an aerial observer on swan census flights over the Park in various 
U. S. Fish and Wildlife Service aircraft every year during the past 
decade. From a population standpoint this information has been 
most valuable in assessing current trends and as a guide to habitat 
evaluations. 

SWAN MANAGEMENT ON THE RED ROCK 
LAKES REFUGE 

GENERAL PRACTICES 

When A. V. Hull assumed the initial managership of the Red Rock 
Lakes Refuge in 1935, an effective liaison was soon established with 
Park officials. Under the resulting association, ideas were exchanged 
on swan restoration measures, the annual swan census was coordi- 
nated, and both offices kept abreast of new developments. In addition, 
a number of projects designed to aid the swan program were placed 
in effect on the Refuge by Hull (1939: 378-382). 

Most of these management measures were time-proved conventional 
wildlife restoration practices, and are continued where practical on 
the Refuge today. One of the most important was the elimination 
of human activity and trespass on or near the swan breeding waters. 
This was based on standard Service regulations, and in this case 
served especially well, since trumpeters are particularly sensitive to 
irregular human activity. 

Marsh management was also begun at an early date on the Refuge. 
Grazing was limited to the conservative carrying capacity of the 
range, in order to help restore the marsh itself to a natural wilderness 
nesting environment. In more recent years the trumpeters' winter 



SWAN MANAGEMENT ON RED ROCK LAKES REFUGE 177 

habitat has been improved through the development of two warm- 
water spring- fed ponds. 

Muskrat trapping was also brought under direct regulation at an 
early date and, in fact, halted for a time. Hull found that muskrat 
houses furnished the main source of nesting sites, and overtrapping 
before establishment of the Refuge was apparently a major factor in 
reducing the population of these marsh rodents to a low level. Pres- 
ent management limits muskrat trapping to removal of only the 
animals surplus to the needs of a balanced marsh habitat, with the 
need for swan nesting sites being kept particularly in mind. 

In order to supplement the few muskrat houses which were avail- 
able as swan nesting sites immediately after the establishment of the 
Refuge, a number of floating artificial nesting platforms were con- 
structed of wood on the ice, loaded with marsh hay to simulate musk- 
rat lodges, and anchored over shallow marsh waters. The swans 
accepted these devices as nesting sites, but their construction was dis- 
continued when the muskrat population again became sufficient to 
ensure a plentiful supply of natural sites. 

Coyotes were very abundant on Refuge ranges for over a decade 
following establishment of this wildlife area. Since they were then 
believed to be one of the few natural limiting factors of the swan 
population, control by hunting, trapping, and poisoning was actively 
employed. In the fall of 1947, coyotes were brought under control 
on ranges surrounding the Refuge by the Branch of Predator and 
Rodent Control. Since their methods have proved very effective in 
suppressing the local coyote populations, no predator control measures 
have had to be carried out within the Refuge during the past 10 years. 
Subsequently, studies and observations have cast considerable doubt 
on the importance of the coyote as a factor limiting the trumpeter 
population. 

Winter feeding of small grain to trumpeters was begun on the 
Refuge during the 1936-37 season and has been carried out every 
year since that time. This program began with a seasonal consump- 
tion of about 100 bushels by the swans and other waterfowl which 
frequented Culver's Pond, an artificial impoundment located at the 
east end of the Refuge and known colloquially as the Widow's Pool. 
Here 41° F. water gushing from the dual Picnic Springs keeps a 
few acres of shallow water open during even the coldest winter 
weather. The grain which is placed out for the swans in this shallow 
pond serves as a valuable supplement to natural foods, which are cus- 
tomarily greatly reduced by the swans and the seasonal waterfowl 
migrants even before winter sets in. 

During recent years, with the increasing swan population, this 
amount has been increased to about 750 bushels. This is fed each 



178 MANAGEMENT 

season on a semiweeldy schedule, with wheat and barley proving 
equally satisfactory. While seasonal feeding of wildlife is a ques- 
tionable management practice under ordinary circumstances, it is 
felt that in this case it is necessary to carry the increasing numbers 
of the rare trumpeters safely through their most difficult season when 
natural food supplies are normally either greatly depleted or entirely 
exhausted. Otherwise, especially during severe winters, starvation 
would probably occur to some extent or the movement of swans to 
other areas outside Federal sanctuaries would result. 

Present plans call for expanding the feeding program to include 
the recently created MacDonald Pond. While less water acreage 
is impounded here, the originating Elk Spring water is warmer 
(59° F.) and creates a larger open-water area during the winter. 
With the winter feeding areas at Culver and MacDonald Ponds in 
operation it is hoped that more swans can be held on the Refuge 
during the winter months, and thus reduce to some extent their 
dependence on waters outside federally protected areas during their 
critical season. 

TRANSPLANTING PROGRAM 

In view of the progress made in the swan restoration program by 
1938 it was decided that the breeding range of the trumpeter should be 
extended. Accordingly, 1 cygnets were transferred from the Red 
Rock Lakes Refuge to the National Elk Refuge near Jackson, 
Wyoming. The following year this transplanting program was en- 
larged to include the vast marshes of the Malheur National Wildlife 
Refuge in southeastern Oregon. A decade later, in 1949, the high and 
isolated mountain valley marshes of the Ruby Lake National Wildlife 
Refuge in northeastern Nevada were included in the plan. 

Table 11 documents the transfers of trumpeters from the Red Rock 
Lakes Refuge to the various areas selected for their introduction from 
1938 through 1957. Twelve of the cygnets which were originally sent 
from the Red Rock Lakes Refuge to Malheur were retransferred to 
Ruby Lake in 1917. Thus the Ruby Lake Refuge has actually received 
a total of 12 more swans, and Malheur 12 less, than table 11 indicates. 

Of the many introductions which were thus made over a period of 
20 years, only the initial group transferred to the National Elk Ref- 
uge has bred successfully to date except for the hypothetical record 
at Ruby Lake cited previously. 1 Aimer P. Nelson, formerly Refuge 
Manager at the Elk Refuge, sums up the history of these introductions 
on that area as follows (correspondence) : 



1 In 1058, a pair of trumpeters at Malheur and another at Ruby Lake Refuge nested 
successfully, bringing off 2 and 6 cygnets respectively. 



Figure 52. — The U. S. Fish and Wildlife Service "snowplane" en route to the 
Culver Pond swan wintering grounds for semi weekly feeding of small grain. 
The Centennial Mountains in background form the Continental Divide along 
their 10,000-foot crest. 



On October 24, 1938, four cygnets were transferred and liberated on this 
refuge. Following liberation, three of the birds were always seen together while 
the fourth did not associate with the other three, and in early December the 
lone cygnet disappeared from the area and was not seen again, while the other 
three remained. 

On October 1. 1939, three additional cygnets were transferred in. These re- 
mained until the Flat Creek and marsh lands began to freeze in late November 
or early December when they also left the area and were not seen again. 

On September 28, 1941, three more cygnets were transferred to the Elk 
Refuge. When these three birds were liberated, we clipped their wing tips 
and they were seen frequently on the area until late spring, when they too 
came up missing. 

From then until 1!)44, the only swans seen on the area were the three adults 
that were transferred in 1938. In the case of tbese three they frequently left 
the refuge during the winter months and were known to be away for as long 
as two months. During their absence, they were at various times reported 
along the Snake River within the valley (Jackson Hole]. The three birds always 
returned to the refuge when the ice in the creek channel began to clear every 
spring and remained throughout the summer season. When these birds were 
2 or 3 years old. two were frequently seen together while the third remained 
to itself. In 1!)44 the pair nested in the Flat Creek niarsb. 



180 



MANAGEMENT 



Since 1944, nesting; has occurred nearly every year on the Elk Ref- 
uge, with two nests established during the seasons of 1948, 1954, and 
1955. The history of the Elk Refuge breedings follows in table 15. 

Since clutch size, hatchability, and early cygnet mortality of the 
Elk Refuge breeders are largely unknown, an accurate comparison 
of these factors with similar data from the Red Rock Lakes area is 
not possible. What little data is available indicates that losses in both 

Table 14. — Trumpeter swans transferred from the Red Rock Lakes Refuge, 

1938 to 1957 



Recipient area 



Number 



Cygnets 



Adults 



Elk Refuge: 

Oct. 24, 1938.. 
Oct. 1, 1939--. 
Sept. 23, 1941. 



Total. 



Malheur Refuge: 
Oct. 16. 1939_ 
Sept. 19. 1941. 
Sept. 4, 1944, . 
Sept. 4, 1945.- 
Sept. 12, 1948. 
July 14, 1954- . 

Sept. 27, 1955. 
Aug. 11, 1956- 
Sept. 25, 1957 _ 



Total. 



Rubv Lake: 

Sept. 12, 1949_ 
Julv 28, 1954. _ 
Sept. 26, 1955. 
Oct. 10, 1956. 
Aug. 2, 1957.. 



Total _ 



Delta Station: 
Aug. 7, 1956. 



Total transferred . 



39 



166 



6 (3 pairs). 

1 (nonbreeder). 



11 (nonbreeders). 



19 



6 (3 pairs). 

19 (nonbreeders). 



25 



3 (nonbreeders). 



17 



Table 15.— Trumpeter swan nesting data, National Elk Refuge, Wyoming, 

1944 to 1957 



Year 


Pairs 
nested 


Cygnets 
initially 
observed 


Cygnets 
raised to 
flying age 


Year 


Pairs 
nested 


Cygnets 
initially 
observed 


Cygnets 
raised to 
flying age. 


1944 


1 
1 

0) 

(') 
2 
1 
1 
1 


2 
4 


3,5 
1 
3 



1 
3 


1,3 

3 



1952. 
1953. 
1954. 
1955. 
1956 
1957. 




1 

1 
2 
2 
(') 
1 


3 

2 

2,2 

3.3 



1 


3 


1945 




2 


1946 




2,1 


1947 




3,3 


1948 







1949 







1950 

1951 


Total 


14 


34 


25 









1 No nests observed. 



SWAN MANAGEMENT ON RED ROCK LAKES REFUGE 181 

the egg and preflight stages of existence are as serious as those observed 
in the Red Rock Lakes population. 

The Malheur Refuge has received a total of 133 trumpeters 
transferred from the Red Rock Lakes Refuge during the period 
1939-57. A variety of methods have been tried at Malheur during 
this period to establish a wild breeding population of these birds, 
but this goal has not yet been achieved. The chief factors contributing 
to failure in the early transplanting efforts were the practices of 
pinioning and confining the flock to a single large pool, where intra- 
specific strife and spatial competition not only created a situation 
which was unfavorable for breeding but led to significant losses from 
accidents and disease. Initial efforts to establish a breeding swan 
population by liberating the transplanted individuals directly into 
the marsh proper failed due to the dispersion and disappearance of the 
liberated birds. 

