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Snow Bunting
Plectrophenax nivalis
Contributed by David Freedland Parmelee
[Published in 1968:
Smithsonian Institution United States National Museum Bulletin 237
(Part 3): 1652-1675]
To those who dwell in the North Temperate Zone, the snow
bunting is the very epitome of an arctic bird, a true creature of
the snows for which it is so aptly named. It usually appears only
in the dead of winter, often on the heels of a storm that has
blanketed the countryside with white. Though certainly capable of
flying southward to warmer climes, it remains with the cold and
snow, and seldom strays below the northern two tiers of the United
States, content to glean its hardy livelihood from the few
seed-spikes of grasses and weeds the carpet of winter leaves
exposed. And as soon as the warming spring sun begins to melt the
wandering drifts, the vagrant flocks disappear as suddenly as they
came, on route back to their northern home.
But to those who know it on its northern breeding grounds, the
snow bunting is the harbinger of warmer times to come. As George
M. Sutton (1932) wrote after spending the long winter on
Southampton Island: "Only the North Countryman knows how
welcome is the cheerful greeting of the little Amauligak
when it returns in the Spring. The whole world may be white, the
sky overcast, and the wind boisterous or cruel; but when the Amauligak
comes, winter is near its end. All of us, even the fatalistic,
phlegmatic Eskimos, found ourselves listening every morning in
February for the familiar note of this bird. But Amauligak's
vital problems are not easily solved, when he returns too early;
so he waits until he is sure the drifts are soon to melt. And it
often seems that he is a long time in coming."
Much of the following account of this species is based on my
own experiences shared with G. M. Sutton (Sutton and Parmelee,
1954) on Baffin Island and with S. D. MacDonald (Parmelee and
MacDonald, 1960) on Ellesmere Island. Other detailed sources
referred to repeatedly by author only in the following pages are
those by Niko Tinbergen (1939), H. F. Witherby et a1. (1941), Finn
Salomonsen (1950-1951), and Alfred Watson (1957).
Spring.--T. S. Roberts (1932) thus
describes the species' departure from its wintering grounds in
Minnesota: "Migrating by day as well as by night, the Snow
Bunting may be seen on days in March and early April passing in a
continuous stream at no great height above the earth. It is not in
flock formation but scattered, the birds calling to one another as
they move steadily onward in undulating, erratic flight, a few
dropping out now and then to alight and feed."
The arrival date of snow buntings on the breeding grounds may
vary considerably from year to year in a given locality.
Salomonsen notes "When the spring is especially inclement the
Snow Bunting can be delayed almost a month." Tinbergen cites
the careful records kept by Johan Petersen, first governor of
Angmagssalik in southern Greenland, which showed first arrivals as
early as February 10th and as late as April 8th, with an average
arrival date for 17 years of March 21st. While Pleske (1928)
attributes such variation to climatic conditions in the breeding
area, Tinbergen thinks it "may be due to a considerable
extent to weather conditions at the last stage of the migration
route." The birds often arrived in southern Greenland
following stormy weather from the east. He adds: "The arrival
of new birds always occurred during the early morning, up to about
6 or 7 a.m.; during the first three hours after midnight, flocks
were often observed that did not alight but passed on."
MacDonald and I observed very much the same arrival pattern in
Ellesmere Island and also noted some diurnal migration in
midafternoon. In Greenland according to Salomonsen: "The
migration covers more than one month and usually continues over
the greater part of May. . . . The first birds to arrive are
always males, as normal in many passeres. However, the sexual
difference in migration is more pronounced in the Snow Bunting
than in any other bird. The females do not arrive until 3-4 weeks
after the males." At 80o N.
in Ellesmere we found the arrival period covered a span of at
least 46 days. We first noted a male on April 16, a female on May
21.
Plumage characteristics show the first males to arrive are
mostly those more than one year old. Few in numbers at first, they
flock near the coast while their numbers gradually increase; some
then disperse to higher country inland. When the first females
arrive some weeks later, they are often accompanied by newly
arriving males, many returning for the first time. We found mixed
flocks common in Ellesmere at the end of the migration period in
late May. The birds in these mixed flocks did not appear to be
mated on arrival.
Arrival dates in the Canadian Archipelago correspond roughly to
those recorded for Greenland and other parts of the species'
circumpolar range, being generally later at higher latitudes. A
few birds occasionally reach low-arctic localities in February,
but the first usually appear in March. The snow buntings seldom
reach the high arctic before April, Greely's (1886) report of one
in Hall Land beyond 81o N. on
March 14th being a notable exception. MacDonald (1953) recorded
the species on the north coast of Ellesmere Island beyond 83o
N. on April 27, and there are earlier April records for more
southern parts of Ellesmere and for high-arctic Greenland. Most
birds probably reach the northernmost breeding grounds in mid to
late May.
Territory.--The nesting habitat
of the snow bunting is confined at low latitudes to bare, stony
mountain-tops, rarely below 3,500 feet in Scotland according to
Witherby et al. (1941). In its arctic home, however, the species
nests from sea level along the coasts to considerable elevations
inland. Salomonsen notes they are found higher in the Greenland
mountains than any other bird, having been observed at 1,027
meters. On Baffin Island Watson recorded females at 1,050 meters,
males at 1,800-2,000 meters. On Bylot Island Van Tyne and Drury
(1959) recorded birds above 900 meters, and at Ellesmere MacDonald
and I frequently saw pairs at 600-700 meters elevation. Its
preferred habitat is rough, rocky country with interrupted
vegetation, as near stony beaches or in sea cliffs in coastal
areas, or in rocky outcrops at higher levels. Some of the lowest
breeding densities occur in grassy tundra with little broken or
rocky ground.
The size of the individual bunting territory may be
surprisingly large, commonly as much as 300 to 400 meters in
diameter. In optimum habitat where the population pressure is
great, Tinbergen records territory diameters "diminished to
about 50 to100 m. in most of the observed cases."
Nevertheless Van Tyne and Drury's (1959) report of two occupied
nests "within five yards of each other in the stone wall of
one Eskimo house" on Bylot Island must be regarded as
exceptional.
