FEATURED SPECIES - LESSER SNOW GEESE
FROM RUSSIA WITH LOVE
By Paul Dye
On far off Wrangel Island, off the northern coast of Russia’s Siberia, in a good weather year, from 60 to 100 thousand Lesser Snow Geese (Anser caerulescens) arrive to begin their cycle of nesting and brood rearing. The Skagit-Fraser flock that winter in Washington and British Columbia, and part of the California wintering flock follow a coastal migration route to staging areas in Alaska, primarily the Stikine River Delta, Cook Inlet, occasionally the Yukon-Kuskokwim Delta, and then to Wrangel Island. The main nesting colony of these birds construct up to 40,000 nests, primarily near the Tunrovaya river in a depression in the Severnye mountains. A small number of these snows (less than 1 %) occasionally also nest on the nearby mainland.
Skagit Snow Geese - Photo by John Munn, WSU Extension Naturalist
Studies have shown that most of the snow geese of the
Wrangel population nest for the first time at the age of 4 or 5 years.
Those geese nesting outside the main colony usually nest in
small groups either near snowy owl nests, or near areas where non-breeding snowy
owls have established residence. This
is an example of one of those symbiotic relationships, where the presence of
another species provides a benefit.
Nesting usually begins at the end of May or during the
first few days of June, depending on snow conditions. The average clutch
consists of from 3 to 4 eggs in size. I
n some years when heavy snow conditions are present, competing pairs fight for
the nest sites in those areas free of snow, resulting in egg dumping, abandoned
nests, and heaps of eggs laid outside the nests in those places.
Social tension has been known to get so high that some nest owners even
kill strange females attempting to lay eggs in their nest. In 1999 three such
‘murdered’ birds were found, and in one case a carcass was trampled into the
ground and covered with the nest material.
In such crowded years, raping of females mated to weak males, and
solitary females is common.
In the seasons with a shortage of nesting territory within
the main colony, there are many available nesting habitats in other parts of the
island, particularly in the snowy owls nesting years.
Still, most of the birds prefer to struggle for nest sites within the
main colony. The number of geese
reproducing outside the colony does not exceed 5% of the population.
This shortage of nesting territory results in these years being low
production years for geese from this colony.
As you can see from the foregoing, production in these
geese is dependent primarily on weather conditions in late June and early July,
but it is also influenced by predation from arctic foxes as the young geese are
growing.
Snow geese, and their surviving offspring begin leaving
Wrangel Island in late August on their southern migration.
Band returns indicate that they travel eastward to Alaska, where an
average of over 2,000 are harvested by natives in the Yukon Kuskokwim Delta.
They then separate into two major wintering subpopulations. Part of the population follows an inland migration route to
the central valley of California, while the other segment travel down the Alaska
and B.C. coasts to wintering areas in the Skagit-Fraser estuaries, with some
going on to California. The first
small flocks arrive on the Skagit-Fraser estuaries in late September and build
in numbers throughout October and early November.
During November, those traveling further move out of the Skagit-Fraser
areas to the Columbia River, where up to 2,000 have been known to winter, and
the rest continue on toward California.
After those continuing on depart, the population in the
Skagit-Fraser population is relatively stable until spring.
This flock declined to a low of 12,346 during 1974-75, and then grew to a
high of 41,104 during 1987-96. Age
ratio counts on the Skagit area of Washington during 1948-96 have ranged from 0%
to 50% juveniles in the fall population, with a pre hunting season mean of 16.9%
for the period.
Snow geese in the Skagit-Fraser estuaries are dependent
upon intertidal marsh vegetation dominated by three-square bulrush (Scirpus
americanus). In addition, snow
geese are also dependent upon diked agricultural fields, primarily using cover
crops such as winter wheat and pasture areas.
Recently, they have also begun using barley fields left for other
wintering waterfowl. Researchers on
Wrangel Island have been able to identify those birds wintering in the Skagit-Fraser
areas by the red facial staining caused by minerals in the tidal marshes of
these areas. This staining is
missing on the birds wintering in other areas.
Hunting seasons for snow geese in the Skagit Delta
generally lasted 93 days prior to 1975. Due
to concerns for the status of the Wrangel Island population, the season was
shortened to 58 days in 1975-76 and 1976-77, and has generally run 79 to 86 days
since that time. Harvest estimates
for the Skagit-Fraser population have averaged 4,869 since 1948 and 2,604 for
the period 1987-96.
The White Goose Subcommittee of the Pacific Flyway Study
Committee, composed of wildlife agency representatives from throughout the range
of lesser snow geese, developed a management plan for the Wrangel Island
population of lesser snow geese in 1992. The
plan sets forth goals, objectives, management challenges, and recommended
management procedures for the Wrangel Island population of lesser snow geese.
In order to address management issues more specific to Washington State,
the Washington Department of Fish & Wildlife developed a state management
plan for Snow Geese in Washington.
This plan, intended to supplement cooperative management actions developed by the Pacific Flyway White Goose Subcommittee to provide population trend and harvest analysis and to determine potential solutions to any current Washington snow goose management problems, consists of the following goals and objectives.
CAPTIVE MANAGEMENT
For those aviculturists wishing to keep a flock of
uniformly white lesser snow geese without the presence of the blue color phase,
these Wrangel Island snows are ideal. Although
an occasional blue goose is seen in their presence in the wild, on the wintering
grounds, these are suspected of being strays from the North American population
of lesser snows that nest in arctic Canada.