As far as the Ruby Lake Refuge effort is concerned, with the 
exception of the hypothetical single breeding record noted near 
the Ruby Lake Refuge in 1953, the efforts to establish a wild breeding 
population of trumpeters at that location have been unsuccessful for 
many of the same reasons affecting the Malheur transplants. 

In addition to the transplants involving only birds-of-the-year, a 
single attempt to achieve the desired goal at Ruby Lake and Malheur 
by transferring known breeding pairs from the Red Rock Lakes Ref- 
uge was attempted in 1954 when 3 pairs of mated trumpeters and 
their offspring were liberated in each marsh area. The adults ap- 
parently remained with their broods at their new locations for a time 
after regaining their flight feathers, but disappeared later. Perhaps 
these adults departed with their cygnets during the fall migration 
along with the whistling swans which pass through these areas dur- 
ing the autumn in considerable numbers. At any rate their fate re- 
mains unknown. 

In 1957 a new transplanting program involving both the Ruby 
Lake and Malheur Refuges was begun. Specifically designed to avoid 
many of the shortcomings of the earlier attempts, the revised pro- 
cedure employs a relatively short-term swan decoy flock, thereby 
n inimizing the bad effects of the long periods of confinement for the 
entire group. This will be employed in connection with banding and 
dyeing techniques used on the liberated birds in order to trace dis- 
persion. 

In 1955, 6 trumpeters were transferred from the Red Rock Lakes 
Refuge to the Delta Waterfowl Research Station, Delta, Manitoba, 
Canada. These birds, 3 adults and 3 cygnets, supplemented the small 
group of Canadian trumpeters already at Delta and were transferred 



182 MANAGEMENT 

Table 16.— Swans banded at the Red Rock Lakes Refuge, 1945 to 1957 



Year 



Number 



Age class 

Cygnets 

Cygnets 

Cygnets 

Cygnets 

Non-breeders • 

Non-breeders ' 

Cygnets , 

Cygnets 

Non-breeders I 

Non-breeders ' 

Cygnets 

Cygnets 

Adults 

Cygnets 

Immatures 

Adults 

Adults 

Immature 

Cygnets 

Non-breeders ' 

Cygnets 

Non-breeders ' 

Non-breeders i 



Location released 



1945 

1948 

1949 

1950 

1951 

1952 

1953 

1955 

1956 

1957 

Total 



Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Ruby Lake Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Malheur Refuge. 
Ruby Lake Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Red Rock Lakes Refuge. 
Malheur Refuge. 
Malheur Refuge. 
Ruby Lake Refuge. 
Ruby Lake Refuge. 
Malheur Refuge. 
National Zoological Park. 
Red Rock Lakes Refuge. 



369 



1 Includes both adult and immature age-classes. 

with the hope that breeding pairs could be established there, with 
methods which could eventually be applied to pertinent United States 
refuge areas. To date the transferred adults have not bred at Delta, 
though pairing has taken place. The cygnets transferred there are, 
of course, not yet sexually mature. 

In 1957 a male and a female trumpeter from the Refuge's non- 
breeding flock were transferred to the National Zoological Park in 
Washington, D. C, for exhibition and research purposes. 

BANDING 

From 1945 to 1957, 261 swans of various age classes have been 
banded and released on the Red Rock Lakes Refuge alone. This was 
done to provide facts relating to local movement or longer migration, 
causes of mortality, longevity, etc. In addition, 107 swans banded at 
Red Rock Lakes have been released elsewhere, 48 on the Malheur and 
57 on the Ruby Lake Refuges and the 2 transferred to the National 
Zoological Park. This information is shown in table 16. 

A total of 369 swans have thus been banded and released. Only 16 
recoveries have been reported as of February 14, 1957, 13 of these 
within the general Red Rock Lakes region, 2 on the Malheur Refuge, 
and 1 in the Ruby Lake marsh. There are no recoveries to reveal 
movement or migration outside their traditional known range or, in 
the case of the transferred individuals, outside the general area in 
which they were introduced. 



MANAGEMENT RECOMMENDATIONS 183 

A breakdown of the causes of death among the 16 recoveries shows 
that shooting was responsible in 5 instances. In the remaining 11 
cases, information is not available, though it is probable that illegal 
shooting played a significant role here also. 

A period of less than 2 years existed between the date of banding 
and that of band recovery in 10 of the 11 cases where pertinent re- 
covery information was available. In the remaining example, a dura- 
tion of slightly over 3 years occurred between banding and recovery 
dates. 

In swan-banding operations on the Refuge, 27 returns of banded 
birds have been noted. The earliest return occurred when a fall- 
banded cygnet was captured again for banding in its initial post- 
juvenile molt the following summer, a period of 11 months. The 
maximum return period thus far was that of a male banded as a 
cygnet in the late summer of 1949 and recaptured in July 1957, a 
period of 7 years 11 months. 

The standard U. S. F. W. S. size 9 aluminum bird band, the largest 
made, was first used in all Refuge trumpeter-swan banding opera- 
tions, until it was discovered that this size was somewhat too small, 
and also that a significant proportion of banded captive trumpeters 
at the Malheur Refuge lost these aluminum bracelets from year to 
year. To avoid this difficulty a locking-type stainless-steel band was 
developed and placed in use in 1955. This steel lock-type band, 
carrying hand-stamped identification data, has been used exclusively 
since that time, except for 12 cygnets transferred to Ruby Lake in 
1956 which were banded with standard aluminum bands when the 
supply of steel bands was temporarily exhausted. 

A trumpeter-swan banding project has also been carried out by 
the Canadian Wildlife Service for a number of years, using the 
standard aluminum bands as well as colored plastic bands for sight 
record purposes. Except for those specific cases previously men- 
tioned, the results of this work are not yet available. 

MANAGEMENT RECOMMENDATIONS 

As has been shown, the trumpeter-swan population in the United 
States has increased manyfold during the past 30 years and is ap- 
parently now being maintained near the highest level which its year- 
round environment will support. For all practical considerations it 
has been saved from any immediate threat of extinction in this 
country; hence the prime goal is to preserve the existing habitat 
necessary to hold the substantial population gains made in recent years 
and to increase their range by transplanting to new localities. 

469060 O— 60 13 



184 



MANAGEMENT 




■ .*■ --•"■ 



V. 







.'* * ^ 



**$***- 







Figure 53. — These trumpeters are only part of the floek of over 200 which pass 
the late winter months on the Refuge awaiting the spring breakup. The 94 
trumpeters visible in this single photograph are more than existed in the 
entire United States 25 years ago. 

Since by far the greatest proportion of breeding pairs is found 
within either the Red Rock Lakes Refuge or the National Parks of 
the area (Yellowstone and Grand Teton), the maintenance of the 
quality of the habitat should not require attention beyond that now- 
being given. Little need is seen at present to develop the main swan 
breeding habitat already included within these Federal sanctuaries. 
Emphasis should rather be laid on preserving and maintaining a 
seasonally balanced habitat for all age classes. 

The Red Rock Lakes Refuge marshes exist in practically a wilder- 
ness state, and as such, may be regarded as almost ideal breeding 
habitat. While a number of artificial nesting islands might be con- 
structed on the open expanse of Upper Red Rock Lake, their occupa- 
tion and defense by territorial nesting pairs would necessarily limit 
the use of these waters by large numbers of nonbreeders. Saving a 






MANAGEMENT RECOMMENDATIONS 



185 




3fl&ife Ji-3 




part of the limited federally protected habitat for the flocked, non- 
breeding segment of the population is important since the only other 
suitable waters are artificial impoundments subject to drawdown with 
the usual unfavorable results. Moreover, the mere accommodation of 
a few additional pairs of breeders on the Refuge probably would not 
increase the cygnet production if the experience to date has provided 
a true index. 

If not filled in by sediments brought down by streams as a result 
of poor watershed practices, the Red Rock Lakes marsh system 
should continue to exist in virtually its present form for many years. 
Even if the threat of siltation becomes acute, the habitat could be saved 
by constructing a series of artificial pools within the Refuge along the 
main tributary streams. These could serve as silt-traps, and thus 
prevent the excessive deposition of alluvium in the already shallow 
lake beds. 

Winter feeding of small grain on the Red Rock Lakes Refuge should 
be continued to the fullest extent practicable. In addition, the possi- 



186 MANAGEMENT 

bilities of initiating winter feeding wherever concentrations of the 
trumpeters exist during this season should be studied. Since arti- 
ficial feeding during the winter apparently meets only a portion of the 
trumpeters' dietary requirements, ways of increasing the production 
or availability of the natural aquatic plants should be explored. This 
is especially applicable to the Island Park area in Fremont County, 
Idaho. In this region a comparatively few mile* of the streambed 
along Henrys Fork of the Snake River and its tributaries form the 
most important single wintering grounds for this species on the 
continent. Winter use is especially concentrated on and in the 
vicinity of the Railroad Ranch. 

Acquisition and management of an adequate portion of the swan 
wintering habitat along Henrys Fork and its tributaries would prevent 
development and hunting pressure which might adversely affect 
the trumpeters during their season of greatest vulnerability. Whether 
or not this is accomplished, special wildlife easements or regulations 
affecting these lands would assure additional protection and food for 
this rare species. A state wildlife sanctuary already exists on a por- 
tion of the Railroad Ranch wintering grounds. Specific recom- 
mendations should result from additional study of this problem in 
the field. 

Investigations into various phases of the life history of the trum- 
peter should be continued both on the Red Rock Lakes Refuge and in 
Yellowstone Park, in fact wherever the time of qualified personnel 
and opportunity exist. Priority in these studies should be placed on 
the following subjects: banding for the purpose of revealing 
trumpeter distribution and mortality ; causes of the low hatchability 
of trumpeter eggs ; factors contributing to the high mortality of cyg- 
nets before flight age is reached; and relation between the density of 
trumpeters on the breeding grounds and production. Investigations of 
specific characteristics of trumpeters held in captivity might also be 
profitably given attention : territorialism, space requirements, breed- 
ing, and dietary considerations. 

Outside their present Rocky Mountain environment, the emphasis 
should be placed on transplanting. In addition to introductions now 
being carried out at the Ruby Lake and Malheur Refuges, further 
efforts to establish a wild population should be extended to suitable 
areas within the former known breeding range of this species. 
Habitat in the Flathead Valley of Montana, the Minnesota-Iowa 
region, the Dakotas, and northwestern Nebraska may have areas suit- 
able for future plantings. 