The early arriving males wander about the breeding grounds in
flocks for several weeks before showing signs of territorial
behavior. Tinbergen notes that as the season progresses, certain
individuals in the flock become noisier, begin to sing softly,
grow more excitable, and quarrel occasionally with their
companions, threatening them with head lowered between the
shoulders, bill pointed toward the enemy, and occasional
fluttering of wings. Such birds leave the flock in a day or two
and isolate themselves on territory of their choosing.
Each male proclaims his occupancy by perching on favored
conspicuous lookout perches within the territory, singing, and
driving off trespassing males. Newly established territories may
not be occupied continuously. Tinbergen observed defending males
that fed on their territories in the morning and often left by
midday to forage elsewhere, but returned later in the day, also
that "The males slept within their territories, using the
same hole for several nights successively, but now and then moving
to a new site." Roosting males that MacDonald and I flushed
at this stage on Ellesmere Island often flew off and alighted
beside the roosting defender of another territory. Surprisingly no
fighting ensued, and both birds simply turned their heads back and
went to sleep again. But when the two were flushed together, they
made a show of animosity, chasing each other and even singing
until both settled down again, sometimes side by side. This
behavior pattern was not seen after the females arrived.
As the season advances the males remain and feed within their
territories for longer periods and become increasingly jealous of
their boundaries. Song increases in intensity, and the defenders
savagely attack other males that approach. The defender often
flies toward its adversary from afar, singing and posturing during
flight, a phenomenon Tinbergen calls "song-flight," in
which the defender "rose steeply with frequent wing-strokes,
then stopped wing-action, sailed in the direction of the stranger,
body curved upward, loudly singing, and keeping its slightly
trembling wings in an approximately horizontal position." The
intruding bird usually flees, and the incident is over. But the
fighting that may follow such an attack, especially between males
of adjacent territories, may be fierce and prolonged. The birds
may rise into the air on fluttering wings, clinging to each other
with bills and feet, or tumble together across rocks and snow.
Feathers fly, but serious injury probably seldom results.
While sight of an intruder is usually enough to provoke attack,
Niko Tinbergen (1939) points out the great importance of sound. A
calling or especially a singing trespasser is certain to evoke
attack, but "Sometimes a male, though foraging on an occupied
territory, remained unnoticed by the owner for some time. This was
especially the case when several birds intruded on one territory
at the same time. We observed in such cases that an intruder,
although he was not attacked himself, crouched every time the
owner of the territory performed a ceremonial flight, keeping
quite flat and motionless, only moving his head slightly to follow
the singing bird with the eyes. This was the first proof we got of
the warning function of the display of a bird holding a
territory."
According to E. M. Nicholson (1930) male buntings on territory
are indifferent to other nonpredatory species, and Tinbergen adds
"Lapland Longspurs, Greenland Wheatears and Redpolls often
lived in Snow Bunting territories but I never noticed any
hostilities." We observed no such interspecific tolerance in
either Baffin Island or Ellesmere Island. In both regions the male
buntings chased other small passerines from the territory. They
were particularly adamant in driving off any wheatears (Oenanthe
oenanthe) which, as Salomonsen points out, occupy a type of
habitat similar to that the bunting prefers.
It is difficult to interpret Watson's observations on Cape
Searle Island, near Baffin Island, after a heavy influx of
migrants in late May. He states "The males occupied
territories and paired with the females though they were clearly
migrants; nearly all had gone by May 25th." Our observations
in Ellesmere indicated that the newly arrived mixed flocks
contained only unpaired birds, but some buntings certainly pair
before arriving at the breeding ground. These probably include
those pairs that roam in the breeding areas before settling on
territories.
Courtship.--Some male buntings
may continue to sing ardently for several weeks before the females
arrive. When the females first appear, the males threaten them as
they would trespassers. But the females remain close by instead of
fleeing, though they may move from one territory to another until
paired. The males then exhibit a new type of behavior, which
Tinbergen describes as follows: "He assumed an erect,
strangely stretched attitude, spreading his tail widely and
spreading the conspicuously colored wings backward and downward.
In this attitude he directed the piebald surface of back and tail
toward the female and then ran quickly away from her. Having run
for some meters, he abruptly turned, came back without any
display, and then repeated the performance. This specialized
display apparently served to demonstrate the conspicuous color
patterns of the plumage."
Sutton and Parmelee describe similar behavior on Baffin Island:
"Males who were with females sometimes lifted their wings
high above their backs, or scuttled rapidly through the snow, with
head lowered, as if showing off. 'Scuttling' males sometimes ran
swiftly in one direction, stopped, turned at a right angle, and
scuttled off again." Witherby et al. express it as:
"Courting male also observed 'dancing' down a scree, raising
wings."
Another display of the male before the female closely resembles
the territorial song-flight already described. He ascends 15 to 30
feet or so into the air and, with wings set high or horizontally,
flutters to the ground singing mostly during the descent and often
after landing. Or he may sing while fluttering down from a
precipitous ledge. As Gabrielson and Lincoln (1959) describe it:
"the males start courtship performance, usually rising from a
perch somewhere on the ground to a point high in the air and then
singing at frequent intervals their rather simple but musical song
as they descend, ending it as they reach the ground. The song is
given on the upward flight as well as on the descent."
Immediately following pairing, the male buntings temporarily
but dramatically stop singing and remain quiet, except when their
mates leave the territory. This led Tinbergen to conclude that the
primary function of the song on territory is to attract a mate, to
which its warning function is of secondary importance, and he
therefore calls it "advertising song."
After pairing the birds move about and forage together on the
territory. The females leave the territory from time to time, but
the males seldom do. Mated males seldom court other females, but
exceptions are known. The males continue their strong defense of
the territory against other males, and the mated females against
other females. As Tinbergen writes:
Mated females do not tolerate other females in their
neighborhood. Fights between two females were of common
occurrence. When two pairs met on their common boundary, a fight
often resulted, and these fights of pair against pair really
consisted of two fights: one of male against male, the other of
female against female. Although we witnessed hundreds of fights of
male Snow Buntings inter se and females inter se, we
only once saw a female attacking a male, and this attack consisted
of a short pursuit of a retreating male after a prolonged fight
between two pairs. We never saw a male attacking a female.
