Transcript Time Budgeting Among Shorebirds in the White Sea Region in

Time Budgeting and Spatial
Distribution Among Shorebirds in
Relation to Tidal Change
Jonathan Hecht,
Jason Maurer,
David Pomeranz
Objectives of Study
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To examine the spatial distribution of residential
shorebird species in the bay near the island
Bolshoye Yeremeyvsky
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To determine whether or not the time budgets of
shorebirds, especially Actitis hypoleucos (Common
Sandpiper), are affected by the tidal cycle
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To determine whether interspecies interactions play
a role in the behaviors of residential species of
interest in the bay
Methodology
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Team of three surveyed an observation site
of approximately 12950 sq. m. using a
Garmin hand-held G.P.S to establish site
dimensions and perimeter
One team member focused exclusively on A.
hypoleucos, recording individuals’ behavior
minute by minute for one hour periods
Remainder of team observed general
behavior patterns of other species over same
time periods over the entire study area
Study Area
N
100 M
Haematopus ostralegus
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Oystercatcher
Nests near island and mainland
shores, from late May to early
June
Feeds on mollusks (especially
mussels [Mytilus edulis]),
crustaceans, and occasionally
insects and polychaetes
Observed upwards of 6
individuals in study area
Somateria mollissima
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Common eider
Nests primarily on small
coastal islands, often in
colonies
Feed on sessile or sluggish
benthic organisms, primarily
M. edulis, but also other
mollusks, echinoderms, and
crustaceans
Observed approximately 10
individuals in study area
Larus canus
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Common gull
Nests primarily on islands near salt
marshes and in areas where
Empetrum nigrum (crowberry) is
found
Terrestrial food includes shore
invertebrates and berries, while
small fish and copepods
complement the diet
Observed approximately 25
individuals in study area
Actitis hypoleucos
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Common Sandpiper
Nests extensively in White
Sea region during June and
July, preferring areas near
rivulet mouths
Feed on insects, small
mollusks, Amphipods, and
fish eggs
Two breeding pairs each
with two juveniles observed
at site
Shore Bird Territorial Zones
Interpreting Common
Sandpiper Behaviors
Vocal Flight
Distance Flight
Foraging and Feeding
Time Budget Observations
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General activity, especially feeding, was
much more vigorous during low tides
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Low tides expose more shoreline and thus
expose more major components of shorebird diet
Majority of feeding behavior observed along
shoreline; high tides greatly reduce this area
This holds true across all observed species
Time Budgeting in Sandpipers
Low Tide
High Tide
Vocal flight
Distant flight
idle
singing
Alarm calls
Paired flight
foraging/feeding
walking
preening
Time Budgeting in Sandpipers Cont.
Preportion of Time Allotted
0,45
0,40
0,35
0,30
0,25
0,20
0,15
0,10
0,05
0,00
Vocal flight
idle
Time allotment for Behaviors of Special
Interest during High and Low Tides.
foraging/feeding
Interspecific Observations
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Common gulls, Oystercatchers, and Common eiders
were very tolerant of each others’ presence during
both idle and feeding times
Territorial disputes were rarely witnessed; results
are likely due to nesting behavior.
The bay is used not only by the four aforementioned
species but also by several transient species
including the common raven, herring gull, and
mergansers.
Disputes usually involved transient species such as
the common raven and the herring gull.
Conclusions
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Low tide is associated with increased levels of
feeding activity among all observed species, while
high tide is associated with increased levels of
idleness.
Interspecific interaction did not appear to be a
significant factor affecting feeding behavior or spatial
distribution of observed species.
The distribution of A. hypoleucos appears to be
greatly affected by the presence of conspecifics.
Relevance to Future Studies
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Behavioral ecology of intertidal invertebrates.
Influence of tidal effects vs. circadian effects.
Co-operative feeding among shorebird
mating pairs.
References Cited
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Anker-Nilssen, T., Bakken V., Strom, H., et
al. The Status of Marine Birds Breeding in the
Barents Sea Region. Norsk Polarinstitutt 2000.
Bianki, V.V. Gulls, Shorebirds and Alcids of Kandalaksha
Bay. Murmansk: Murmanskoe Knizhnoe
Izdatel’stvo, 1967.