Owing to the vulnerability of trumpeters to shooting, possibly the 
most important single requirement in transplanting, outside of favor- 



Figure 54. — Trumpeters feed in Culver Pond with mallards, Barrows goldeneyes 
and common goldeneyes on gTain placed out by Refuge personnel. 



able habitat factors, is provision for sufficiently protected wintering 
waters, preferably in close proximity to managed breeding grounds. 
It is difficult to see how a wild population of these slow-maturing, 
conspicuous, low-flying birds could ever become established and thrive 
if they were compelled by the freezing of their breeding grounds to 
run the waterfowl hunter gauntlet each fall in moving to far distant 
wintering grounds. 

The problems of successfully transplanting the trumpeter do not 
appear to be beyond solution if similar experience with the mute 
swan is comparable. In addition to the success of this exotic species 
in acclimating itself in both England and Denmark as a feral resident, 
during the past half century the mute swan has become firmly estab- 
lished in the thickly populated lower Hudson River Valley and 
vicinity. The mute has become established in Michigan, with a popu- 
lation wintering in Grand Traverse Bay and reportedly breeding on 
waters near East Jordan (correspondence). The numbers of these 
birds have increased steadily, about as follows: L948 or 15)49, 2; 1950, 
5; 1951, 8; 1952, 11; 1953, 13; 1954, 17; 1955, 24; 1956, 41. 



188 MANAGEMENT 

While the trumpeter usually lays a smaller clutch of eggs than the 
mute swan, and may be more vulnerable to shooting as well, there is 
no obvious reason why it should not respond to a sound program of 
transplanting and management if hunting losses can be eliminated or 
reduced to a low level. 

As the trumpeter population becomes more widely distributed, the 
possibility of hybridization with the mute swan may become a threat. 
With feral mute swans spreading to new areas, and with the tendency 
for swan hybrids to be fertile, some interbreeding between the two 
species is possible. This could be serious when the small total popula- 
tion of trumpeters is considered. Such a possibility must be guarded 
against, and controls be undertaken when and where the swan breeding 
populations begin to overlap. 

Because of its rarity, beauty, and other intrinsic qualities, the 
trumpeter is greatly sought for display and breeding purposes, both 
by public and private institutions and individuals. A few are being 
kept in captivity for display and observation purposes, though at 
their present level of abundance none can be provided to aviculturists 
specifically for breeding purposes, nor would their release to breeders 
generally be in keeping with the responsibilities of the U. S. Fish and 
Wildlife Service as set forth in domestic regulations and international 
migratory bird treaty agreements. It is the objective of the Bureau 
to maintain the wild population of these rare fowl at an optimum 
level — the greatest number which can be consistently supported in their 
natural environment. Any swans which may be surplus to this re- 
sponsibility should be included in the program to establish other 
wild breeding flocks, or loaned to qualified public zoological parks for 
display and breeding purposes. With continued diligent manage- 
ment and protection, the transplanting program should assure the 
continued growth in numbers and expansion of the range of the 
trumpeter swan in this country. 




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Appendix 1. Excerpt from "Observations on the genera of the 

swans" 

By Alexander Wetmore, Smithsonian Institution. From Journal of 
the Washington Academy of Sciences, vol. 41, No. 10, October 15, 1951. 

Externally the species of white swans are so similar that the student of study 
skins has difficulty in separating them. The comparative anatomist, . . . work- 
ing with skeletons, has no trouble whatever in dividing them into two principal 
groups on characters so evident that they cannot be disregarded. The differences 
are most apparent in the form of the trachea, sternum, and furculum. Follow- 
ing is a summary of these anatomical characters, with indication of the alloca- 
tion of the species of the Northern Hemisphere and South America : 

a. Trachea passing directly into thorax, not entering sternum; furculum simple; 

tail cuneate genus Cygnus 

Cygnus Bechstein, Orn. Taschenb., pt. 2, 1803:404. Type, by monotypy, 

Anas olor Gmelin. 
Sthenelus Stejneger, Proc. U. S. Nat. Mus. 5:184, 185. Aug. 5, 1882. 

Type, by monotypy, Anas melancoripha Molina. (Not Sthenelus 

Marschall, 1873, emendation for Sthelenus Buquet, 1860, for a genus 

of Coleoptera.) 
Sthenelides Stejneger, Auk 1 (3):235. July 1884. Type, by monotypy, 

Anas melancorphia Molina. New name for Sthenelus Stejneger 

(preoccupied). 
Euolor Mathews and Iredale, Austr. Avian Rec. 3 (5): 117. Dec. 28, 

1917. Type, by original designation, Anas olor Gmelin. 
Species included: 

Cygnus olor (Gmelin) (skeleton examined). 
Cygnus melancoriphus (Molina) (skeleton examined). 
aa. Trachea making a loop that enters the sternum; furculum especially modified 

at symphysis to accommodate this loop; tail rounded genus Olor 

Olor Wagler, Isis, 1832:1234. Type, by subsequent designation, Cygnus 

musicus Bechstein = Anas cygnus Linnaeus (Gray, 1840). 
Clangocycnus Oberholser, Emu 8 (pt. 1); 3. July 1, 1908. Type, by 

monotypy, Cygnus buccinator Richardson. 

b. Trachea entering anterior end of sternum smoothly, without a dorsal loop. 

subgenus Olor. 
Species included: 

Olor columbianus (Ord) (skeleton examined) . 
Olor cygnus (Linnaeus) (skeleton examined). 
Olor bewickii Yarrell. 
bb. Trachea making a dorsal loop as it enters sternum, protected by a bony case 
that projects into the anterior end of the body cavity 

subgenus Clangocycnus 
Species included: 

Olor buccinator (Richardson) (skeleton examined). 
The shape of the furculum and the looping of the trachea in the sternal keel 
are developed in the growing young, the loop lengthening and expanding to the 
end of the sternum as the individual becomes fully adult. This change with 
age has led to misunderstanding of the characters by some not familiar with it. 
The arrangement of the genera above, it may be noted, is identical with that 
of Stejneger in his Outlines of a monograph of the Cygninae, published in 1882. 

198 



APPENDIX 2 



199 



Appendix 2. — Status and Distribution of Trumpeter Swans in 
the United States, 1954 

[Census, August 19-September 3] 



Location 


Groups l 


Adult- 
cygnet 
ratio 


Total 

swans 


Montana 
Red Rock Lakes Refuge: 2 
Lower Red Rock Lake 

Red Rock River, marsh and potholes. . 

Upper Red Rock Lake and East 
Marsh. 3 

Swan Lake and adjacent marsh pot- 
holes. 

Culver Pond 


/2-1, 2-0, 2-0, 2-0 

\2-0, 2-0, 2-0, 2-2. 

?2-0, 2-3, 2-0, 2-0, 
2-0, 2-0, 2-1, 2-0, 
2-0, 2-0, 1-0, 2-0, 
2-0, 2-0, 2-4, 2-0, 

' 2-0, 2-3, 2-0, 2-0, 
2-0, 2-0, 2-0, 2-2, 
2-0, 2-0, 2-3, 2-0, 

12-0. 

/2-3, 2-0, 2-0, 199-0, 

\55-0. 

[2-0, 2-3, 2-3, 2-0, 
2-0, 2-0, 2-0, 2-0, 

[2-0. 
1-0 


16:3 
57:16 

260:3 
18:6 

1:0 


19 
73 

263 

24 

1 






Total 




352:28 

12:0 
4:8 
2:0 
6:0 

18:0 
7:0 


380 


Centennial Valley (outside Refuge): 
Red Rock River, except Blake Slough. 

Blake Slough _ _ _ _ 

Jones Reservoirs . 


1-0, 11-0 

2-8,2-0 

2-0 

6-0 

18-0 

7-0. . . 


12 

12 

2 


Passmore potholes ._ ._ . 
Stibal pothole __ 
Lima Reservoir 


6 
18 

7 








Total 




49:8 

2:2 

4:1 
1:0 


57 


Beaverhead National Forest: 
Elk Lake 


2-2 

2-0, 2-1 

1-0 


4 


Gallatin National Forest: 
Hebgen Reservoir 
Aldrich Lake __ _ 


5 
1 






Total 




7:3 

2:0 

2:1 


10 


All other areas: 

Ennis Lake _. __. 
Conklin Reservoir (Antelope Valley) . . 


2-0 

2-1 


2 
3 


Total 




4:1 


5 








Grand total (Montana). 




412:40 

2:0 
2:0 
2:0 
1:0 
2:0 
2:0 


452 


Idaho 

Targhee National Forest: 

Beaver Lake _____ 

Pond, 1 mi. northwest of Steele Lake.. 

Steele Lake (Idaho and Wyoming) 

Pond, '{» in i. northeast of Goose Lake 
Goose Lake _ _ . .._______ 

"The Hole" 


2-0 

2-0 

2-0 

1-0 

2-0 

2-0 


2 
2 
2 
2 
1 
2 


Total 




11:0 


11 



See footnotes at end of tabic 
4C!m;<;o O — 60 14 



200 



APPENDIX 2 



Location 


Groups l 


Adult- 
cygnet 
ratio 


Total 

swans 


Island Park Area: 
Henrys Lake 


2-0, 2-2 ... 


4:2 

2:0 

2:4 

19:1 


6 


Island Park Reservoir 


2-0 


2 


Gold Lake 


2-4 


6 


Silver Lake 


2-1, 6-0, 2-0, 9-0. _. 


20 






Total 




27:7 


34 


Grand total (Idaho) 




38:7 

2:0 
2:4 
3:2 
6:0 
2:1 
2:0 
1:0 
2:0 
2:4 
2:0 
1:0 
2:0 
2:0 
2:0 
2:0 
2:0 
2:0 
4:0 

2:3 
2:0 
2:0 
2:0 
1:0 

4:3 

2:6 
3:0 
2:0 
3:0 


45 


Wyoming 

Yellowstone Park: 

Pond, south of Bunsen Peak_ 


2-0 

2-4 


2 


Geode Lake 


6 


Trumpeter Lake . 
Fern Lake _ 


3-2 


5 


6-0 


6 


Tern Lake.. _ 
White Lake outlet _ 


2-1 

2-0 . 


3 
2 


Solfatara Lake 


1-0 


1 


Grebe Lake. 


2-0 


2 


Madison Junction Lake 


2-4 


6 


Mouth of Alum Creek 


2-0 


2 


Mouth of Pelican Creek. _ 


1-0 

2-0 

2-0 


1 


Beach Springs. 