The females at this stage are not yet sexually receptive, and
rebuff the males' frequent attempts to copulate. This results in
the conspicuous sexual flights, in which the males chase their
mates swiftly both close to and high above the ground in a most
dazzling manner. These flights according to Tinbergen invariably
follow unaccomplished coition. They may continue for several
weeks, but they decline rapidly when the female becomes oestrously
receptive.
During this period paired birds, often one following the other,
explore the various niches and fissures on the territory,
presumably searching for nest sites. Even unpaired males on
territory show interest in holes by entering them. Tinbergen
describes the nest stage thus:
The beginning of this new period was marked by a change in
the behavior of the female. She had until now shown interest in
holes, but never had picked up nesting materials. On a certain
day, the female suddenly took some moss in her bill, carried it
for a few seconds or even less, and then dropped it again. On this
same day she did not flee when the male, as on previous days,
approached her, but adopted an attitude which was never seen
before: she kept her back quite flat and horizontal, pointed her
bill upward and lifted the tail. The male mounted and coition was
accomplished.
The carrying of nesting material therefore indicated, in all
instances studied, the beginning of the female's oestrous period.
. . .
After this first day the birds regularly performed coition,
most frequently during the early morning, between about 2 and 6
a.m., and not more than 2 to 5 times a day.
Shortly after the first copulations the female started
building, that is, she not only collected pieces of moss, but she
really carried mouthfuls of it to a hole. What she did with it
when she entered the hole, we were unable to see. Nesting
activities were most persistent immediately after coition.
Nesting.--The female snow bunting
builds the nest alone, though the male often accompanies her to
and from the nest site and occasionally even picks up nesting
material and offers it to her. She may gather nesting material
from afar, in which case the male does not follow her much beyond
territorial limits. Also she may start several nests and abandon
them before choosing the one she finishes.
The species utilizes a variety of sites, but almost always
hides the nest in some hole or cranny, though sometimes only under
moss. The nest is often a foot or more back in a narrow rock
fissure where it is inaccessible. Frequently it is built under
loose rocks on the ground or in scree, and not infrequently in
stone foundations or buildings. Nests have been reported in skulls
and in such artificial sites as wooden boxes, metal containers,
wire coils, construction rubble, and other debris. Where rock or
artificial sites are lacking, the buntings will use cracks or
holes in soft ground, especially where the earth is frost-heaved
into piles of mud. Nests in soft ground rest in depressions that
presumably the buntings themselves scratch out.
Exposed nests are exceptional. Watson noted one "open to
the sky" in a hollow between a shrub and a boulder on Baffin
Island. Of three that MacDonald and I found on Ellesmere, one was
between two hummocks on the tundra far from rocks or mud mounds,
and two were on narrow rock ledges. The tops of all three were
completely open and exposed. We found several others in shallow
sandstone niches that were partially exposed, but not from above.
The rather large, loosely constructed, thick-walled nest is
composed chiefly of dry grasses, sometimes partially or mainly of
mosses, lichens, roots, or leaves. A considerable amount of grass
often projects from its sides, adding to its bulky appearance. In
some localities it is characteristically sandy, in others it may
contain bits of mud. The deep nest cup is variously lined, thickly
or thinly, with finer dry grasses, rootlets, occasionally downy
willow seeds, and invariably with one or more kinds of feathers or
fur. White ptarmigan feathers are commonly used, also feathers of
jaegers, gulls, and snowy owls. The fur of dogs, arctic foxes,
lemmings, and hares, and the coarse guard hairs and soft wool of
the musk ox have all been reported. No doubt the birds find
suitable the feathers and fur of any other species at hand.
The buntings sometimes reuse their old nests, though this
phenomenon has not been widely reported. Watson found a nest on
Baffin Island with two linings, the older one from the previous
year. Two active nests MacDonald and I found on Ellesmere Island
were old ones lined afresh, with the bases of the old structures
still frozen to the ground when found. This reuse of old nests is
probably not related so much to the shortness of the breeding
season as to the lack of good, perhaps preferred nest sites in
certain situations. The common occurrence of several old
unoccupied nests in some nesting areas, however, attests the
frequent abundance of nest sites.
A nest Sutton and I found on Baffin Island, started on June 15,
was ready for lining June 19; by June 20 much hair had been added,
by June 22 feathers had also been added and the first egg laid.
Watson reports another Baffin Island nest built and lined in
4 days and the first egg laid on the 5th day. The brief time of 14
hours with the first egg laid the 2nd day Joseph S. Dixon (1943)
reports for nest building at an Alaskan site must be exceptional.
G. T. Kay (1944) reports captive birds taking up to 6 days.
Tinbergen notes that females may continue to add lining to the
nest for 2 or 3 days after laying the first egg. In extreme cases,
according to Watson, the first egg may be laid on dry sand before
nest building even starts, and the nest built around it while the
clutch is completed.
Tinbergen found that in two cases the interval between the
first observed copulation and the laying of the first egg was 13
days in one, 8 days in the other. He also states that females do
not allow the males to copulate after they lay the first egg.
Observers agree that eggs are laid during the early morning, as
early as 3:00 a.m., and that generally one is laid each day until
the clutch is complete. Watson reported 2 days between laying of
two eggs at one nest.
The spread of egg laying at any one locality, even at high
latitudes, may be considerable, in some cases more than a month.
Tinbergen quotes Manniche's finding eggs at Danmarks Havn,
Greenland, from June 6 to July 18. Though eggs may be laid earlier
at low latitudes--mid-May in Iceland and late May in Scotland--egg
laying is not necessarily late at high latitudes. MacDonald and I
believe egg laying started at 80o
N. in Ellesmere in early June, certainly no later than June 10,
which is earlier than many reports for lower latitudes.
The peak of egg laying appears to be mid-June in west-central
Ellesmere and in southern Baffin Island at the opposite end of the
Canadian Arctic Archipelago, but Watson found it to be late June
in eastern Baffin Island. Of interest also is Salomonsen's
observation that egg laying in Greenland averages at least a week
earlier in the sunny interior than on the colder outer coast.
