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UNITED STATES
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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 0
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
0
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 V2
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 C02. 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
0 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 swrans 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
swTans. 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 AATill 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 A7alid 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- actiAre 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 7y2
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 among1 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
0
3
2
4
1
0
0
0
0
3
3
5
2
4
1
4
0
2
0
2
3
0
3
4
0
4
0
2
0
2
3
3
3
4
0
4
0
0
0
2
3
3
3
2
0
4
0
2
0
2
3
3
3
1
1
4
0
2
0
0
3
3
3
0
1
3
0
2
0
2
3
3
0
1
1
2
0
3
0
2
3
3
3
1
1
2
0
0
0
2
No. 2
3
No. 3
2
No. 4
3
No. 5
1
No. 6
1
No. 7
2
No. 8
0
No. 9
3
No. 10
0
Total
31
17
5
3
0
0
1
1
2
1
2
1
1
1
1
1
1
1
0
0
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 snow7. 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 7y2'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
0
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
0
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
0
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
0
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
0 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
k4
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
0
13
10
0
18
12
0
17
11
0
18
9
0
22
2
0
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
0
0
3,5
1
3
0
1
3
0
0
1,3
0
3
0
1952.
1953.
1954.
1955.
1956
1957.
1
1
2
2
(')
1
3
2
2,2
3.3
0
1
3
1945
2
1946
2,1
1947
3,3
1948
0
1949
0
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 — 0 ; 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 — 0 ; 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 — 0 ; 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 — 0 ; 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, 0 ; .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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