2 


Mouth of Trail Creek 


2 


Upper Yellowstone River _ . . 


2-0 


2 


Mouth of Chipmunk Creek 


2-0 

2-0 

2-0 

4-0 

2-3 


2 


Yellowstone Lake near Delusion Lake. 
Delusion Lake 


2 

2 


Ponds between Delusion Lake and 

Flat Mountain Arm. 
Riddle Lake 


4 
5 


Shoshone Lake 


2-0 


2 


Heart Lake 


2-0 


2 


Pond, 1 mi. west of Beula Lake 
Pond, 2 mi. west of Boundary Creek 

patrol cabin. 
Pond, 2 mi. north of Bechler River 


2-0 

1-0 


2 
1 


4-3 ... _ .. 


7 


Ranger Station. 
Robinson Lake 


2-6 - 


8 


Lilypad Lake 


3-0 


3 


Phone Line Lake 


2-0. 


2 


Pond, south of mouth of Mountain 


3-0 


3 


Ash Creek. 






Total 




64:23 

2:4 
2:0 
4:0 


87 


Grand Teton National Park: 

Pond, 3 mi. northwest of Moran 


2-4 


6 


Emma Matilda Lake 


2-0 .- -- 


2 


Two Ocean Lake 


4-0 


4 


Total. . ^ 




8:4 


12 








Grand Total (National Parks) 

National Elk Refuge 
Teton National Forest: 

Bridger Lake. . . 

Snake River 


2-0, 2-3, 2-0, 4-0 ... 

2-0 

2-0 


72:27 
10:3 

2:0 
2:0 


99 
13 

2 
2 


Total 




4:0 


4 



See footnotes at end of table. 



APPENDIX 3 



201 



Location 


Groups 1 


Adult- 
cygnet 
ratio 


Total 

swans 


Targhee National Forest: 

Pond, 3 mi. west of Fish Lake. _ - 


2-0 

1-0 


2:0 
1:0 
3:0 

2:0 
2:2 
2:0 


2 

1 


Pond, 1 mi. southwest of Winegar 

Lake. 
Loon Lake 


3-0 

2-0 

2-2 

2-0 


3 

2 


Indian Lake - 


4 


Reservoir 1 mi. southwest of Indian 
Lake. 


2 


Total 




16:2 


18 








Grand total (Wyoming) 




98:32 
7:0 
5:3 


130 


Nevada 
Ruby Lake Refuge 4 


7-0 

5-3 


7 


Oregon 
Malheur Refuge 4 


8 






Total for all areas 




560:82 


642 









' First number in combination denotes adults, second cygnets. 

2 Does not include 21 swans (13 adults and 8 cygnets) transferred to Malheur and Ruby Lake Refuges 
earlier in the year. 

3 East marsh includes only those potholes draining into the Upper Lake. 

4 Transplanted swans. 

Appendix 3. — Measurements of Trumpeter Swan Eggs 

The following measurements of the eggs of trumpeter swans were 
recorded in 1955 on Red Rock Lakes marshes from a random sample 
of 21 nests which contained normal clutches. Measurements were 
made accurately to the nearest half-millimeter at the points of 
greatest length and girth. These measurements are believed to be 
representative of this species in its United States breeding habitat. 



Length Width 



Mm. Mm. 

Clutch No. 1: 

Eggl 116 72.5 

Egg2 111.5 69.5 

Egg3 118 75 

Egg4 119 74 

Egg5 117.5 74 

Clutch No. 2: 

Eggl 106 70.5 

Egg 2 105.5 71 

Egg3 106 71 

Egg4_ 106 68 

Egg 5 110 71 

Egg6 111.5 70 

Egg 7 109.5 70 

Egg8 108 70 



Length Width 



Mm Mm. 

Clutch No. 3: 

Eggl 119.6 75 

Egg2 118.5 74 

Egg3 118.5 74.5 

Egg 4. 121 76 

Egg5 — 123 74 

Clutch No. 4 : 

Eggl 112 73.5 

Egg2 - 112.5 74 

Egg3 -- 113 73 

Egg4 112 72.5 

Egg5 114.5 72.5 



202 



APPENDIX 4 



Length Width 



Length Width 



Mm. Mm. 



Mm. Mm. 



Clutch No. 5: 

Egg 1 108.5 

Egg2 111 

Egg 3... 113.5 

Egg4 113 

Egg 5 108 

Egg6 Ill 

Clutch No. 6: 

Eggl 109 

Egg 2 109.5 

Egg3 110.5 

Egg 4 107.5 

Egg 5 108 

Clutch No. 7: 

Eggl 108 

Egg2 107 

Egg3 108 

Egg 4 109 

Egg5 110 

Clutch No. 8: 

Eggl 112 

Egg 2 105.5 

Egg 3 109 

Egg 4 106 

Egg 5 110.5 

Egg6 106.5- 

Clutch No. 9: 

Eggl.. 106 

Egg2 113 

Egg3 110 

Ege4 110 

Egg 5 109 

Egg 6 109 

Clutch No. 10: 

Eggl 118 

Egg 2 117 

Egg 3 114 

Egg 4.... 117 

Egg 5 117 

Clutch No. 11: 

Eggl 104.5 

Egg 2 ---- 104 

Egg3 106 

Egg4 107 

Egg 5 108 

Clutch No. 12: 

Eggl 104 

Egg 2 106 

Egg3 105 

Egg4 105 

Egg 5 105 

Egg 6 104 



71 

70.5 

69 

68 
71 
71 

71 

73 

72.5 

72 

71.5 

72 

72 

72 

71.5 

73 

72.5 

71.5 

72 

71 

72.5 

72 

75 
75 
74 
73 

75 
75 

76.5 
75 

75.5 
74.5 

77 

72 

70.5 

71 

71.5 

72.5 



Clutch No. 13: 

Egg 1 120 

Egg 2 116.5 

Egg3 114 

Egg4 117 

Clutch No. 14: 

Eggl. 113.5 

Egg2 113.5 

Egg3 111 

Egg4 108 

Egg5 109 

Egg 6 110 

Clutch No. 15: 

Egg 1 114.5 

Egg 2 115.5 

Egg 3... 114 

Egg4 111.5 

Egg 5 113.5 

Egg6 113 

Clutch No. 16: 

Egg 1 116 

Egg 2 121.5 

Egg 3 114 

Egg4 117 

Clutch No. 17: 

Egg 1 109 

Egg 2 107.5 

Egg 3 105.5 

Egg 4 105.5 

Egg 5 108.5 

Egg 6 109 

Clutch No. 18: 

Egg 1 110 

Egg 2 111.5 

Egg 3 106 

Egg 4 112 

Egg 5 108 

Clutch No. 19: 

Eggl 107 

Egg 2 106.5 

Egg 3 104.5 

Egg4 111.5 

Clutch No. 20: 

Eggl 109 

Egg 2 108 

Egg3 104 

Egg 4 109 

Clutch No. 21: 

Eggl 115 

Egg 2 114 

Egg3 112 



76 
74 
74 
72 

76.5 

75 

74.5 

74 

77.5 

74 

74.5 

72 

73 

73 

71.5 

74 

73 
73 

74 
74 

71 

69.5 

67.5 

69 

69.5 

70.5 

71.5 
72 
72 
72 



72 

74 
74 
73 

72 
72 

70.5 
71 



Appendix 4. — Food Analysis 

The following detailed data were obtained by stomach or scat 
analysis. 

Stomach contents of predator-killed cygnet, estimated age 4 weeks, in Yellow- 
stone Park, found and examined by Condon : 

Freshwater fairy shrimp (Eubranchipus sp.) — three complete specimens 

plus several fragments 
Carex sp. — shoot fragments 
Char a sp. — small piece 
Quartz sand grit — considerable quantity 
Stomach contents of 6 cygnets, estimated ages 3-4 weeks, found dead, 5 on 
loafing ground and 1 at nesting site, at Red Rock Lakes Refuge (Montana) on 
July 12, 1951, by Banko (analysis by Charles C. Sperry, Section of Food Habits, 
U.S. Fish and Wildlife Service, March 19-20, 1952) : 



FOOD ANALYSIS 203 

209941 (RR1) female. 

Percentage of animal matter — 0; of vegetable — 100; of gravel — 40. 

Contents : Leaf and stem fragments of aquatic plants — 98 percent. 
Seeds: 34 Car ex (plus fragments of a few more) — 2 percent; 1 
Eleocharis, 1 Hippuris, and 2 Myriophyllum — trace. 

209942 (RR2) sex (?) : 

Percentage of animal matter — trace ; of vegetable — 100 ; of gravel — 25. 

Contents : Leaf and stem fragments of aquatic plants — 95 percent. 
Seeds: 126 Carex (and fragments of a few more) — 5 percent; 5 Eleo- 
charis, 1 Galium, and 2 Myriophyllum — trace. 

209943 (RR 3) female, weight 449.5 gms. 

Percentage of animal matter — ; of vegetable — 100 ; of gravel — 18. 
Contents : Leaf and stem fragments of aquatic plants — 80 percent. 
Seeds: 208 Carex (plus many fragments) — 20 percent; 2 Eleocharis, 

1 Galium, 2 Hippuris, 2 Myriophyllum, 2 Potamogeton, and 5 
Scirpits — trace. 

209944 (RR4) male. 

Percentage of animal matter — ; of vegetable — 100 ; of gravel — 75. 
Contents : Leaf and stem fragments of aquatic plants — 100 percent. 

209945 (RR 5) male, weight 381 gms. 

Percentage of animal matter — ; of vegetable — 100 : of gravel — 20. 

Contents : Leaf and stem fragments of aquatic plants — 90 percent. 
Seeds: 86 Carex (and fragments of about as many more) — 10 per- 
cent; 4 Eleocharis, 1 Myriophyllum, and 11 Scvrpus — trace. 

209946 (RR 6) sex ( ?), weight 447 gms. 

Percentage of animal matter — 0; of vegetable — 100; of gravel — 25. 
Contents : Leaf and stem fragments of aquatic plants — 90 percent. 
Seeds : 51 Carex (and fragments of about as many more) —10 percent ; 

2 Eleocharis and 1 Scirpus — trace. 

Analysis of 17 samples of droppings from Grebe Lake, Yellowstone Park. 
Collected September 2, 1943, by O. J. Murie : 

Algae — About % of the droppings are hard or very hard and these almost 
invariably consist largely of filamentous green algae intermingled with 
much fine quartz grit. 

Carex — Four of the 17 envelopes contained droppings that consisted largely 
of remains of Carex spikes (the perigynia, achenes, scales and rachis). 