Data on clutch size from various parts of the species' range,
summarized by Tinbergen and by Watson, indicate that, as Lack
(1947) pointed out for this and other species, the average size of
the clutch increases with latitude. Our observations from
Ellesmere substantiate this. Eight clutches we found at 80o
N. varied from 6 to 8 eggs and averaged 6.8--a significantly high
sample.
Eggs.--The snow bunting usually lays
4 to 7 eggs, but sometimes only 3 or as many as 9. The ground
color is greenish, pale bluish, grayish, or creamy white with
spots, blotches, and occasional small scrawls of greenish and
purplish browns such as "dusky drab," "Natal
brown," "olive brown," "Rood's brown,"
"Clove brown," and black. The undermarkings of
"purplish gray" or "pale Quaker drab" are
frequently very prominent. There is much variation; some eggs will
be heavily marked with scrawls, others only with spots. The
markings generally are scattered over the entire surface, although
they frequently tend to concentrate at the large end where they
may form a loose wreath, or make a solid cap over the top of the
egg. Some types are very pale and marked only with light browns
such as "wood brown" or "fawn color" and
without undermarkings.
The measurements of 50 eggs average 22.9 by 16.5 mm; the eggs
showing the four extremes measure 26.4 x 17.3, 23.4 x 18.3,
20.3 x 15.8, and 21.3 by 15.2 millimeters.
Young.--Though one or two observers
have reported seeing males on the nest, most are agreed that
incubation is entirely by the female. The males feed their mates
frequently during egg laying and incubation, and are conspicuous
in carrying food. On and off the nest the females will beg for
food by calling and fluttering their wings just as the young do
later. The females also feed themselves; Watson noted one that
left the nest regularly to feed for an hour in mid-afternoon.
Opinions differ as to when incubation
starts. Tinbergen states that in southeast Greenland it
"begins from one to three days after completion of the
clutch." Watson reports that in eastern Baffin Island:
"At nearly every closely watched nest the female began to sit
from the time the first egg was laid. The sole exception was at
one sheltered nest where incubation did not start till the third
egg was laid, though the nights were cold and frosty and light
snowfalls frequent." Our experiences in both Baffin and
Ellesmere islands showed incubation usually started with the
laying of the third or fourth egg.
The incubation period, that is
the interval between the laying and the hatching of the last egg,
varies from 10 to 15.5 days, apparently dependent on the
attentiveness and effectiveness of the female in her duties.
Witherby et al. note it recorded as 10 to 12 days by Ekblaw, 12 to
13 days by Thompson, and 14 to 15 days by Sutton. One we timed at
Baffin and one at Ellesmere each fell somewhere between 12 and13
days. All these variations are close to or within the range Watson
gives as10.25 - 10.5 to 14.5 - 15.5 days. The 21-to-22-day
incubation period Gabrielson and Lincoln (1959) report for Alaska
is confusing, and probably measured from the laying of the first
to hatching of the last egg.
Regarding hatching, Watson comments: "At most nests the
habit of incubating the eggs during the laying period resulted in
a marked spread in hatching. For example, a clutch of four
produced three young in over 4 and probably 5 days; other periods,
for clutches of 5 and 7 eggs from which 5 and 6 hatched, were 3 -
4 days and at least 4 1/2 days." The greatest spread
undoubtedly results when incubation of a large clutch starts with
the first egg and all the eggs hatch.
Newly hatched buntings are thinly covered with down and quite
helpless. When touched they open their mouths wide but produce no
audible sound. When 2 days old they make faint food cries which
gradually become louder as the birds develop. Tinbergen writes:
"While the young were being fed, they uttered a long, high
note, which became louder as they grew older, and which called
attention to the nests from a great distance." Nicholson
(1930) says "The loud metallic chittering of nestlings
carried quite 150 yards."
The many young calling conjointly produce the great noisiness
so characteristic of a heavily populated breeding ground.
Both parents feed the nestlings, the female being at first the
more active and persistent. The food consists of various insects
and arachnids gathered both on and off territory. The males at
this time are somewhat less adamant in defense of their nesting
territories, and may forage together amicably in favored nearby
areas--a sort of no man's land among territories. Females still
beg food, sometimes successfully from males other than their
mates, and then give it to the young. Food begging at this time
apparently has little or no sexual function.
The females frequently brood after feeding and during cold
periods. At one Baffin Island nest Watson writes: "The female
was often seen sitting on the young during the coldest few hours
of the night till a time when in one nest the oldest young was12
days old, and the youngest 8 days old and only three days from
finally leaving this nest."
Both parents tend to nest sanitation by carrying fecal sacs
from the nest. Shortly before the young leave the nest, their
feces lose the mucous sac and resemble adult feces. At this time
the young also develop a new and distinctive food cry which
enables the parents to find them more readily after they start to
disperse.
The brood may leave the nest en masse, but more often only part
of it leaves, followed by the rest considerably later. Some young
may leave the nest and even the nest crevice, and then return to
it later. This complex dispersal pattern makes it difficult to
determine the duration of the fledging period. Watson found that
the interval from hatching until the individual left the nest for
the last time varied from 10 to 17 days. Generally young buntings
leave the nest proper before they can fly well, though they may
remain in the nest crevice for another day or so. Some young fly
strongly when 13 - 14 days old.
Once outside the nest crevice the brood soon scatters, even
beyond the male's territorial boundaries. Those advanced young
that disperse early are largely or entirely cared for by the male
parent, who readily locates them through the food call. The
remaining siblings are probably tended by the female until
parent-offspring relations dissolve, for Tinbergen found
fledglings fed by the same parent each time. The young still
flutter their wings and call noisily when begging food.
Territorial defense by the males now declines rapidly, singing
becomes lax, and some males may start their prenuptial molt while
still feeding young. The fact that territorial defense declines at
fledging, a most critical time in the breeding cycle, has led some
investigators to question the food function of the territory,
though its sexual function is widely held.
