Shorebirds, as their name suggests,
are most commonly seen by the shores of oceans, lakes and
wetlands. During migration, they are most often seen feeding
in large groups on coastal mudflats, or flying in flocks
of thousands, weaving patterns in the sky above the sea.
Indeed, shorebirds are rarely seen inland, unless you are
lucky enough to follow them to their Arctic breeding grounds.
In the Arctic, shorebirds form one of the most diverse groups
of ground nesting birds, with over 50 species nesting in
the arctic regions of the world.
On Bylot Island, the three most abundant nesting
shorebirds are Baird’s Sandpiper (Calidris bairdii),
White-rumped Sandpiper (Calidris fuscicollis), and American
Golden Plover (Pluvialis dominica). Other shorebird species
observed nesting on Bylot Island since 2005 include Black-bellied
Plover (Pluvialis squatarola), Pectoral Sandpiper (Calidris
melanotos), Red Phalarope (Phalaropus fulicaria),
Common Ringed Plover (Charadrius hiaticula), and Ruddy
Turnstone (Arenaria interpre). However, other shorebird
species have been observed on Bylot Island. For a complete list
of potential breeders take a look at our bird species list.
Of all migrating organisms, shorebirds exhibit one of
the most impressive migratory strategies. For example, both
the White-rumped and Baird’s Sandpipers cover an astounding
15,000 km from wintering areas at the southern tip of South
America to their breeding grounds in the Canadian Arctic.
At the end of the breeding season, when the young are fully
grown (late July through early August), adults and young
head south, either inland or along the eastern shores of
Canada and the USA. Those migrating inland will often stop
for several days at a time to refuel at wetland sites such
as the Cheyenne Bottoms in Kansas (one of the largest stopover
sites for shorebirds in the interior USA) from late August
to early October. Those that choose to migrate along the
coast may stop to refuel and rest at the Bay of Fundy, Canada
and/or Delaware Bay, USA (the sites of some of the largest
concentrations of migrating shorebirds in North America).
From sites such as these, shorebirds will head further south,
stopping to feed as necessary, until they reach their southerly
wintering grounds. This trek may take anywhere from 5 weeks
to 2 months. One of the most well known wintering areas
for White-rumped Sandpipers is Tierra del Fuego, where thousands
of birds can be found feeding along the shorelines from
November through March.
Shorebirds are currently becoming a subject of management concern
due to recently documented declining population trends for several
species. The factors driving these declines have not yet been confirmed,
however, they likely involve loss and/or degradation of habitat
at migratory stopover sites and wintering grounds, and climate driven
changes occurring on the breeding grounds. Ecological research focussing
on non-harvested arctic wildlife, such as shorebirds, is rare. By
collecting detailed information on basic ecological parameters on
shorebirds, our research is providing information that is essential
to determine if current declines are associated with changes in
reproductive success on the breeding grounds.
Bylot Island offers a great opportunity to study factors
affecting reproductive success of shorebirds. The abundant
glacier valleys provide excellent habitat for shorebirds,
in the form of highly productive wetland
and mesic tundra . Shorebirds generally arrive in the
Qarlikturvik Valley just as the first patches of snow free
tundra appear in late May and early June. The first species
to arrive are often the Baird’s Sandpipers and the
American Golden Plover, generally followed a few days later
by the White-rumped Sandpipers. Upon arrival, most birds
are caught up in a foraging frenzy in an attempt to rebuild
the reserves depleted during their long migration. Early
season food resources may be limiting for shorebird reproduction.
Food resources may be in short supply as the tundra is still
frozen and many areas are still covered in snow. While rebuilding
reserves for reproduction, shorebirds must also search for
and defend mates, nests and feeding territories. Shorebirds
generally lay a clutch of 4 eggs, which hatch in 21 days
for sandpipers or 25 days for plovers. The timing of laying
is important because shorebirds must synchronize the hatching
of eggs with peaks in resource abundance later in the season
in order for young to have access to abundant resources
(see the insect
page for more information).
Though the timing of hatch is critical for the growth and survival of young,
even more crucial is the ability of shorebirds to ensure
that their nests survive until hatch. Nest predation is
an important source of mortality for shorebirds. On Bylot
Island, our data indicates that the Arctic
Fox is the principal predator of shorebird nests. Shorebird
eggs are an alternative prey resource for the Arctic Fox
, which preys primarily on small mammal. As is the case
with the Greater
Snow Goose eggs, predation on shorebird eggs may be
higher when the abundance of lemmings is low. Alternately,
when lemmings are abundant, the Arctic Fox will focus on
lemmings, and shorebirds may experience reduced predation
pressure and increased nest success. Shorebird breeding
success is known to be linked to lemming cycles via predators
at other sites in the Arctic, however, this relationship
has yet to be confirmed in for North American populations.
Shorebird research is a recent addition to the ecological monitoring
on Bylot Island, having been initiated in 2005. The goals of the
shorebird project are primarily to study the effects of climate,
food availability and trophic interactions (i.e. predation by
Arctic Foxes and avian predators) on shorebird distribution, breeding
output and population dynamics.
Our specific objectives are to:
1) Monitor shorebird nests to record nest success and timing
2) Record predation events using remote camera systems to identify
3) Sample insects to compare timing of shorebird breeding with
To meet these objectives, an intensive survey and monitoring
of shorebird nests is conducted each summer. By collecting data
on shorebird nesting phenology and success, seasonal abundance
of insects, predation pressure (estimated using real and artificial
nests), alternative prey abundance (lemmings and geese) and local
weather variables, we hope to quantify the relative importance
of various environmental factors affecting reproductive success
of shorebirds on Bylot Island.
In an attempt to study reproductive success of the same individuals
over several years, a sample of shorebirds are banded with unique
color coded plastic bands. This shorebird banding program will
eventually enable us to estimate annual survival of Bylot Island
shorebirds, and potentially re-observe individuals during migration
or on the wintering grounds.
Nest success varied greatly from year to year (1% to 80%). Nest
success for shorebirds appears to be higher in years when there
is a greater abundance of lemmings
(i.e. 2007). This trend, however, is only evident for Baird’s
and White-rumped Sandpipers.
All of the predation events that have been recorded at shorebird
nests during 2006 and 2007 revealed the Arctic Fox as the nest
predator. These photos were taken with Silent
Image Reconyx cameras.
Timing of breeding
Baird’s Sandpipers were among the first to arrive and initiate
nests, followed by the White-rumped Sandpipers and the American
Golden Plovers. All nests were initiated within a two week period
(from 10 June to 22 June). In 2007, birds arrived later than usual
and egg laying was delayed in comparison to previous years.
Nests hatched within a two week period between 4 July and 20
July. Hatching dates were synchronized with peaks in arthropod
abundance in 2005 (14 July) and 2006 (12 July).