Potamogeton — Seeds of a Potamogeton resembling P. pusillus were found 
in one sample. It is suspected that the unidentified herbaceous vegeta- 
tion found in 6 samples (of the 17) may be largely Potamogeton. 

Nuphar polysepala — In a sample consisting largely of Carex but also con- 
taining considerable algae, fragments of the seed wall of Nuphar polysepala 
were present to the extent of 10-20 percent of the whole. 

Sagittaria — Shredded tissues in one sample are suggestive of Sagittaria 
but definite identification could not be made. 

State of plant material — Most, possibly all, of the plant material seems to 
have been in a living state when eaten though in some cases the color of 
the substance does not seem to support this. 

Insect — Animal material was almost negligible in the dropping samples. 
However, in the one sample containing seed fragments of Nuphar to- 
gether with Carex, there were numerous specimens of caddis fly larvae 
(Trichoptera) totaling possibly 5 percent of the whole. 



204 APPENDIX 4 

Report on the examination of 2 stomachs collected on the Red Rock Lakes 
Refuge, Montana, by A. V. Hull. Analysis by Sperry : 

206172, female, killed by flying into a fence. December (early) 193.S. 

Stomach — full ; gullet — full. 

Percentage of animal matter — trace ; vegetable — 100 ; sand and gravel, 
etc.— 10. 

('(intents: Potamogeton pectinatus, 443 tubers (largest being i/> x % 
inch) and fragments of rootstock — 100 percent ; 1 caddis larvae ease — 
trace : fragments of 2 gastropods — trace, and possibly taken as 
"gravel", which was 70 percent fine sand. Weight of food : gullet — 
4 oz. ; gizzard — 3% oz. Weight of gravel: 2 oz. (in gizzard). 
20«r.K>, sex ( V) . June 10, 1939. 

Stomach— full ; gullet— full. 

Percentage of animal matter — trace ; vegetable — 100 ; of sand and gravel, 
etc.— 15. 

('(intents : Potamogeton pectinatus, 597 tubers (largest being % x % x % 
inch), rootstock fragments and parte of leafy plant— 96 percent (leafy 
part about 6) ; other leaf and stem material: Ranunculus aquatilis — 
3 percent; CeratopJiyllum — trace; also algae (fine stringy type) — 1 
percent. Seeds: 29 Carex, 1 Hippuris vulgaris, 3 Scripus acutus, 84 
Potamogeton, 1 Sparganium, and 1 Zannichellia — trace; 2 caddis 
larvae cases — trace. Notes on weights: food (wet) — 11% oz. ; sand 
and gravel — 2 oz. ; stomach and gullet tissue (wet) — 6 oz. 

Stomach examinations of trumpeters found at Picnic Springs, Red Rock Lakes 
Refuge, Montana, by A. V. Hull. Report by E. R. Kalmbach, in charge, Denver 
Laboratory. U.S. Fish and Wildlife Service: 

212892, adult. Examined by F. M. Uhler, April 2-7, 1937. 
Percentage of animal matter — 0: vegetable — 100 percent: 3 lead shot. 

gravel, etc. — 30 percent. 
Contents : leaves and stems of white water buttercup ( Ranunculus sp. — 
probably R. trichophyllus) — 70 percent; aquatic mosses {Ambly- 
stegium sp. — 30 percent and Fissidens sp. — trace). 

212893, juvenile. Examined by C. Cottam, April 2-7, 1937. 

Percentage of animal matter — ; vegetable — 100 percent ; 17 lead shot, 
gravel, etc. 

Contents: 1 seed of Potamogeton perfoliatus ; moss plant fiber: unde- 
termined plant fiber. (The stomach was too nearly empty to give 
percentages. ) 

212894, juvenile. Examined by C. Cottam, April 2-7, 1937. 

Percentage of animal matter — 1 percent : vegetable — 99 percent ; 11 
lead shot, tooth of Thomomys sp., gravel, etc. — 33 percent. 

Contents: plant fiber of white water buttercup. Ranunculus (Ratrach- 
ium), probably trichophyllus — 63 percent: moss, Fissidens, probably 
grandifrons — 30 percent: moss, Calliergon sp. — 3 percent; moss, 
Amblystegium sp. — 1 percent; buds and leaves of Potamogeton 
panormitanus — 1 percent; 3 seeds of Potamogeton perfoliatus — tr. ; 
7 seeds (2 species of Carex sp. — tr. ; undetermined plant fiber — 1 per- 
cent : 3 larvae of caddis fly of ."> species, one of which appeared to be 
a Hydropsychidae — 1 percent: fragments of larvae of Dytiscidae — tr. 
mollusk shell fragment — tr. (Feather fragments — 2 percent). 

On the basis of the material available I should say that each bird had 
succumbed to lead poisoning. The stomach of the adult male contained 



APPENDIX 5 



205 



three pellets of lead, weighing 0.248 gram. The juvenile female had eleven 
pellets of lead, weighing 0.498 gram, and the juvenile male, seventeen pellets, 
weighing 0.857 gram. 

In each instance there was a pronounced greenish discoloration of the 
contents, and a hardening of the gizzard pads. 



Appendix 5. — Supplementary Data, Annual Swan Census 



Period 



Fall 1929. 



Summer 1930. 



Summer 1931. 



Summer 1932. 



Summer 1933. 



Summer 1934. 



Summer 1935. 
Summer 1936. 



Summer 1937. 



Aug. 4-7. 1938. 



Aug. 15-16, 1939. 
Aug. 16-17, 1940. 

Aug. 15-16, 1941.. 
Aug. 20-22, 1942.. 
Aug. 26-28, 1943. 
Aug. 12-18, 1944. 



Coverage; Agency 



Yellowstone Park (NTS) - 



Yellowstone Park, Jack 
son Lake Swamp 

(NPS). 

Expanded coverage in 
Yellowstone Park 

(NPS). 



Further expanded cover- 
age in Yellowstone 
Park, also including 
Red Rock Lakes area 
(NPS). 

Coverage similar to 1932 
(NPS). 



do 



.do. 



Yellowstone Park plus 
adjacent areas (NPS). 

R.R.L. Refuge and ad- 
jacent areas (FWS). 

Coverage similar to 1936 
(NPS and FWS). 



.do. 



Coverage similar to 1938 
(NPS and FWS). 



Yellowstone Park only 
partially covered 
(NPS). 

Refuge census expanded 
to include many con- 
tiguous areas (FWS). 

Yellowstone Park only 
covered (NPS). FWS 
coverage expanded. 

No census in Yellowstone 
Park. 

FWS coverage same as 
1941. 

No census in Yellowstone 
Park. 

FWS coverage similar to 
1942. 

Yellowstone Park and ad- 
jacent areas (NPS). 

R.R.L. Refuge and ad- 
jacent areas (FWS). 



Remarks 



Survey only, complete 
census not attempted; 1 
nesting pair located 
(Trumpeter Lake). 

Survey expanded; 1 nest- 
ing pair — Trumpeter 
Lake, Tern Lake, Jack- 
son Lake swamps. 

Initial complete census 

attempted; nesting pairs 

—Yellowstone Park (4), 

Jackson Lake swamps 

(1). 

Nesting pairs — Yellow- 
stone Park (4) Red Rock 
Lakes (5), Hebgen Res- 
ervoir (1). 

Nesting pairs — Yellow- 
stone Park (3), Red 
Rock Lakes (7) (aerial 
census recommended for 
1934). 

Nesting pairs — Yellow- 
stone Park (6), Red 
Rock Lakes (7), Henrys 
Lake (3), Rock Lake, 
Wyo. (1). 

Detailed data missing 



Bridger Lake and Squirrel 

Meadows included. 
Henrys Lake, Elk Lake, 

Blake Slough included. 
Coverage probably not 

quite as complete as 

1936. 

Winegar area adjacent 
Yellowstone Park in- 
cluded; both Park and 
Refuge counts con- 
ducted Aug. 4-7. 

Coverage probably equal 
to or slight lv greater 
than in 1938. 

Park areas missed in 1940 
held 10 swans in 1939. 

Malheur and Elk Refuges 
included for first time. 



Areas adjacent Yellow- 
stone Park not included. 

Ennis and Elk Lakes in- 
cluded. 

No census personnel for 
park due to World War 
II and bad fire season. 

No census personnel for 
park— World War II. 



Including Indian, Loon. 

Puddle, Chain Lakes. 
Sheridan Reservoir, 

Wade, and Conklin 

Lakes. 



References 



Joseph Lixon, 1931: 452. 
Wright and Thompson, 
1935: 104. 

Wright and Thompson, 

1935: 104. 
E. L. Arnold, ltr., August 

1930. 
Q. W. Wright, ltr., May 2, 

1934. 
Q. W. Wright, ltr., May 2, 

1934. 

Do. 



Do. 



F. W. Childs. ltr., Oct. 20, 
1934. 



Unsigned report (NPS 

files). 
E. B. Rogers, ltr., Aug. 19, 

1936. 
A.V. Hull, ltr., July 28, 

1936. 
E. B. Rogers, ltr., July 24, 

1937 
A. V.' Hull, ltr., Aug. 5, 

1937. 
E. B. Rogers, ltr., Aug. 15, 

1938 
A. V.' Hull. ltr.. Sept. 8, 

1938. 

E. B. Rogers, ltr., Aug. 23, 

1939. 
A. V. Hull, ltr., Aug. 19, 

1939. 
E. B. Rogers, ltr., Sept. 24, 

1940. 
A. V. Hull, ltr., Oct. 31, 

1940. 



E. B. Rogers, ltr., Aug. 19, 

1941. 
A.V. Hull, ltr.. Aug. 20, 

1941. 
E. B. Rogers, ltr., Aug. 18, 

1942. 
A. V. Hull, ltr., Sept. 11, 

1942 
E. B. Rogers, ltr., Oct. 8, 

1943 
w. .\V. Sharp, ltr., Sept. 2, 

1943 
E. B. Rogers, ltr., Sept. 1, 

1944. 
\\ . M . Sharp, undated ltr., 

1944. 



206 



APPENDIX 5 



Appendix 5. — Supplementary Data, Annual Swan Census— Con. 



Period 



Aug. 16-31, 1945. 



Aug. 11-17, 1946. 



Aug. 10-16, 1947.... 

Aug. 16-20, 1948. ... 

Aug. 3-5, 1949. ... 

Aug. 1-4, 1950 

July 31-Aug. 3, 1951 

July 16-21, 1952 

Aug. 3-6, 1953 

Aug. 31-Sept. 3, 1954 
Aug. 29-31, 1955... . 
Aug. 27-31, 1956.... 
Aug. 20-23, 1957.... 