A first sign of coming fledgling independence is when the young
buntings start to show interest in insects, which they do well
before their remiges are full grown. Tinbergen noted that one
young that left the nest on June 28, tried to catch a mosquito
July 2, though its male parent fed it until July 10. On July 9
this chick uttered its first "trembling note" similar to
that of adults living in flocks, and the parent-offspring
relationship dissolved by July 11. There can be no doubt that this
new "contact-note" functions to bring the young together
in the loose flocks they now form.
The swarming of young buntings in large flocks at this time has
been widely reported. MacDonald and I found them particularly
conspicuous in the Slidre Fiord area of Ellesmere Island in early
August. The fiord shores had comparatively few buntings during the
nesting period, for most of them bred in the rocky interior. When
the species started returning to the fiord shores on August 5,
most of the birds were full-tailed, unattended juveniles,
presumably of early broods. They came by the hundreds, appearing
near the beaches in the early morning and fanning out in small
groups over the low country during the day, and their numbers
increased daily. Here they remained until they completed their
postjuvenal molt in early September.
Not all young buntings flock as described above. Some remain
with the adults, when the latter retire to secluded places to
complete the postnuptial molt. Whether these represent family
groups or simply mixed flocks is not certain. By this time,
although an occasional fragment of song may still be heard, the
sexual bonds between pairs have been broken.
Both Witherby et al. and Salomonsen cite evidence that the snow
bunting is occasionally double brooded, that is the female may
proceed with a second nesting after successfully fledging its
first brood. Tinbergen noticed one case of double-broodedness,
which was not clearly defined; the female abandoned her first
brood, which perished, and proceeded with another nesting with a
second mate. Apparently bigamy may occur in either sex when one of
the pair remains sexually potent longer than usual. But as
Tinbergen points out, the rigid division of labor between the two
sexes in caring for the young does not permit effective double-broodedness.
Despite the shortness of the summer season, early nesting snow
buntings, even at 80o N., might
have time for a second brood, but apparently they rarely do. The
sudden decline of sexual flights and song as nesting progresses
and the failure of either to recur more than spasmodically is also
good evidence that single broods each summer are the rule in the
true Arctic.
Plumages and Molts.--The
natal down is variously described as grayish or brownish. Witherby
et al. describe the nestling as "Down, dark grey, fairly
long; distribution, inner supra-orbital, occipital, humeral,
spinal, ulnar, femoral, and crural. Mouth, externally gape yellow;
beak (pale) yellow." Van Tyne and Drury (1959) describe an
8-day-old nestling as "bill, Cadmium Yellow to Cartridge Buff
(at rictus); mouth lining, near Deep Corinthian Red; legs and
feet, near Ecru Drab. The head, back, and lesser wing coverts of
this bird were covered (along the usual tracts) with long natal
down, Hair Brown in color. Not the slightest trace of down
remained on an eleven-day female in the same nest (nor on an older
fledgling collected nearby two days later). The eleven-day
nestling weighed 32.3 grams and was extremely fat (2.3 grams of
free fat were removed from the underparts). The fledgling was also
very fat."
Juveniles differ from first-year birds chiefly in body plumage.
Their upper parts, according to Witherby et al., are dusky or
buffish-gray streaked with black, the mantle being most buffy and
heavily streaked; the underparts are buffy with dusky markings on
upper breast and flanks, whitish-buff in the center of breast and
belly, dusky gray on chin and center of throat. The median wing
coverts are grayish-black tipped with white, not white as in first
winter birds; the lesser coverts differ in being grayish-black
fringed with grayish-white, rather than black with buffish-white
tips or white flecks. The sexes are similar, but the females have
more black on the secondaries and outer rectrices. In comparing
five juveniles from Frobisher Bay, Baffin Island, with three from
Wainwright, Alaska, Richard Graber found the Alaskan specimens
tended to be "buffier" throughout, the buffiness being
especially noticeable on the auriculars.
The first winter plumage is acquired by an incomplete
postjuvenal molt in which the juvenal wings (except the median and
lesser coverts) and tail are retained. The resulting plumage
strongly resembles that of adults, but in young males the flight
feathers are darker than those of adults, and the brown of the
upper parts may be darker. First-year females have darker
secondaries than older females.
The juveniles molt while flocking, often near the coast, though
some may complete it inland. At high latitudes in Canada and
Greenland the juveniles molt very rapidly, and acquire their new
plumage by late August or early September. One young bird we
collected at 80o N. in Ellesmere
Island had nearly completed its postjuvenal molt by August 17.
The adults acquire their fall plumage by a postnuptial molt
that is complete or nearly so. The males start molting about
fledging time, as early as mid-July in parts of the Canadian
Arctic Archipelago and Greenland, the females slightly later. By
late July and early August both sexes are molting heavily, and
they seek secluded places where they are met singly or in small
groups that may include both sexes and young birds. The adults
often molt so many flight feathers within a short interval that
they become temporarily almost flightless, and escape their
enemies only by scurrying swiftly over the rocks.
Salomonsen notes that though the molt may not be completed by
early October at lower latitudes and in Iceland, it is
particularly rapid at high latitudes in Greenland where migration
starts in early September. This is also true in Ellesmere Island,
where we found adults in fresh new plumage by late August.
The fresh adult fall plumage is essentially the breeding dress
heavily overlaid with brown above and, to a lesser degree, below
(pectoral band more or less prominent). The plumage is immediately
sensitive to abrasion, which produces a great variation of
plumages both individually and seasonally. As abrasion continues,
certain colored areas become whiter and the wing pattern more
pronounced. The bill, which is black during the breeding season,
becomes yellowish, often with a dusky tip.
According to Witherby et al., an incomplete molt affecting the
throat and facial region takes place in March, the new feathers
being pure white except the ear coverts, which are buffy in males,
tawny in females. Continued abrasion in spring produces the boldly
black and white breeding plumage of the male. The female becomes a
less striking gray and white, characteristically speckled and
streaked with brownish to grayish-black above and white below.