Captive management of these snows does not differ
appreciably from that of the more common North American lesser or greater races.
If kept in a small flock (I recommend 4 pair or more) they nest readily, with
reasonable fertility. Their feed
needs are simple, in that while they relish fresh grass to graze, they subsist
perfectly well on a diet of whole grains and prepared poultry rations.
Of course, in spring, just prior to nesting season, I increase the
protein content of their feed, as I do for most other species to about 20%.
Like all the other snow goose races, these Wrangel Island
birds are very hard on any lawn grass areas you might wish to maintain within
their enclosure. Unlike Brant,
Emperors, Ross and Lesser Whitefronts, that clip the tips off grass shoots when
they graze it, snows often grab whole clumps of grass and pull it out of the
ground, roots and all. For
this reason, maintaining any attractive lawn areas in their enclosure is a
difficult job. Even though I
maintain my flock of snows in an almost 1 acre pen, I seem to only be able to
maintain lawn areas by fencing the geese off it for two months at a time,
allowing the grass time to recover. I
try to time their access to lush grass to those periods when it is important to
stimulate egg laying and later on, for brood rearing.
This seems to work, although the recovering grass areas do, on occasion,
need over-seeding with grass seed to mend “ratty looking” areas.
My captive Wrangel Island snows, once they are satisfied
with their facilities and decide to initiate nesting, are not terribly
particular about the actual nest site. They tend to spread their nests widely
around the enclosure, probably to keep the aggressive ganders from constantly
fighting. As you might expect, the
larger and tougher the gander, the larger the nest site he defends.
Nest sites vary from the odd hidden nook against a building
or fence, to thickly vegetated locations under shrubs and trees.
One of the favorite nest sites for my snows are the raised “see
through” structures designed for my Emperor Geese. These
nest structures are 30” wide by 30” high, and 36” deep from front to back.
They have a solid back and
roof, but have widely spaced planking, or “half rounds” (outer log edges
purchased from a local mill) on both sides, and have a completely open front.
I place these structures on a raised area of coarse sand for good
drainage to minimize egg loss from wet ground conditions in a rainy spring.
Within the structure, on the sand, I install an old discarded automobile
tire, which I fill halfway with more sand, and the rest of the way with hay or
coarse cedar shavings. The use of
the cedar shavings is preferred in any enclosure also housing eiders, as the
presence of mold on hay can cause aspergillosis, if contacted by the eiders.
Snow Geese nest year after year in same structure
A pair of what I consider “contented” or “well
adjusted” snows will produce about 5 or 6 eggs per clutch, although an
occasional pair may lay only 1 or 2. As
occurs in the wild, “dump nests” do occur, possibly due to a shortage of
nest sites, but also sometimes because of a shortage of eligible males,
resulting in trios. If I notice
dump nesting early enough I remove all but 6 eggs, and incubate the removed eggs
under bantams or in an incubator, in order to prevent a poor hatch.
Snow Goose goslings practically “raise themselves”,
although many factors can cause their loss.
I seem to have best success rearing them by separating family groups into
portable 4’ by 8’ pens that are moved around lawn areas to provide a steady
supply of fresh, clean grass. I
supplement the grass with twice/daily feedings of a good waterfowl or gamebird
starter feed, accompanied by a small amount of standard rations for the adults.
These portable pens house the family groups for
approximately the first two weeks, and protect the young geese from aggression
by other family groups, and predation by hawks, owls, and eagles.
I have been surprised by the efficiency of these predators, especially
eagles, in harassing the parents of families left out in the main enclosure,
causing them to run ahead of their goslings.
The predator then simply lands in between the parents and young, and eats
the young geese as they run past. By
the end of the two week period the goslings are able to keep up with their
parents.
The portable pens also provide a level of protection from
pathogens, such as coccidia, and parasites, such as gapeworm, that seem to
eventually find their way into an established goose flock.
I suspect these maladies are brought in by wild bird visitors, and
especially by visiting wild geese. There
still would be some level of exposure to these pests via the parents, but the
idea is to keep it low enough the gosling’s developing immune system is able
to keep it in check. If not, the
isolated families are easy to keep track of, and the remedies for these problems
easy to administer.
Another big advantage of separating family groups is the
ability to let the goslings get big enough to be fitted with bands that identify
their family. Since they are still
not fully grown I use color-coded wire ties that can easily be replaced as they
grow. This has the obvious
advantage of assuring that you can provide unrelated pairs to other breeders
when they are available. I have
found that if the broods are allowed to run all together from the beginning, an
aggressive pair will sometimes “kidnap” goslings from less aggressive pairs,
and you lose the ability to keep track of bloodlines.
For those aviculturists contemplating a new species to
enjoy, I can certainly recommend these lesser snows. Although easily managed, a flock of these white geese gliding
gracefully across a pond, or grazing peacefully in a pasture is a pleasure to
behold.
References:
Washington Snow Goose Management Plan Outline, Draft 4/96, Washington Department
of Fish & Wildlife
Breeding Of The Lesser Snow Goose in Limited Nesting Area,
V. V. Baranyuk (1999)
Mineral Staining of Facial Plumage as an Indicator of The Wintering Ground Affinities of Wrangel Island Lesser Snow Geese, V. V. Baranyuk, J. E. Hines, and E. V. Syroechkovsky