Coverage; Agency 



No census in Yellowstone 
Park (NPS). 

R.R.L. Refuge and adja- 
cent areas (FWS). 



Yellowstone Park, great- 
est coverage to date 
(NPS). 

R.R.L. Refuge and adja- 
cent areas (FWS). 



Yellowstone Park, cover- 
age similar to 1946 
(NPS). 

Refuge and adjacent area 
coverage similar to 1946 
(FWS). 

Yellowstone Park and 
adjacent areas (NPS). 

FWS coverage of refuge 
and adjacent areas simi- 
lar to 1947. 

Coverage similar to 1948 
(NPS and FWS). 



Coverage similar to 1949 
(NPS and FWS). 



Coverage comparable to 
1950 (NPS and FWS). 



Aerial coverage, similar to 
1951 (NPS and FWS). 



Aerial coverage, similar to 
1952 (NPS and FWS). 



Aerial coverage, similar to 
1953 (NPS and FWS). 



Aerial coverage, similar to 
1954 (NPS and FWS). 



Aerial coverage, similar to 
1955 (NPS and FWS). 



Aerial coverage, similar to 
1956 (NPS and FWS). 



Remarks 



No census personnel 

World War II. 
Coverage similar to 1944.. 



Ground count swans on 21 
of 68 lakes checked. 

Aerial coverage for 1st 
time. 



Oround and aerial counts 
in park. 

Aerial counts in refuge and 
vicinity. 



Park, refuge, and adjacent 
areas covered aerially; 
similar to 1947, Ruby 
Lake Refuge included. 

Aerial counts all areas; 
Railroad Ranch area 
added. 

Aerial counts, all areas 



.do. 



Bridger Lake and waters 
north of Moran, Wyo., 
added. 

Upper Jackson Hole areas 
included for first time. 



Teton National Park 
added. 



Does not include 6 swans 
transferred from Red 
Rock Lakes to Delta, 
Manitoba, before census. 

Same NPS and FWS ob- 
servers conducted census 
1950-1956. 

Pair-family-group status 
tabulated for 3d year. 



References 



E. B. Rogers, ltr., Aug. 13, 

1945. 
Refuge Narrative Report, 

May-August 1945. 
MacDonald, ltr., Oct. 1, 

1945. 
E. B. Rogers, ltr., Aug. 27, 
1946. 

Refuge Narrative Report, 

May-August 1946. W. 

M . Sharp, undated report, 

1946. 
E. B. Rogers, ltr., Sept. 10, 

1947. 

Refuge Narrative Report, 

May-August 1947. 
W. N. Anderson, ltr., Sept. 

19, 1947. 
E. B. Rogers, ltrs., Aug. 24 

and Sept. 1, 1948. 
W. N. Anderson, ltr., 

Sept. 22, 1948. 

E. B. Rogers, ltr., Aug. 9, 

1949. 
Refuge Narrative Report, 

May-August 1949. 
E. B. Rogers, ltr., Aug. 11, 

1950. 
Refuge Narrative Report, 

May-August 1950. 
E. B. Rogers, ltr., Aug. 6, 

1951. 
Refuge Narrative Report, 

May-August 1951. 
E. B. Rogers, ltrs., July 22, 

1952. 
Refuge Narrative Report, 

May-August 1952. 
NPS Circular 12, Aug. 14, 

1953. 
Refuge Narrative Report, 

May-August 1953. 
NPS Circular 7, Sept. 8, 

1954. 
Refuge Narrative Report, 

May-August 1954. 
NPS Circular 11, Sept. 8, 

1955. 
Refuge Narrative Report, 

May-August 1955. 
NPS Circular 15, Sept. 7, 

1956. 
Refuge Narrative Report, 

May-August 1956. 
NPS Circular 15, Aug. 21, 

1957. 
Refuge Narrative Report, 

May-August 1957. 



INDEX 



accidents, 143. 

Adams, Edward, 22, 23, 24, 27, 189. 

Adams, Lowell, 2. 

aggression, interspecific, 104-106. 

Alaska, 2. 

Copper River Basin (includes 
Bremner and Tasnuma Rivers), 
32, 33-36, 52-54, 114. 
fossil swans, Kodiak Island, 9. 
Kenai Peninsula, 33-35, 114, 116. 

130. 
life zones, 38. 
migration, spring, 27. 
population : 

early trumpeter records, 22, 23, 

25. 
recent records. 7, 31-35, 145. 
swan census, 1949-57, 32. 
Alberta, 2, 31, 37, 38, 58, 80. 
Allen, J. A., 10, 189. 
American Fur Company, 13. 
Anderson. R. M., 24, 189. 
Arkansas, 26. 
Arkansas River, 15. 
Armstrong, E. A.. 87, 101. 102, 189. 
aspergillosis, 140. 141. 
Atwood, Earl L., 3. 

Audubon, John James, 13, 15, 26, 28, 76, 
124, 167, 189. 

banding, 28, 182-183. 

bantam hens, 115. 124. 

Bailey, Alfred. 20, 28. 

Bailey, Florence, 28, 189. 

Bailey. Vernon, 17, 22, 35, 189. 

Baird. Spencer F., 17: with Thomas M. 

Brewer and Robert Ridgway. 24, 167- 

168, 189. 
Barnston. George. 17. 19. 23, 27. 125- 

126, 189. 
Harrows, Oeorge. see Oberhansley. 
Bates, J. M.,24. 189. 
bear, 131, 135. 



Bear River Migratory Bird Refuge, 129. 
Beard, Dan, et al., 137, 189. 
Bedford, Duke of, 168, 170, 171. 
Beebe, William, 5, 189. 
Beed, Watson E., 42. 
behavior, 77-93, 99-100. For aspects 
not listed in Contents, sec under swan 
species. 
Belknap, Jeremy, 10, 189. 
Bellrose, Frank, 136. 
Beltrami, Count G. E., 12. 14, 24. 
Bent, A. C, 21, 24, 26, 27, 28, 86, 114, 

126, 169, 190. 
Biological Survey, U.S., 166, 174. 
Blaauw, F. E., 70. 77, 117, 129, 143, 168, 

170, 171, 172, 190. 
Blines, Jasper, 12, 24, 190. 
bobcat, 133. 
botulism, 141. 
Branson, J., 33. 

breeding, 93-100: see also habitat. 
age, 94-96. 
range : 

Bewick's, whooper, whistling 

swans, 7. 
trumpeter. 7. 

Canadian, 14, 18-19. 
United States, 10-11, 12- 
13, 15-16, 20, 21, 22-26, 
31-37, 38-54. 
maps, 26, 39, 52. 
Brewer, Thomas. 167-168. 
British Columbia : 
behavior. 78, 81. 
breeding, 16, 31, 32. 
captivity, 170. 
distribution and range. 2, 7, 16, 26, 

27. 29, 31. 32. 33. 
food, 128. 

lead poisoning, 137-138. 
parasites, 141. 
predation, 134. 
starvation, 139. 
wintering, 7, 29, 31, 33. 



207 



208 



INDEX 



Brooks. Allan, 20: with H. S. Swarth, 

23, 190. 
Brower. J. V.. 21, 24. 190. 
Burnett. W. L., 20, 190. 
Butler. A. W.. 25. 190. 

California. 16, 17. 20, 28, 29. 
Canada. (See also Alberta, British Co- 
lumbia, Delta Waterfowl Research 
Station) : 

captivity, 168. 

distribution and range, 14, 17-19, 
23, 27, 37, 145. 

interspecific tolerance, 80. 

nesting, 113. 

longevity. 143. 

swan skin trade. 12, 13, 19. 
Canadian Company, 12, 13. 
Canadian Wildlife Service. 2, 37, 183. 
Cameron, E. S., 24, 69, 126. 
captivity of trumpeter. 123-124, 167- 

172. 188: see Malheur, Delta, 
census, annual swan, 144—161, 20.J-206. 
Chaddock. T. T.. 141. 142. 190. 
Chenopis atratus, 5, (5; see swan, black. 
Chesapeake Bay, 126, 129. 
Chicago Natural History Museum. 23. 

24. 
Christian. J. J.. 164. 190. 
clutch size, 114. 

Coale. H. K.. 9. 19. 24. 169, 190. 
Colorado. 20. 28. 
Columbia River, 12. 16-17, 25, 27, 28, 

126, 128. 

Colwell. Gwen, 78, 81. 190. 
Condon. David de Lancey. 2, 30. 64. 70. 
79-80. 85. 106. 110, 111, 112, 116, 123, 

127. 131. 132. 135. 13(5. 137. 138-139, 
175, 190. 

Connecticut. 10, 169. 

Cooke, Wells W., 24, 190. 

Cooper, J. G., 16, 27, 190. 

COOt, 104-105. 

Copper River Basin, see Alaska. 

Coues, Elliot, 11. 12, 21. 24, 25. 68, 100. 

< 'ot tain. Clarence, 35. 

Cowan, Ian McTaggart, 2!t. 128, 141-141, 

101. 
coyotes, 133. 134-135, 174, 177. 
Culver. Lillian, 169-170. 
Currituck Sound, 129. 



cygnets, trumpeter: 

captivity. 124-124, 171. 

description, 62-63, 70-71. 

development, 117-122. 

food, 122-125. 

mortality, 132, 173. 

population dynamics, 14.1-164. 

supervision by parents, 117, 118. 

and weather, 138-139. 

weight. 117, 120. 
cygnets, whistling, 63. 
Cygninae. description and systematica. 

2, 5, 6. 
('Minus melancoriphus, 5, ; .sec swan, 

black-necked. 
Cygnus, olor, 5, 6: .sec swan, mute. 
Cygnus paloregonus, 8. 

Dall, W. H., and H. M. Bannister, 23, 

31, 191. 
Darling, J. N. 175. 
death, see mortality. 
Delacour. Jean. 6, 70, 91, 95. 116-117, 

168 : and Ernst Mayr, 91, 94, 191. 
Dementiev. Georges, and N. Gladkov, 

6, 191. 
Denmark, 104-105. 129, 130, 187. 
Delta Waterfowl Research Station, 3, 

71, 120. 129. 136. 140, 142, 181. 
Derscheid. J. M.. 172, 191. 
De Smet, Pierre Jean. 14, 15-16, 24. 
Dewar, J. M.. 98, 191. 
Dickinson, E. M.. 140-141. 
disease, 140-141. 
display. 86-93. 95. 
distribution, trumpeters : 

I nited States, 6-7, 8-37, 199-201. 