The spring molt, according to Salomonsen, is aided to some
extent by the bunting's habit of feeding on hard snow, which wears
down the facial feathers. Newly arriving males reach the breeding
ground in spring, still veiled with brown, some heavily, and a few
individuals may retain traces of the veiling well into the nesting
season. Others are in breeding dress complete with black bills as
early as April 26, possibly earlier. Changes in plumage and
appearance can be sudden. One Ellesmere Island male had
considerable brown about the head and neck when we banded it April
29th; only a trace of the brown remained when we recaptured it two
days later on May 1st.
Male buntings are dimorphic in that their primary coverts grade
from pure white through black-tipped and largely dark, to almost
or completely dark (Manning et al., 1956). Salomonsen considers
the pure white and black-tipped to be the normal adult condition,
and the uniform black-brown coverts a "retarded"
condition frequently, though not invariably, found in first-year
birds. Most early arrivals on the breeding grounds have white or
lightly black-tipped coverts, indicating that the old birds
commonly are the first to migrate north.
Food.--The deep snows of the low
arctic are a great obstacle to the buntings moving northward in
spring, and many observers have noted the difficulties the birds
encounter in their search for food. In coastal Alaska for
instance, A. M. Bailey (1948) notes of their arrival in early
April: "winter seems to have a firm grip upon the barren land
at this time, with frozen ground offering little in the way of
food, but the flocks of birds scatter throughout the native
villages, securing a precarious living where the winds have blown
the snow clear." They fare no better in Greenland, where
Salomonsen notes the early arrivals depend extensively on Eskimo
villages and wind-blown snow fields.
Though the layman might assume conditions to be even more
severe at higher latitudes, the opposite is true. Lack of
precipitation makes the high arctic a desert with very little snow
and the land is a refuge for birds arriving in the early spring.
The buntings move among the grass tops exposed by the thin snow,
gleaning an easy food supply. On the coastal slopes of Ellesmere
Island, MacDonald and I noted thousands of bunting tracks leading
from one grass tuft to another. The newly arrived birds were
obviously hungry, and those near our camp fed ravenously at the
banding traps for several days before joining the flocks of those
already fattened.
Food in the early spring consists primarily of various seeds,
especially of the grass Pea in the far north. In summer and
fall the birds eat a mixed diet of insects (mainly Coleoptera,
Lepidoptera, Hemiptera, and Diptera), spiders, and seeds and buds.
They feed their nestlings and young fledglings animal food
exclusively, so far as known. Gabrielson (1924) found the summer
food of a few buntings collected near Hudson Bay and the Pribilof
Islands to be one-third animal (beetles, crane flies, spiders) and
two-thirds vegetable (seeds of grasses, sedges, smartweed).
Martin, Zim, and Nelson (1951) list bristlegrass, ragweed,
pigweed, sandgrass, goosefoot, and oats as the leading plant
species in the diet, and "Fly larvae and pupae, particularly
of the cranefly, caterpillars, beetles, and true bugs constitute
the major portion of the animal diet. Crustaceans are also
consumed, particularly sand fleas." Nichols (in Pearson et
al., 1936) reports that they eat "locust" eggs in
Nebraska. The winter food is primarily grass and weed seeds, but
Forbush (1929) notes that "along the coast [it] takes tiny
crustaceans and other small forms of marine life, sometimes
following the retreating waves or gleaning in pools like
sandpipers."
Voice.--Witherby et al. characterize
the male snow bunting's song as: "short, but musical, bold
and loud for size and with fair variety of phrasing. Typical
version might be rendered 'turee-turee-tureet-turiwee.'
From rock or other low perch and on wing." Salomonsen
describes it as a "short rippling warble of distinct
structure, but rather varying, consisting of 9 - 14 syllables,
repeated sometimes with intervals of 5 - 10 seconds or delivered 3
- 4 times without pauses as a long continuous song." He
writes several versions: "ditree-ditreedipitree-ditree-ditree"
and "deeiti-dee-ditreeditreeditree."
To Sutton and myself on Baffin Island "Songs seemed
invariably to include a repetition of certain polysyllabic
phrases. Ordinary songs (i.e., songs not given in flight) sounded
like (1) sir plee si-chee whee-cher; sir plee si-chi whee-cher
and (2) chor-i-bee-chee, chor-i-bee-chee, chip-i-deer.
Flight songs were more complex." Tinbergen speaks of locally
restricted song "dialects" among the Greenland buntings
which, he points out, the young males must either inherit or learn
in the nest.
The species' call notes have been variously written as chee,
tee, djjj, a loud, high-pitched tweet, a rather
rippling twitter tirrirrirripp, and a rippling yet rather
hard stirrrp, among others. According to Tinbergen they are
of two main types, a long monosyllabic peee, and a
trembling note that Salomonsen transcribes as pirrr or pirrr-rit.
Given on the ground or in flight, these function as communication
signals between individuals or contact notes between members of
the flock.
Males on territory have a threatening note Tinbergen writes pEEE,
which they direct at trespassers of both sexes, but whether the
males discriminate between sexes in such cases is uncertain.
Tinbergen also notes that the actual attack on one male by another
is often preceded by a special shrill, trembling cherr.
Most peculiar from singing males newly on territory is a long,
high note that Tinbergen says "resembled more or less the
screaming of a Swift, though it was much softer, and which I
therefore will call the 'Swift' call. It was often performed two
or three times in rapid succession and was often accompanied by
trembling of the wings and panting. Both Swift call and wing
trembling sometimes occurred separately. . . . This behavior must
be considered as an outlet for unsatisfied sexual impulse."
On Baffin Island when a male brought food to an incubating
female on the nest, as he disappeared into the nest crevice Sutton
and I "heard odd, rather angry-sounding cries of churr,
churr." We described the food cry of young buntings after
leaving the nest crevice as "zhip or zhi-dip."
Salomonsen thinks the fledgling's food call sounds like pitt-pitt.
Witherby et al. add: "Anxiety-note a musical, plaintive,
piping 'tuu.'" Nichols (in Pearson et al., 1936) says
the buntings call beez-beez when disturbed. Gabrielson and
Lincoln (1959) state: "The alarm note is a hard, rattling chir-r-r."
