Time Budgeting and Spatial Distribution Among Shorebirds in Relation to Tidal Change Jonathan Hecht, Jason Maurer, David Pomeranz

Objectives of Study To examine the spatial distribution of residential shorebird species in the bay near the island Bolshoye Yeremeyvsky To determine whether or not the time budgets of shorebirds, especially Actitis hypoleucos (Common Sandpiper), are affected by the tidal cycle To determine whether interspecies interactions play a role in the behaviors of residential species of interest in the bay

Methodology Team of three surveyed an observation site of approximately 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 100 M N

Haematopus ostralegus 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 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 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 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 Foraging and Feeding Distance Flight Vocal Flight

Time Budget Observations General activity, especially feeding, was much more vigorous during low tides – 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. Time allotment for Behaviors of Special Interest during High and Low Tides.

Interspecific Observations 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 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 Behavioral ecology of intertidal invertebrates. Influence of tidal effects vs. circadian effects. Co-operative feeding among shorebird mating pairs.

References Cited Anker-Nilssen, T., Bakken V., Strom, H., et al. The Status of Marine Birds Breeding in the Barents Sea Region. Norsk Polarinstitutt Bianki, V.V. Gulls, Shorebirds and Alcids of Kandalaksha Bay. Murmansk: Murmanskoe Knizhnoe Izdatel’stvo, 1967.