Canada, 14, 17-19, 23, 27, 37, 145. 
Dixon, Joseph. 130-131. 173. 174. 175, 

191. 205. 
ducks. 101. 104-105. 

goldeneyes, 00, 187. 

mallard. 59, 93. 105, 187. 

merganser. 59. 

pintails. 93. 

ruddy, 105. 

scaup, lesser, 105. 

eagle. 56. 

bald. 88. 

golden. 133. 134. 
Edge. Rosalie, 176. 
Edwards. Ralph, 83, 134. 



INDEX 



209 



eggs, trumpeter : 

clutch size, 114. 

description, 113-114. 201-202. 

failure, 130-131. 

incubation and hatching, 114-115, 
116. 

price, 19. 
Ellis, John, 98, 191. 
Emergency Conservation Committee, 

176. 
England, 97, 168, 187. 

Queen of, 168. 
Erickson, Ray C. 3, 65, 91-92, 94-95, 

101. 105, 125. 
Errington, Paul, 164, 191. 
escape-distance, 78-79. 
Evans, A. H., 143. 191. 

family ties, 06-98, 117-120, 121-122. 
Featherstonhaugh, Duane, 24, 32, 61, 

80, 81, 105, 136, 137, 191. 
Fish and Wildlife Service, U.S., 2, 23, 
40, 144-145, 188. 

I>enver Wildlife Research Labora- 
tory, 123, 127, 137. 
Patuxent Research Refuge, 143. 
168, 170. 
flight, 73. 74-77. 
Florida, 8. 
flyways : 

Atlantic. 7. 20, 37. 
Central. 20, 35-37. 
.Mississippi. 20. 28, 37. 
Pacific, 7, 20, 28-35. 
food : 

other swans, 129. 

trumpeter, 122-130, 177-17S. 185- 
186, 202-205. 
foot deformities. 140. 
Forhush, Edward Howe, 20, 00, 10.1 

166, 191. 
Fordyce, A. Blaine. 3, 31. 
France. 168. 
Franklin Ray. 17, 18. 
French, Cecil. 21. 24. 170, 171. 
Friedmann, Herbert K., 3. 0, 101. 

Gabrielson, Ira .V. 20. and S. <;. Jew- 

ett. 32, 191. 
Germany, 129. 
Glacier National Park, 28. 

goose, Canada. 105, 172. 
snow. 106. 



Grand Teton National Park, 105, 120, 

184, 200. 
Grundtvig, F. L., 25, 192. 
Groves, Frank W., 29. 
gull, 132, 133, 140. 

habitat, breeding, 19-20, 38, 39-54. 
wintering, 55-61. 
maps, 26, 39, 52. 
Haecker, F. W., R. A. Moser. and J. B. 

Schwenk. 37, 192. 
Hanson, Fred, 169-170. 
Hanson, James F., 3. 
Hanson, Alta, 3, 169. 
Hart, R. O., 106, 192. 
hatching dates, 115-116. 
Hayden, A., 24, 173. 
Hearne, Samuel, 11, 26-27, 192. 
Heerman. A. L., 17, 192. 
Heinroth; Oskar and Magdelena, 3, 90, 

114, 129, 192. 
Henrys Fork, see Snake River. 
Herman, Carlton M., 142-143. 
Hewett, Stanley, et al., 29. 
Hilden. O., and P. Linkola, 89, 192. 
Hilprecht, Alfred, (i, 62, 70, 94, 101, 129, 

133, 143. 192. 
Hochhaum. H. Albert. 3, .S3, 106. 120. 

192. 
Holman. John P., 83. 134. 192. 
Hornaday, William T., 165, 192. 
Howard, L. O.. and W. F. Fiske. 163, 

192. 
Hudson Bay. 11. 19. 
Hudson's Bay Company. 11, 12, 13, 17- 

19. 
Hudson River. 02, 187. 
Hughes, J.O., 126, 192. 
Hull, A. V., 33, 11.-). 127, 128, 135, 137, 

170. 102, 204,20o. 
Hunt. Clarence. 173. 
hunting, 135-137. 166, 173, 174, 176, 187. 
hybridization, 172. 188. 

icing of swan plumage, 139-140. 

Idaho. 2. 24. 28, 30-31. 33. 54, 00. 70, 78, 
98, 130. 137. 13S. 144. 100. 10!). 17.-,, 
170. 200: see Island Park. Snake Riv- 
er. Railroad Ranch. 

illegal kills. 130 137. 173. 174. 170. 

Illinois. S, 0. 20,169. 

Illinois Natural History Survey, 136. 

incubation, 114-115; artificial, 116. 



210 



INDEX 



Indiana, 24. 

Indians, 4-5, 9, 10, 11, 13-14. 

interspecific tolerance. 80-83, 91, 104- 

106. 
Iowa, 20, 24, 25. 38, 167-168, 186. 
Island Park, 30, 55, .16-67, 61, 98, 137, 

139, 140, 143, 147, 200. 

Jackson Hole. 20, 24, 30. 55, 60, 139, 

166. 
James Bay, 19. 
James. Edwin. 25, 193. 
Jellison. William, 142. 
Jewett, S. G., et al., 29, 193. 
Johnsgard, Paul, 3. 
Johnson, Jim, 33. 

Kalnibach, E. R., 137, 204-205. 

Kansas, 20. 

Keating, William, 13, 193. 

Kellogg Bird Sanctuary, 126, 170, 171- 

172. 
Kenai Peninsula,. sec Alaska. 
Kennedy, George, 2. 
Kentucky, 13-14, 15. 167. 
Kenyon, Karl. 7. 
Kepner, E. L., 32. 
Kittams. Walter H., 2, 176. 
Kluijver, H. X., 164, 193. 
Knight. W. C., 21, 24, 193. 
Kodiak Island, see Alaska. 
Kortright, F. H., 65, 143, 193. 
Kumlien, Ludwig, and X. Hollister. 25. 

193. 
Kubichek. W. F.. 129. 

Lacey Act, 165. 

Lack, David, 164. 103. 

LaNoue. Francis, 72. 

Lattin, Frank H., 19, 193. 

Lawson, John, 10, 25, 26, 193. 

lead poisoning, 136, 137-138, 142, 204- 
205. 

legends. 4-5. 

legislation, protective. 165-167. 

Lewis and Clark expedition, 11-12, 24, 
25, 68, 125. 

life cycle, 62-143. 

life history studies needed, 186. 

Lima Reservoir. 147, 151, 199. 

Lister. R.. 37. 193. 

London, swan-skin market, see Hud- 
son's Bay Company. 



London Zoological Gardens. 168. 

Long. Stephen H. 13, 25, 26. 

longevity, 143. 

Lorenz, Konrad, 7!>, 90, 193. 

Louisiana, 15, 20. 

Low. G. C. !)7-0,s, 103. 

MacFarlane, Roderick. 17-l!>, 23, 113, 

114,193; sec Mair. 
Mackay, Ronald H.. 2, 31, 36, 122, 194. 
Mackenzie River, 17, 38, 113. 
Madison River, 36, 55, 59, 60, 61, 134. 
Madsen, H., 194. 
Maine, 169. 

Mair. Charles, and Roderick MacFar- 
lane, 18, 194. 
Malheur National Wildlife Refuge : 

accidents, 143. 

banding, 182-183. 

behavior, 83, 101, 105. 

breeding age, 94-95. 

disease, 141. 

food, 125, 128. 

management. 186. 

mortality, 133. 

population, 147, 200. 

transplanting, 29, 178, 180, 181. 
management of trumpeters, 165-188. 

recommendation, 183-138. 
Marler. George, 176. 
Maryland. 20. 
Massachusetts. 10, 169, 170. 
mating fidelity, 96. 
McDermott, John F., 13, 194. 
McKinney, Frank, 3, 91. 
McLean. Donald, 28, 29, 78, 194. 
menage a trois, 98. 
Merriam, C. Hart, 10, 21, 24, 194. 
Merrill. D. E.. 20, 194. 
Michigan, 28, 62, 187, see Kellogg Bird 

Sanctuary, 
migration. 25-37. 146-147. 
Migratory Bird Conservation Act, 166. 
Migratory Bird Treaty Act, 136, 165- 

166, 169, 171. 
mink, 132. 
Minnesota. 13, 16, 20. 24. 27, 28, 37, 38, 

169, 186. 
Mississippi River, 14, 15, 26 : see Fly- 
ways. 
Missouri, 11,12,20,24,38. 
Missouri River, 11, 25. 
Monson, Melvin A., 33, 52-54, 114, 194. 



INDEX 



211 



Montana, 16, 20, 24, 28, 31, 36, 38, 54, 
55, 60, 61, 134 ,136, 144, 166, 169, 170, 
174, 186, 200; see Red Rock Lakes 
Refuge. 

Mosher, A. D., 24, 194. 

mortality, 131-142, 183. 

Morton, Thomas, 10. 

Munro, J. A., 23, 29, 31, 78, 128, 137- 
138, 139, 194. 

Murie, Adolph, 135, 194. 

Murie, Olaus, J., 127, 139-40, 203. 

muskrat, 43, 51, 105, 106, 111. 112, 177. 

National Elk Refuge : 

breeding, 80, 95, 96. 

hunting, 167. 

incubation, 115. 

population, 200. 

transplanting, 178, 180. 

wintering, 30, 55, 60, 61. 
National Museum, U.S., 2, 3, 23, 24. 
National Park Service, 2, 60, 144-145, 
172-176 ; see Condon. Dixon Ober- 
hansley, Thompson, Wright. 
National Zoological Park, 169, 182. 
Nebraska, 20, 24, 27, 36, 38, 186. 
Nelson, Aimer P., 80, 115, 178-179. 
Nelson, E. W., 23, 32, 194. 
Nevada, 29, 178, 200; see Ruby Lakes 

Refuge, 
nesting : 

nest building, 45, 111-113. 

nest sites and territory, 106-11, 154, 
177. 
New England, 10. 
New Hampshire, 10. 
New Mexico, 20. 
New York Zoological Park. 141. 143. 

165. 
New York Zoological Society, 16!>. 
Newberry, I. S., 16-17, 28, 194. 
Nice, Margaret M., 100. 110, 194. 
Nicholson, A. J., 164-165, 195. 
non-nesters, 110. 
North American Wildlife Conference, 

174. 
North Carolina, 10-11. 20. 2.".. 
North Dakota. 20. 24, 37. 120. 1st;. 
Northwest Company, 13. 
Nute, Grace Lee. 13. 195. 
Nuttall, Thomas, 19, 195. 