Tinbergen observed that whenever a predator appeared the birds
"uttered a special call, a monosyllabic, soft weee,"
which he heard elicited by the appearance of a peregrine falcon, a
merlin, roaming Eskimo dogs, and occasionally by his own approach
to a nest or fledged young.
Behavior.--Of its behavior in
Minnesota, T. S. Roberts (1932) writes:
"The Snowflake is a ground-loving bird, seldom alighting
in trees, and roosting at night on the earth or snow beneath the
shelter of some weed or tuft of grass. It is gregarious in the
highest degree, and the vast flocks that formerly assembled in
springtime almost obscured the skies as they towered above the
weed fields from which they had arisen, whirling and circling in
perfect unison, now up, now down, making with their thousands of
wings a noise like the rushing of the wind."
Despite their marked gregariousness when away from the breeding
grounds, the snow buntings do not associate much with other
species. When they do, it is most often with the Lapland longspur.
Wendell Taber wrote me that he usually looked for one to a half
dozen longspurs in a New England flock of buntings. Ralph Palmer
(1949) writes that in Maine: "Most common associates seen in
flocks of this species are Horned Larks and Lapland Longspurs. On
March 23, 1929, at Brunswick, I saw a single Snow Bunting with a
flock of Bronzed Grackles."
The compact migrating and wintering flocks wheel and circle in
characteristic fashion over the upland fields and sea beaches,
descending abruptly and skimming low over the ground before
settling. The flight of the individual bird is somewhat
undulating, but hardly swift. B. Nelson (1944) timed one at 20
mph, another at 26 mph. On the ground the birds may scatter widely
while feeding. Their normal gait is a walk or a quick run, and
they occasionally hop or jump over the snow surface.
While they spend most of their time on the ground, in the south
the buntings sometimes perch in trees or on the roofs of
buildings, and may even line up on an electric wire like so many
swallows. Forbush (1929) states: "I have seen an apple tree
almost covered by a great flock of these birds, and they may be
seen now and then on fences or stone walls, but I have never seen
a Snow Bunting in the woods."
In a letter to Mr. Bent from Colebrook, New Hampshire,
Hildegarde C. Allen describes their snow-bathing: "Whenever
the mercury drops and the wind blows snow, in they come with their
sweet calling in the wind, space themselves neatly on the
ridgepole, and are with us on feeders, porch, and lawn till the
next real thaw. They so love to swim in the light snow,
particularly if it is both snowing and blowing and about zero.
They seem almost like chickens dusting."
According to Scholander et al. (1950a, 1950b) snow buntings
under cold stress can tolerate -40o
F, but at -58o F their body
temperatures drop seriously within an hour. Thus at very low
temperatures the birds must depend on behavioral thermoregulation
to some extent, and particularly to avoid windchill which must
often be a hazard to them. A. M. Bagg (1943) reports their
burrowing into snowdrifts during -35o
F weather in Massachusetts and remaining huddled in their
individual holes throughout the day, emerging "only
occasionally to feed on a nearby chaff pile." Salomonsen
states: "The birds in a flock have often a common
roosting-place in which they spend the night, as a rule in
cavities or crevices in rocks, in which they crouch close together
in order to take shelter against the cold of the night."
Witherby et al. state "Roosts, sometimes singly, but often
in parties, in shelter of stones, clods, grass-tussocks, etc., on
ground; also recorded in quarry." Forbush (1929) writes:
"When the snow is soft, these birds are said to dive into it
(as they do sometimes when pursued by hawks), and there pass the
night. When the snow is frozen hard, the flocks sleep in the open,
protected from the north wind only by some slight rise in the
ground, by sand dunes, or by a stone wall. . . . Snow Buntings are
necessarily very light sleepers; when caged, they are said to be
always awake and moving, when approached in the night. The wild
birds leave their resting place at the first hint of light in the
east, and begin feeding while it is still quite dark. They have
never been known to roost in trees at night."
Roosting during the winter and at low latitudes probably
coincides with and is governed by the hours of darkness.
Conceivably in the continuous daylight that shines on much of
their northern breeding grounds the birds might stay awake and
active indefinitely, but they usually go to roost and sleep part
of each day, usually when the sun is lowest. Tinbergen found that
in southeastern Greenland the buntings "awoke earlier from
day to day during April, until at the beginning of May their
activities started at about 1 a.m. Although the nights grew
lighter until the end of June, the birds did not rise any earlier
from about the middle of May onward; a certain amount of sleep,
about 2 to 3 hours, apparently is necessary."
Roosting behavior on the high northern breeding grounds has not
been widely reported. The following paragraphs are adapted largely
from the account MacDonald and I prepared of our observations near
Slidre Fiord in west-central Ellesmere Island between April 16 and
September 27, 1955.
When the first male buntings returned to Slidre Fiord,
apparently the same day we arrived there, the sun was continuously
above the horizon. When it was low these early arrivals roosted at
Eureka Weather Station in a lumber pile, as many as 28 of them at
once.
Away from the station they roosted out of the wind in
shallow niches in sandstone outcrops. A single gully often had
several such roosts. During the early spring the number of
buntings at a given roost fluctuated considerably; anywhere from 1
to 24 birds might be found roosting together, and even the most
favored sites were unoccupied at times. The birds slept squatted
down with their heads turned back and their bills tucked under
their scapulars. Most slept in shadowy niches, but some in direct
sunlight. Even at -25o F we
never saw them huddled together for warmth as Salomonsen reports.
After territories were established in the gullies near the
coast, only a few buntings roosted there, but these continued to
occupy the same roosts. New flocks were arriving daily, and more
buntings than ever inhabited the coastal slopes during late May.
Although daily maximum air temperatures did not reach thawing
until May 28, evaporation and heat absorption from imbedded grains
of wind-blown sand produced deep pits along the fronts of
snowbanks that made excellent shelters where the newcomers of both
sexes roosted together. The largest number of buntings seen in one
of these snow roosts was 14. While these banks were accessible to
predators, mammals could not climb them without noisily shattering
the ice crystals that formed during the cool hours.