Oherhansley, Frank, and Maynard Bar- 
rows, 74, 82, 84, 85, 106, 111, 112, 115, 
117, 120, 122-123, 125, 126-127, 175. 

Ohio, 9, 167, 68, 170, 171. 

Ohio River, 11, 14, 15, 28. 

Olor beicickii, 6 ; see swan, Bewick's. 

Olor buccinator, 6 ; see swan, trumpe- 
ter. 

Olor columbianus, 6, 7; see swan, whis- 
tling. 

Olor cygnus, 6 ; see swan, whooper. 

Oregon, 8, 9, 16, 20, 29, 140; see Mal- 
heur Refuge. 

Orton, Alda, 35, 195. 

otter, 132. 

Pacific Railroad Surveys, 16-17. 

pair formation, 94. 

Paleocycnus, 8. 

Paludan, Knud, and J0rgen Fog, 104- 

105, 129, 130. 195. 
parasites, 141-143. 
Parmalee, P. W., 9, 195. 
Patrick, R. W.. 82, 195. 
Philadelphia Zoological Garden, 143, 

169. 
Pilder, Hans, 12, 195. 
Pirnie, Miles D., 126, 170, 171-172. 
population, 7, 61. 144: dynamics, 145- 

104. 
Poulsen, II.. 78, 7!t. 85, 07. KM). 114-115, 

195. 
predation, ."><*>. 

avian. 131-134. 

mammalian, 131. 133, 134-135. 

on eggs, 130-131. 

control at Yellowstone. 1 14. 
prenesting behavior, 99 100. 
Puget Sound. Hi. 27. 

Railroad Ranch. 56, .",7. 60, 01. 66, 1SH. 
range of trumpeter, ('». 20, 39 ; see dis- 
tribution. 
Red Rock Lakes area. 21-22, 160. 162, 

100 170. 173-174. 
Red Rock Lakes Migratory Waterfowl 
Refuge: 

description of refuge. 2. 38, 40-49, 

51, 102. 
establishment 1. 28, 166, 174. 
map, 40. 



212 



INDEX 



Red Rock Lakes Migratory Waterfowl 
Refuge — Continued 
trumpeters at : 

banding. 28. 182-1N<>. 
behavior, 78-79, SO-si. 82-83, 

92. 
breeding and nesting, 20, 21, 24, 
28, 40-49, 95, 98, 99, 103-104, 
106, 107-108, 110, 111-113, 
114, 115-117, 119-120, 154, 
174. 
cygnets, 119-121, 123-124, 131- 

133. 
description. 65, 72-73. 
food, 123-124, 127-128. 
limiting factors. 131-133. 134. 
135. 136. 137. 138, 140. 142. 
143. 
management, 176-178, 184-186. 
migration. 26, 27. 
population. 145, 146. 147. 150, 

151-155, 162, 199. 
predation, 130, 132. 
transplanting, 29, 178, 180. 
wintering, 55, 58, 59, 61, 88, 138, 
139, 187. 
renesting, 116. 
Richardson. John, 14. 19, 23, 27, 64. 65 : 

see Swainson. 
Roberts, T. S., 12, 24, 169, 195. 
Rogers, Edmund B., 2, 175, 205-206. 
Rooney, James. 2. 

Ruby Lake National Wildlife Refuge : 
banding. 182-183. 
breeding age, 96. 
disease, 141. 
population, 147, 200. 
predation. 133. 

transplanting, 29, 178-179, 181. 186. 
Russia, 22. 

Salter. Robert, 30, 195. 

Saskatchewan, 27. 

Saunders. Aretas A.. 24, 195. 

Scott, Peter, and James Fisher, 73, 81- 

82, 118-119. 195. 
Sharp. Ward M., 115, 117, 120. 132-124, 

132, 134. 140. 142, 175, 195, 205. 
Sibley. Charles L.. 172. 195. 
Silloway, P. M.. 24. 195. 
Simon, James R., 120. lit.".. 
Skinner, M. P., 21. 24, 172, 196. 
skunk, 133. 



Smith. H. M.. 21. 

Smith. II. S.. 164. 196. 

Smith, Stuart G.. and Eric Hosking, 82, 

196. 
Smithsonian Institution. National Mu- 
seum. 2, 3, 23. 
Snake River, 30. 55. 56-57, 59, 128, 136, 

176, 186. 
Soper, J. D., 23, 37, 196. 
South Dakota, 13.27, 186. 
Spencer, David, 33, 114, 116. 
Sperry, Charles S., 21, 24, 175, 202-203, 

204. 
starvation, from freezeup, 139. 
Stejneger. Leonard, 65, 67-68. 196, 198. 
Stewart. Robert E., and Joseph H. Man- 
ning. 7. 126, 12!). 196. 
Stowe, Leland, 83, 196. 
Suckley, George, 16, 24, 27, 196. 
Swainson, William, and John Richard- 
son, 14, 27, 196. 
swan : 

description, swans of the world, 

198. 
legend and tradition, 4-5. 
Bewick's, 6, 7, 14, 62. 100. 
black, 5. 6, 70, 116, 129. 
black-necked, 5. 6, 70, 86, 116. 129. 
mute : 

behavior, 82, 94. 
bill, 5. 

Classification, 6. 
description, 5-6, 62. 
egg-laying, 114. 
escape-distance, 78-79. 
feral. 62, 187. 
food. 126. 129. 
hybridization, 172, 188. 
incubation, 114, 115. 
mating fidelity, 97-98. 
territory. 100-101. 104-105. 
transplanting, 187. 
trumpeter (topics not listed in 
Contents) : 
accidents, 143. 
hill, color. 65 : size. 07-08. 
botulism, 141. 

captivity, raised in. 123-124. 
carrying young. 86. 
comparison with whistling 

swan. 7. 10, 14. (.4-69. 
cygnets : see cygnet, trumpeter. 



INDEX 



213 



swan — continued 

trumpeter (topics not listed in 
Contents ) — continued 

disease, 140-141. 

drinking, 85, 86. 

eggs, see eggs, trumpeter. 

head attitude, 86. 

hybridization, 172, 188. 

family ties, 96-98, 117-120, 
121-122. 

foot, attitude, 86, 121 ; deform- 
ities, 140. 

hunting, 22, 135-137, 166. 

icing of plumage, 139-140. 

illegal kills, 136-137, 142, 204- 
205. 

molt, 72-74. 

plumage shaking, 84, 85-86. 

predation, 130, 132, 134-135, 
174. 

productivity, 148, 149, 152, 153, 
157. 158 ; see population dy- 
namics. 

resting, 84-85. 

sex differences, external, 86, 
120. 

starvation, 139. 

submerging and diving, 84. 

tail feather count, 65. 

trachea. 14, 67. 

weather and mortality. 138- 
140. 
whistling : 

comparison with trumpeter, 7, 
10, 14, 64-69. 

description, 6. 7, 63-64. 

disease, 141. 

distribution, 7, 33. 60. 

eggs, 19. 

escape-distance, 78. 

hybridization, 172. 

parasites, 141-142. 

population, continental. 7. 

trachea, 14, 66. 

wintering. 60-61. 
whooper: 

behavior, 87. 89. 94. 

cygnets. 118-119. 

description, 6, 14. 62. 

distribution. 6-7. 

escape-distance, 78-812. 



swan — continued 

whooper — continued 

flight, 76. 

food, 129. 

hybridization, 172. 

incubation, 115. 

interspecific tolerance, 100. 

molt, 73. 

territory, 100, 102. 
swan skins, trade in and commercial 

use. 12, 13, 19. 
Swann, H. Kirke, 143, 196. 

territorialism, 99, 100-110. 

Texas, 20, 21. 

Thomas, E. S.,9,24. 

Thompson, Ben, 21, 35, 131, 173, 174, 

196, 205. 
Thwaites, R. G., 9. 16, 24, 27, 196. 
Ticehurst, Norman F., 5, 196. 
Toll, Roger, 174, 175. 
Townsend, John Kirk, 27. 
transplanting, 29, 178-182 ; see Malheur, 

National Elk, Ruby Lake Refuges. 
Traylor, Melvin, 23. 
Tnule, Sam A., 3, 24, 31. 
tuberculosis, avian, 140-141. 

Utah, 35, 169. 

Virginia, 20. 

Ward. Peter, 71. 142. 

Washington. 20. 24. 28, 29, 33 : »ee Pu- 

get Sound. 
Washington. D.C.. 168-169, 170. 

National Zoological Park. 169, 182. 
Watson. W. Verde. 105-106, 197. 
Watterson, W. II.. 94. 197. 
weather and mortality, 138-140. 
Weeks-McLean Law. it;.".. 
Weiser, C. S., 76, 1!>7. 
Wetmore, Alexander. (>. 8, 198, 197. 
Wetmore, Cecil, 3, 169. 
Widmann, Otto, 12.24. 197. 
Wilke. Ford. 7. 197. 
Wilson, C. P., 13. 
winter — 

counts, 60-61. 

management. 177-178, 17!>. 185 186. 

range. 10. 12. 15, 10-17. 20. 27-28, 
29-33,36,54 55, 144. 

maps. 26,39,52. 



214 



INDEX 



Wisconsin, 20, 24, 38, 141, 142. 

Witherby, H. F., et al., 6, 76, 82, 89, 
100-101, 114, 115, 122, 126, 197. 

Woburn, Abbey, 97, 168. 

Wood, J. C, 20, 24, 197. 

Wood, Norman A., 21, 197. 

Wright, George, 21, 35, 131, 173, 174, 
175, 197, 205. 

Wyoming, 2, 20, 24, 28, 35, 54, 55, 136, 
144, 166, 200; see Jackson Hole, Na- 
tional Elk Refuge, Yellowstone Na- 
tional Park. 

Yarrell, William, 14. 
Yellowstone National Park : 

description of swan habitat, 38, 48- 
53. 

breeding, 20, 24, 35, 48-52. 
wintering, 55, 58-59, 61. 
map, 52. 



Yellowstone National Park — Continued 
trumpeters in : 

behavior, 79, 82, 99, 105, 121. 

description, 70, 71, 72. 

food, 122-123, 125, 126-127. 

hatching, 115-116. 

illegal kills, 136. 

interspecific tolerance, 106. 

management, 174-176 ; recom- 
mendations, 184. 

molt, 74. 

nesting, 99. 

population, 146, 147, 155-160, 
161, 162-163, 172, 173, 200. 

predation, 105, 130-131, 132, 
134-135, 174-176. 

protection, 165. 

studies, 172-176. 

weather and mortality, 138- 
139. 
Yellowstone region, 21. 
Yocom, C. F., 24, 197. 



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