During May the buntings roosted principally between 9 p.m. and
2 a.m. A few birds, especially the hungry new arrivals, moved
about at all hours. Most birds seemed to feed heavily between 6
and 8 p.m., just before going to roost. With the influx of new
males and females and the start of courtship, roosting became less
regular. By early June it was decidedly irregular, but even then
most buntings roosted when the sun was lowest. Once courtship was
over, roosting became regular again. No communal roosting was
observed during the nesting period. The males usually roosted on a
rock or bank within their territories while the females incubated
or brooded on the nests.
In August the mixed flocks of adults and young fanned out to
roost among the rocks on steep banks. As these flocks gradually
became larger, some birds roosted on rocky slopes, others among
boulders in the nearly dry stream beds. On August 21st we flushed
30 or more buntings roosting under a huge snowbank undercut by
running water; the number of droppings showed this roost had been
used for some time.
During August and September a few birds continued to roost
singly or in small groups in the sandstone outcrops, rock piles,
and mud cracks, and the gully roosts near the coast again became
popular. But the large flocks, some containing a hundred or more
birds by September, commonly roosted on the open tundra where the
ground was eroded and hummocky. Occasionally Lapland longspurs
roosted with the buntings. As in spring, the birds fed heavily
from 6 to 8 p.m. before retiring. By September they started going
to roost somewhat earlier, usually between 8 and 9 p.m., and the
coming of night made them roost even earlier. By late September
they were roosting by 7:30 p.m.
Enemies.--Probably the snow
buntings' greatest foe in spring is the elements. Sutton (1932)
describes dramatically how hundreds of buntings succumbed from
starvation or exposure on Southampton Island during stormy weather
in late May and early June. Weak from lack of food and dazed by
the wind, they were easily caught by hand, and many were destroyed
near the settlement by Eskimo children and dogs. Under normal
spring conditions when the birds are healthy and the weather
clement, predators probably catch few buntings. MacDonald and I
watched dogs and arctic foxes stalking buntings unsuccessfully on
Ellesmere Island, though one fox track led to a bunting kill.
Arctic foxes are doubtless one of the principal destroyers of
bunting nests and of young buntings. When a fox appears on the
nesting grounds, the old birds flock together in common defense.
We watched some 20 fluttering over and behind one hunting fox, but
how successful their distraction displays are is speculative.
Where weasels are plentiful they also take their toll of young
birds. Unpretentious despoilers of bunting and other small
passerine ground nests are the brown and collared lemmings. These
small rodents may only partially destroy a clutch of eggs, but
this causes the parents to desert the nest. They may destroy all
or part of a brood of small young.
Among potential avian predators on the breeding grounds are
snowy owls, the several arctic falcons, and the jaegers that
quarter the tundra so fast and low. On Ellesmere Island, Tener (in
Godfrey, 1953) found the remains of an adult snow bunting in an
adult long-tailed jaeger, and a long-tailed jaeger chick
regurgitated a bunting fledgling while MacDonald and I were
handling it. Bunting remains are often numerous at gyrfalcon and
peregrine falcon aeries. The gyrfalcons commonly follow the
bunting hordes along the coasts in the fall; one that MacDonald
and I shot had just eaten four buntings.
Though buntings are still used for food occasionally in parts
of Europe and Asia, happily they are no longer hunted for market
in North America. William Dutcher's (1903) report of 80,000
buntings for the gourmet trade "found by a State game warden
in a cold storage warehouse in one of the larger eastern
cities" staggers the imagination.
Fall and Winter.--On
Southampton Island Sutton (1932) comments: "The prompt fall
departure of the passerine birds surprised me. I had expected to
find Snow Buntings, Lapland Longspurs, and horned larks all
through the fall, and perhaps irregularly throughout the winter.
But with the coming of the snows these hardy species disappear
just as definitely as do the familiar birds of the Eastern United
States, when September frosts begin to be sharp. . . ."
At the high latitude of Ellesmere Island, most buntings leave
for the south by the middle of September. Prior to migration,
mixed flocks of buntings of both sexes and all ages may gradually
combine to form the enormous numbers sometimes seen along the
coasts in fall. A single flock seldom numbers more than a hundred
birds, usually much less, but occasionally upward of a thousand or
more buntings will form a more or less loose flock. These great
hordes may linger for some days, the flocks constantly breaking up
into smaller ones and then regrouping.
On the other hand, Sutton (1932) notes that at Southampton
Island "Premigratory flocks are not usually formed until the
very eve of departure for the south. Family-flocks are to be seen
during most of the fall. Buntings linger throughout October, and
even until November, though most of them depart by the last of
September." Salomonsen reports that the majority migrate from
Greenland from late September to mid-October.
A few buntings may remain at or near the breeding areas after
the main body has left. Late departure dates even at high
latitudes may extend well into October or later. Personnel at the
Alert Weather Station at 83o N.
on the north coast of Ellesmere Island told me of seeing two
buntings there November 27, feeding on spilled oats. The birds
flew off into total darkness beyond the station lights and were
not seen again. C. G. and E. G. Bird (1941) report from MacKenzie
Bay in northeast Greenland "still a few around the station on
10 December." Salomonsen notes that "The greater part of
the Snow Buntings leave Greenland in the autumn, but a small
minority stay in winter in the southern parts of the country.
Wintering specimens have been recorded in all parts of the
low-arctic region."
On the more southerly wintering grounds the flocks may vary
from a few to hundreds, sometimes thousands of individuals.
Alexander DuBois wrote Taber in a letter of a flock ot 400 near
Ithaca, N.Y. Gabrielson and Lincoln (1959), T. S. Roberts (1932)
and others have commented on species' varying in abundance from
year to year; regions where they winter commonly one year may find
them scarce or wholly absent the next.
Though there is no territorial fighting in winter, aggressive
individuals in the flocks often fight in much the same manner,
usually over food. These fights are motivated by the establishment
of peck-order and apparently have no sexual connotation.
Snow Bunting*
Plectrophenax nivalis
Contributed by David
Freedland Parmelee
*Original Source: Bent,
Arthur Cleveland and collaborators (compiled and edited by Oliver
L. Austin, Jr.). 1968. Smithsonian Institution United States
National Museum Bulletin 237 (Part 3): 1652-1675. United States
Government Printing Office
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